Isolated Adrenocorticotropic Hormone (ACTH) Deficiency as an Immune-Related Adverse Event Following Combination...

Area of Science:

• Endocrinology
• Oncology
• Immunology

Background:

• Isolated adrenocorticotropic hormone (ACTH) deficiency is a rare pituitary disorder affecting only ACTH secretion.
• Immune checkpoint inhibitors (ICIs) are increasingly recognized as a cause of immune-related adverse events (irAEs), including endocrine dysfunction.

Observation:

• A 65-year-old man developed fatigue and anorexia six weeks after nivolumab and ipilimumab therapy for esophageal cancer.
• Blood tests revealed hyponatremia and hyperkalemia, leading to a diagnosis of isolated ACTH deficiency.

Findings:

• Retrospective analysis showed eosinophilia and mild hyponatremia prior to thyrotoxicosis diagnosis, suggesting subclinical hypoadrenocorticism.
• These subtle abnormalities may indicate early-stage ACTH deficiency preceding overt adrenal insufficiency symptoms.

Implications:

• Healthcare providers must monitor for eosinophilia and electrolyte disturbances during ICI treatment.
• Early endocrinologist consultation is recommended for any detected abnormalities to manage potential irAEs effectively.