Question 1

An 82-year-old man living alone in a bungalow came to the clinic complaining of feeling generally unwell for about the last 3–4 months and of losing about 9.5 kg (21 lbs) in weight during this period. On further enquiry he said he had been having night sweats for the last month. He also has a past history of angina and arthritis and was on medication. On examination he did not look well. He was pyrexic but had no lymphadenopathy. Bibasal crepitus on the lower zone was heard on chest auscultation. He had hepatosplenomegaly and clubbing.

Investigations showed: white cell count 12.3 × 109/l (neutrophils 52%, lymphocytes 39%), haemoglobin 9.1 g/dl, and all other routine investigations normal. A chest X-ray showed 1- to 2-mm- diameter miliary shadows all over the lung fields. The Mantoux test was negative. No bacteria grew in a sputum culture. What is the probable cause of the illness and the X-ray finding?

Explanation

Correct Answer: B- Miliary tuberculosis Explanation Miliary tuberculosis This is a case of miliary tuberculosis, which is caused by a diffuse, widely disseminated spread of tubercle bacilli via the bloodstream. In older patients it is difficult to diagnose and is universally fatal if left untreated. Miliary tuberculosis presents with a gradual onset of vague ill health, loss of weight and then fever. It can also present as tubercular meningitis. Hepatosplenomegaly is seen in advanced disease. Choroidal tubercles can be seen in the eyes.

Investigations • Chest X-ray – initially this might be normal; later on, the chest X-ray reveals the presence of small, 1- to 2- mm lesions. • Computed tomography might show a lung parenchymal abnormality at an early stage. • Mantoux test – but this is negative in up to half of patients with severe disease. • Transbronchial biopsy – positive at an early stage. • Biopsy of liver and bone marrow might be required. Bacterial endocarditis Bacterial endocarditis is incorrect. Many of the symptoms described in this case could be attributed to infective endocarditis however the milliary pattern seen on the chest radiograph is most suggestive of milliary tuberculosis. Mycoplasma pneumonia Mycoplasma pneumonia is incorrect. Bacterial pneumonias would be associated with a shorter history of symptoms, weight loss would not be as severe, chest radiographs would show consolidation. Sarcoidosis Sarcoidosis is incorrect. Sarcoidosis would not be associated with fever and night sweats. Chest radiograph would show hilar lymphadenopathy +/- interstitial lung disease. Staphylococcal pneumonia Staphylococcal pneumonia is incorrect. Bacterial pneumonias would be associated with a shorter history of symptoms, weight loss would not be as severe, chest radiographs would show consolidation (perhaps with cavitation in Staphyococcal pneumonia).

Question 2

A 36-year-old primary schoolteacher who works in a deprived area of London presents with increasing shortness of breath accompanied by sudden-onset, right- sided pleuritic chest pain. She gives a history of influenza for a few days before this acute presentation and also says she suffered a pulmonary embolus 2 years ago while taking the contraceptive pill (and describes her pain as identical to that she experienced on that occasion). On further questioning it transpires that her mother had suffered from recurrent deep vein thrombosis. Arterial blood gases reveal a pO2 of 7.2 kPa on a non re- breather mask, with a pCO2 of 3.2 kPa. Her chest X-ray reveals a wedge-shaped area of consolidation affecting her right middle and lower lobes. The white blood cell count is normal. Which diagnosis fits best with this clinical picture?

Explanation

Correct Answer: C- Recurrent pulmonary embolism Explanation Recurrent pulmonary embolism The suspicion, given that this lady has had a previous pulmonary embolism while taking the oral contraceptive pill, is that she has an inherited disorder of clotting. It is crucial during the initial work- up to take extra samples for clotting studies before commencing heparin treatment. Predisposing factors for recurrent pulmonary embolism include:

• Antithrombin III deficiency • Protein C deficiency • Factor V Leiden mutation As she has suffered a further pulmonary embolism while off the contraceptive pill, lifelong warfarin treatment should be considered. Bronchial carcinoma Bronchial carcinoma is incorrect. There is no mention of smoking history, she is young and her symptoms are of sudden onset. Bronchial carcinoma is unlikely in view of these factors. Furthermore, no mass lesion is described on her chest radiograph and she has a presentation in keeping with recurrent pulmonary embolism. Pneumothorax Pneumothorax is incorrect. Pneumothorax often presents with sudden onset of shortness of breath and pleuritic chest pain. However, with this degree of hypoxia secondary to a pneumothorax in an individual with no history of chronic lung disease, a pneumothorax would be seen on the chest radiograph. Staphylococcal pneumonia Staphylococcal pneumonia is incorrect. Although a staphylococcal pneumonia might be a plausible

alternative, with the history of previous pulmonary embolism a second clot needs to be excluded. Tuberculosis Tuberculosis is incorrect. Her job and its location raise the possibility of tuberculosis, but this is not very likely given the sudden onset of symptoms, normal white cell count and the history suggestive of recurrent pulmonary embolism.

Question 3

A 62-year-old man with a heavy smoking history is referred to the Chest Clinic after a mass is seen on his chest X-ray. Which of the following clinical features might indicate a possibility of curative surgical resection for bronchial carcinoma?

Explanation

Correct Answer: B- Hypercalcaemia Explanation Hypercalcaemia Hypercalcaemia can be due to bony secondaries or to production of parathyroid hormone- (PTH)- like peptide by the tumour. If the hypercalcaemia is due to PTH-like peptide production, then the tumour might be operable. Forced vital capacity (FVC) < 1.5 pre-operatively Forced vital capacity (FVC) < 1.5 pre-operatively is incorrect. FVC of less than 1.5 essentially means there is unlikely to be sufficient reserve after pneumonectomy. Invasive superior vena cava (SVC) obstruction Invasive superior vena cava (SVC) obstruction is incorrect. The tumour is inoperable if there is invasive SVC obstruction, which occurs in 4% of cases, usually with small-cell carcinoma. Ipsilateral malignant pleural effusion Ipsilateral malignant pleural effusion is incorrect. The tumour is inoperable if there is malignant pleural involvement. Left recurrent laryngeal nerve palsy Left recurrent laryngeal nerve palsy is incorrect. The tumour is inoperable if there is left recurrent laryngeal nerve palsy (signifies mediastinal nodes).

Question 4

A 60-year-old patient was referred with a 1-year history of persistent cough productive of mucopurulent sputum throughout the year. He has been treated by his GP for recurrent chest infections. What is the most likely diagnosis?

Explanation

Correct Answer: B- Bronchiectasis Explanation Bronchiectasis Bronchiectasis should be suspected when there is a history of persistent cough productive of mucopurulent or purulent sputum throughout the year. Patients have frequently been treated for recurrent chest infections and labelled as ‘bronchitic’, often despite the absence of a history of smoking. Those presenting as adults often recall a ‘chesty cough’ or ‘wheezy bronchitis’ associated with upper respiratory tract infections in childhood, followed by complete resolution of symptoms in their teens and early adult life, before the symptoms return after a viral trigger. Patients might produce mucoid sputum early in their disease, developing purulent sputum when they suffer an exacerbation associated with a viral upper respiratory tract infection. • Productive cough • Postnasal drip – common (there is a history of chronic sinusitis in around 30%) • Tiredness – many patients find this more troublesome than the productive cough • Acute exacerbations, with:

o Purulent sputum o Pleuritic chest pain o Haemoptysis o Fever o Wheeze (less commonly) Allergic asthma Allergic asthma is incorrect. There are no symptoms to suggest a diagnosis of atopic asthma here. There is no mention of breathlessness, wheeze, allergic rhinitis or allergic conjunctivitis. Cough in asthma is usually dry unless there is intercurrent infection. Carcinoma of the lung Carcinoma of the lung is incorrect. The duration of symptoms makes lung malignancy an unlikely cause. Lung cancer can present with non-resolving respiratory infection with productive cough due to endobronchial obstruction by tumour, but there would be a much shorter duration of symptoms. Without treatment most patients would be dead within a year of the onset of lung cancer. Interstitial lung disease Interstitial lung disease is incorrect. Interstitial lung disease would initially present as exertional breathlessness with dry cough. In more advanced disease, traction bronchiectasis can occur and result in productive cough, but the history given here is more in keeping with bronchiectasis than interstitial lung disease. Sarcoidosis Sarcoidosis is incorrect. Interstitial lung disease due to sarcoidosis presents as exertional breathlessness and dry cough.

Question 5

A 46-year-old cardiologist attended a local conference last weekend and fell ill with a fever of up to 40°C that lasted for 2 days. He had associated shortness of breath and a dry cough. In addition, he had loose motions for a day. His blood results showed deranged liver function tests and hyponatraemia. His white cell count was 10.2 × 109/l. Bibasal consolidation was seen on his X-ray. What would be the most effective treatment for his condition?

Explanation

Correct Answer: D- Clarithromycin Explanation Clarithromycin This is a case of Legionella pneumonia. Legionella outbreaks are seen in previously fit individuals staying in hotels or institutions where the shower facilities and/or the cooling system are contaminated with the organism. The incubation period is 2–10 days.Flu-like symptoms, fever, malaise and myalgia typically precede the development of a dry cough and dyspnoea. Extrapulmonary symptoms include anorexia, diarrhoea and vomiting, hepatitis, renal failure, confusion and coma. A chest X-ray shows bibasal consolidation, sometimes with a small pleural effusion. Blood results show an elevated white count, hyponatraemia and deranged liver function tests. Urinalysis might show haematuria. Diagnosis is by the urinary antigen test, which is highly specific. It is important to remember that the organism does not show up on Gram-staining.The preferred treatment is with the macrolide, clarithromycin. Ciprofloxacin can also be effective and rifampicin can be used. Amoxicillin Amoxicillin is incorrect. Amoxicillin monotherapy would be an appropriate treatment for a typical pneumonia of low severity. This case describes Legionella pneumonia which requires macrolide therapy. Cefuroxime Cefuroxime is incorrect. Cefuroxime is rarely prescribed now due to risk of Clostridium difficile infection. Ciprofloxacin Ciprofloxacin is incorrect. Ciprofloxacin is a 2nd line treatment for Legionella pneumonia e.g. if the patient cannot tolerate or is allergic to macrolides. The most effective treatment of the options given is clarithromycin. Flucloxacillin Flucloxacillin is incorrect. Flucloxacillin would be an appropriate treatment for a suspected Staphylococcal pneumonia.

Question 6

A 56-year-old smoker is transferred to your hospital with increasing breathlessness and haemoptysis. On examination he is suspected of having early stridor. What is the most appropriate pulmonary function test in this case?

Explanation

Correct Answer: C- Flow–volume loop Explanation Flow–volume loop Stridor in lung cancer is strongly suggestive of large- airway obstruction and is a medical emergency. Flow– volume loops show typical flattening caused by large- airways obstruction. Stridor complicating cancer requires urgent treatment and this can include steroids, radiotherapy, chemotherapy or endobronchial stenting. FEF25%–75% (average expired flow over mid- expiratory range of forced vital capacity manoeuvre) FEF 25%–75% (average expired flow over mid- expiratory range of forced vital capacity manoeuvre) is incorrect. This is a measure of flow in the small airways and would therefore not be helpful to determine a cause for the stridor.

FEV1 (forced expiratory volume in 1 s)

FEV1 (forced expiratory volume in 1 s) is incorrect. The

FEV1 reflects lower airway obstruction and therefore would not be as helpful as a flow–volume loop to determine a cause for the stridor.

TLC (total lung capacity)

TLC (total lung capacity) is incorrect. This is a measure of lung volume and would not be as helpful as a flow– volume loop to determine a cause for the stridor. Vmax50 (maximal flow at 50% of vital capacity) Vmax50 (maximal flow at 50% of vital capacity) is incorrect. This would not be as helpful as a flow– volume loop to determine a cause for the stridor.

Question 7

A patient with small-cell lung cancer has a serum sodium concentration of 121 mmol/l. The patient is asymptomatic. What is the most appropriate therapy?

Explanation

Correct Answer: A- Fluid restriction Explanation Fluid restriction This is a ‘know it or you don’t’ question. The continual secretion of antidiuretic hormone (ADH) in an amount in excess of the body’s needs leads to overhydration in both the intracellular and extracellular compartments. This is known as the ‘syndrome of inappropriate antidiuretic hormone secretion’ (SIADH). The cancer most commonly associated with this syndrome is small-cell lung cancer, where it is clinically obvious in 10% of cases, with subclinical involvement detectable by a water-loading test in more than 50%. The cerebral oedema resulting from water intoxication causes drowsiness, lethargy, irritability, mental confusion and disorientation, with seizures and coma being the most profound features. Peripheral oedema is remarkably rare. The patient is usually asymptomatic until the

sodium level falls below 120 mmol/l and the hyponatraemia is dilutional in type, with a low serum osmolality. Urine osmolality usually exceeds 300 mOsmol/kg. Restriction of fluid to a daily intake of 700–1000 ml redresses the hyponatraemia. In addition, desmethyl chlortetracycline (demeclocycline) 600–1200 mg daily is often effective. Glucocorticoids Glucocorticoids is incorrect. The most appropriate therapy here is fluid restriction to redress the hyponatraemia. Hypertonic fluid infusion Hypertonic fluid infusion is incorrect. Infusion of hypertonic saline is hazardous, often precipitating cardiac failure or more rarely too rapid correction of

sodium can lead to central pontine myelinolysis. It is therefore usually reserved for use in very severe/life- threatening hyponatraemia with altered consciousness or fits. Start chemotherapy Start chemotherapy is incorrect. The most appropriate therapy here is fluid restriction to redress the hyponatraemia. Start radiotherapy Start radiotherapy is incorrect. The most appropriate therapy here is fluid restriction to redress the hyponatraemia.

Question 8

A 70-year-old man attends the clinic. He is an ex-smoker of 50 pack-years. He has chronic obstructive pulmonary disease, with an FEV1 of 40% predicted and minimal bronchodilator reversibility. He is breathless after walking 500 m and was keen to be referred to discuss the possibility of pulmonary rehabilitation. What do you tell him?

Explanation

Correct Answer: C- His walking distance should improve after the rehabilitation programme Explanation His walking distance should improve after the rehabilitation programme Pulmonary rehabilitation has been found to lead to significant improvements in functional exercise capacity. His exercise tolerance is too poor to be considered for the rehabilitation programme His exercise tolerance is too poor to be considered for the rehabilitation programme is incorrect. Patients with very limited exercise tolerances may benefit from pulmonary rehabilitation and in the most severely limited patients chair-based exercises can be taught. His lung function should improve after the rehabilitation programme His lung function should improve after the rehabilitation programme is incorrect. Pulmonary rehabilitation does not improve lung function. If his exercise tolerance did improve following pulmonary rehabilitation, this would be a long-lasting improvement If his exercise tolerance did improve following pulmonary rehabilitation, this would be a long-lasting improvement is incorrect. Decline in exercise tolerance and heath status tends to occur 6–12 months after the completion of a course. The effect of sustained improvement with ongoing rehabilitation has yet to be evaluated. Rehabilitation will make little difference to the length of any future hospital stays Rehabilitation will make little difference to the length of any future hospital stays is incorrect. Patients who have completed pulmonary rehabilitation experience no fewer hospital admissions because of chest problems, but their hospital stays are likely to be shorter.

Question 9

A 60-year-old man who has a 30 pack-year smoking history comes to clinic with worsening shortness of breath over the last 6 months. He works as a baker and keeps racing pigeons. On examination, he is clubbed, has saturations of 91% on air and has widespread fine inspiratory crepitations. His chest X- ray shows reticulonodular shadowing and computed tomography (CT) confirms reticulation, mainly subpleural, and some honeycombing. What is the diagnosis?

Explanation

Correct Answer: E- Usual interstitial pneumonitis Explanation Usual interstitial pneumonitis Dyspnoea, clubbing and inspiratory crepitations are the classic features of usual interstitial pneumonitis. A chest X-ray will show reticulation, which is classically subpleural in distribution and on computed tomography (CT) and honeycombing. Hypersensitivity pneumonitis Hypersensitivity pneumonitis is incorrect. With hypersensitivity pneumonitis the expected findings would be ground-glass shadowing, with reticular and nodular patterns. Langerhans cell histiocytosis Langerhans cell histiocytosis is incorrect. In Langerhans cell histiocytosis nodules and cystic lesions would classically be seen on CT. Occupational asthma Occupational asthma is incorrect. Wheeze rather than crackles would be heard in occupational asthma and clubbing would not be present. CT might show non- specific features of air trapping. Pulmonary sarcoidosis Pulmonary sarcoidosis is incorrect. Pulmonary sarcoidosis does not cause clubbing and crepitations would be associated with end-stage fibrotic disease. Typically lungs are clear to auscultation in pulmonary sarcoidosis. CT thorax will show nodularity, including fissural nodularity in a bronchovascular and subpleural distribution.

Question 10

You are asked to review a patient with known asthma on the haematology ward. He is neutropenic from chemotherapy for Hodgkin lymphoma. He has a cough and a low-grade fever, sparse crepitations on chest examination and his chest X-ray shows diffuse pulmonary shadowing. He has been on broad-spectrum antibiotics for 1 week with no improvement. His sputum has shown a few hyphae, but is culture-negative. Blood cultures have been negative. Aspergillus precipitins are negative, as is an Aspergillus skinprick test. What is the diagnosis?

Explanation

Correct Answer: C- Invasive aspergillosis Explanation Invasive aspergillosis This man has invasive aspergillosis, due to his immunosuppression. He has fungal hyphae in his sputum and a corresponding clinical and radiological picture. He is unable to mount an immune response and so precipitin and skinprick tests are negative. Allergic bronchopulmonary aspergillosis Allergic bronchopulmonary aspergillosis (ABPA) is incorrect. ABPA is an IgE-mediated hypersensitivity reaction associated with exposure to Aspergillus. It presents with wheeze and cough often productive of thick mucus plugs. Chest radiograph shows transient pulmonary infiltrates (which are not widespread, as is described in this case). Blood tests show high IgE levels and antibodies to Aspergillus, so the skinprick is positive and precipitins are high if there is no immunosuppression. By virtue of the fact that this patient is heavily immunosuppressed it would be very unlikely for him to develop ABPA. Aspergilloma Aspergilloma is incorrect. Aspergilloma is a fungal ball in an area of previously damaged lung tissue, such as old tuberculosis. It does not cause diffuse pulmonary infiltrates as are described in this case. It usually causes high levels of Aspergillus antibody, so precipitins are high, although the skinprick test is negative as there is no IgE-mediated allergy to Aspergillus. Pneumocystis pneumonia Pneumocystis pneumonia is incorrect. Pneumocystis pneumonia does not cause hyphae in the sputum. Systemic candidosis Systemic candidosis is incorrect. Candida can be identified and cultured from the sputum. It rarely causes objective evidence of lung invasion and is not recognised as having specific radiological features.

Question 11

A 32-year-old alcoholic man is brought to the Emergency Department having been found collapsed on a street corner. He is a frequent attender at the hospital with intoxication, is known to have chronic liver disease with hepatitis C, and has one previous episode of haematemesis due to oesophageal varices. On examination he is drowsy and confused, his BP is 100/70 mmHg, pulse is 90/min and regular, and his temperature is 38.2 °C. Auscultation of the chest reveals coarse right- sided crackles, with decreased breath sounds at the right base. Investigations:

Hb 10.5 g/dl

WCC 13.1 × 109/l

Neutrophils 11.2 × 109/l PLT 100 × 109/l

Na+ 131 mmol/l

K+ 4.5 mmol/l

Creatinine 95 μmol/l CRP 171 mg/l

CXR Right lower lobe consolidation with evidence of cavitation Which of the following is the most likely diagnosis?

Explanation

Correct Answer: B- Klebsiella pneumonia Explanation Klebsiella pneumonia Klebsiella pneumonia occurs with increased frequency in debilitated patients, particularly those with a history of alcoholism. It leads to cavitation, as seen here. Aspiration pneumonia Aspiration pneumonia is incorrect. Aspiration pneumonia is predominantly associated with changes in the right upper and middle lobes. Legionnaire’s disease Legionnaire's disease is incorrect. Legionnaire’s is a much more rare cause of community-acquired pneumonia, and is often associated with diarrhoea. Staphylococcal pneumonia Staphylococcal pneumonia is incorrect. The other common cause of cavitating pneumonia is staphylococcal infection, although that occurs most frequently post influenza, of which there is no mention here. Tuberculosis Tuberculosis is incorrect. Tuberculosis typically affects the upper lobes or apical lower lobes.

Question 12

Which of the following is the best agent for treating chlamydial pneumonia in a woman who is 25-weeks pregnant?

Explanation

Correct Answer: C- Erythromycin Explanation Erythromycin Macrolide antibiotics (eg erythromycin) are the treatment of choice for Chlamydia pneumonia and other atypical pneumonias. The most frequent side-effects are nausea, vomiting and diarrhoea. Treatment is likely to be most effective when it is given over a longer time, when suboptimal doses are avoided and if compliance is strict. In this case macrolides would have the best evidence of safety in pregnancy and efficacy, although most evidence to support safe use is in the third trimester. The other choices are incorrect – All of these antibiotics are less effective than macrolides in treating Chlamydial pneumonia therefore erythromycin is the most appropriate treatment of the options given. Piperacillin, clindamycin and ampicillin can be safely used in pregnancy. Imipenem should be avoided in pregnancy given evidence of toxicity in animal studies. Ampicillin Ampicillin is incorrect. As described this would be less effective than erythromycin. Clindamycin Clindamycin is incorrect. As described this would be less effective than erythromycin. Imipenem Imipenem is incorrect. Imipenem should be avoided in pregnancy. Piperacillin Piperacillin is incorrect. As described this would be less effective than erythromycin.

Question 13

A 64-year-old demolition worker presents to his GP with a severe, dull, right-sided chest pain. He first noticed it some months ago and he is now having particular problems with shortness of breath. Apparently he was given an asthma inhaler for shortness of breath around 2 years earlier. On examination he appears to have a right- sided pleural effusion and has finger clubbing. He admits to having been exposed to asbestos. On further questioning he says that his brother, who worked with him, died of ‘some sort of lung cancer’ around 2 years ago. X-ray confirms a right pleural effusion with evidence of pleural plaques elsewhere. What diagnosis would fit best with this clinical picture?

Explanation

Correct Answer: C- Mesothelioma Explanation Mesothelioma The clue to the answer here is the occupation, and the fact that a co-worker has already died of a cancer related to the chest. A restrictive lung defect, evidence of asbestosis, and now a painful pleural effusion would fit best with a diagnosis of mesothelioma. Diagnosis is confirmed by pleural biopsy. The median survival after diagnosis ranges from 12 to 21 months depending on staging. The cancer is poorly responsive to any form of intervention, however, and it is notable that a significant number of patients survive far less than 2 years. Asthma Asthma is incorrect. Asthma is not associated with pleural effusions or finger clubbing. Additionally, the presence of pleural plaques, chest pain and previous asbestos exposure make mesothelioma the most likely diagnosis. Bronchial carcinoma Bronchial carcinoma is incorrect. Although bronchial carcinoma can present with dyspnoea and a pleural effusion, the presence of finger clubbing, pleural plaques and previous asbestos exposure makes mesothelioma the most likely diagnosis. Rheumatoid arthritis Rheumatoid arthritis is incorrect. Rheumatoid arthritis can be associated with pleural effusions but there is no mention of any joint symptoms, and the presence of finger clubbing, pleural plaques and previous asbestos exposure makes mesothelioma the most likely diagnosis. Tuberculosis Tuberculosis is incorrect. Tuberculosis can present with a pleural effusion. However, there is no mention of contact with tuberculosis and there is no history of fevers or sweats. Furthermore, the presence of finger clubbing, pleural plaques and previous asbestos exposure makes mesothelioma the most likely diagnosis.

Question 14

A patient with small-cell lung cancer has a serum sodium concentration of 121 mmol/l. Which of the following is the most likely cause?

Explanation

Correct Answer: E- Syndrome of inappropriate antidiuretic hormone secretion Explanation Syndrome of inappropriate antidiuretic hormone secretion Continual secretion of vasopressin (antidiuretic hormone, ADH) in amounts in excess of the body’s needs leads to overhydration in both the intracellular and extracellular compartments – the so-called ‘syndrome of inappropriate antidiuretic hormone secretion’ or SIADH. The commonest cancer to cause this syndrome is small-cell cancer of the lung and it is clinically obvious in 10% of people with this tumour, with subclinical involvement detectable by a water-loading test in more than 50%. Clinical and biochemical features:

• The cerebral oedema resulting from water intoxication causes drowsiness, lethargy, irritability, mental confusion and disorientation, with seizures and coma being the most profound features. Peripheral oedema is remarkably rare. The patient is usually asymptomatic until the sodium concentration falls below 120 mmol/l. • The hyponatraemia is dilutional in type, with a low serum osmolality. Urine osmolality usually exceeds 300 mOsmol/kg. Restriction of fluid to a daily intake of 700– 1000 ml might be sufficient to redress the hyponatraemia. • Demethylchlortetracycline (demeclocycline) 600– 1200 mg daily induces nephrogenic diabetes insipidus, making water restriction unnecessary. However, it has an unpredictable onset, only works in approximately 60% patinets and can be associated with renal dysfunction. • Tolvaptan, an arginine vasopressin (AVP) antagonist, promotes aquaresis and can lead to a contolled increase in serum sodium. • Infusion of hypertonic saline is hazardous, often precipitating cardiac failure or cerebral oedema but may be required in severe hyponatraemia in the presence of seizures, impaired mental status or coma. Treatment with hypertonic saline should be stopped once symptoms resolve, a safe serum sodium concentration is achieved, or the maximum sodium correction limits are approached (<12mEq/L increase in serum sodium in 24 hours). Bone metastases Bone metastases is incorrect. Bone metastases are not a cause of hyponatraemia. Liver metastases Liver metastases is incorrect. Liver metastases are not a cause of hyponatraemia. Sodium-reduced water drinking

Sodium-reduced water drinking is incorrect. Psychogenic polydipsia is a cause of hyponatraemia but given this lady has small cell lung cancer SIADH is more likely

Sodium-restricted diet

Sodium-restricted diet is incorrect. This is unlikely to cause significant hyponatraemia

Question 15

Which one of the following features is most characteristic of small-cell bronchial carcinoma?

Explanation

Correct Answer: D- Hyponatraemia Explanation Hyponatraemia Syndrome of inappropriate antidiuretic hormone secretion (SIADH) resulting in hyponatraemia occurs in approximately 15% of patients with small-cell lung cancer. A history of prior asbestos exposure A history of prior asbestos exposure is incorrect. Asbestos exposure increases the risk of lung cancer but is most associated with pleural malignancy (malignant mesothelioma). Cancer cell origin from small lymphocytes Cancer cell origin from small lymphocytes is incorrect. Small-cell lung cancer is of neuroendocrine cell origin. Has a relatively better prognosis than other bronchial cancers Has a relatively better prognosis than other bronchial cancers is incorrect. The prognosis is very poor and survival beyond two 2 years is exceptional. Surgery is often the only possible treatment Surgery is often the only possible treatment is incorrect. By the time the diagnosis has been made the tumour is usually disseminated, so that surgery is seldom considered.

Question 16

A 37-year-old patient with haemophilia A has been complaining of fever and dry cough. An interstitial pneumonia was diagnosed. He only makes intermittent contact with medical services. After 7 days' treatment with doxycycline 200 mg/day his temperature was still 39 °C and a chest X- ray showed increased interstitial infiltrates. Which is the most likely diagnosis?

Explanation

Correct Answer: E- Pneumocystis jirovecii pneumonia Explanation Pneumocystis jirovecii pneumonia Pneumocystis jirovecii pneumonia (formerly called Pneumocystis carinii) typically presents with gradually increasing dyspnoea and cough over weeks, but sometimes as an acute illness with rapid deterioration over a few days. Patients with haemophilia A were more susceptible to HIV due to frequent blood transfusions that were not screened in the past. The chest X-ray usually reveals diffuse ground-glass opacities, which strongly suggests the diagnosis, but it sometimes shows nodular opacities, lobar consolidation, or even a normal film. Cystic abnormalities and spontaneous pneumothoraces in patients with known or suspected HIV infection are usually caused by Pneumocystis jirovecii pneumonia. Pneumocystis jiroveciipneumonia is unlikely in a patient who has had a CD4+ cell count above 200 cells/µl in the preceding 2 months in the absence of other HIV- associated symptoms. Approximately 90% of patients with Pneumocystis jirovecii pneumonia have an elevated serum lactic dehydrogenase, but this may also occur with other pulmonary diseases. Candida pneumonia Candida pneumonia is incorrect. This is a reasonable differential diagnosis here, but the dry cough is classical of Pneumocystis jirovecii pneumonia and one might expect a history of oral candidiasis if candida pneumonia was suspected in an immunocompromised patient. Extrinsic allergic alveolitis Extrinsic allergic alveolitis is incorrect. There is no mention of a potential allergen/precipitin to cause extrinsic allergic alveolitis; the history is more suggestive of respiratory infection and the diagnosis of haemophilia A is supposed to trigger the candidate to suspect HIV infection from blood transfusion and a subsequent opportunistic respiratory infection. Mycoplasma pneumonia Mycoplasma pneumonia is incorrect. Mycoplasmal pneumonia is likely to be adequately treated by doxycycline, making other diagnoses more likely. Ornithosis Ornithosis is incorrect. There is no mention of avian exposure to suggest Chlamydia psittaci pneumonia (ornithosis). In addition, doxycycline is an appropriate treatment for this infection, so improvement rather than deterioration after treatment would be more likely.

Question 17

You review a 72-year-old man with severe chronic obstructive pulmonary disease (COPD), who asks about the provision of oxygen therapy at home. In which of the following settings have randomised controlled trials shown that long-term oxygen therapy (LTOT) reduces mortality?

Explanation

Correct Answer: B- Cor pulmonale caused by chronic airflow obstruction Explanation Cor pulmonale caused by chronic airflow obstruction Two controlled studies (in a mostly male population) indicated that life can be prolonged by the continuous delivery of 2 l/min of oxygen via nasal prongs to achieve saturations of greater than 90% for a large proportion of the day and night. Improvements in pulmonary artery hypertension were obtained in patients who used oxygen for more than 15 h/day, but mortality was only improved in patients who used oxygen for more than 18 h/day. Long-term oxygen therapy (LTOT) should therefore be considered in patients with chronic obstructive pulmonary disease (COPD) and a forced expiratory volume in 1 s (FEV1) of less than 1.5 l, an arterial partial pressure of oxygen (Pao2) of less than 7.3 kPa and carboxyhaemoglobin of less than 3%. Although oxygen cylinders can be provided for intermittent use by patients for the relief of symptoms of breathlessness, they have no effect on prognosis. Asthma Asthma is incorrect. Although oxygen cylinders can be provided for intermittent use by patients for the relief of symptoms of breathlessness, they have no effect on prognosis. Cystic fibrosis Cystic fibrosis is incorrect. Although oxygen cylinders can be provided for intermittent use by patients for the relief of symptoms of breathlessness, they have no effect on prognosis. Idiopathic pulmonary fibrosis Idiopathic pulmonary fibrosis is incorrect. Although oxygen cylinders can be provided for intermittent use by patients for the relief of symptoms of breathlessness, they have no effect on prognosis. Pulmonary sarcoidosis Pulmonary sarcoidosis is incorrect. Although oxygen cylinders can be provided for intermittent use by patients for the relief of symptoms of breathlessness, they have no effect on prognosis.

Question 18

A 28-year-old man presents with sudden left-sided pleuritic chest pain while working on a house clearance. He is usually fit and well, has no significant medical problems and takes no medication. On examination his respiratory rate is 20 bpm, his BP is 125/82 mmHg, and pulse is 85 bpm and regular. He is in pain, although breath sounds are normal on auscultation. Investigations:

Hb 13.4 g/dl

WCC 8.1 × 109/l

PLT 201 × 109/l

Na+ 137 mmol/l

K+ 4.3 mmol/l

Creatinine 100 μmol/l

CXR 1 cm left-sided pneumothorax O2 saturation 98% on air Which of the following is the correct way to manage him?

Explanation

Correct Answer: C- Discharge with review in clinic in approximately 2 weeks Explanation Discharge with review in clinic in approximately 2 weeks This patient has a minimal pneumothorax and his pain should settle with adequate analgesia. As such it is appropriate to discharge him with review in clinic in approximately 2 weeks. Of course he should be warned to return as soon as possible if shortness of breath or pain worsens. Admit for overnight observation Admit for overnight observation is incorrect. This patient has a minimal pneumothorax and his pain should settle with adequate analgesia. As such it is appropriate to discharge him with review in clinic in approximately 2 weeks. Of course he should be warned to return as soon as possible if shortness of breath or pain worsens. Attempt percutaneous aspiration Attempt percutaneous aspiration is incorrect. In the event the pneumothorax was > 2 cm in size, aspiration would be the initial management of choice. Discharge with review after 12 h Discharge with review after 12 h is incorrect. This patient has a minimal pneumothorax and his pain should settle with adequate analgesia. As such it is appropriate to discharge him with review in clinic in approximately 2 weeks. Of course he should be warned to return as soon as possible if shortness of breath or pain worsens. Insert chest drain Insert chest drain is incorrect. In the event the pneumothorax was > 2 cm in size, chest drain insertion may be considered following a failed aspiration.

Question 19

You are asked to review a 28-year-old man who is thought to originate from Afghanistan who has presented to an immigration centre claiming asylum. He has been diagnosed with HIV for which HAART has been commenced. There is a past history of tuberculosis as a child for which he was successfully treated with triple anti-bacterial therapy. Over the past few days he has developed a severe cough, productive of bloody sputum. On examination he is pyrexial 37.8 °C, his BP is 105/70 mmHg, and pulse is 80 bpm and regular. There are scattered coarse crackles on auscultation of the chest.

Investigations:

Hb 11.0 g/dl

WCC 7.9 × 109/l

PLT 194 × 109/l

Na+ 137 mmol/l

K+ 4.2 mmol/l

Creatinine 115 μmol/l

CXR Bilateral pleural effusions, widespread nodular consolidation Which of the following is the most likely diagnosis?

Explanation

Correct Answer: E- Tuberculosis Explanation Tuberculosis Given this patient has a history of tuberculosis that was previously treated and a recent diagnosis of HIV, the most likely diagnosis is immune reconstitution syndrome that has led to reactivation of the latent tuberculosis infection. In a patient like this with a past history of infection, additional prophylaxis against tuberculosis can be considered at the same time as starting HAART. The chest X- ray appearance fits with disseminated pulmonary tuberculosis. Invasive aspergillosis Invasive aspergillosis is incorrect. Immunosuppressed individuals are at increased risk of developing invasive aspergillosis. However, untreated, this condition is rapidly fatal and thus the diagnosis is unlikely in the history described. Pneumocystis jirovecii Pneumocystis jirovecii is incorrect. Immunosuppressed individuals are at increased risk of developing Pneumocystis jirovecii infection. However, the history of a severe cough with bloody sputum is not classical and pleural effusions are also not usually found in this type of pneumonia. Pseudomonal pneumonia Pseudomonal pneumonia is incorrect. Immunosuppressed individuals are at increased risk of developing pseudomonal infection. However, one would expect a leukocytosis and, with the history of previous tuberculosis and the presence of nodular consolidation and pleural effusions, a diagnosis of tuberculosis is more likely. Staphylococcal pneumonia Staphylococcal pneumonia is incorrect. Immunosuppressed individuals are at increased risk of developing staphylococcal pneumonia. Classically this causes a cavitating pneumonia rather than nodular consolidation and, with the history of previous tuberculosis and the presence of nodular consolidation and pleural effusions, a diagnosis of tuberculosis is more likely.

Question 20

A 65-year-old woman has been diagnosed with lung cancer. Which of the following statements is true?

Explanation

Correct Answer: B- Hypercalcaemia can occur without bone metastasis Explanation Hypercalcaemia can occur without bone metastasis Hypercalcaemia can occur as a paraneoplastic syndrome with squamous-cell carcinoma. This is caused by the production of a parathyroid hormone-related peptide by the tumour, which increases bone resorption, and renal tubular reabsorption of calcium. Hypercalcaemia associated with bone metastases is best treated with intravenous steroids Hypercalcaemia secondary to bone metastases is best treated with intravenous fluids and bisphosphonates. (Steroids are mainly used for treating hypercalcaemia associated with sarcoidosis). Hypertrophic pulmonary osteoarthropathy (HPOA) is commonly seen patients with small-cell carcinoma Hypertrophic pulmonary osteoarthropathy (HPOA) is characterised by a painful symmetrical arthropathy involving the wrist, ankle and knee joints. It is most commonly seen in patients with non- small cell cancer. Inappropriate secretion of antidiuretic hormone (SIADH) is commonly seen in patients with squamous-cell carcinoma SIADH is most common in patients with small-cell carcinoma. Paraneoplastic syndromes occur more commonly with squamous-cell carcinomas Paraneoplastic syndromes comprise a variety of non-metastatic, metabolic or neuromuscular manifestations of lung cancer. They are commonly associated with small-cell carcinoma, apart from hypercalcaemia which is seen in association with squamous cell cancer.

Question 21

A 25-year-old man with bilateral closed femoral shaft fractures treated with intramedullary nailing develops progressive hypoxemia, a petechial rash over his axillae and conjunctivae, and confusion 36 hours postoperatively. His arterial blood gas reveals a pO2 of 55 mmHg. What is the most likely diagnosis?

Explanation

This patient exhibits the classic triad of fat embolism syndrome: hypoxemia, neurologic compromise, and a petechial rash. It is a known complication of long bone fractures, particularly of the femur, usually occurring 24 to 72 hours after injury.

Question 22

A 62-year-old heavy smoker with known non-small cell lung carcinoma presents with increasing thigh pain. Radiographs reveal a 3.5 cm lytic lesion in the subtrochanteric region of the right femur with cortical destruction. His Mirels' score is 10. What is the most appropriate management?

Explanation

A Mirels' score of 9 or greater indicates a high risk for impending pathologic fracture. Prophylactic surgical fixation, typically with an intramedullary nail, followed by adjuvant radiotherapy is the standard of care to prevent fracture and relieve pain.

Question 23

A 68-year-old woman is recovering on postoperative day 4 following an elective right total hip arthroplasty. She suddenly develops pleuritic chest pain, tachypnea, and a heart rate of 115 bpm. An ECG demonstrates sinus tachycardia with an S1Q3T3 pattern. Which of the following is the most likely diagnosis?

Explanation

Sudden onset of dyspnea, pleuritic chest pain, tachycardia, and right heart strain signs on ECG (S1Q3T3) in the postoperative period are highly suspicious for a pulmonary embolism. Deep vein thrombosis and PE are major risks following major lower extremity orthopedic surgery.

Question 24

A 45-year-old recent immigrant presents with chronic back pain, intermittent night sweats, and a progressive kyphotic deformity of the thoracic spine. MRI demonstrates destruction of the T8 and T9 vertebral bodies with relative sparing of the intervertebral disc initially, along with a large paraspinal fluid collection. What is the most likely diagnosis?

Explanation

Tuberculous spondylitis frequently presents with indolent symptoms, kyphosis, and large paraspinal (cold) abscesses. Unlike pyogenic infections, TB often begins in the anterior vertebral body and spares the disc space until late in the disease process.

Question 25

According to the American College of Chest Physicians (ACCP) guidelines, what is the recommended duration of pharmacological venous thromboembolism (VTE) prophylaxis following an elective total hip arthroplasty?

Explanation

The ACCP recommends extending pharmacological VTE prophylaxis for up to 35 days postoperatively for patients undergoing major orthopedic surgery, such as total hip arthroplasty. This extended duration significantly reduces the incidence of late VTE.

Question 26

A 35-year-old woman presents with a swollen, painful knee of 6 months' duration. Radiographs show juxta-articular osteopenia, peripheral osseous erosions, and gradual joint space narrowing. What do these radiographic findings classically represent?

Explanation

The Phemister triad consists of juxta-articular osteopenia, peripherally located osseous erosions, and gradual narrowing of the joint space. It is the classic radiographic presentation of articular tuberculosis.

Question 27

A 70-year-old man presents with generalized fatigue, severe back pain, and hypercalcemia. Radiographs of his skull reveal multiple 'punched-out' lytic lesions. Serum protein electrophoresis shows an M-spike. Which of the following is the most definitive primary treatment for his skeletal disease?

Explanation

The clinical presentation is classic for multiple myeloma (CRAB criteria: hyperCalcemia, Renal involvement, Anemia, Bone lytic lesions). Treatment is primarily medical with chemotherapy and bisphosphonates, reserving surgery for impending or actual pathologic fractures.

Question 28

A 28-year-old man sustains a closed midshaft tibia fracture. Six hours later, he develops excruciating leg pain exacerbated by passive stretch of his toes. His diastolic blood pressure is 80 mmHg. A compartment pressure reading confirms acute compartment syndrome. What is the critical threshold for the delta pressure?

Explanation

Acute compartment syndrome is diagnosed when the delta pressure (diastolic blood pressure minus intracompartmental pressure) falls to less than 30 mmHg. Immediate four-compartment fasciotomy is indicated to prevent irreversible ischemia.

Question 29

A 45-year-old man with a 15-year history of ankylosing spondylitis presents to the emergency department after a low-speed motor vehicle collision complaining of severe lower neck pain. Neurological exam is normal. Plain radiographs are difficult to interpret due to pre-existing deformity. What is the most appropriate next step?

Explanation

Patients with ankylosing spondylitis have rigid, osteopenic spines highly susceptible to unstable fractures even from minor trauma. A CT scan of the entire cervical spine is mandatory to rule out an occult fracture, as plain films are notoriously inadequate in this population.

Question 30

A 55-year-old woman with severe, long-standing rheumatoid arthritis is scheduled for an elective total knee arthroplasty. Before clearing her for surgery, the anesthesiologist requests specific imaging to assess the risk of a catastrophic complication during intubation. Which imaging study is required?

Explanation

Patients with severe rheumatoid arthritis are at high risk for atlantoaxial subluxation. Flexion-extension radiographs of the cervical spine are essential preoperatively to evaluate for instability that could cause spinal cord injury during endotracheal intubation.

Question 31

A 65-year-old woman suffers a distal radius fracture after a fall from a standing height. Dual-energy X-ray absorptiometry (DEXA) reveals a T-score of -2.8 at the femoral neck. According to the World Health Organization (WHO) criteria, what is her diagnosis?

Explanation

A T-score of -2.5 or lower defines osteoporosis. Because she also has a fragility fracture (distal radius), her classification upgrades to severe (or established) osteoporosis.

Question 32

A 75-year-old man presents with chronic, intractable right shoulder pain and an inability to actively elevate his arm beyond 40 degrees (pseudoparalysis). Radiographs reveal a massive, retracted rotator cuff tear with superior migration of the humeral head articulating with the acromion. What is the most reliable surgical option?

Explanation

In the setting of rotator cuff arthropathy with pseudoparalysis, a reverse total shoulder arthroplasty is the treatment of choice. It alters the center of rotation, allowing the deltoid to effectively elevate the arm without a functioning rotator cuff.

Question 33

A 6-month-old infant is diagnosed with developmental dysplasia of the hip (DDH) after failing 6 weeks of treatment in a Pavlik harness. Ultrasound confirms persistent dislocation. What is the most appropriate next step in management?

Explanation

If a Pavlik harness fails to achieve reduction in an infant with DDH after 3 to 4 weeks, continuing it is contraindicated due to the risk of 'Pavlik harness disease'. The next step is typically closed reduction and application of a hip spica cast under anesthesia.

Question 34

A 13-year-old obese boy presents with a 3-week history of right groin pain and a limp. On examination, he walks with an antalgic gait, and his right hip goes into obligate external rotation when flexed. Radiographs confirm a slipped capital femoral epiphysis (SCFE). What is the standard surgical treatment?

Explanation

The classic presentation of SCFE includes obligate external rotation with hip flexion. The gold standard of treatment is in situ fixation across the physis, typically utilizing a single partially threaded cannulated screw, to prevent further slippage.

Question 35

A 6-year-old girl falls onto her outstretched hand and sustains a Gartland type III supracondylar humerus fracture. On evaluation, the hand is well-perfused and warm with brisk capillary refill, but the radial pulse is absent. What is the most appropriate initial management?

Explanation

For a 'pink, pulseless' hand associated with a severely displaced supracondylar fracture, the standard initial step is urgent closed reduction and percutaneous pinning. The radial pulse frequently returns once the brachial artery is unkinked by the reduction.

Question 36

A 42-year-old man presents to the emergency department with acute lower back pain, bilateral sciatica, and perineal numbness. He reports difficulty initiating urination. Which of the following clinical findings is considered the most sensitive for diagnosing cauda equina syndrome?

Explanation

Urinary retention is the hallmark early sign of cauda equina syndrome. A post-void residual volume greater than 100-200 mL is highly sensitive and should prompt emergent MRI and surgical decompression.

Question 37

A 30-year-old man sustains an open diaphyseal fracture of the tibia in a motorcycle accident. The wound is 12 cm long with extensive soft-tissue crushing and periosteal stripping, requiring a rotational flap for coverage. According to the Gustilo-Anderson classification, what is the recommended empiric antibiotic regimen?

Explanation

This is a Gustilo-Anderson Type IIIb open fracture. Current guidelines recommend a first-generation cephalosporin (like cefazolin) combined with an aminoglycoside (like gentamicin) to cover both Gram-positive and Gram-negative organisms in severe open fractures.

Question 38

A 12-year-old boy with homozygous sickle cell disease presents with high fever and severe localized pain in his left thigh. MRI is highly suggestive of acute osteomyelitis of the femoral diaphysis. While Staphylococcus aureus remains a common pathogen, which of the following organisms is uniquely associated with osteomyelitis in this patient population?

Explanation

Patients with sickle cell disease are particularly susceptible to osteomyelitis caused by Salmonella species due to functional asplenia and bowel ischemia. Empiric antibiotic therapy must cover both S. aureus and Salmonella.

Question 39

A 15-year-old boy presents with progressive pain in his left thigh. Plain radiographs show a permeative diaphyseal lesion in the femur with a multilamellated 'onion skin' periosteal reaction. A biopsy is performed. Which of the following chromosomal translocations is most characteristic of this tumor?

Explanation

The clinical and radiographic presentation is classic for Ewing sarcoma. Ewing sarcoma is genetically defined by the t(11;22) translocation, resulting in the EWS-FLI1 fusion protein in approximately 85% of cases.

Question 40

A 25-year-old man fell on his extended wrist 6 months ago. He did not seek medical care at the time but now presents with chronic radial-sided wrist pain. X-rays reveal a scaphoid nonunion with avascular necrosis of the proximal pole. The retrograde blood supply to the scaphoid is primarily derived from branches of which artery?

Explanation

The major blood supply to the scaphoid enters distally via the dorsal carpal branch of the radial artery and flows retrograde to the proximal pole. This retrograde anatomy makes proximal pole fractures highly susceptible to avascular necrosis and nonunion.

Question 41

A 24-year-old man sustains bilateral closed femoral shaft fractures in a motor vehicle collision. Thirty-six hours later, he becomes confused, develops a petechial rash over his axillae and conjunctivae, and requires supplemental oxygen for hypoxemia. What is the most likely diagnosis?

Explanation

Fat embolism syndrome typically presents 24 to 72 hours after long-bone fractures. It is classically characterized by Bergman's triad: hypoxemia, neurological abnormalities, and a petechial rash.

Question 42

A 45-year-old male immigrant presents with chronic back pain, night sweats, and a progressive kyphotic deformity. MRI reveals destruction of the T8 and T9 anterior vertebral bodies, sparing of the posterior elements, destruction of the intervening disc space, and a large paraspinal abscess. What is the most likely diagnosis?

Explanation

Tuberculous spondylitis (Pott's disease) typically involves the anterior vertebral body and crosses the disc space, leading to anterior wedging and a gibbus deformity. The presence of a paraspinal (cold) abscess strongly supports this diagnosis.

Question 43

An 80-year-old woman is undergoing a cemented hemiarthroplasty for a displaced femoral neck fracture. Immediately upon cement pressurization and stem insertion, her end-tidal CO2 abruptly drops, and she becomes severely hypotensive. What is the most likely cause?

Explanation

Bone cement implantation syndrome (BCIS) is characterized by hypoxia, hypotension, and an unexpected drop in end-tidal CO2 during cementation. It is likely caused by the embolization of marrow contents into the pulmonary circulation.

Question 44

A 60-year-old man with known lung carcinoma presents with right thigh pain that is moderate with weight-bearing. Radiographs reveal a 2.5 cm lytic lesion in the peritrochanteric region, occupying about half the cortical diameter. According to Mirels' criteria, what is the most appropriate management?

Explanation

This patient has a Mirels' score of 10 (peritrochanteric = 3, moderate pain = 2, lytic = 3, size 1/3-2/3 = 2). A score of 9 or greater indicates a high risk of impending pathologic fracture, warranting prophylactic internal fixation.

Question 45

A 55-year-old heavy smoker complains of right shoulder pain radiating down the medial aspect of his arm to his little finger. Examination reveals ipsilateral ptosis and miosis, but a normal shoulder exam. What is the most likely diagnosis?

Explanation

A Pancoast tumor located in the lung apex can invade the lower brachial plexus (C8, T1) and the cervical sympathetic chain. This causes radicular medial arm/hand pain and Horner's syndrome (ptosis, miosis, anhidrosis).

Question 46

A 68-year-old man who underwent a total hip arthroplasty 10 days ago presents with sudden shortness of breath, pleuritic chest pain, and hemoptysis. His ECG shows sinus tachycardia and an S1Q3T3 pattern. What is the next best diagnostic step?

Explanation

This patient has a high clinical probability of an acute pulmonary embolism. CT pulmonary angiography (CTPA) is the gold standard and most appropriate initial imaging modality in this scenario.

Question 47

A 72-year-old female on warfarin for atrial fibrillation requires emergency surgical decompression for cauda equina syndrome. Her INR is 3.5. What is the most effective therapy for the rapid reversal of her anticoagulation?

Explanation

Prothrombin complex concentrate (PCC) provides the most rapid and complete reversal of vitamin K antagonists like warfarin. Intravenous Vitamin K is typically given concurrently but takes hours to take effect.

Question 48

A 30-year-old man presents with chronic, insidious monoarthritis of the knee. Radiographs reveal juxta-articular osteopenia, peripheral osseous erosions, and gradual narrowing of the joint space. What is the classic eponym for this radiographic triad?

Explanation

Phemister's triad consists of juxta-articular osteopenia, peripheral osseous erosions, and gradual joint space narrowing. It is a classic radiographic hallmark of tuberculous arthritis.

Question 49

A 40-year-old man with long-standing ankylosing spondylitis presents with insidious onset of dyspnea. Pulmonary function tests demonstrate a normal FEV1/FVC ratio but decreased total lung capacity. Which pulmonary complication is most characteristic of this underlying disease?

Explanation

Apical pulmonary fibrosis is a classic extra-articular manifestation of advanced ankylosing spondylitis. It presents as a restrictive lung disease pattern on pulmonary function tests.

Question 50

A 65-year-old man is scheduled for an elective total hip arthroplasty under spinal anesthesia. He is receiving prophylactic doses of low-molecular-weight heparin (LMWH). According to current guidelines, how long before the spinal block should the last dose of LMWH be administered?

Explanation

To minimize the risk of a spinal epidural hematoma, guidelines recommend that prophylactic (low-dose) LMWH be discontinued at least 12 hours prior to neuraxial anesthesia placement.

Question 51

An 18-year-old male with homozygous sickle cell disease sustains a closed femoral shaft fracture. On post-injury day 2, he develops chest pain, fever, tachypnea, and new pulmonary infiltrates on his chest X-ray. What is the best initial management?

Explanation

This presentation is highly suspicious for acute chest syndrome. Initial management focuses on supportive care, including oxygenation, aggressive hydration, analgesia, and broad-spectrum antibiotics, often followed by blood transfusion.

Question 52

A 60-year-old man with squamous cell carcinoma of the lung presents with confusion, lethargy, and severe diffuse bone pain. Laboratory results show a corrected serum calcium of 14 mg/dL. What is the initial treatment of choice?

Explanation

The most critical and rapid initial treatment for severe hypercalcemia of malignancy is aggressive volume expansion with intravenous normal saline. This restores intravascular volume and promotes renal calcium excretion.

Question 53

A 35-year-old woman presents with dactylitis of her hands. Hand radiographs reveal cystic, "lace-like" lucencies in the phalanges with intact but thinned cortices. A chest radiograph demonstrates bilateral hilar lymphadenopathy. What is the most likely diagnosis?

Explanation

Osseous sarcoidosis classically presents with lace-like, cystic bone lesions in the phalanges of the hands or feet. This finding is strongly supported by the presence of bilateral hilar lymphadenopathy on chest imaging.

Question 54

A 28-year-old male involved in a high-speed collision sustains bilateral femur fractures. On post-injury day 3, he is intubated for hypoxemia. His PaO2/FiO2 ratio is 150 mmHg, and a chest radiograph shows bilateral diffuse opacities. According to the Berlin definition, what is his condition?

Explanation

Under the Berlin definition, Acute Respiratory Distress Syndrome (ARDS) is categorized by the PaO2/FiO2 ratio. A ratio between 100 and 200 mmHg with bilateral opacities defines moderate ARDS.

Question 55

A 55-year-old woman with a 15-year history of seropositive rheumatoid arthritis presents with chronic cough. Chest X-ray reveals multiple peripheral pulmonary nodules, some of which are cavitating. She has a history of coal dust exposure. What is this syndrome known as?

Explanation

Caplan syndrome is a condition characterized by the combination of rheumatoid arthritis and pneumoconiosis, presenting with multiple, well-defined cavitating rheumatoid nodules in the lungs.

Question 56

A 62-year-old heavy smoker presents with symmetric, painful swelling of his wrists and ankles. Clinical examination reveals prominent digital clubbing. Radiographs show solid periosteal new bone formation along the diaphyses of the distal radius and ulna. What is the most important next diagnostic step?

Explanation

This patient is exhibiting signs of hypertrophic pulmonary osteoarthropathy (HPOA). Because HPOA is strongly associated with underlying bronchogenic carcinoma, a chest X-ray is the crucial next step.

Question 57

A 45-year-old man undergoes intramedullary nailing for a closed tibia fracture. When is he at the HIGHEST risk of developing the full clinical presentation of fat embolism syndrome?

Explanation

Fat embolism syndrome most commonly manifests 24 to 72 hours following a major long bone fracture. Earlier presentations are rare, and respiratory failure beyond one week is more suspicious for venous thromboembolism.

Question 58

A 32-year-old male with known spinal tuberculosis at T8-T9 presents with new-onset lower extremity weakness and hyperreflexia. The neurological deficit in Pott's disease is most commonly directly caused by which of the following?

Explanation

Neurological deficits in Pott's disease typically result from mechanical compression of the spinal cord by an epidural abscess, inflammatory granulation tissue, or posterior displacement of bony fragments.

Question 59

A 70-year-old male with severe COPD is being evaluated preoperatively for a total knee arthroplasty. Which pulmonary function test parameter is considered the strongest predictor of significant postoperative pulmonary complications?

Explanation

An FEV1 of less than 50% of the predicted value is a well-established and highly reliable indicator of increased risk for postoperative pulmonary complications in non-cardiothoracic surgeries.

Question 60

A 65-year-old woman undergoes an uncomplicated elective total hip arthroplasty. According to major societal guidelines (AAOS/ACCP), what is the minimum recommended duration for pharmacologic venous thromboembolism (VTE) prophylaxis postoperatively?

Explanation

Current guidelines recommend a minimum of 10 to 14 days of VTE prophylaxis following major orthopedic surgery such as total hip arthroplasty, with many protocols suggesting extension up to 35 days for high-risk patients.

Question 61

A 22-year-old man sustains a closed comminuted femur fracture in a motor vehicle collision. On postoperative day 2, he becomes acutely confused, tachypneic, and develops a petechial rash over his axillae and chest. Arterial blood gas shows a pO2 of 55 mmHg. Which of the following best describes the dual pathophysiology of this syndrome?

Explanation

Fat Embolism Syndrome (FES) has a biphasic pathophysiology. It begins with mechanical occlusion of the pulmonary microvasculature by fat droplets, followed by a biochemical phase where lipase degrades the fat into highly toxic free fatty acids that damage the pneumocytes.

Question 62

A 45-year-old immigrant presents with a 6-month history of insidious mid-back pain, low-grade fevers, and recent-onset lower extremity weakness. MRI reveals destruction of the T8 and T9 vertebral bodies with relative preservation of the intervertebral disc initially, along with a large paraspinal fluid collection. What is the most likely diagnosis?

Explanation

Tuberculous spondylitis (Pott disease) typically presents with insidious back pain, constitutional symptoms, and paraspinal abscesses. Unlike pyogenic infections, TB often begins in the anterior vertebral body and characteristically spares the disc space until late in the disease.

Question 63

A 65-year-old heavy smoker presents with an unprovoked pathologic fracture of the proximal humerus. Radiographs show a destructive lytic lesion. He has no known history of malignancy. What is the most appropriate next step in his workup before considering operative fixation?

Explanation

In a patient presenting with an unknown primary malignancy and a pathologic fracture, complete staging must be performed before any surgical intervention. CT of the chest, abdomen, pelvis, and a bone scan will identify the primary source and extent of skeletal disease.

Question 64

A 70-year-old man requires a total hip arthroplasty. His past medical history is significant for Heparin-Induced Thrombocytopenia (HIT) diagnosed 2 years ago during a hospital admission. Which of the following is the most appropriate pharmacologic deep vein thrombosis (DVT) prophylaxis for this patient?

Explanation

Fondaparinux is a synthetic pentasaccharide that does not cross-react with HIT antibodies, making it a safe and effective DVT prophylaxis agent for patients with a history of HIT. Both unfractionated and low-molecular-weight heparins are strictly contraindicated.

Question 65

A 60-year-old woman with a 25-year history of severe rheumatoid arthritis is scheduled for elective total knee arthroplasty. She reports occasional neck stiffness but no radicular pain. Which of the following preoperative imaging studies is mandatory prior to general anesthesia?

Explanation

Patients with severe rheumatoid arthritis are at high risk for atlantoaxial instability. Flexion-extension lateral cervical spine radiographs are mandatory to rule out subluxation, which could lead to fatal spinal cord compression during endotracheal intubation.

Question 66

A 68-year-old woman on postoperative day 3 following a total knee arthroplasty presents with sudden onset dyspnea, tachypnea, and pleuritic chest pain. ECG shows sinus tachycardia and an S1Q3T3 pattern. What is the most appropriate initial diagnostic study to confirm the suspected diagnosis?

Explanation

The clinical presentation is highly suspicious for a pulmonary embolism. CT pulmonary angiography (CTPA) is the gold standard and most appropriate initial imaging test to confirm the presence of pulmonary emboli in the postoperative setting.

Question 67

A 45-year-old man with ankylosing spondylitis and a classic bamboo spine presents for elective bilateral total hip arthroplasty. Preoperative pulmonary function testing is performed. What pattern of lung disease is most expected in this patient?

Explanation

Ankylosing spondylitis causes fusion of the costovertebral joints and thoracic spine rigidity, leading to severely restricted chest wall expansion. This results in a classic restrictive pulmonary defect on spirometry.

Question 68

A 25-year-old man is rescued after his legs were trapped under a collapsed wall for 14 hours. He has swollen, tense thighs and his urine output drops dramatically, with the urine appearing dark brown. What is the primary mechanism of his acute kidney injury?

Explanation

The patient has crush syndrome leading to rhabdomyolysis. The destruction of skeletal muscle releases massive amounts of myoglobin, which is directly toxic to the renal tubular epithelium and precipitates to form obstructing casts.

Question 69

During closed reduction and percutaneous pinning of a supracondylar humerus fracture, a healthy 6-year-old boy suddenly develops tachycardia, masseter muscle rigidity, and a rapidly rising end-tidal CO2. The anesthesiologist administers the definitive antidote. What is the mechanism of action of this life-saving drug?

Explanation

The patient is experiencing malignant hyperthermia. The definitive treatment is Dantrolene, which works by inhibiting the ryanodine receptor (RyR1), thereby preventing the release of calcium from the sarcoplasmic reticulum and halting muscle hypermetabolism.

Question 70

An 82-year-old man sustains a displaced femoral neck fracture. His medical history includes placement of a bare-metal coronary stent 2 months ago, for which he takes aspirin and clopidogrel. To balance his cardiac and surgical risks, what is the most widely accepted perioperative management of his antiplatelet therapy?

Explanation

In urgent orthopedic trauma such as hip fractures, delaying surgery drastically increases mortality. The standard compromise is to continue aspirin for cardiac protection while holding clopidogrel (or proceeding if the risk of stent thrombosis outweighs bleeding risks), without excessive delays.

Question 71

A 12-year-old boy with sickle cell anemia presents with a 3-day history of high fever, left leg pain, and localized swelling over the proximal tibia. Radiographs show a patchy lucency. While Staphylococcus aureus remains a common cause of osteomyelitis, which organism is characteristically more common in this patient population compared to healthy children?

Explanation

Patients with sickle cell disease are functionally asplenic and suffer from repeated bowel ischemia, which allows for bacterial translocation. This makes them uniquely susceptible to osteomyelitis caused by encapsulated organisms, characteristically Salmonella species.

Question 72

An 80-year-old man with advanced Paget disease of bone presents with increasing exertional dyspnea, peripheral edema, and a bounding pulse. Echocardiography reveals high-output cardiac failure. What is the underlying pathophysiology linking his skeletal disease to this cardiac condition?

Explanation

Paget disease is characterized by hyperactive bone remodeling. The pagetic bone is highly vascular, functioning physiologically like a massive arteriovenous fistula. In severe polyostotic disease, this shunting can lead to high-output heart failure.

Question 73

A 16-year-old boy with severe Hemophilia A presents with a massively swollen, tense, and painful right knee. A diagnostic joint aspiration is considered. Prior to aspiration or any major orthopedic surgical intervention, what percentage of normal Factor VIII activity should be targeted via replacement therapy?

Explanation

In patients with severe Hemophilia A, performing invasive procedures without adequate factor replacement will lead to uncontrolled hemorrhage. For major orthopedic surgery or deep aspirations, the target Factor VIII activity must be restored to 80-100% of normal.

Question 74

A 66-year-old man undergoes an uncomplicated lumbar laminectomy. On postoperative day 2, he develops exquisite pain, severe erythema, and swelling in his right first metatarsophalangeal joint. Joint aspiration confirms negatively birefringent needle-shaped crystals. Which of his home antihypertensive medications most likely precipitated this event?

Explanation

The patient is experiencing an acute gout flare, confirmed by negatively birefringent crystals (monosodium urate). Thiazide diuretics (like hydrochlorothiazide) are a classic trigger for gout as they decrease the renal excretion of uric acid, leading to hyperuricemia.

Question 75

A 35-year-old man sustains a severe traumatic brain injury and a transverse acetabular fracture in a fall. He undergoes open reduction and internal fixation of the acetabulum. To prevent heterotopic ossification, which is highly prevalent in this clinical scenario, what is the most appropriate prophylactic regimen?

Explanation

Patients with combined head trauma and acetabular fractures are at very high risk for heterotopic ossification. Prophylaxis typically consists of NSAIDs (e.g., indomethacin) for several weeks or a single perioperative dose of localized radiation therapy.

Question 76

A 55-year-old woman is treated with a cast for a conservatively managed distal radius fracture. She is highly anxious about developing complex regional pain syndrome (CRPS). Which of the following oral supplements has been shown in some randomized controlled trials to decrease the incidence of CRPS following wrist fractures?

Explanation

Several studies, notably by Zollinger et al., have demonstrated that 500 mg of Vitamin C daily for 50 days following a distal radius fracture significantly reduces the risk of developing complex regional pain syndrome (CRPS).

Question 77

A 24-year-old man with a displaced closed femoral shaft fracture develops a petechial rash across his axillae, confusion, and hypoxemia 48 hours post-admission. What is the most appropriate initial management for this condition?

Explanation

Fat embolism syndrome typically presents with a triad of hypoxemia, neurological abnormalities, and a petechial rash 24 to 72 hours after long bone fractures. The mainstay of treatment is supportive care, primarily focusing on maintaining adequate oxygenation and ventilation. Corticosteroids and heparin have not been proven to change the overall outcome.

Orthopedic Prometric MCQs - Chapter 4 Part 1

Orthopedic Prometric MCQs - Chapter 4 Part 9

Orthopedic Prometric MCQs - Chapter 4 Part 9

Chapter Index