Our recruitment case on 11/18/29 was about an older patient with urothelial carcinoma on pembrolizumab (PD-1 checkpoint inhibitor) presenting with nausea, vomiting and decreased PO intake. DDx was complicated by the fact that they had CKD 5 not on dialysis (with acute mild worsening of his AKI) but they were ultimately diagnosed with PD-1 induced hypophysitis – rare complication of PD-1 inhibitors (more common with combination of checkpoint inhibitors). Some more information here: Checkpoint hypophysitis – 11.18
Take home points:
Vomiting is a reflex with 4 main activating pathways
Treatment can be tailored to the activating pathway
Avoidance of anchoring and rethinking DDx when patients don’t improve
Checkpoint inhibitors are commonly used and list of indications is expanding
Most organ systems can be affected by toxicity, always have IrAEs in your differential diagnosis