Respiratory McQs 2

Question 1

A 68-year-old man has 3 years of progressive exertional dyspnea and a dry cough. He is a non-smoker. On examination there are bilateral basal fine "Velcro" crackles and finger clubbing. HRCT shows bilateral basal honeycombing with traction bronchiectasis and subpleural reticulation. Biopsy shows temporally heterogeneous fibrosis with fibroblastic foci. Most likely diagnosis?

Accepted Answer

Idiopathic pulmonary fibrosis — Basal honeycombing + subpleural reticulation + temporally heterogeneous fibrosis with fibroblastic foci on biopsy = UIP pattern, the histologic hallmark of IPF. Velcro crackles and clubbing are characteristic clinical features.

Question 2

A 62-year-old woman with IPF has worsening dyspnea over 2 weeks without infection. HRCT now shows new bilateral ground-glass opacities superimposed on her existing fibrosis. Most likely complication?

Accepted Answer

Acute exacerbation of IPF — New bilateral ground-glass opacities superimposed on pre-existing UIP fibrosis without an identifiable cause = acute exacerbation of IPF. It carries very high short-term mortality.

Question 3

Pulmonary function testing in a patient with IPF is most likely to show which pattern?

Accepted Answer

Restrictive pattern with reduced TLC and reduced DLCO — Fibrosis reduces lung compliance causing restrictive physiology. Reduced DLCO reflects destruction of the alveolar-capillary membrane. FEV1/FVC ratio is preserved or increased.

Question 4

A 71-year-old man who worked as a shipyard insulator for 30 years presents with progressive dyspnea and right-sided pleuritic chest pain. CXR shows a large right pleural effusion. CT scan shows diffuse pleural thickening encasing the right lung. Pleural biopsy shows spindle and epithelioid cells staining positive for calretinin and WT-1 and negative for CEA. Most likely diagnosis?

Accepted Answer

Malignant mesothelioma — Asbestos exposure + diffuse pleural thickening encasing the lung + calretinin/WT-1 positive and CEA negative = malignant mesothelioma. Latency period after asbestos exposure is typically 25–45 years.

Question 5

Which immunohistochemical marker distinguishes malignant mesothelioma from metastatic adenocarcinoma to the pleura?

Accepted Answer

Calretinin positive — Mesothelioma is positive for calretinin, WT-1, and D2-40. Metastatic adenocarcinoma is positive for CEA, TTF-1, and Napsin-A. These markers are essential in distinguishing the two.

Question 6

A 55-year-old man with heart failure has a right-sided pleural effusion. Thoracentesis shows fluid protein of 2.1 g/dL, serum protein 7.0 g/dL, fluid LDH 88 U/L, and serum LDH 300 U/L. Most likely type of effusion?

Accepted Answer

Transudate — Fluid/serum protein ratio less than 0.5 and fluid/serum LDH ratio less than 0.6 (Light's criteria) = transudate. Heart failure, nephrotic syndrome, and cirrhosis cause transudative effusions by hydrostatic or oncotic mechanisms.

Question 7

A 48-year-old woman with breast cancer develops a right pleural effusion. Thoracentesis yields fluid protein of 5.2 g/dL, serum protein 6.8 g/dL, fluid LDH 420 U/L, and serum LDH 310 U/L. Cytology shows malignant cells. Most likely type of effusion?

Accepted Answer

Exudate — Fluid/serum protein ratio greater than 0.5 and fluid/serum LDH ratio greater than 0.6 (Light's criteria) = exudate. Malignancy, infection, and inflammation cause exudative effusions by increasing capillary permeability.

Question 8

A 35-year-old man undergoes thoracic duct injury during left-sided neck dissection surgery. Two days later he develops a left pleural effusion. Thoracentesis yields milky white fluid with triglycerides of 210 mg/dL. Most likely diagnosis?

Accepted Answer

Chylothorax — Milky white pleural fluid with triglycerides greater than 110 mg/dL = chylothorax due to thoracic duct injury or obstruction. Lymphoma is the most common non-traumatic cause.

Question 9

A 45-year-old man has a 3-month history of recurrent sinusitis, epistaxis, haemoptysis, and haematuria. CXR shows bilateral cavitating nodules. Urinalysis shows red cell casts. c-ANCA (PR3-ANCA) is strongly positive. Most likely diagnosis?

Accepted Answer

Granulomatosis with polyangiitis — Upper airway disease + pulmonary cavitating nodules + glomerulonephritis + c-ANCA/PR3 positive = GPA (formerly Wegener granulomatosis). The classic triad is upper airway, lower airway, and renal involvement.

Question 10

A 38-year-old woman with asthma develops peripheral blood eosinophilia of 18%, p-ANCA positivity, and a new mononeuritis multiplex. CXR shows transient pulmonary infiltrates. Most likely diagnosis?

Accepted Answer

Eosinophilic granulomatosis with polyangiitis — Asthma + eosinophilia + p-ANCA + neuropathy + transient pulmonary infiltrates = EGPA (formerly Churg-Strauss syndrome). Asthma is the hallmark preceding systemic vasculitis.

Question 11

A 24-year-old male smoker presents with haemoptysis and progressive dyspnea. Urinalysis shows proteinuria and red cell casts. CXR reveals bilateral alveolar infiltrates. Anti-GBM antibodies are strongly positive. Renal biopsy shows linear IgG deposits along the glomerular basement membrane. Most likely diagnosis?

Accepted Answer

Goodpasture syndrome — Pulmonary haemorrhage + rapidly progressive glomerulonephritis + anti-GBM antibodies + linear IgG deposits = Goodpasture syndrome. Type II hypersensitivity against alpha-3 chain of type IV collagen in GBM and alveolar basement membrane.

Question 12

A 55-year-old granite quarry worker has 20 years of exposure to silica dust. He now has progressive dyspnea and a dry cough. CXR shows upper lobe predominant nodules with eggshell calcification of hilar lymph nodes. Pulmonary function shows a restrictive pattern. Most likely diagnosis?

Accepted Answer

Silicosis — Upper lobe nodules + eggshell calcification of hilar nodes + silica dust exposure = silicosis. Histologically shows birefringent silica particles in whorled hyalinized collagen nodules. Predisposes to tuberculosis.

Question 13

A 32-year-old woman with no cardiopulmonary disease has progressive exertional dyspnea, syncope on exertion, and loud P2 on auscultation. Right heart catheterization shows mean pulmonary artery pressure of 38 mmHg with normal pulmonary capillary wedge pressure. Most likely diagnosis?

Accepted Answer

Primary (idiopathic) pulmonary arterial hypertension — Young woman + elevated mPAP with normal PCWP (excluding left heart disease) + no secondary cause = idiopathic PAH. Associated with BMPR2 mutations. Plexiform lesions are the histologic hallmark.

Question 14

A 70-year-old man with severe COPD has increasing drowsiness. ABG shows pH 7.28, PaO2 55 mmHg, PaCO2 72 mmHg, and HCO3 32 mEq/L. Most likely type of respiratory failure?

Accepted Answer

Type 2 (hypercapnic) respiratory failure — Elevated PaCO2 greater than 45 mmHg + hypoxaemia + raised bicarbonate indicating chronic compensation = Type 2 respiratory failure. Caused by pump failure from COPD, neuromuscular disease, or chest wall disorders.

Question 15

A 28-year-old woman develops sudden dyspnea following amniotic fluid embolism. ABG shows pH 7.48, PaO2 52 mmHg, and PaCO2 28 mmHg. CXR shows bilateral infiltrates. Most likely type of respiratory failure?

Accepted Answer

Type 1 (hypoxaemic) respiratory failure — Low PaO2 with low or normal PaCO2 = Type 1 hypoxaemic respiratory failure. Caused by V/Q mismatch or shunt, as in pneumonia, pulmonary oedema, ARDS, and pulmonary embolism.

Question 16

A 52-year-old obese man (BMI 38 kg/m²) presents with daytime somnolence, loud snoring, and morning headaches. His wife reports he stops breathing repeatedly during sleep. ABG shows mild hypoxaemia and hypercapnia. Polysomnography shows apnoea-hypopnoea index (AHI) of 38 events/hour. Most likely diagnosis?

Accepted Answer

Obstructive sleep apnoea — Obesity + snoring + witnessed apnoeas + daytime somnolence + AHI greater than 30 = severe OSA. Upper airway collapse during sleep causes repetitive hypoxaemia, hypercapnia, and arousal.

Question 17

A 35-year-old woman has recurrent episodes of flushing, wheezing, and diarrhoea. CXR shows a 1.5 cm endobronchial mass in the right mainstem bronchus causing recurrent right lower lobe atelectasis. Urine 5-HIAA is markedly elevated. Bronchoscopy reveals a vascular pink-tan submucosal mass. Most likely diagnosis?

Accepted Answer

Bronchial carcinoid tumour — Endobronchial vascular mass + flushing/wheezing/diarrhoea + elevated urine 5-HIAA = bronchial carcinoid. It is a low-grade neuroendocrine tumour arising in central bronchi, more common in younger patients and non-smokers.

Question 18

A 30-year-old woman of childbearing age presents with progressive dyspnea, recurrent pneumothoraces, and chylous pleural effusions. HRCT shows diffuse thin-walled cysts throughout both lungs with no zonal predominance. Spirometry shows an obstructive pattern. Most likely diagnosis?

Accepted Answer

Lymphangioleiomyomatosis — Young woman + diffuse bilateral thin-walled cysts + recurrent pneumothoraces + chylous effusions = LAM. Caused by TSC2 mutations leading to smooth muscle proliferation around airways and lymphatics. Worsens with oestrogen.

Question 19

A 60-year-old coal miner with 35 years of underground work has progressive dyspnea and a productive cough. CXR shows upper lobe predominant small nodular opacities and a large conglomerate mass in the right upper lobe greater than 1 cm. Spirometry shows a mixed obstructive and restrictive pattern. Most likely diagnosis?

Accepted Answer

Complicated coal workers pneumoconiosis — Small upper lobe nodules progressing to large conglomerate masses (progressive massive fibrosis greater than 1 cm) in a coal miner = complicated CWP. Simple CWP has nodules smaller than 1 cm without conglomeration.

Question 20

A 45-year-old aerospace engineer has 3 months of dyspnea, weight loss, and hilar lymphadenopathy. CXR and HRCT show bilateral upper lobe reticulonodular infiltrates. Transbronchial biopsy shows non-caseating granulomas. No organisms are found. Beryllium lymphocyte proliferation test (BeLPT) is positive. Most likely diagnosis?

Accepted Answer

Chronic berylliosis — Non-caseating granulomas + occupational exposure to beryllium (aerospace, electronics) + positive BeLPT = chronic berylliosis. Clinically and histologically identical to sarcoidosis but distinguished by occupational history and BeLPT.

Respiratory McQs 2

Questions, Answers & Explanations