Breathless 3

A 51 year old man presents with a low grade fever, non productive cough and dyspnea for 2 weeks, which rapidly worsened over the last 2 days.

He also felt unwell and experienced anorexia and weight loss over the preceding 3 months.

He has engaged in unprotected sexual intercourse with commercial sex workers over the years, most recently last month.

His chest x-ray shows diffuse interstitial infiltrates in the lung fields, with a normal cardiac silhouette.

Select Relevant Investigations
Full Blood Count

Performed

WBC/DC: 4,250/mm3 (4,600 - 11,000)
70% neutrophils
25% lymphocytes
Hb: 12.6 g/dL (11.5 - 18.5)
Platelets: 350,000/mm3 (150,00 - 450,000)
HIV Screening

Performed

The HIV screening test is positive.
A follow-up western blot assay is also positive.
Arterial Blood Gases

Performed

On 60% oxygen:
PaO2: 60.5 mmHg (> 62 on room air)
PaCO2: 25.1 mmHg (35 - 45)
pH: 7.53 (7.35 - 7.45)
HCO3: 26 mmol/L (18 - 24)
Sputum Induction + Microscopy

Performed

Gram stain: negative
Ziehl-Neelsen stain: negative
Giemsa stain: multiple thick walled cysts and pleomorphic trophozoites with reddish nuclei and bluish cytoplasm
Methenamine Silver stain: Stains the walls of the cysts

Select Relevant Management
Sulfamethoxazole/Trimethoprim
Antituberculous Therapy
Antiretroviral Therapy
Acyclovir