Synopsis
Recognise and grade multisystem immune-related adverse events, exclude infection and cancer complications in parallel, deliver organ-specific immunosuppression or hormone replacement, and plan a safe taper and rechallenge decision.
- Immune-related adverse events follow checkpoint activation and may affect skin, bowel, liver, lung, endocrine, kidney, nervous, cardiac, eye, joint or blood systems.
- Timing ranges from days after the first dose to months after treatment ends, so previous immunotherapy remains relevant in every acute history.
- Grade from the patient's baseline and organ threat, not symptom count alone; mild fatigue can precede adrenal crisis, myocarditis or neurological overlap.
Key red flags
Hypotension, hyponatraemia, hypoglycaemia, severe hyperglycaemia or polyuria can indicate adrenal, pituitary, pancreatic or thyroid emergency.
Investigation priorities
Detect injury in the symptomatic system and screen multisystem involvement.
Management branches
A new organ symptom or biochemical abnormality occurs after checkpoint exposure.
- Hold immunotherapy when clinically important toxicity is plausible and assess ABCDE stability, baseline function and all involved organs.
- Notify acute oncology and the relevant specialist early for cardiac, neurological, pulmonary, hepatic, bowel or endocrine concern.
Key medicines
Systemic corticosteroid for significant immune toxicityMany grade 2 toxicities start oral prednisolone 0.5–1 mg/kg/day; many grade 3–4 toxicities use intravenous methylprednisolone or equivalent 1–2 mg/kg/day. The threatened organ can require a different or pulse regimen, so use the current organ-specific protocol and taper commonly over at least 4–6 weeks after objective improvement.
Hydrocortisone for suspected adrenal crisisGive 100 mg intravenously or intramuscularly immediately, then 200 mg over 24 hours by continuous intravenous infusion or 50 mg intravenously or intramuscularly every 6 hours, with rapid 0.9% sodium chloride resuscitation and endocrine input.