Hiccups as the first presentation of secondary adrenal insufficiency associated with advanced cervical cancer.

Hiccups could be the first manifestation of adrenal insufficiency (AI). Hiccups in patients with AI are often mediated by hyponatremia. Hyponatremia is less frequent in secondary AI than in primary AI. However, hyponatremia can result from increased antidiuretic hormone due to loss of cortisol. The differential diagnosis should include AI-induced hyponatremia if hiccups occur in patients with advanced cancer, as metastasis to adrenal gland or pituitary gland could cause AI.