A 48 year old woman presents with progressive dyspnea for 1 week. There was no cough or chest pain.

She was diagnosed with metastatic cancer of the right breast 1 year ago, for which a radical mastectomy was performed. She completed her 6th cycle of chemotherapy three months ago.

On admission, her oxygen saturation was 82%, which improved to 99% with high flow oxygen. A full blood count and chest x-ray are normal.

Select Relevant Investigations
HRCT chest


There are patchy areas of ground-glass attenuation, in a background of interlobular septal thickening.
Sputum induction & culture


Gram stain: negative
Giemsa & Methenamine Silver stains: negative
Culture results will be available in 3 days.
Arterial blood gas


On room air:
pH: 7.46 (7.35 - 7.45)
pO2: 68 mmHg (> 79 on room air)
PCO2: 32 mmHg (35 - 45)
HCO3: 23 mmol/l (24 - 32)
Bronchoalveolar lavage


A Giemsa stain reveals multiple thick walled cysts and pleomorphic trophozoites with reddish nuclei and bluish cytoplasm. The cyst walls are stained by Methenamine Silver. Blood is not seen in any lavage aliquots.

Select Relevant Management
DVT Prophylaxis
Intubation & Ventilation stat