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

SUMMARY: Hiccups are a common symptom characterized by intermittent spasmodic contraction of the diaphragm. Most hiccups are transient, but some are refractory. Patients with intractable hiccups often have abnormalities of the diaphragm, medulla oblongata, and lesions affecting nerve fibers connecting them. Moreover, electrolyte abnormalities, including hyponatremia, are frequently observed in patients with intractable hiccups. Adrenal insufficiency (AI) is one of the causes of hyponatremia. However, hiccups are not commonly the first presentation. Herein, we describe a case of a 45-year-old woman complaining of refractory hiccups. The patient was initially diagnosed with hiccups associated with cervical cancer metastasis to the liver and peritoneum. The administration of chlorpromazine did not have a beneficial effect on her hiccup. Fasting hypoglycemia and hyponatremia were later found. Her serum cortisol level was low without an elevation of adrenocorticotropic hormone level. MRI of the pituitary gland showed metastatic lesion in the pituitary gland and stalk. Thus, the patient was diagnosed with secondary AI due to cervical cancer metastasis to the pituitary gland and stalk. Administration of hydrocortisone improved her hiccups with the normalization of serum sodium level. Therefore, differential diagnosis in advanced cancer patients with hiccups should include AI-induced hyponatremia. LEARNING POINTS: 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.