ICU · oncology

Immune Checkpoint Inhibitor Toxicity in the ICU

Also known as Checkpoint inhibitor toxicity · Immune-related adverse events (irAEs) · ICI pneumonitis · ICI myocarditis · ICI colitis · Immunotherapy toxicity · Anti-PD-1 toxicity · Anti-CTLA-4 toxicity · Nivolumab toxicity · Pembrolizumab toxicity · Ipilimumab toxicity

Immune checkpoint inhibitor (ICI) toxicity — immune-related adverse events (irAEs) from CTLA-4 (ipilimumab), PD-1 (nivolumab, pembrolizumab), and PD-L1 (atezolizumab, durvalumab) inhibitors causing pneumonitis, colitis, hepatitis, endocrinopathy (thyroiditis, hypophysitis, adrenalitis), myocarditis, nephritis, neurotoxicity, and dermatological reactions. ICU presentation: respiratory failure (pneumonitis), shock (myocarditis, adrenal crisis), severe colitis with perforation, encephalitis, Guillain-Barre syndrome variant, and Stevens-Johnson syndrome. Management framework: stop ICI, grade severity, corticosteroids (oral prednisone 0.5-1 mg/kg/day for grade 2; IV methylprednisolone 1-2 mg/kg/day for grade 3-4, or pulse dosing such as 1 g/day if life-threatening), second-line immunosuppression for steroid-refractory disease (infliximab or vedolizumab for colitis, mycophenolate for pneumonitis/hepatitis, IVIG/plasma exchange for neurologic syndromes), and permanent discontinuation for grade 4 toxicity except endocrinopathies controlled on hormone replacement. Pneumonitis 5% overall with anti-PD-1/PD-L1 (10% combination, 3% monotherapy); myocarditis 1.14% prevalence, median onset 34 days, mortality 35-50%; colitis the signature CTLA-4 toxicity; endocrine irAEs mostly within 12 weeks of starting ICI.

Checked against its sources on 2 Sept 2026