Lower Respiratory Tract Infections and Tuberculosis — WACS Viva & Clinical Scenarios (Respiratory Medicine)

Exam-style lower respiratory tract infections and tuberculosis viva scenarios with examiner probes and model answers for Internal Medicine candidates.

Scenarios covered

• SCENARIO 1: A 68-year-old male with a background of type 2 diabetes presents with a 4-day history of productive cough with rust-coloured sputum, high-grade fever, right pleuritic chest pain, and progressive shortness of breath. On examination, he is confused (Abbreviated Mental Test score 6/10), respiratory rate is 34 breaths/min, blood pressure is 84/52 mmHg, pulse rate is 118 beats/min, and oxygen saturation is 88% on room air. Bronchial breath sounds and dullness to percussion are noted over the right lower zone. Serum urea is 9.4 mmol/L.
• SCENARIO 2: A 34-year-old female presents with persistent productive cough, drenching night sweats, and marked weight loss over the past 8 weeks. Sputum GeneXpert MTB/RIF detects Mycobacterium tuberculosis with rifampicin resistance not detected. Baseline liver function tests reveal ALT 32 IU/L and total bilirubin 14 umol/L. She is initiated on fixed-dose combination anti-tuberculosis therapy (Rifampicin, Isoniazid, Pyrazinamide, Ethambutol). Three weeks later, she presents to the emergency department with persistent nausea, vomiting, scleral icterus, and right upper quadrant abdominal tenderness. Repeat
• SCENARIO 3: A 29-year-old newly diagnosed HIV-positive male with a baseline CD4 count of 28 cells/uL is diagnosed with smear-positive pulmonary tuberculosis and commenced on first-line anti-tuberculosis therapy. Two weeks later, antiretroviral therapy (Dolutegravir, Tenofovir disoproxil fumarate, Lamivudine) is initiated. Three weeks after starting antiretroviral therapy, he experiences high-grade fever, enlarging painful cervical lymphadenopathy, worsening dyspnoea, and new extensive infiltrates on repeat chest radiography, despite adherence to medications and initial sputum smear clearance.
• SCENARIO 4: A 54-year-old male admitted 6 days ago for severe acute pancreatitis on mechanical ventilation in the intensive care unit develops new purulent endotracheal secretions, worsening oxygenation index (PaO2/FiO2 ratio dropping from 280 to 160 mmHg), temperature of 39.1°C, and new patchy alveolar consolidation in the left lower lobe on portable chest radiography.
• SCENARIO 5: A 42-year-old male with poorly controlled advanced HIV disease presents with a 2-week history of dry, non-productive cough, profound exertional breathlessness, and fever. Physical examination reveals tachypnoea (respiratory rate 32 breaths/min) and resting SpO2 of 82% on room air with minimal adventitious sounds on chest auscultation. Arterial blood gas analysis on room air demonstrates pH 7.48, PaO2 52 mmHg, PaCO2 31 mmHg, and HCO3 23 mmol/L.