A Case of Cancer-Associated Hyponatraemia: Primary Adrenal Insufficiency Secondary to Nivolumab

Area of Science:

• Oncology
• Endocrinology
• Immunology

Background:

• Immune checkpoint inhibitors (ICIs) represent a significant advancement in cancer therapy.
• ICI treatment is associated with immune-related adverse events (irAEs), particularly affecting endocrine glands.
• Limited data exist on managing ICI-induced endocrine irAEs.

Observation:

• A 74-year-old male with non-small cell lung cancer developed fatigue, nausea, vomiting, and severe hyponatremia while on nivolumab.
• Endocrine evaluation revealed primary hypothyroidism and adrenal insufficiency with elevated ACTH, despite negative adrenal antibodies and no adrenal lesions.
• The patient was diagnosed with nivolumab-induced primary adrenal insufficiency.

Findings:

• Nivolumab withdrawal and initiation of glucocorticoid and mineralocorticoid replacement therapy led to complete clinical and biochemical recovery.
• This case highlights a rare but serious irAE of nivolumab therapy.
• The diagnostic workup excluded other causes of adrenal insufficiency.

Implications:

• Oncologists and endocrinologists must maintain a high index of suspicion for irAEs in patients receiving ICIs.
• Prompt diagnosis and management of ICI-induced adrenal insufficiency are essential for favorable patient outcomes.
• Awareness of these potential side effects is critical for safe and effective cancer immunotherapy.