Secondary Adrenocortical Insufficiency in Liver Cancer Patient After Treatment With Cadonilimab: A Case Report.

Immune checkpoint inhibitors (ICIs) offer important clinical benefits in antitumor therapy. However, they may cause potential and unpredictable immune-related adverse events (irAEs) due to the non-specific immunity activation. Although adrenocortical insufficiency (AI) is a rare irAE, rapid identification and treatment can help patients avoid life-threatening cortisol crises. We describe the case of a 60-year-old Chinese male patient with liver cancer who developed intractable hyponatremia, fatigue, and loss of appetite three months after completing treatment with cadonilimab. Intravenous rehydration and symptomatic treatment were ineffective. The diagnosis of ICI-induced secondary AI was confirmed after refinement of cortisol levels and adrenocorticotropic hormone (ACTH). Additionally, mild subclinical hypothyroidism was identified as a concurrent endocrine finding. Electrolyte disturbances and general malaise improved markedly after oral administration of exogenous cortisol hormone. This case supports existing evidence regarding ICI-related secondary AI and highlights the importance of timely endocrine evaluation in patients with persistent hyponatremia and non-specific systemic symptoms.