Name an immune checkpoint inhibitor adverse event that requires prompt evaluation.

• A. Alopecia
• B. Nausea
• C. Hypertension
• D. Colitis

Answer: (D)

Immune checkpoint inhibitors can trigger immune-related adverse events by inflaming normal tissues. The colon is a particularly important site because colitis can start with diarrhea and abdominal pain and can escalate quickly to dehydration, electrolyte disturbances, or even perforation if not treated promptly. This is why prompt evaluation is essential: you need to confirm whether symptoms are due to an irAE, rule out infectious causes, and assess severity to guide immediate management.

Evaluation begins with a careful symptom history and physical, followed by labs and stool studies for infections (including C. difficile) to distinguish infection from irAE. In more clear or severe cases, endoscopic evaluation with biopsies helps gauge the extent of colitis and rule out other processes. Management hinges on severity: for moderate to severe colitis, hold the immune therapy and start systemic corticosteroids promptly, with escalation to additional immunosuppressants like infliximab if there is not adequate improvement within a few days. Early recognition and treatment reduce the risk of serious complications and allow safer continuation of cancer therapy when appropriate.

Alopecia, nausea, and hypertension can occur with cancer therapies and ICIs, but they do not typically require the same urgent evaluation as colitis.