Infectious Disease
Case 31: A Breathless Homosexual Patient
CASE
A 27‐year‐old homosexual man presented with a 6‐month history of worsening breathlessness, chest pain and a non‐productive cough. He had been unsuccessfully treated in the community with antibiotics. On general inspection he had difficulty in breathing with a respiratory rate of 25 breaths/min, his arterial blood pressure was 130/75 mmHg and he had a heart rate of 100 beats/min. His oxygen saturation was 94% on air. This rapidly declined to 77% on minimal exertion. His hypoxia was confirmed by arterial blood gas; with a PaO2 of 8.33 kPa. He had a temperature of 38°C.
Examination of his chest revealed fine inspiratory crackles in both his lung bases. He also had a purplish indurated plaque on his palate. You obtained a chest radiograph which showed clear lung fields. The registrar had appropriately arranged for a HIV test, which came back positive, and he had a CD4 count of 45/mm3.
QUESTION 1
Your score this session: 0 of 0
Which of the following is the most useful investigation in establishing the diagnosis?