Question 1

A 60-year-old man presents with a history of cough and weight loss. He has smoked 40 cigarettes a day since he was 17 years old. He describes recent darkening of his skin and the chest X-ray reveals a mass (suspicious for lung cancer) at the left hilum. What is the most likely histology?

Explanation

Correct Answer: D- Small-cell carcinoma Explanation Small-cell carcinoma Endocrine symptoms are seen in patients with lung cancer due to the syndrome of ectopic hormone secretion. Small-cell lung cancer and bronchial carcinoid tumours are both associated with ectopic adrenocorticotropic hormone (ACTH) secretion, which can cause increased skin pigmentation. In small-cell lung cancer, around 5% of cases are thought to manifest ectopic ACTH secretion. Adrenal metastatic spread should be excluded with appropriate imaging. Treatment of the clinical or biochemical abnormalities associated with endocrinopathies of non-endocrine origin is best directed at the primary disorder. In neoplastic disease, this might involve surgical excision, radiotherapy or chemotherapy. If the cancer cannot be targeted, symptomatic treatment should be given. Adenocarcinoma Adenocarcinoma is incorrect. Although adenocarcinoma could present as a hilar mass, it is not associated with ectopic ACTH production (that would explain the increased skin pigmentation). Large-cell carcinoma Large-cell carcinoma is incorrect. Although large-cell carcinoma could present as a hilar mass, it is not associated with ectopic ACTH production (that would explain the increased skin pigmentation). Mesothelioma Mesothelioma is incorrect. Mesiothelioma is a malignant pleural tumour that is related to asbestos exposure. It does not present as a hilar mass and is not associated with ectopic production of ACTH. Squamous-cell carcinoma Squamous-cell carcinoma is incorrect. Squamous-cell carcinomas are not associated with ectopic ACTH production; they are often associated with hypercalcaemia due to parathyroid hormone- related peptide secretion.

Question 2

Which of the following is most likely to cause upper- lobe fibrosis on chest X-ray?

Explanation

Correct Answer: A- Ankylosing spondylitis Explanation Ankylosing spondylitis Causes of upper-lobe fibrosis on a chest X-ray are:

• Ankylosing spondylitis (affects the apices) • Tuberculosis • Sarcoidosis • Extrinsic allergic alveolitis • Silicosis • Allergic bronchopulmonary aspergillosis (ABPA) • Post-radiotherapy Idiopathic pulmonary fibrosis Idiopathic pulmonary fibrosis is incorrect. Idiopathic pulmonary fibrosis is more likely to be associated with lower lobe fibrosis. Rheumatoid arthritis Rheumatoid arthritis is incorrect. Rheumatoid arthritis is more likely to be associated with lower lobe fibrosis. Scleroderma Scleroderma is incorrect. Scleroderma is more likely to be associated with lower lobe fibrosis. Systemic lupus erythematosus Systemic lupus erythematosus is incorrect. Systemic lupus erythematosus is more likely to be associated with lower lobe fibrosis.

Question 3

Which cell type produces surfactant?

Explanation

Correct Answer: E- Type II pneumocyte Explanation Type II pneumocyte

Phospholipid molecules that reduce surface tension in the alveolar air–liquid interface are called surfactant. Surfactant is produced in conjunction with proteins from alveolar type II epithelial cells (type II pneumocytes) lying free in the alveolar spaces against alveolar walls. Alveolar macrophage Alveolar macrophage is incorrect. Surfactant is produced in conjunction with proteins from alveolar type II epithelial cells (type II pneumocytes) lying free in the alveolar spaces against alveolar walls. Endothelial cell Endothelial cell is incorrect. Surfactant is produced in conjunction with proteins from alveolar type II epithelial cells (type II pneumocytes) lying free in the alveolar spaces against alveolar walls. Goblet cell Goblet cell is incorrect. Surfactant is produced in conjunction with proteins from alveolar type II epithelial cells (type II pneumocytes) lying free in the alveolar spaces against alveolar walls. Type I pneumocyte Type I pneumocyte is incorrect. Surfactant is produced in conjunction with proteins from alveolar type II epithelial cells (type II pneumocytes) lying free in the alveolar spaces against alveolar walls.

Question 4

A 26-year-old man presents with fever, headache and a moderately productive cough. The chest X- ray shows increased interstitial markings. Laboratory examinations show an elevated lactate dehydrogenase (LDH), anaemia and cold agglutinins. What is the most likely diagnosis?

Explanation

Correct Answer: C- Mycoplasma pneumonia Explanation Mycoplasma pneumonia Acute, cold, autoimmune, haemolytic anaemia is commonly seen in adolescents and young adults following infection with Mycoplasma pneumoniae. Haemolysis occurs approximately 1–2 weeks following infection and is most commonly associated with a rise in polyclonal anti-I IgM antibodies with mycoplasma pneumonia. The typical patient is usually a young adult who experiences a respiratory tract infection accompanied by headache, myalgia, cough and fever, whose chest X-ray shows bronchopneumonia. The cough is often non- productive, but when sputum is obtained it is mucoid, shows predominantly mononuclear cells and shows no dominant organism. The diagnosis should be suspected in patients with a relatively mild form of pneumonia, particularly in previously healthy young adults. A characteristic feature is the relatively high frequency of extrapulmonary complications, including:

• Rash • Neurological syndromes (aseptic meningitis, encephalitis, neuropathies), • Myocarditis • Pericarditis • Haemolytic anaemia The pathogen lacks a cell wall and so is not susceptible to penicillin, cephalosporins or other antibiotics active against the bacterial cell wall. The therapeutic agents most commonly used are macrolides such as erythromycin, clarithromycin, azithromycin or doxycycline. Chlamydia pneumonia Chlamydia pneumonia is incorrect. Chlamydia pneumonia is a typical cause of pneumonia and, as such, many features in this case are compatible. However, cold agglutinins are associated with mycoplasmal pneumonia, not chlamydial pneumonia. Extrinsic allergic alveolitis Extrinsic allergic alveolitis is incorrect. The history of productive cough, fever and cold agglutinins make an infective cause of symptoms most likely – mycoplasmal pneumonia in particular. Non-Hodgkin lymphoma Non-Hodgkin lymphoma is incorrect. Fever, anaemia and elevated LDH levels may be features of non- Hodgkin lymphoma but the chest X-ray would be likely to show lymphadenopathy rather than increased interstitial markings and the productive cough makes mycoplasma pneumonia more likely. Pneumocystis jirovecii Pneumocystis jirovecii is incorrect. P. jirovecii pneumonia may present with increased interstitial infiltrates on a chest radiograph; however, the cough is often dry. Blood tests may show lymphopenia. Cold agglutinins are not associated with P. jirovecii pneumonia. The lack of history suggesting immunodeficiency makes P. jirovecii pneumonia unlikely.

Question 5

A 61-year-old woman with nephrotic syndrome comes to the Respiratory Clinic with increased shortness of breath over the past 2 months. A large, left-sided pleural effusion was first diagnosed by her GP at the the time of onset of symptoms, and he prescribed an increased dose of diuretics. Despite increased furosemide and peripheral oedema having resolved, the effusion is unchanged on chest X- ray. Which of the following is the most appropriate next step?

Explanation

Correct Answer: C- Diagnostic pleural aspiration Explanation Diagnostic pleural aspiration In this situation, where peripheral oedema has resolved in response to increased diuretic therapy, although the effusion is unchanged, diagnostic pleural aspiration for cytology, protein, LDH, pH, gram stain, culture and sensitivity is most appropriate. Blind pleural biopsy Blind pleural biopsy is incorrect. Pleural biopsy could be considered, although this is usual post the aspiration results, and is undertaken under radiological guidance. CT thorax CT thorax is incorrect. A CT thorax may be appropriate here and should be considered particularly if diagnostic aspiration reveals the effusion is an exudate. Increased furosemide Increased furosemide is incorrect. Furosemide appears to have had no effect on the effusion thus far, despite resolving the peripheral oedema, so increasing the dose further without further investigation to establish the underlying aetiology of the effusion is inappropriate. Therapeutic drainage Therapeutic drainage is incorrect. Therapeutic drainage is not considered until the underlying diagnosis has been established.

Question 6

A 72-year-old woman is admitted with sudden-onset, left-sided pleuritic chest pain with shortness of breath. She is being treated for asthma, which has been well controlled on a low dose of inhaled corticosteroids and long-acting ß-agonist. She underwent a left hemiarthroplasty 12 days ago and was discharged because she was doing well. Her chest is clear on auscultation. She is tachycardic (132 bpm) and an electrocardiogram shows sinus tachycardia. Her peak expiratory flow rate (PEFR) is 300 l/min (best 400 l/min). Arterial blood gases are as follows: pH 7.34, Pao2 7.6 kPa, Paco2 3.5 kPa. She is started on oxygen. A chest X-ray is normal. What would be the most appropriate immediate action you as the medical FY2 should take?

Explanation

Correct Answer: C- Start low-molecular-weight heparin, suspecting pulmonary embolus, and request computed tomographic pulmonary angiography Explanation Start low-molecular-weight heparin, suspecting pulmonary embolus, and request computed tomographic pulmonary angiography A CTPA would be the imaging investigation of choice in this case, after starting low-molecular- weight heparin Request a chest X-ray in expiration Request a chest X-ray in expiration is incorrect. A small pneumothorax, not apparent on the inspiratory chest X- ray, is unlikely because it would not cause marked hypoxia. Request d-dimers urgently Request d-dimers urgently is incorrect. The symptoms and findings point towards a pulmonary embolism, for which the clinical probability is high. Therefore, checking D-dimers is inappropriate as they should only be measured when the probability of a pulmonary embolus is low and further investigations would not be pursued. Start low-molecular-weight heparin, suspecting pulmonary embolus, and request a ventilation/perfusion (V/Q) scan Start low-molecular-weight heparin, suspecting pulmonary embolus, and request a ventilation/perfusion (V/Q) scan is incorrect. The diagnostic investigation of choice is computed tomographic pulmonary angiogram (CTPA), particularly in individuals with chronic lung disease. Start nebulised bronchodilators and monitor the PEFR Start nebulised bronchodilators and monitor the PEFR is incorrect. Her peak expiratory flow rate is only mildly reduced (75% of best). It is unlikely that this patient’s symptoms are due to an exacerbation of her asthma.

Question 7

A 62-year-old patient has been admitted with a large, left-sided pneumothorax. He has a past history of chronic obstructive pulmonary disease (COPD), for which he has a home nebuliser and takes a high-dose Seretide inhaler. A chest drain was inserted some 60 h earlier, yet when you review it, the drain is still swinging and producing bubbles. Which of the following is the most appropriate next step?

Explanation

Correct Answer: A- Cardiothoracic surgical review Explanation Cardiothoracic surgical review In this situation suction may cause further damage, therefore surgical review is preferred with consideration for thoracoscopy and surgical pleurodesis. In patients who are unfit for surgery, either medical pleurodesis or a Heimlich valve could be considered. Suction is not routinely recommended and in this situation may cause further damage. When used in primary spontaneous pneumothorax (PSP) suction must be used with caution. Pressures should be in the range of -10–20 cm H20. Caution is advised in PSP because of the risk of pulmonary oedema developing, which appears to be a more common problem in younger patients and in those with larger PSPs. Change the drain for a larger bore one Change the drain for a larger bore one is incorrect. There is no evidence that a larger bore chest drain will cause a non-traumatic pneumothorax to resolve more quickly. There is, however, a higher risk of complications. Remove the drain anyway Remove the drain anyway is incorrect. This would be dangerous as the continued bubbling suggests an ongoing air leak. Suction at -15 cm H20 Suction at -15 cm H2O is incorrect. Suction is not routinely recommended and in this situation may cause further damage. Suction at -25 cm H20 Suction at -25 cm H2O is incorrect. Suction is not routinely recommended and in this situation may cause further damage.

Question 8

A 60-year-old man presents to the clinic with a 6-month history of dyspnoea on exertion and a non- productive cough. On examination, there is clubbing and crepitations are heard at the lung bases. Lung function tests show a reduced vital capacity and an increased ratio of the forced expiratory volume in 1 second to the forced vital capacity (increased

FEV1/FVC). What is the most likely diagnosis?

Explanation

Correct Answer: D- Idiopathic pulmonary fibrosis Explanation Idiopathic pulmonary fibrosis This is a classical history of interstitial lung disease. Idiopathic pulmonary fibrosis (IPF), previously known as cryptogenic fibrosing alveolitis (CFA), is a progressive and usually fatal disease of unknown cause characterised by sequential acute lung injury with subsequent scarring and end-stage lung disease. It may occur in any decade of life but it is most commonly seen between the ages of 50 and 60 years; it is slightly more common in males. Clinical features:

• A history of progressive breathlessness on exertion in the absence of wheeze is typical • A dry cough might be present, but sputum production is unusual until the later stages of the disease • Constitutional symptoms such as weight loss and lethargy can occur • Haemoptysis is uncommon, but should suggest the development of lung malignancy – people with idiopathic pulmonary fibrosis have a seven- to 14-fold increased risk of developing lung cancer • Chest pain is uncommon • Lung function tests show a restrictive picture Recent reclassification of the group of idiopathic interstitial pneumonias has allowed characterisation of seven different histological patterns based on lung- biopsy analysis; the pattern in IPF is that of usual interstitial pneumonia (UIP). Bronchiectasis Bronchiectasis is incorrect. Bronchiectasis would be associated with a productive cough in most cases. Carcinoma of the lung Carcinoma of the lung is incorrect. The duration of symptoms is too long for a lung malignancy to be a likely cause of this man’s condition. Chronic obstructive pulmonary disease Chronic obstructive pulmonary disease (COPD) is incorrect. COPD would be associated with a decreased

FEV1/FVC ratio. Tuberculosis Tuberculosis is incorrect. The duration of symptoms along with lack of classical symptoms of tuberculosis such as fever, productive cough, night sweats and weight loss make this diagnosis unlikely.

Question 9

A 28-year-old woman presents to the Emergency Department with an acute asthmatic attack. Which of the following lung function abnormalities is she likely to have?

Explanation

Correct Answer: E- Increased residual volume Explanation Increased residual volume Because of gas trapping there is an increase in residual volume and an increase in total lung capacity, but the ratio of residual volume (RV) to total lung capacity (TLC) is increased (TLC = vital capacity (VC) + RV). Increased airway conductance Increased airway conductance is incorrect. Airway conductance (the reciprocal of airway resistance) is decreased in acute asthma. Increased forced expiratory ratio Increased forced expiratory ratio is incorrect. The classic abnormalities are reduced forced expiratory volume in 1 s (FEV1) and reduced forced vital capacity (FVC) with a decrease in FEV1/FVC. Increased forced vital capacity Increased forced vital capacity is incorrect. The classic abnormalities are reduced forced expiratory volume in 1 s (FEV1) and reduced forced vital capacity (FVC) with a decrease in FEV1/FVC. Increased gas transfer factor Increased gas transfer factor is incorrect. Gas transfer would be difficult to measure in acute asthma, but can be elevated in stable asthma, where there might be chronic hyperinflation giving rise to a greater surface area for blood/gas interfacing.

Question 10

A 32-year-old chronic intravenous heroin abuser presents to the Emergency Department with increasing shortness of breath and general debility. He has been using heroin for the past 15 years and has had a number of hospital admissions for overdoses, skin infections and respiratory infections over the past few years. On examination: he is pyrexial (37.6 °C), blood pressure 115/72 mmHg, pulse 75 bpm. His right chest is dull to the mid-zone.

Investigations show:

Haemoglobin 10.5 g/dl White cell count 9.2 × 109/l

Platelets 215 × 109/l

Sodium 139 mmol/l

Potassium 4.6 mmol/l

Creatinine 135 µmol/l A postero-anterior chest X-ray shows a right-sided pleural effusion to the mid-zone. A pleural aspiration failed to produce a specimen. Which of the following is the most appropriate

investigation with respect to the pleural effusion?

Explanation

Correct Answer: E- Ultrasound scan of the chest and aspiration Explanation Ultrasound scan of the chest and aspiration Ultrasound is more sensitive in detecting effusions than chest radiographs and can be performed at the time of aspiration to improve the success rate and reduce risk of complications from aspiration. Bronchoscopy Bronchoscopy is incorrect. Bronchoscopy will not allow access or visualisation of the pleural space. Contrast-enhanced computed tomography of the chest Contrast-enhanced computed tomography of the chest is incorrect. CT chest is less sensitive for showing septations than ultrasound imaging. The failure to aspirate in this case may be because the diagnosis is empyema with multiple septations. Ultrasound-guided aspiration is recommended by the British Thoracic Society to improve the success rate of aspiration and reduce the risk of complications, eg pneumothorax. There are a number of possible causes of the effusion in this case, with infection and malignancy both possibilities. Given his long history of intravenous heroin abuse, HIV infection cannot be ruled out. Lateral chest X-ray Lateral chest X-ray is incorrect. Ultrasound is more sensitive in detecting effusions than chest radiographs and can be performed at the time of aspiration to improve the success rate and reduce risk of complications from aspiration. Thoracoscopy Thoracoscopy is incorrect. Thoracoscopy may be required in the investigation and management of pleural effusions, but is not a first-line investigation/procedure.

Question 11

A 40-year-old man presents with a 2-month history of cough and breathlessness. He has also noticed haemoptysis, which he says has worsened gradually. On examination he has bilateral basal crepitations. His chest X-ray shows diffuse shadowing. He has moderate renal failure. He is previously well and holds down a job as a solicitor. Which investigation would be most useful in obtaining a diagnosis?

Explanation

Correct Answer: C- Renal biopsy Explanation Renal biopsy Goodpasture syndrome consists of diffuse pulmonary haemorrhage and glomerulonephritis with linear deposition of antibodies (90% of which are directed against the α3 chain of type IV collagen) along the glomerular basement membrane (GBM). Serological testing for anti-GBM antibodies and ANCA (anti-neutrophil cytoplasmic antibody) is crucial for confirming the diagnosis, and a renal biopsy is almost always warranted. Some healthy individuals exposed to inhaled oils, hydrocarbons or solvents can have borderline raised anti-GBM antibody levels. Anti-GBM antibodies have also been detected in HIV-negative patients with Pneumocystis pneumonia. Bronchoscopy Bronchoscopy is incorrect. Bronchosopy may show evidence of pulmonary haemorrhage in Goodpasture syndrome but is not definitively diagnostic. Computed tomography (CT) of the thorax Computed tomography (CT) of the thorax is incorrect. CT of the thorax would be likely to form part of the

investigation work-up of this gentleman and would show the degree of pulmonary haemorrhage and any lung parenchymal abnormality, but it would not be definitively diagnostic. Histology is required. Sputum sample Sputum sample is incorrect. Sputum sampling would help rule out infective cause of this man’s symptoms, but this is a history of Goodpasture syndrome and the sputum culture result would be expected to be normal. Ventilation/perfusion scan Ventilation/perfusion scan is incorrect. Ventilation/perfusion scans are an investigation for pulmonary embolism, which is not likely based on this history.

Question 12

A 26-year-old office secretary who smokes 10-15 cigarettes per day presented in the clinic after a couple of episodes of haemoptysis. She also said that she had felt tired recently and gave a history of treatment for a respiratory tract infection a couple of months ago. She said that she feels she never fully recovered from that infection and has been persistently coughing ever since. On examination, she looked pale, had minimal pedal oedema and diffuse crepitations on chest auscultation. Her urine was positive for protein and blood. A full blood count showed anaemia and the chest X-ray showed blotchy shadows over the lung fields. She is ANCA negative. What is your probable diagnosis?

Explanation

Correct Answer: B- Goodpasture syndrome Explanation Goodpasture syndrome This is a case of Goodpasture syndrome, which usually occurs in people over the age of 16 years. It starts with an upper respiratory infection, followed by cough, intermittent haemoptysis and tiredness. Later on, anaemia develops and a massive episode of haemoptysis can occur. The typical chest X-ray picture is a manifestation of intrapulmonary haemorrhage. These features are followed, in weeks or months, by the development of glomerulonephritis. The basic cause of the disease is a type II cytotoxic reaction against the basement membrane of both the kidneys and lungs. Glomerulonephritis might present as asymptomatic proteinuria and/or microscopic haematuria. This is followed later on by the development of the acute nephritic syndrome, nephrotic syndrome and chronic renal failure. Bronchogenic carcinoma Bronchogenic carcinoma is incorrect. Despite her smoking history lung cancer would be very unlikely in a 26-year-old. The urinalysis findings, and chest radiograph appearances are not in keeping with bronchogenic carcinoma. Her total smoking exposure is also unlikely to be associated with the development of a bronchogenic carcinoma. Granulomatosis with polyangiitis Granulomatosis with polyangiitis is incorrect. Granulomatosis with polyangiitis may present with predominant respiratory symptoms, often with symptoms of granuloma formation, e.g. nosebleeds for a number of months before diagnosis. Alternatively patients may present with renal disease, those presenting with respiratory symptoms are said to have around an 80% chance of eventual renal dysfunction. Pulmonary tuberculosis Pulmonary tuberculosis is incorrect. This is a history of vasculitis. There is no history of fever or exposure to TB and the symptoms and test results are more in keeping with vasculitis. Sarcoidosis Sarcoidosis is incorrect. The symptoms are in keeping with vasculitis. Sarcoidosis would not be associated with positive urinalysis unless history was suggestive of renal calculi. ANCA would be negative in sarcoidosis and chet radiograph would most likely show bilateral hilar lymphadenopathy +/- pulmonary infiltrates.

Question 13

A 29-year-old man is admitted feeling a little more tired than usual. He has no history of previous respiratory disease and works as a builder. On examination he is 184 cm in height, with a blood pressure of 142/80 mmHg, and his pulse is 80 bpm. His oxygen saturation is 95% on air. Breath sounds appear normal bilaterally on auscultation and his respiratory rate is 16/min. The chest X-ray shows a 1-cm rim of air on the right-hand side of the chest. Which of the following is the most appropriate management?

Explanation

Correct Answer: C- Discharge Explanation Discharge We are not given any indication that this man is in distress because his saturation is 95% and his respiratory rate is 16/min. With only a 1-cm rim of air, British Thoracic Society (BTS) guidelines therefore would suggest that he can be safely discharged, with instructions to return if he has significant pleuritic chest pain or feels more short of breath. Admit and observe Admit and observe is incorrect. We are not given any indication that this man is in distress because his saturation is 95% and his respiratory rate is 16/min. With only a 1-cm rim of air, British Thoracic Society (BTS) guidelines therefore would suggest that he can be safely discharged, with instructions to return if he has significant pleuritic chest pain or feels more short of breath. Aspiration Aspiration is incorrect. Significant shortness of breath or a rim of air of 2 cm or greater necessitates air aspiration as long as there is no history of previous chest pathology. Large-size chest drain Large-size chest drain is incorrect. Large-size chest drains are not recommended as first-line intervention in a atraumatic pneumothorax. Small-size chest drain Small-size chest drain is incorrect. If there is a history or evidence of previous chest disease, a small- bore chest drain is recommended if there is s ignificant shortness of breath or a rim of air of 2 cm or greater.

Question 14

A 24-year-old medical student (height 165 cm, weight 78 kg) has been complaining of a few months’ history of shortness of breath on exertion and of coughing up blood once. She is a few days away from her final examinations and smokes 20 cigarettes per day. She takes no medication except for the oral contraceptive pill. Her only past medical history of note is a DVT after a long flight from Australia. What is the most likely diagnosis?

Explanation

Correct Answer: C- Pulmonary embolism Explanation Pulmonary embolism Acute pulmonary embolism can present in diverse ways:

• A syndrome of pleuritic pain or haemoptysis, in the absence of circulatory collapse, is the most frequent mode of presentation. This was the mode of presentation in 60% of patients recruited in a collaborative

investigation, the Prospective Investigation of Pulmonary Embolism Diagnosis (PIOPED). • A syndrome of dyspnoea in the absence of haemoptysis or pleuritic pain or circulatory collapse occurred in 25% in the PIOPED study. • Circulatory collapse (systolic blood pressure less than 80 mmHg or loss of consciousness) was an uncommon mode of presentation, occurring in only 15% in the PIOPED study. Obesity and a high oestrogen content in oral contraceptives have been linked to thromboembolic events. Most patients with pulmonary embolism were found to have smoked at one time or to be active smokers at the time of their pulmonary embolism. Goodpasture syndrome Goodpasture syndrome is incorrect. Goodpasture syndrome may present with pulmonary haemorrhage, and therefore haemoptysis, but the duration of symptoms is too long for this diagnosis to be likely. Hyperventilation syndrome due to stress Hyperventilation syndrome due to stress is incorrect. Haemoptysis is not a feature of hyperventilation and the other features described in this case point towards a more likely diagnosis of pulmonary embolism (obesity, previous DVT, contraceptive use and smoking). Sarcoidosis Sarcoidosis is incorrect. Haemoptysis is not a feature of sarcoidosis and the other features described in this case point towards a more likely diagnosis of pulmonary embolism (obesity, previous DVT, contraceptive use and smoking). Tuberculosis Tuberculosis is incorrect. There is no mention of fever, night sweats or weight loss. The history of obesity, previous DVT, haemoptysis and contraceptive use point towards pulmonary embolism.

Question 15

A 59-year-old woman with severe rheumatoid arthritis presents to the Respiratory Clinic with worsening shortness of breath. She has had rheumatoid arthritis for 17 years and she is now managed with a methotrexate- based regime. Other medical history of note includes hypertension, for which she is treated with ramipril 10 mg daily. On examination, she has evidence of severe rheumatoid joint disease. Crackles are heard on auscultation of the chest.

Investigation:

Hb 11.0 g/dl

WCC 4.8 x 109/l

PLT 345 x 109/l

Sodium 139 mmol/l

Potassium 4.5 mmol/l

Creatinine 140 µmol/l Chest X-ray shows patchy consolidation, small pulmonary nodules and small bilateral pleural effusions. Computed tomography (CT) of the thorax shows patchy ground-glass opacities (peribronchovascular region), bronchial wall thickening, areas of bronchial dilatation and centrilobular pulmonary nodules. Pulmonary function testing demonstrates a restrictive pattern, with reduced diffusion capacity for carbon monoxide (Dlco) with a fall in oxygenation on exercise. Which of the following is the most likely diagnosis?

Explanation

Correct Answer: C- Cryptogenic organising pneumonia Explanation Cryptogenic organising pneumonia Cryptogenic organising pneumonia (COP) occurs in patients with rheumatoid arthritis or other connective tissue disorders, and is associated with the typical radiographic and pulmonary function test picture seen here. Corticosteroids are the treatment of choice for COP, although relapse occurs on withdrawal of steroids in around 30% of cases. Bronchiectasis Bronchiectasis is incorrect. In bronchiectasis, chronic sputum production would be expected as a predominant symptom with a history of recurrent respiratory infections. Although bronchiectasis may not be visible on a chest radiograph it would almost certainly be noted on

CT scanning and pulmonary function tests would show an obstructive not restrictive pattern of spirometry.

Although bronchial dilatation has indeed been noted on this lady’s imaging, there is clearly more going on here to explain her symptoms. Chronic eosinophilic pneumonia Chronic eosinophilic pneumonia is incorrect. Chronic eosinophilic pneumonia is associated with an obstructive picture on pulmonary function testing. Idiopathic pulmonary fibrosis Idiopathic pulmonary fibrosis is incorrect. Idiopathic pulmonary fibrosis is classically associated with a ‘usual interstitial pneumonia’ which can be detected on High- resolution computed tomography (HRCT) in approximately 80% of cases and classically affects the lung bases. Methotrexate-related pulmonary fibrosis Methotrexate-related pulmonary fibrosis is incorrect. Methotrexate-related pulmonary fibrosis is typically associated with ‘non-specific interstitial pneumonia’. CT features are variable and can include centrilobular nodules, reticulation and diffuse parenchymal opacification. However, the radiology findings in this case, particularly the peribronchial distribution that is mentioned, are more suggestive of bronchiolitis obliterans organising pneumonia (BOOP).

Question 16

A 69-year-old former coal-miner is referred to you by the on-call team. There is a smoking history and he has been managed by his GP for chronic obstructive pulmonary disease (COPD). He has been admitted with dyspnoea that is now so bad that he is unable to manage at home and cannot walk from the chair to the bathroom. He has a cough that is productive of black sputum. Lung function tests show a mixed restrictive and obstructive picture. A chest X-ray shows marked changes with massive fibrotic masses, predominantly in the upper lobes. There are also changes consistent with lung destruction and emphysema. His rheumatoid factor is positive. Which diagnosis fits best with this clinical picture?

Explanation

Correct Answer: D- Progressive massive fibrosis Explanation Progressive massive fibrosis Progressive massive fibrosis (PMF) is associated with fibrotic masses in the apices, sometimes up to 10 cm in diameter. There are also emphysematous changes. There is a mixed obstructive and restrictive lung defect with reduced transfer factor. Rheumatoid factor and antinuclear antibody are often positive. There is usually a history of dust inhalation (eg coal dust), and PMF can progress rapidly, even in the absence of further dust exposure, leading to respiratory failure and eventually death. Category 2 pneumoconiosis progresses to PMF in around 7% of cases. The rate of progression of category 3 pneumoconiosis is much higher, at around 30%. The 0–3 classification is defined by the International Labour Organisation and reflects an increasing density of small opacities on the chest radiograph. Asthma Asthma is incorrect. The majority of this history is not in keeping with asthma, eg black sputum, no mention of wheeze, mixed spirometry pattern (airflow restriction is not in keeping with asthma), fibrotic masses, lung destruction and emphysema on chest X-ray (in pure asthma the chest X-ray will be normal or show hyperinflation). Category 1 pneumoconiosis Category 1 pneumoconiosis is incorrect. Category 1 pneumoconiosis is the least severe form of pneumoconiosis and chest radiograph will show just a few opacities and normal lung markings will be clearly visible. Chronic obstructive pulmonary disease Chronic obstructive pulmonary disease is incorrect. Given this man’s smoking history and presence of emphysema on his chest X-ray it is reasonable to believe he has a degree of COPD. However, the Question: asks which option best fits the clinical picture and, given the additional features mentioned re his chest X-ray findings, black sputum, positive rheumatoid factor and his occupational history, then progressive massive fibrosis is the correct option. Tuberculosis Tuberculosis (TB) is incorrect. A previous history of pulmonary TB is a risk factor for the development of PMF in individuals with silicosis, but this scenario is not suggestive of active pulmonary TB. There is no history of weight loss, fevers, night sweats or purulent sputum. The chest radiograph does not show lymphadenopathy or consolidation.

Question 17

A 29-year-old breathless Afro-Caribbean woman is referred by the ophthalmologists with anterior uveitis and a suspected diagnosis of sarcoidosis. Which of the following clinical features is most strongly associated with sarcoidosis?

Explanation

Correct Answer: C- Decreased gas-transfer factor (DLCO) with decreased gas-transfer coefficient (KCO) Explanation Decreased gas-transfer factor (DLCO) with decreased gas-transfer coefficient (KCO) Decreased gas transfer factor (DLCO) accompanied by elevated gas transfer coefficient (KCO) is characteristic of extrathoracic restriction and not of intrapulmonary restriction – both are usually decreased in intrapulmonary sarcoidosis. A slowly worsening picture of breathlessness with no periods of improvement A slowly worsening picture of breathlessness with no periods of improvement is incorrect. Spontaneous remission of respiratory symptoms is not uncommon and might allow a ‘wait and see’ policy to be adopted at the outset before embarking on immunosuppressive therapy. Bronchoalveolar lavage shows an eosinophilia Bronchoalveolar lavage shows an eosinophilia is incorrect. Bronchoalveolar lavage typically shows a lymphocytosis. Obstructive defect on spirometry Obstructive defect on spirometry is incorrect. Spirometry usually shows a restrictive defect. Positive Mantoux test Positive Mantoux test is incorrect. Mantoux or Heaf testing is usually negative and reflects cutaneous anergy.

Question 18

A 17-year-old girl has chronic cough and recurrent respiratory infections over the past 2–3 years. Which one of the following pieces of clinical information in her history would point most strongly to the development of bronchiectasis?

Explanation

Correct Answer: E- Previous whooping cough in early childhood Explanation Previous whooping cough in early childhood A history of previous whooping cough is a well-known risk factor for bronchiectasis. History of eczema History of eczema is incorrect. Eczema is not associated with bronchiectasis. History of wheeze History of wheeze is incorrect. Wheeze often occurs in bronchiectasis, but asthma would be the most likely diagnosis in an adolescent complaining of wheeze. Pale stools and low weight Pale stools and low weight is incorrect. Pale stools and low weight suggests cystic fibrosis. Pepperpot calcification on chest X-ray Pepperpot calcification on chest X-ray is incorrect. Pepperpot calcification on a chest X-ray suggests previous varicella infection, which rarely gives rise to further symptoms.

Question 19

A 30-year-old man from Russia is seen in the Emergency Department. He was diagnosed with pulmonary tuberculosis (TB) 4 months ago in Russia and is taking rifampicin and isoniazid. He comes because of a productive cough, fevers, weight loss and malaise. What would you like to do next?

Explanation

Correct Answer: A- Admit him to hospital, send a sputum sample and add the current WHO recommendations for multidrug-resistant tuberculosis (MDRTB) Explanation Admit him to hospital, send a sputum sample and add the current WHO recommendations for multidrug-resistant tuberculosis (MDRTB) The concern with this man is one of MDRTB. He is failing on his current regime and has clinical features of active TB. Management should involve sending sputum for culture and polymerase chain reaction (PCR) testing before starting further treatment. If he has confirmed MDRTB, ensure he is on five or more drugs to which the organism is likely to be susceptible. Risk factors for MDRTB • Poor compliance (the most common reason) • Previous anti-TB treatment • HIV infection • Contact with drug-resistant TB Admit him to hospital, send a sputum sample and start him on amoxicillin Admit him to hospital, send a sputum sample and start him on amoxicillin is incorrect. Although this man could have a superimposed simple bacterial infection, this should not deter you from investigating and treating him for TB, as most of the antibiotics used for TB will cover the usual bacterial chest pathogens. Admit him to hospital, send a sputum sample and start him on amoxicillin and pyrazinamide Admit him to hospital, send a sputum sample and start him on amoxicillin and pyrazinamide is incorrect. Amoxicillin will not treat tuberculosis, therefore this plan would only involve the addition of one anti-tuberculous agent, is incorrect management and could induce further antibiotic resistance and limit treatment options further. Admit him to hospital, send a sputum sample and start him on pyrazinamide Admit him to hospital, send a sputum sample and start him on pyrazinamide is incorrect. A single drug should never be added to a failing TB regime. Add two or three, ideally drugs to which the organism is known to be sensitive and which the patient has not taken previously. Send a sputum sample and arrange to see him in outpatients Send a sputum sample and arrange to see him in outpatients is incorrect. This gentleman has possible MDRTB and therefore needs urgent admission and isolation while he is further investigated and treated.

Question 20

A 44-year-old woman presents with peripheral calcinosis, sclerodactyly and oesophageal reflux. On further questioning it transpires that she has also had worsening shortness of breath over the past few months and Raynaud’s phenomenon when she goes out on a cold day or puts her hands into cold water. On examination, her blood pressure is 155/91 mmHg and her pulse is 92 bpm and regular. She has multiple telangiectasia, and sclerodactyly with peripheral calcinosis. Auscultation of the chest reveals scattered crackles. Investigations show:

haemoglobin 12.9 g/dl, white cell count 8.2 × 109/l, platelets 203 × 109/l, sodium 138 mmol/l,

potassium 4.4 mmol/l, creatinine 134 µmol/l. Which of the following is the most likely pulmonary manifestation of this disorder?

Explanation

Correct Answer: C- Non-specific interstitial pneumonia Explanation Non-specific interstitial pneumonia The diagnosis here is non-specific interstitial pneumonia (NSIP). Scleroderma, the obvious underlying condition here, is associated with generalised interstitial lung disease. Case series and multiple lung biopsy reviews suggest that NSIP is the most usual pattern of fibrotic lung disease seen in scleroderma. Treatment: Cyclophosphamide and mycophenolate mofetil might have an effect on progression of fibrotic lung disease, and the usual range of agents such as PDE- 5 inhibitors and endothelin-receptor antagonists can be used in the treatment of pulmonary hypertension. Bronchiectasis Bronchiectasis is incorrect. Bronchiectasis is not classically associated with scleroderma; however, case series have been described. The most likely pulmonary manifestations that occur in scleroderma are pulmonary hypertension and NSIP. Irreversible obstructive lung defect Irreversible obstructive lung defect is incorrect. The diagnosis here is NSIP, which would be associated with a restrictive pattern on spirometry. Pulmonary haemorrhage Pulmonary haemorrhage is incorrect. Pulmonary haemorrhage can occur in scleroderma but is relatively rare. The findings described in this case are more in keeping with NSIP. Reversible obstructive lung defect Reversible obstructive lung defect is incorrect. The diagnosis here is non-specific interstitial pneumonia, which would be associated with a restrictive pattern on spirometry.

Question 21

During the incorporation of a non-vascularized cortical bone graft, which sequence of events is primarily responsible for the replacement of the necrotic graft with viable host bone?

Explanation

Cortical bone grafts heal via creeping substitution. Osteoclasts at the tips of cutting cones resorb the dead bone, followed directly by osteoblasts laying down new bone.

Question 22

A 45-year-old male presents with acute knee pain. Aspiration yields 40 mL of cloudy fluid. Cell count reveals 65,000 WBCs/mm3 with 85% polymorphonuclear leukocytes. Crystals are negatively birefringent under polarized light. What is the most likely composition of these crystals?

Explanation

Monosodium urate crystals, which cause acute gout, are needle-shaped and strongly negatively birefringent. Calcium pyrophosphate dihydrate crystals (pseudogout) are rhomboid and weakly positively birefringent.

Question 23

Ligaments and tendons exhibit viscoelastic properties. Which of the following best describes the phenomenon where a tissue subjected to a constant deformation experiences a gradual decrease in stress over time?

Explanation

Stress relaxation is the decrease in stress over time when a viscoelastic material is held at a constant strain. Creep is the progressive deformation over time under a constant load.

Question 24

A 16-year-old boy presents with severe night pain in his right tibia that is dramatically relieved by NSAIDs. Radiographs show a 7 mm radiolucent nidus surrounded by dense sclerotic bone. Which of the following is the most appropriate definitive management?

Explanation

The clinical presentation is classic for an osteoid osteoma. Radiofrequency ablation (RFA) is currently the gold standard and most appropriate definitive, minimally invasive treatment.

Question 25

A 65-year-old man presents with progressive bowing of his right femur and increasing hat size. Laboratory studies show normal calcium and phosphorus, but markedly elevated alkaline phosphatase. Which of the following is the primary cellular defect in this disease?

Explanation

Paget's disease of bone is primarily an osteoclast disorder characterized by highly active, multinucleated osteoclasts. This leads to a secondary, disorganized increase in osteoblastic activity.

Question 26

During a deltopectoral approach to the shoulder, the cephalic vein is identified. Which interval is being utilized, and which nerve is at greatest risk if dissection proceeds excessively inferior to the subscapularis?

Explanation

The deltopectoral interval lies between the pectoralis major and anterior deltoid. The axillary nerve is at risk inferior to the lower border of the subscapularis muscle.

Question 27

According to the Young-Burgess classification, an anteroposterior compression type II (APC-II) pelvic ring injury is characterized by rupture of which of the following ligaments?

Explanation

An APC-II injury involves symphyseal diastasis with tearing of the anterior sacroiliac, sacrotuberous, and sacrospinous ligaments. The posterior sacroiliac ligaments remain intact, providing vertical stability.

Question 28

A 28-year-old carpenter sustains a laceration to the volar aspect of his index finger, severing both the FDS and FDP tendons. The injury is located between the distal palmar crease and the proximal interphalangeal joint. In which flexor tendon zone is this injury?

Explanation

Zone II extends from the A1 pulley (distal palmar crease) to the FDS insertion (mid-middle phalanx). It contains both the FDS and FDP within a tight fibro-osseous sheath.

Question 29

An obese 13-year-old boy presents with an obligatory external rotation of his right hip when it is passively flexed. Radiographs reveal a slipped capital femoral epiphysis (SCFE). Which of the following is the most likely direction of epiphyseal displacement relative to the femoral neck?

Explanation

In SCFE, the femoral epiphysis typically displaces posteriorly and inferiorly relative to the femoral neck. The clinical sign is obligate external rotation during hip flexion.

Question 30

In total hip arthroplasty, which of the following bearing surface combinations offers the lowest wear rate but the highest risk of catastrophic failure from brittle fracture?

Explanation

Ceramic-on-ceramic bearings have the lowest volumetric wear rate and no associated metal ion release. However, they carry a unique risk of squeaking and catastrophic brittle fracture.

Question 31

A 42-year-old man presents with severe lower back pain, bilateral sciatica, saddle anesthesia, and urinary retention with overflow incontinence. MRI confirms a massive L4-L5 central disc herniation. What is the maximum generally accepted timeframe for surgical decompression to optimize sphincter recovery?

Explanation

Cauda equina syndrome is an absolute surgical emergency. Decompression within 48 hours is widely accepted to offer the best chance for optimal recovery of urinary and bowel sphincter function.

Question 32

Which of the following radiographic findings on a weight-bearing AP view of the foot is most indicative of a subtle Lisfranc injury?

Explanation

A diastasis greater than 2 mm between the bases of the first and second metatarsals on an AP weight-bearing radiograph strongly suggests a Lisfranc ligament disruption. The "fleck sign" typically occurs at the base of the second metatarsal.

Question 33

Articular cartilage is highly specialized to resist compressive forces. Which component of the extracellular matrix is primarily responsible for its compressive stiffness due to its ability to retain water?

Explanation

Aggrecan is a large proteoglycan containing negatively charged glycosaminoglycans. These negative charges attract water, providing articular cartilage with its ability to resist compressive loads.

Question 34

A 30-year-old male suffers a highly comminuted tibial plateau fracture. He develops escalating pain out of proportion to the injury. Compartment pressure measurements show an anterior compartment pressure of 38 mmHg and a diastolic blood pressure of 60 mmHg. What is the most appropriate next step?

Explanation

The patient has a delta pressure of 22 mmHg (Diastolic BP 60 - Compartment Pressure 38). A delta pressure less than 30 mmHg in the setting of clinical signs dictates immediate surgical fasciotomy.

Question 35

A 25-year-old female presents with knee pain. Radiographs reveal an eccentric, lytic, epiphyseal lesion in the distal femur extending to the subchondral bone. A biopsy confirms Giant Cell Tumor of Bone (GCT). Which medication works by inhibiting RANKL to reduce recurrence in surgically difficult GCTs?

Explanation

Denosumab is a monoclonal antibody against RANKL. In Giant Cell Tumors, the neoplastic stromal cells express RANKL, which recruits osteoclast-like giant cells; denosumab breaks this cycle.

Question 36

A 4-week-old neonate presents with pseudo-paralysis of the right leg and fever. An ultrasound reveals a significant hip effusion. Joint aspiration confirms septic arthritis. Which of the following is the most appropriate empiric antibiotic regimen?

Explanation

In neonates, common pathogens include S. aureus, Group B Strep, and Gram-negatives. Empiric therapy requires an anti-staphylococcal agent (Vancomycin) and a 3rd-generation cephalosporin (Cefotaxime, avoiding ceftriaxone due to biliary sludging).

Question 37

A 6-month-old infant is treated with a Pavlik harness for developmental dysplasia of the hip (DDH). Two weeks later, the baby exhibits decreased active extension of the left knee. What is the most likely complication?

Explanation

Excessive hip flexion in a Pavlik harness can compress the femoral nerve against the inguinal ligament. This leads to femoral nerve palsy, manifesting as decreased active knee extension.

Question 38

A patient sustained a mid-shaft humerus fracture and subsequently developed a complete radial nerve palsy. Three months later, there is no clinical or EMG evidence of recovery. Which muscle is most commonly transferred to the Extensor Carpi Radialis Brevis (ECRB) to restore wrist extension?

Explanation

In standard radial nerve palsy tendon transfers, the Pronator Teres (innervated by the median nerve) is transferred to the ECRB to effectively restore wrist extension.

Question 39

A 22-year-old female undergoes ACL reconstruction using a bone-patellar tendon-bone (BPTB) autograft. Which of the following is the most frequent complication specific to this graft choice compared to a hamstring autograft?

Explanation

The most common specific complication of using a bone-patellar tendon-bone autograft is anterior knee pain (donor site morbidity). It occurs significantly more often than with hamstring autografts.

Question 40

A 72-year-old woman sustains a distal radius fracture. A DEXA scan reveals a T-score of -3.1 in the lumbar spine. She is prescribed teriparatide. What is the mechanism of action of this medication?

Explanation

Teriparatide is a recombinant human parathyroid hormone (PTH 1-34). When given intermittently, it acts as an anabolic agent, primarily stimulating osteoblast activity and new bone formation.

Question 41

A 12-year-old boy presents with a history of recurrent fractures, cranial nerve palsies, and diffuse sclerosis of the skeletal system on radiographs, including a "rugger jersey" spine appearance. Which of the following is the primary pathophysiological defect in this condition?

Explanation

This patient has osteopetrosis, a disease characterized by impaired osteoclast function. A common genetic defect is a mutation in carbonic anhydrase II, which prevents osteoclasts from creating the acidic environment necessary for bone resorption.

Question 42

A 6-year-old girl is evaluated for recurrent fractures with minimal trauma. Examination reveals a bluish tint to her sclerae and mild hearing loss. This condition is most commonly caused by a mutation affecting which of the following proteins?

Explanation

Osteogenesis imperfecta is most commonly caused by autosomal dominant mutations in the COL1A1 or COL1A2 genes. This leads to defective synthesis of Type I collagen, the predominant collagen in bone, sclera, and dentin.

Question 43

A 65-year-old man presents with progressive hearing loss, increasing hat size, and deep, aching bone pain in his right thigh. Radiographs show cortical thickening and trabecular coarsening. What is the characteristic histological finding of the bone in the mixed phase of this disease?

Explanation

Paget's disease of bone in its mixed osteoblastic/osteoclastic phase is characterized histologically by a mosaic pattern of lamellar bone with prominent, haphazard cement lines. This results from chaotic and rapid bone turnover.

Question 44

A 7-year-old boy with a highly restricted diet presents with bleeding gums, petechiae, and bone pain. Radiographs reveal a periosteal reaction and a dense zone of provisional calcification. The underlying biochemical defect involves the impaired function of which process?

Explanation

The patient has scurvy due to Vitamin C deficiency. Vitamin C is an essential cofactor for prolyl and lysyl hydroxylases, and its deficiency leads to impaired hydroxylation and subsequent failure of collagen cross-linking.

Question 45

A 2-year-old child presents with bowed legs, costochondral junction enlargement, and delayed closure of the fontanelles. Radiographs show widened, cupped, and frayed metaphyses. Which zone of the physis is massively expanded in this condition?

Explanation

In rickets, there is a failure of mineralization in the zone of provisional calcification. This lack of mineralization prevents normal apoptosis of chondrocytes, leading to massive expansion of the hypertrophic zone.

Question 46

A newborn is noted to have rhizomelic shortening of the limbs, frontal bossing, and midface hypoplasia. The condition is linked to a gain-of-function mutation in the FGFR3 gene. What is the effect of this mutation on the physis?

Explanation

Achondroplasia is caused by a constitutively active FGFR3 mutation. FGFR3 normally acts as a negative regulator of bone growth; its overactivity profoundly inhibits chondrocyte proliferation in the proliferative zone.

Question 47

A 72-year-old woman presents with acute swelling, pain, and erythema of her right knee. Joint aspiration yields a cloudy fluid. Microscopic analysis of the fluid is most likely to reveal which of the following if she has pseudogout?

Explanation

Pseudogout is caused by the deposition of calcium pyrophosphate dihydrate (CPPD) crystals in the joint. Under polarized light microscopy, these crystals appear rhomboid-shaped and exhibit weak positive birefringence.

Question 48

A 45-year-old woman presents with symmetrical polyarthritis of her wrists and metacarpophalangeal joints. Serological testing reveals high titers of a highly specific autoantibody. This antibody targets which of the following?

Explanation

Anti-cyclic citrullinated peptide (anti-CCP) antibodies are highly specific (up to 95%) for rheumatoid arthritis. They play a critical role in the pathogenesis and early diagnosis of the disease.

Question 49

A 15-year-old boy presents with progressive distal femur pain. Radiographs demonstrate a destructive lesion with a "sunburst" periosteal reaction and a Codman triangle. Which of the following gene mutations is most strongly associated with the pathogenesis of this tumor?

Explanation

Osteosarcoma is the most likely diagnosis given the clinical and radiographic findings. It is strongly associated with mutations in tumor suppressor genes, predominantly Rb (Retinoblastoma) and p53 (Li-Fraumeni syndrome).

Question 50

A 10-year-old girl presents with fever, weight loss, and severe pain in her mid-thigh. Radiographs show a permeative diaphyseal lesion with an "onion-skin" periosteal reaction. Which chromosomal abnormality is diagnostic for this condition?

Explanation

Ewing sarcoma typically presents in the diaphysis of long bones in children and is characterized by the t(11;22) chromosomal translocation. This creates the EWS-FLI1 fusion protein, which acts as an aberrant transcription factor.

Question 51

A 60-year-old man presents with back pain, anemia, and elevated creatinine. Radiographs reveal multiple punched-out lytic lesions in the skull and spine. Which laboratory finding is essential to confirm the diagnosis?

Explanation

Multiple myeloma is diagnosed by the presence of a monoclonal spike (M-protein, usually IgG or IgA) on serum protein electrophoresis (SPEP). It is a plasma cell dyscrasia leading to lytic bone lesions, renal failure, anemia, and hypercalcemia.

Question 52

A surgeon plans to use demineralized bone matrix (DBM) to augment a posterolateral spinal fusion. Which of the following best describes the biological properties of DBM?

Explanation

Demineralized bone matrix (DBM) lacks live cells, so it is not osteogenic. It provides a scaffold (osteoconductive) and contains bone morphogenetic proteins (BMPs) that stimulate bone formation (osteoinductive).

Question 53

Articular cartilage relies on its distinct zones for unique biomechanical properties. The high tensile strength and ability to resist shear stress in the superficial zone are primarily due to which structural feature?

Explanation

In the superficial (tangential) zone of articular cartilage, Type II collagen fibers are arranged parallel to the articular surface. This specific orientation provides high tensile strength and resistance to shear forces.

Question 54

During the process of secondary fracture healing, the transition from a soft cartilaginous callus to a hard bony callus is critically dependent on which of the following microenvironmental changes?

Explanation

Fracture healing transitions from a soft callus (chondrogenesis) to a hard callus (osteogenesis) via endochondral ossification. This process requires neovascularization, which increases local oxygen tension and favors osteoblastic bone formation.

Question 55

During skeletal muscle contraction, the release of calcium ions from the sarcoplasmic reticulum directly triggers the exposure of myosin-binding sites on actin. Calcium achieves this by binding to which specific protein?

Explanation

Calcium binds to Troponin C on the thin filament, causing a conformational change. This shifts tropomyosin away from the myosin-binding sites on the actin filament, allowing cross-bridge cycling to begin.

Question 56

A 30-year-old man sustains a severe laceration to his volar wrist, completely transecting the median nerve. Over the next few weeks, the distal nerve segment undergoes a specific physiological process. What is this process called?

Explanation

Following a complete nerve transection, the axon distal to the injury undergoes Wallerian degeneration. This involves the breakdown and clearance of the axon and myelin sheath by Schwann cells and macrophages.

Question 57

A 25-year-old man presents with chronic inflammatory back pain and stiffness that improves with exercise. Radiographs show squaring of the vertebral bodies and syndesmophyte formation. What is the most common extraskeletal manifestation of this condition?

Explanation

Ankylosing spondylitis is an HLA-B27 associated seronegative spondyloarthropathy. Anterior uveitis is its most common extraskeletal manifestation, affecting approximately 25-30% of patients.

Question 58

A 40-year-old hiker from the northeastern United States presents with monoarticular arthritis of the knee. Joint fluid analysis is negative for crystals but demonstrates a high leukocyte count. Serology is positive for Borrelia burgdorferi. What is the first-line treatment for this stage of the disease?

Explanation

Lyme arthritis is a late manifestation of Lyme disease. The first-line treatment for Lyme arthritis without neurologic involvement is a 28-day course of oral doxycycline or amoxicillin.

Question 59

A 30-year-old woman presents with knee pain. Radiographs reveal an eccentric, lytic lesion in the distal femoral epiphysis. Biopsy shows numerous multinucleated giant cells. Which cells in this tumor are the actual neoplastic cells driving the disease?

Explanation

In a Giant Cell Tumor of bone, the spindle-shaped mononuclear stromal cells are the true neoplastic cells. They express high levels of RANKL, which recruits and stimulates normal macrophages to fuse into the characteristic reactive multinucleated giant cells.

Question 60

A 5-year-old boy presents with proximal muscle weakness, pseudohypertrophy of the calves, and a positive Gowers sign. Genetic testing confirms a deletion in the dystrophin gene. What is the pattern of inheritance for this disorder?

Explanation

Duchenne Muscular Dystrophy (DMD) is an X-linked recessive disorder caused by mutations in the dystrophin gene. It predominantly affects males, while females are typically asymptomatic carriers.

Question 61

A 65-year-old female undergoes total hip arthroplasty. During the informed consent, she asks about the lowest wear rate among bearing surfaces. Which of the following bearing surface combinations offers the lowest volumetric wear rate?

Explanation

Ceramic-on-ceramic bearing surfaces offer the lowest volumetric wear rates of all available combinations. They are extremely hard and scratch-resistant but carry specific risks such as squeaking and catastrophic component fracture.

Question 62

A 6-year-old boy falls from monkey bars and sustains a Gartland type III supracondylar humerus fracture. Examination reveals weakness in flexing the interphalangeal joint of the thumb. Which nerve is most likely injured?

Explanation

The anterior interosseous nerve (AIN), a branch of the median nerve, is the most commonly injured nerve in extension-type pediatric supracondylar humerus fractures. AIN injury results in the inability to flex the interphalangeal joint of the thumb and the distal interphalangeal joint of the index finger (OK sign).

Question 63

A 25-year-old male sustains a severe knee hyperextension injury. Plain radiographs reveal an avulsion fracture of the lateral tibial capsule (Segond fracture). This radiographic finding is most highly associated with an injury to which of the following structures?

Explanation

A Segond fracture is an avulsion fracture of the anterolateral proximal tibia and is highly pathognomonic for an anterior cruciate ligament (ACL) tear. It represents an avulsion of the anterolateral ligament complex.

Question 64

In the setting of a high-energy closed tibial shaft fracture, which of the following is the most reliable early clinical indicator of acute compartment syndrome?

Explanation

Pain out of proportion to the injury and exacerbated by passive stretch of the muscles in the involved compartment is the most sensitive and earliest clinical sign of compartment syndrome. Pulselessness, pallor, and paralysis are late and unreliable signs.

Question 65

A 14-year-old boy presents with knee pain and a destructive, sunburst periosteal reaction in the distal femur on X-ray. Biopsy confirms osteosarcoma. Which of the following genetic abnormalities is most classically associated with this patient's condition if he has a familial syndrome?

Explanation

Mutations in the RB1 tumor suppressor gene are highly associated with the development of osteosarcoma, particularly in patients with hereditary retinoblastoma. The t(11;22) translocation is characteristic of Ewing sarcoma.

Question 66

A 30-year-old male sustains a non-displaced scaphoid waist fracture. Which of the following arteries provides the primary blood supply to the proximal pole, increasing its risk for avascular necrosis?

Explanation

The primary blood supply to the scaphoid comes from the dorsal carpal branch of the radial artery, which enters distally and flows retrograde. This retrograde blood supply puts proximal pole fractures at high risk for avascular necrosis.

Question 67

A 45-year-old construction worker falls from a height and sustains an axial load injury to his foot. Radiographs reveal widening of the space between the base of the first and second metatarsals. What is the key stabilizing ligament injured in this condition?

Explanation

The Lisfranc ligament runs from the medial cuneiform to the base of the second metatarsal and is critical for midfoot stability. Injury to this ligament results in diastasis between the first and second rays, defining a Lisfranc injury.

Question 68

A 70-year-old female presents with neck pain, clumsiness in her hands, and difficulty with balance. Examination reveals a positive Hoffmann's sign and hyperreflexia in the lower extremities. What is the most likely diagnosis?

Explanation

Cervical myelopathy presents with upper motor neuron signs (hyperreflexia, Hoffmann's sign, positive Babinski) due to spinal cord compression. Hand clumsiness and gait disturbances are classic clinical manifestations.

Question 69

A 13-year-old obese male complains of a 3-week history of dull, aching groin and knee pain. On examination, as the affected hip is flexed, it obligately rotates externally. Radiographs show a slip of the proximal femoral epiphysis. What is the most appropriate initial management?

Explanation

Slipped capital femoral epiphysis (SCFE) is treated primarily with in situ percutaneous screw fixation to prevent further slippage. Closed reduction is contraindicated as it significantly increases the risk of avascular necrosis.

Question 70

A 22-year-old male is brought to the trauma bay after an MVC with an open-book pelvic fracture and systolic blood pressure of 80 mmHg. A pelvic binder is applied. To be most effective in reducing pelvic volume, the binder should be centered over which of the following anatomic landmarks?

Explanation

Pelvic binders should be placed directly over the greater trochanters to maximize closure of the pelvic ring and reduce pelvic volume. Placement over the iliac crests is incorrect and can potentially worsen the deformity.

Question 71

During bone graft incorporation, creeping substitution occurs. Which of the following bone graft options undergoes the most rapid creeping substitution?

Explanation

Cancellous autograft undergoes the most rapid and complete creeping substitution due to its porous architecture, viable osteoblasts, and optimal combination of osteoconductive, osteoinductive, and osteogenic properties.

Question 72

A 35-year-old runner complains of sharp heel pain, worst with the first steps in the morning. Examination reveals tenderness at the medial tuberosity of the calcaneus. Initial conservative management fails. What is the most common histological finding in this condition?

Explanation

Plantar fasciitis is histologically a degenerative condition (fasciosis) rather than an acute inflammatory one. The classic histological findings include myxoid degeneration, angiofibroblastic hyperplasia, and microtears.

Question 73

In the evaluation of bone morphogenetic proteins (BMPs), which BMP has been FDA-approved for use in acute open tibial shaft fractures?

Explanation

Recombinant human BMP-2 (rhBMP-2) is FDA-approved for use as an adjunct in acute, open tibial shaft fractures stabilized with an intramedullary nail. It is also approved for anterior lumbar interbody fusion (ALIF).

Question 74

A 60-year-old female with a history of breast cancer presents with a pathologic subtrochanteric femur fracture. What scoring system is most commonly used to predict the risk of pathologic fracture in long bones with metastatic lesions?

Explanation

The Mirels score evaluates the risk of pathologic fracture in long bones based on site, size, nature of the lesion (blastic vs. lytic), and pain. A score of 9 or higher generally indicates the need for prophylactic internal fixation.

Question 75

A 28-year-old female sustains a closed midshaft femur fracture. 48 hours postoperatively, she develops confusion, a petechial rash over her axillae, and hypoxemia. What is the most likely diagnosis?

Explanation

The classic triad of Fat Embolism Syndrome (FES) includes respiratory distress, neurologic abnormalities, and a petechial rash. It typically presents 24 to 72 hours after long bone trauma.

Question 76

During a surgical approach to the anterior cervical spine (Smith-Robinson approach), the dissection interval is between the carotid sheath and which of the following structures medially?

Explanation

The standard anterior approach to the cervical spine utilizes an internervous and intermuscular plane. The interval is between the carotid sheath contents laterally and the midline visceral structures (trachea and esophagus) medially.

Question 77

A 30-year-old man sustains a clean zone II flexor tendon laceration. During the repair, preserving the pulleys is essential to prevent bowstringing. Which two annular pulleys are most critical to preserve?

Explanation

The A2 and A4 pulleys are mechanically the most crucial for preventing bowstringing of the flexor tendons and maintaining full active range of motion of the digit.

Question 78

A 55-year-old man presents with progressive inability to extend his ring and small fingers. Examination shows palpable cords and nodules in the palmar fascia. Pathogenesis of this condition is primarily mediated by which of the following cell types?

Explanation

Dupuytren's contracture is characterized by fibroproliferative disease of the palmar fascia. The myofibroblast is the primary effector cell responsible for the excessive collagen production and tissue contraction seen in this disease.

Question 79

When performing a total knee arthroplasty, balancing the flexion and extension gaps is critical. If the extension gap is tight but the flexion gap is well-balanced, which of the following steps is the most appropriate next action?

Explanation

A tight extension gap with a balanced flexion gap requires addressing structures that only affect extension. Releasing the posterior capsule or resecting more distal femur will open the extension gap without significantly altering the flexion gap.

Question 80

A 21-year-old athlete undergoes an Achilles tendon repair. Postoperatively, the biomechanical property of the tendon where it deforms gradually over time under a constant load is known as:

Explanation

Creep refers to the progressive time-dependent deformation of a viscoelastic material when subjected to a constant force. Stress relaxation, conversely, is the decrease in stress over time when the material is held at a constant strain.

Question 81

A 24-year-old male sustains a closed femoral shaft fracture. Thirty-six hours later, he develops acute confusion, tachypnea, and hypoxemia. Which of the following is considered a major criteria for diagnosing his most likely condition according to Gurd's criteria?

Explanation

This patient has Fat Embolism Syndrome (FES). According to Gurd's criteria, the major criteria include petechial rash, respiratory insufficiency, and cerebral involvement.

Question 82

A 65-year-old male smoker presents with a severe ache in his proximal humerus. Radiographs reveal a large lytic lesion. Laboratory workup shows hypercalcemia. Biopsy indicates a metastatic epithelial malignancy. Which primary lung cancer subtype is most frequently associated with hypercalcemia due to parathyroid hormone-related peptide (PTHrP) secretion?

Explanation

Squamous cell carcinoma of the lung is a classic cause of paraneoplastic hypercalcemia mediated by the secretion of PTHrP. Small cell lung cancer is more typically associated with SIADH or ACTH production.

Question 83

A polytrauma patient develops acute respiratory distress syndrome (ARDS) following bilateral femur fractures and massive fluid resuscitation. What is the primary pathophysiological mechanism underlying the pulmonary edema seen in ARDS?

Explanation

ARDS is characterized by non-cardiogenic pulmonary edema resulting from diffuse inflammatory injury to the alveolar-capillary membrane, which significantly increases its permeability.

Question 84

A 70-year-old woman undergoes a total hip arthroplasty. Four days postoperatively, she experiences sudden onset pleuritic chest pain and dyspnea. An ECG shows sinus tachycardia and an S1Q3T3 pattern. What is the most appropriate initial diagnostic imaging test for the suspected condition?

Explanation

The clinical presentation strongly suggests a pulmonary embolism. CT pulmonary angiography is the gold standard and most appropriate initial imaging test to diagnose a PE in this setting.

Question 85

A 45-year-old man with long-standing Ankylosing Spondylitis presents for pre-operative evaluation before a total hip arthroplasty. Which of the following pulmonary function test patterns is most characteristic of his systemic disease?

Explanation

Ankylosing spondylitis typically causes fusion of the costovertebral joints, leading to a rigid chest wall. This results in a classic restrictive pattern on pulmonary function tests with a normal FEV1/FVC ratio and reduced TLC.

Question 86

A 15-year-old boy is diagnosed with conventional high-grade osteosarcoma of the distal femur. Staging imaging is ordered. Which of the following is the most common site of initial distant metastasis for this tumor?

Explanation

The lungs are the most common site of initial distant metastasis for osteosarcoma, typically spreading hematogenously. CT of the chest is a mandatory component of staging.

Question 87

According to the American Academy of Orthopaedic Surgeons (AAOS) clinical practice guidelines, which of the following is an acceptable primary pharmacologic agent for the prevention of symptomatic pulmonary embolism following elective total knee arthroplasty in a standard-risk patient?

Explanation

The AAOS guidelines support the use of Aspirin as a primary prophylactic agent against venous thromboembolism in standard-risk patients undergoing elective total joint arthroplasty.

Question 88

The conversion of 25-hydroxyvitamin D to its most active form, 1,25-dihydroxyvitamin D, primarily occurs in the kidneys. Extrarenal 1-alpha-hydroxylase activity leading to hypercalcemia is classically seen in which of the following pulmonary conditions?

Explanation

Sarcoidosis and other granulomatous diseases can cause hypercalcemia due to ectopic production of 1-alpha-hydroxylase by alveolar macrophages within the granulomas.

Question 89

A 30-year-old immigrant presents with chronic back pain, night sweats, and a kyphotic deformity of the thoracic spine. Imaging reveals destruction of the T8-T9 intervertebral disc and adjacent vertebral endplates, along with a paraspinal soft tissue mass. Which of the following is the most likely causative organism?

Explanation

This is a classic presentation of spinal tuberculosis (Pott's disease), characterized by indolent infection, anterior wedging/kyphosis, disc space destruction, and cold abscesses.

Question 90

A 60-year-old patient requires prophylactic intramedullary nailing for an impending pathologic fracture of the femur. Preoperative staging reveals the primary tumor is a renal cell carcinoma. What is the most critical preoperative intervention to minimize intraoperative complications?

Explanation

Bone metastases from renal cell carcinoma and thyroid carcinoma are highly vascular. Preoperative embolization is critical to prevent massive, life-threatening intraoperative hemorrhage.

Question 91

A 32-year-old male sustains a closed tibial shaft fracture. Twelve hours later, he complains of severe leg pain that is unrelieved by intravenous opioids. Passive stretch of the toes dramatically exacerbates the pain. Which of the following is the most reliable early clinical indicator of acute compartment syndrome?

Explanation

Pain out of proportion to the injury and pain elicited by passive stretch of the muscles in the involved compartment are the most reliable and earliest clinical signs of acute compartment syndrome. Pulselessness is a very late and unreliable sign.

Question 92

A 12-year-old boy presents with a permeative lytic lesion in the diaphysis of his femur and an associated large soft tissue mass. Biopsy demonstrates sheets of small round blue cells. Which chromosomal translocation is most characteristic of this pathology?

Explanation

The clinical and histological picture describes Ewing sarcoma. The classic chromosomal translocation found in about 85% of Ewing sarcoma cases is t(11;22), resulting in the EWS-FLI1 fusion protein.

Question 93

A 65-year-old female with a recent acute osteoporotic vertebral compression fracture is started on Denosumab. What is the specific mechanism of action of this medication?

Explanation

Denosumab is a fully human monoclonal antibody that binds to RANKL (Receptor Activator of Nuclear factor Kappa-B Ligand), preventing it from activating RANK on the surface of osteoclasts, thereby inhibiting osteoclast maturation and survival.

Question 94

In a hemodynamically unstable patient with an anterior-posterior compression (APC) type III pelvic ring injury, what is the primary biomechanical rationale for applying a circumferential pelvic binder?

Explanation

A pelvic binder internally rotates the hemipelves, effectively reducing the intrapelvic volume. This promotes the tamponade effect on bleeding cancellous bone surfaces and the presacral venous plexus, which are the most common sources of hemorrhage.

Question 95

A 55-year-old diabetic male presents with rapidly progressive erythema, swelling, and severe pain in his lower leg. Crepitus is absent, but the LRINEC score is 10. Intraoperative findings reveal grayish necrotic fascia and a lack of normal tissue resistance to blunt dissection. Which organism is classically associated with Type II (monomicrobial) necrotizing fasciitis?

Explanation

Type II necrotizing fasciitis is monomicrobial and is most classically caused by Group A Streptococcus (Streptococcus pyogenes), sometimes in conjunction with Staphylococcus aureus.

Question 96

A 13-year-old obese boy presents with knee pain and a limp. On physical examination, as the affected hip is flexed, it obligatorily externally rotates. Radiographs show a widening of the proximal femoral physis with a "slip" of the epiphysis. What is the most severe common complication if this condition is treated with forceful closed reduction?

Explanation

Forceful closed reduction of a Slipped Capital Femoral Epiphysis (SCFE) significantly increases the risk of stretching or tearing the retinacular vessels, leading to iatrogenic avascular necrosis of the femoral head.

Question 97

A 28-year-old male sustains a spiral fracture of the distal third of the humeral shaft (Holstein-Lewis fracture). On examination, he demonstrates an inability to extend his wrist or fingers. At what specific anatomical location is the involved nerve most vulnerable to entrapment or injury in this specific fracture pattern?

Explanation

In a Holstein-Lewis fracture (distal third spiral humerus fracture), the radial nerve is tethered and particularly vulnerable to injury or entrapment as it pierces the lateral intermuscular septum to pass from the posterior to the anterior compartment.

Question 98

Articular cartilage relies on a specific extracellular matrix composition for its unique biomechanical properties, including load-bearing and low friction. Which collagen type is the predominant structural protein in the extracellular matrix of normal adult hyaline articular cartilage?

Explanation

Type II collagen accounts for 90-95% of the collagen in normal hyaline articular cartilage. It provides the tensile strength and framework that restrains the swelling pressure of the proteoglycans.

Question 99

An orthopedic surgeon is planning to revise a fractured femoral stem but opts to retain a well-fixed cobalt-chromium modular head. If a new titanium alloy stem is implanted and mated with the existing cobalt-chromium head, what type of corrosion is theoretically most accelerated at this modular junction?

Explanation

Galvanic corrosion occurs when two dissimilar metals (such as titanium and cobalt-chromium) are in physical contact within an electrolytic solution (body fluid), creating a local electrochemical cell that accelerates corrosion of the less noble metal.

Question 100

A 60-year-old female with long-standing, poorly controlled rheumatoid arthritis presents with progressive neck pain, clumsiness in her hands, and hyperreflexia in all four extremities. Flexion-extension radiographs demonstrate an atlanto-dens interval (ADI) of 9 mm. What is the primary pathophysiological cause of this specific upper cervical instability?

Explanation

Atlantoaxial subluxation in rheumatoid arthritis is primarily caused by inflammatory pannus eroding and destroying the transverse ligament of the atlas, which normally stabilizes the odontoid process against the anterior arch of C1.

Orthopedic Prometric MCQs - Chapter 4 Part 1

Orthopedic Prometric MCQs - Chapter 4 Part 7

Orthopedic Prometric MCQs - Chapter 4 Part 7

Chapter Index