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1. General Principles & Basic Science MCQs

Practice Set 36 of 789

This practice set contains high-yield board review questions covering key concepts in 1. General Principles & Basic Science. Each clinical scenario is designed to test your diagnostic and management skills relevant to this subspecialty.

Question 701

Topic: Biology, Genetics & Bone Healing
Children with severe osteogenesis imperfecta (Type III) are commonly treated with intravenous bisphosphonates. This medication primarily exerts its effect by which of the following mechanisms?
. Stimulating osteoblast differentiation
. Increasing type I collagen cross-linking
. Promoting osteoclast apoptosis
. Upregulating FGF23 production
. Enhancing renal calcium reabsorption

Correct Answer & Explanation

. Promoting osteoclast apoptosis

Explanation

Bisphosphonates are analogues of inorganic pyrophosphate that inhibit bone resorption by promoting osteoclast apoptosis. This increases overall bone mineral density and reduces fracture rates in patients with osteogenesis imperfecta.

Question 702

Topic: Biology, Genetics & Bone Healing

A 3-year-old child presents with severe bowing of the legs, short stature, and a waddling gait. Laboratory tests reveal normal serum calcium, very low serum phosphate, normal PTH, and elevated alkaline phosphatase. Genetic testing shows a mutation in the PHEX gene. What is the primary pathophysiologic mechanism of this disorder?

. Inadequate dietary vitamin D intake
. Defective renal 1-alpha-hydroxylase activity
. End-organ resistance to calcitriol
. Excessive production of Fibroblast Growth Factor 23 (FGF23)
. Autoimmune destruction of parathyroid glands

Correct Answer & Explanation

. Excessive production of Fibroblast Growth Factor 23 (FGF23)

Explanation

The presentation describes X-linked hypophosphatemic rickets caused by a PHEX gene mutation. This defect leads to excessive circulating levels of FGF23, which promotes massive renal phosphate wasting and inhibits calcitriol synthesis.

Question 703

Topic: Biology, Genetics & Bone Healing

A 5-year-old boy with a history of recurrent fractures and blue sclerae is diagnosed with Osteogenesis Imperfecta type I. Which of the following medical treatments has been shown to most effectively decrease fracture incidence and increase bone mineral density in this population?

. Recombinant human parathyroid hormone
. Intravenous pamidronate
. High-dose Vitamin D and Calcium
. Growth hormone therapy
. Denosumab

Correct Answer & Explanation

. Intravenous pamidronate

Explanation

Intravenous bisphosphonates, such as pamidronate, have been shown to significantly reduce fracture rates, alleviate bone pain, and increase vertebral bone mineral density in children with osteogenesis imperfecta.

Question 704

Topic: 1. General Principles & Basic Science
A 72-year-old woman who smokes 5–10 cigarettes per day and has a past history of whooping cough presents with chronic cough and recurrent chest infections for review. She admits to producing frequent amounts of purulent sputum and of intermittently suffering night sweats for a number of months. There have also been occasional episodes of haemoptysis. Chest X-ray reveals hyperinflation, crowded lung markings and small, cyst-like spaces at the lung bases. What is the most likely underlying pathology?
. Asthma
. Bronchial carcinoma
. Bronchiectasis
. Chronic lung abscess
. Tuberculosis

Correct Answer & Explanation

. Bronchiectasis

Explanation

The past history of whooping cough and smoking, coupled with the X-ray changes, are very suggestive of bronchiectasis. Non-pharmacological management involves self-physiotherapy and adequate hydration. Chronic intermittent oral antibiotic therapy is used by some physicians, although it might encourage the development of multi-drug resistance and its use is not universally endorsed. Influenza and pneumococcal vaccinations are strongly recommended. Surgical referral might be recommended for patients with chronic severe localised infection that fails to resolve after intravenous antibiotic therapy.

Question 705

Topic: 1. General Principles & Basic Science

A 52-year-old patient from a chemical factory presents with cough and is found to have a squamous lung carcinoma. He is quite sure that it is work related. He smoked five cigarettes per day until he was aged 34, having started smoking at the age of 16. What is the most likely cause?

. Aromatic amines
. Coal dust
. Isocyanates
. Polyvinyl chloride
. Smoking

Correct Answer & Explanation

. Isocyanates

Explanation

Correct Answer: C- Isocyanates Explanation Isocyanates Isocyanates are a recognised risk factor for the development of non-small-cell lung cancer. Other aetiological factors include smoking, asbestos exposure and exposure to polycyclic hydrocarbons or the products of coal burning. Exposure to isocyanate fumes occurs in chemical workers, particularly those who work in the rubber industry, and this exposure is most likely to be associated with squamous-cell carcinoma of the bronchus. Most squamous-cell carcinomas present as obstructive lesions, which can manifest as infection. Around 10% of cases present with cavitating lesions, but widespread metastases occur relatively late. Aromatic amines Aromatic amines is incorrect. Aromatic amines are associated with bladder carcinoma. Coal dust Coal dust is incorrect. There is nothing in the history to suggest coal dust exposure. Polyvinyl chloride Polyvinyl chloride is incorrect. Exposure to vinyl chloride is associated with angiosarcoma of the liver. Smoking Smoking is incorrect. He has a relatively low smoking exposure in terms of patient years; as such, it is isocyanates which are likely to have had a larger impact on his lung cancer risk.

Question 706

Topic: 1. General Principles & Basic Science
An 81-year-old woman who had consulted her GP with symptoms of flu 2 weeks earlier now presents to the Emergency Department. For the past few days she has had increasing cough, associated with purulent sputum and haemoptysis. Her daughter visited and noticed that she had become acutely confused and arranged an ambulance. On arrival to the department she is found to be agitated, with a respiratory rate of 35/min. Blood gases reveal that she is hypoxic, her white blood cell count is 20 × 10^9/l, predominantly neutrophils. Her creatinine concentration is 250 μmol/l. Chest X-ray reveals patchy areas of consolidation, with necrosis and empyema formation. What diagnosis best fits this clinical picture?
. Chlamydia psittaci pneumonia
. Haemophilus influenzae pneumonia
. Mycoplasma pneumonia
. Staphylococcus aureus pneumonia
. Streptococcus pneumoniae pneumonia

Correct Answer & Explanation

. Streptococcus pneumoniae pneumonia

Explanation

Correct Answer: D. Staphylococcal pneumonia typically occurs after a preceding viral illness. Patchy areas of consolidation occur that eventually break down into abscesses. Pneumothorax, pleural effusion, and empyema are common in staphylococcal pneumonia.

Question 707

Topic: Infection, Pharmacology & VTE
A 50-year-old retired boilermaker with shortness of breath comes to the Respiratory Clinic. He has smoked ten cigarettes per day for the past 30 years. The GP wonders if he has obstructive lung disease and the man arrives with his spirometry results, which show: forced expiratory volume in 1 s (FEV1) 1.74 l (predicted 3.0 l), forced vital capacity (FVC) 2.5 l (predicted 2.8 l); post-salbutamol FEV1 1.81 l, post-salbutamol FVC 2.7 l; transfer factor 55%. Which of the following is the most likely diagnosis?
. Asbestos-related pleural plaque disease
. Asthma
. Emphysema
. Pulmonary embolism
. Pulmonary fibrosis

Correct Answer & Explanation

. Emphysema

Explanation

Correct Answer: C. The FVC is only slightly reduced, but the ratio of FEV1 to FVC is significantly reduced. Transfer factor is also reduced at 55%. With reversibility of less than 10% post-salbutamol, the most likely diagnosis is chronic obstructive pulmonary disease (COPD), specifically emphysema.

Question 708

Topic: 1. General Principles & Basic Science

A 60-year-old woman presents with chronic progressive shortness of breath and bibasal crepitations. Which of the following is the most likely diagnosis?

. Extrinsic allergic alveolitis
. Idiopathic pulmonary fibrosis
. Progressive massive fibrosis
. Sarcoidosis
. Tuberculosis

Correct Answer & Explanation

. Idiopathic pulmonary fibrosis

Explanation

Correct Answer: B- Idiopathic pulmonary fibrosis Explanation Idiopathic pulmonary fibrosis Idiopathic pulmonary fibrosis is characterised by an inflammatory cell infiltrate. The main symptoms are dry cough, exertional dyspnoea and malaise. Signs include cyanosis, finger clubbing and fine end-inspiratory crepitation at the bases and in the axillae. Bilateral lower- zone reticulonodular shadows are seen on chest X-ray. Lung damage is often irreversible but pirfenidone is recommended between 50% and 80% predicted. Lung transplantation may be considered. Overall, the median survival is 2–3 years following diagnosis. Extrinsic allergic alveolitis Extrinsic allergic alveolitis is incorrect. Extrinsic allergic alveolitis shows a predilection for the upper zones,although, when severe, can affect all zones. Progressive massive fibrosis Progressive massive fibrosis is incorrect. Progressive massive fibrosis describes a stage of a number of occupational lung diseases which are caused by mineral dusts – silicosis and coal-worker’s pneumoconiosis. When the irregular or linear opacities become large shadows late in the course of these diseases this is then called ‘progressive massive fibrosis’. Sarcoidosis Sarcoidosis is incorrect. Sarcoidosis affects upper zones and midzones, although, when severe, it can affect all zones. Tuberculosis Tuberculosis is incorrect. Tuberculosis shows a predilection for the upper zones, although, when severe, it can affect all zones.

Question 709

Topic: 1. General Principles & Basic Science
Surgical resection in carcinoma of the lung is most likely to be contraindicated in the presence of which one of the following?
. Adenocarcinoma
. Forced expiratory volume in 1 s 25% of predicted
. Ischaemic heart disease
. Pulmonary artery involvement
. Superior vena cava obstruction

Correct Answer & Explanation

. Forced expiratory volume in 1 s 25% of predicted

Explanation

Correct Answer: B. The functional criteria for pneumonectomy generally require an FEV1 > 1.5 l or > 50% of predicted. An FEV1 of 25% of predicted is significantly below the threshold required for safe surgical resection.

Question 710

Topic: 1. General Principles & Basic Science

A 22-year-old student attends the clinic for his 6-week check after admission with pneumonia. Which of the following complications of pneumonia is most likely to be a chronic rather than an acute complication of the infective process?

. Bronchiectasis
. Bronchopleural fistula
. Empyema
. Lung abscess
. Organising pneumonia

Correct Answer & Explanation

. Bronchiectasis

Explanation

Correct Answer: A- Bronchiectasis Explanation Bronchiectasis This is a ‘know it or you don’t’ question. The diagnosis of bronchiectasis can only be made after the illness because temporary or reversible bronchial dilatation is sometimes seen during the acute illness. Bronchopleural fistula Bronchopleural fistula is incorrect. Bronchopleural fistula is an acute complication of the infective process. Empyema Empyema is incorrect. Empyema is an acute complication of the infective process. Lung abscess Lung abscess is incorrect. Lung abscess is an acute complication of the infective process. Organising pneumonia Organising pneumonia is incorrect. Organising pneumonia is an acute complication of the infective process.

Question 711

Topic: 1. General Principles & Basic Science

A 54-year-old man who has a suspicious area on his chest X-ray, thought to be a tumour on CT scanning, is referred for PET imaging. Which of the following is the usual tracer used for PET imaging in lung cancer?

. Alanine
. Aspartame
. Fluorodeoxyglucose
. Fluorodopa
. Metomidate

Correct Answer & Explanation

. Fluorodeoxyglucose

Explanation

Correct Answer: C- Fluorodeoxyglucose Explanation Fluorodeoxyglucose Rapidly dividing tumour cells of course require large amounts of glucose to satisfy their energy needs. As such it is avidly taken up by tumour cells and phosphorylated by hexokinase, which then allows it to be visualised on PET scanning. Alanine Alanine is incorrect. Alanine is not a tracer used for PET imaging in lung cancer. Aspartame Aspartame is incorrect. Aspartame is not a tracer used for PET imaging in lung cancer. Fluorodopa Fluorodopa is incorrect. Fluorodopa (FDOPA) is a tracer used in the imaging of adrenal tumours. Metomidate Metomidate is incorrect. Metomidate is a tracer used in the imaging of adrenal tumours.

Question 712

Topic: 1. General Principles & Basic Science
A 65-year-old man complains of lethargy, fever, dry cough, headache, chest pain and increasing shortness of breath. He returned from a cruise 2 days ago. His chest X-ray shows bilateral infiltrates, the pO2 is 8.35 kPa. What is the most appropriate therapy?
. Amphotericin B
. Ampicillin
. Erythromycin
. Intravenous corticosteroids
. Isoniazid

Correct Answer & Explanation

. Erythromycin

Explanation

Correct Answer: C. This patient has Legionella pneumonia. A macrolide antibiotic, such as erythromycin or clarithromycin, is the drug of first choice due to its ability to penetrate intracellularly into alveolar macrophages.

Question 713

Topic: 1. General Principles & Basic Science
A 29-year-old woman with brittle asthma is admitted to the Emergency Department with a viral exacerbation of her asthma. Her usual peak flow is around 490 l/min and she is managed with a high-dose Seretide inhaler. On examination her blood pressure is 145/80 mmHg, pulse 105 bpm and regular. She has a respiratory rate of 40/min and looks exhausted. On auscultation you can hear wheeze and decreased air entry. Her peak flow is measured at 180 l/min. Investigation: Hb 13.1 g/dl, WCC 8.1 x 10^9/l, PLT 249 x 10^9/l, Sodium 141 mmol/l, Potassium 3.9 mmol/l, Creatinine 110 μmol/l, paO2 10.5 kPa, pCO2 6.4 kPa. Her peak flow has not improved 30 min after admission despite salbutamol and Atrovent nebulisers and intravenous hydrocortisone. You arrange review by the Intensive Therapy Unit registrar. While you are waiting for her visit, which of the following is the most appropriate next management step?
. Inhaled helium/oxygen mixture
. Intravenous aminophylline
. Intravenous magnesium
. Intravenous salbutamol
. Non-invasive positive-pressure ventilation

Correct Answer & Explanation

. Intravenous magnesium

Explanation

Correct Answer: C. Intravenous magnesium is recommended in acute severe asthma that has not responded to initial inhaled bronchodilator therapy.

Question 714

Topic: 1. General Principles & Basic Science
A 62-year-old woman is admitted with confusion and increased respiratory rate. She has been managed by her GP for shortness of breath and is taking ramipril and indapamide for hypertension and has a salbutamol inhaler. She came to the Emergency Department with her daughter because of concerns that she was getting worse. On examination her blood pressure is 112/62 mmHg and she has a pyrexia of 37.8 °C. The pulse is 75 bpm and regular and the heart sounds are normal. Auscultation of the chest reveals scattered crackles and wheeze. Investigations show: Hb 13.1 g/dl, WCC 9.2 x 10^9/l, Platelets 201 x 10^9/l, Sodium 138 mmol/l, Potassium 4.5 mmol/l, Bicarbonate 24 mmol/l, Creatinine 130 μmol/l, Po2 9.1 kPa, Pco2 7.2 kPa, pH 7.2. Which of the following is the most likely diagnosis?
. Acute on chronic respiratory acidosis
. Acute respiratory acidosis
. Chronic respiratory acidosis
. Metabolic acidosis
. Mixed metabolic and respiratory acidosis

Correct Answer & Explanation

. Acute respiratory acidosis

Explanation

Correct Answer: B. This woman is hypercapnic with a decreased pH. This has occurred too quickly for metabolic compensation to occur via renal bicarbonate reabsorption, which takes 3–5 days. It is therefore an acute respiratory acidosis.

Question 715

Topic: 1. General Principles & Basic Science

A 50-year-old woman comes to the clinic complaining of breathlessness on exertion, which has been worsening for 1 year. This is accompanied by wheeze which worsens with exercise, and during the course of the summer when she also has severe hayfever. She has never smoked. The chest X-ray shows mild hyperinflation but is otherwise unremarkable. Her lung function test results are shown below:

Test Result Predicted

FEV1 (l) 1.1 1.7-3.0

FVC (l) 2.7 2.0-3.5 FRC (l) 4.2 1.7-3.4

TLC (l) 6.5 3.6-5.6

Tlco (mmol/min per kPa) 5.86 5.7-9.5 Kco (mmol/min per kPa per l) 1.63 1.66 What is the most likely diagnosis?

. Asthma
. Bronchiectasis
. Chronic obstructive pulmonary disease
. Interstitial lung disease
. Pulmonary haemorrhage

Correct Answer & Explanation

. Asthma

Explanation

Correct Answer: A- Asthma Explanation Asthma This woman has obstructive spirometry, with raised lung volumes. This is suggestive of asthma or chronic obstructive pulmonary disease (COPD). She has never smoked and has a normal transfer factor and so she is more likely to have asthma. Bronchiectasis Bronchiectasis is incorrect. Bronchiectasis can lead to a mild obstructive defect, but would not tend to show such marked hyperinflation. History would usually include a chronic productive cough. Chronic obstructive pulmonary disease Chronic obstructive pulmonary disease is incorrect. Non- smokers can develop COPD, but they tend to have a heavy passive smoke exposure and be older. Interstitial lung disease Interstitial lung disease is incorrect. Interstitial lung disease would lead to a restrictive defect with a reduced transfer factor. Pulmonary haemorrhage Pulmonary haemorrhage is incorrect. There are no features in the history to suggest pulmonary haemorrhage, which would have a much shorter history plus potentially coexistent symptoms of vasculitis or renal failure. Pulmonary haemorrhage would lead to a raised Tlco and Kco (transfer factor and transfer coefficient for carbon monoxide).

Question 716

Topic: 1. General Principles & Basic Science
A 40-year-old man presents with a 2-month history of cough and breathlessness. He has also noted haemoptysis, which he says has gradually worsened. On examination he has bilateral basal crepitations. His chest X-ray shows diffuse shadowing. He has moderate renal failure. What is the most likely diagnosis?
. Bronchial carcinoma
. Goodpasture syndrome
. Legionella pneumonia
. Pulmonary embolism
. Tuberculosis

Correct Answer & Explanation

. Goodpasture syndrome

Explanation

Correct Answer: B. Goodpasture syndrome consists of diffuse pulmonary haemorrhage and glomerulonephritis with linear deposition of antibodies along the glomerular basement membrane. The combination of renal failure and pulmonary haemorrhage is classic for this condition.

Question 717

Topic: 1. General Principles & Basic Science
A 28-year-old woman comes to the clinic for review 4 weeks after discharge from the ward following an asthma attack. She was diagnosed with asthma at the age of 7 years and has been taking inhaled beclometasone 400 μg and salbutamol as required since then. She tells you that since discharge she has been using her salbutamol three times a day and has been waking two or three times a night with coughing. On examination, her peak flow is 340 l (predicted is 570 l). She has scattered wheeze throughout both lung fields on examination. She had a good inhaler technique with volumatic as assessed in the clinic. Investigation: Hb 13.1 g/dl, WCC 6.5 x 10^9/l, PLT 231 x 10^9/l, ESR 12 mm in 1 hour, Sodium 140 mmol/l, Potassium 4.9 mmol/l, Creatinine 80 μmol/l. The chest X-ray shows no evidence of consolidation. Which of the following is the most appropriate management plan for her?
. Add low-dose oral theophylline to her regimen
. Add omalizumab
. Add oral montelukast to her regimen
. Add twice-daily inhaled salmeterol to her regimen
. Change her to 800 μg of fluticasone

Correct Answer & Explanation

. Add oral montelukast to her regimen

Explanation

Correct Answer: C. Adding oral montelukast is recommended as a trial in patients who have failed to gain control on low-dose inhaled corticosteroids according to current guidelines.

Question 718

Topic: 1. General Principles & Basic Science

A 30-year-old carpenter lacerates his volar index finger, resulting in a Zone II flexor tendon injury. Following primary repair of the flexor digitorum profundus and superficialis, which rehabilitation protocol is most appropriate to minimize adhesion formation while protecting the repair?

. Immobilization in extension for 4 weeks
. Early active extension with rubber band passive flexion
. Immediate unrestricted active range of motion
. Immobilization in flexion for 6 weeks
. Continuous passive motion without active involvement

Correct Answer & Explanation

. Early active extension with rubber band passive flexion

Explanation

Early controlled motion protocols, such as the Kleinert or modified Duran protocols, are standard for Zone II repairs. This stresses the repair enough to prevent dense adhesions while avoiding excessive tension that could lead to rupture.

Question 719

Topic: Biology, Genetics & Bone Healing
During secondary bone healing of a long bone fracture treated with a cast, a soft callus forms. Which type of collagen is the predominant structural component of this early soft callus?
. Type I collagen
. Type II collagen
. Type III collagen
. Type IV collagen
. Type X collagen

Correct Answer & Explanation

. Type II collagen

Explanation

In secondary bone healing, the soft callus is composed primarily of cartilaginous tissue, which is predominantly made of Type II collagen. As endochondral ossification progresses, this is gradually replaced by Type X and eventually Type I collagen.

Question 720

Topic: Biology, Genetics & Bone Healing

A 35-year-old woman is diagnosed with an unresectable giant cell tumor of the sacrum. Her oncologist prescribes denosumab. What is the mechanism of action of this medication in the treatment of giant cell tumor of bone?

. Inhibition of vascular endothelial growth factor (VEGF)
. Direct apoptosis of the multinucleated giant cells
. Monoclonal antibody targeting the RANK ligand
. Inhibition of the mammalian target of rapamycin (mTOR) pathway
. Stimulation of osteoprotegerin (OPG) breakdown

Correct Answer & Explanation

. Monoclonal antibody targeting the RANK ligand

Explanation

Denosumab is a human monoclonal antibody that binds to the Receptor Activator of Nuclear factor Kappa-B Ligand (RANKL). This prevents the activation and maturation of the osteoclast-like giant cells that cause bone destruction.

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