Immune-Related Adverse Events (irAEs) - Pneumonitis
• More common w/ anti-PD-1, but serious toxicity rare. Combination therapy confers significantly higher risk; risk also increased in combination with targeted therapy for lung ca.
• Timing: Highly variable onset, later than other irAEs.
• Signs/sx: Dyspnea (53%), cough (35%), increased sputum production; life-threatening presentations include acute interstitial pneumonia/ARDS; 1/3rd of patients asymptomatic
• Diagnosis: Low threshold to obtain CT/HRCT, CXR often not helpful; workup Ddx (viral and bacterial PNA, COP, COPD exacerbation, heart failure, lymphangitic carcinomatosis/disease progression, PE): VBG, influenza/RSV PCR, resp viral panel, BCx, SpCx and smear, sputum for PCP if at risk, consider BAL; NT-proBNP, troponin, TTE, CTPE/LENI. Imaging non-specific: GGOs, NSIP-like, COP-like, HP-like.
• Treatment: Oxygen, glucocorticoids (prednisone 1-2 mg/kg/d or methylprednisolone 1mg/kg) prolonged taper, consider empiric abx, diuresis
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