Pneumocystis jiroveci (PCP) pneumonia

fever, night sweats, dyspnea on exertion, dry (“doorstop”) cough CXR w/ interstitial pattern, ↓ PaO2, ↑ A-a ∇, ↑ LDH, ⊕ PCP sputum stain, ⊕ β-glucan Rx if PaO2 >70: TMP-SMX 15–20 mg of TMP/kg divided tid, avg dose = DS 2 tabs PO tid Rx if PaO2 <70 or A-a gradient >35: prednisone before abx (40 mg PO bid; ↓ after 5 d) HIV ⊕ smokers much more likely to die from lung cancer than OI (JAMA 2017;177:1613)