Thank you to Cary Kraft and Jake Mayfield for presenting a great case of a patient with advanced HIV/AIDS who presented with shortness of breath, hypoxic on RA, and ultimately found to have PCP!
Top Learning Pearls
- In HIV with a lower CD4 count, Occam’s razor falls apart. Consider multiple different simultaneous disease processes!
- Pts with moderate severity PCP defined by A-a O2 gradient >35 or pAO2 <70, require adjunctive corticosteroids’
- Remember the hemoglobin dissociation curve and the handy trick of 30-60 60-90 (~pAO2 30 = SaO2 60, pAO2 60 = SaO2 90)
- elevated LDH is suggestive with >80% sensitivity, but poor specificity for PCP
- Beta-d-glucan can be elevated in PCP (but also elevated in other fungal infections, as is a cell wall component), has a sensitivity >90% but specificity of only 65-90%
- radiographic: on CXR diffuse bilateral interstitial infiltrates, on CT should see extensive GGO or cysts
- DEFINITIVE diagnosis requires microscopy and staining, most commonly from bronchoscopy with BAL
- Mild disease: A-a O2 gradient < 35 and/or pAO2 >70: treat with TMP-SMX
- Moderate disease: A-a O2 gradient >35 and <45 and/or pAO2 >60 and <70: treat with TMP/SMX + adjunctive corticosteroids.
- Severe disease: A-a O2 gradient > 45, pAO2 <60, and/or there is potential for fatigue leading to respiratory failure: treat with TMP/SMX (IV if necessary) + steroids
Once patients complete initial 21 days of treatment, they should continued reduced dose for prophylaxis.
A Brief Note on Mycobacterium Kansasii..
- Usually presents as lung disease, very similar to TB, but in HIV positive individuals can cause disseminated disease
- Common clinical presentation is chest pain, cough, hemoptysis, fever/night sweats. Cavitation is common!
- Is found in cities throughout the US, is found in tap water