Pneumocystis pneumonia (PCP) is a fungal lung infection that strikes people with advanced HIV, usually when the CD4 count is under 200 cells/µL. It often starts slowly but can lead to severe low oxygen and respiratory failure.
Key symptoms
- Dry cough that slowly gets worse over weeks
- Shortness of breath, mostly on exertion
- Fever, sweats and fatigue
- Weight loss
- White patches in the mouth (thrush)
What you find on exam
- Fast breathing and heart rate
- Oxygen saturation that drops with walking
- Lung exam often normal or with few crackles
- Oral thrush and other signs of a weak immune system
Tests
- Arterial blood gas to measure oxygen and decide on steroids
- Chest X-ray: diffuse haziness on both sides; CT if X-ray is normal
- HIV test, CD4 count and viral load
- Induced sputum or bronchoscopy to find the organism; LDH often high
Treatment basics
- Trimethoprim-sulfamethoxazole for 21 days
- Prednisone if PaO2 is under 70 mmHg or the A-a gradient is 35 or more
- Oxygen and breathing support as needed
- Start antiretroviral therapy within about 2 weeks
- Prevention with trimethoprim-sulfamethoxazole while CD4 stays under 200
Red flags
- Saturation dropping fast or rising work of breathing
- Sudden chest pain and breathlessness from a pneumothorax
- Confusion or low blood pressure
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Sources: CDC, Guideline for Isolation Precautions (2007) and PPE sequence; NCCPA PANCE Content Blueprint; NBOME COMLEX-USA clinical presentations. Written by Making Synapses. Making Synapses is not affiliated with these organizations.