A report describes a case of a 7-year-old boy who presented to the emergency department with a 2-week history of nausea, vomiting, intermittent left-sided abdominal pain, and left-sided headache. He reported a recent feeling of tiredness and extreme thirst. He also documented a history of chronic constipation but no known allergies, fever, or dysuria. His family history contained his mother with an astrocytoma and his grandmother with Crohn′s disease. 

Physical examination revealed the patient to be fatigued, pale, and tachycardic, with a blood pressure of 100/72 mmHg, a pulse of 104 beats/min, a temperature of 100 °F (37.8 °C), a respiratory rate of 18 breaths/min. He appeared euvolemic but was later described as dehydrated.

Laboratory investigation at the presentation showed hyponatremia, low serum osmolality, and normal serum potassium and glucose. His complete blood count was normal, and a comprehensive urine drug analysis was negative. Random urine chemistries showed elevated sodium (198 mmol/L), potassium (151 mmol/L), and osmolality (998 mOsm/kg). 

His acute abdomen X-ray series revealed a large stool burden. Magnetic resonance imaging of the brain revealed prominence of the pituitary gland but no evidence of a mass.

He was diagnosed with Autoimmune primary adrenal insufficiency and autoimmune hypothyroidism (consistent with APS-II), which prompted the use of hydrocortisone, fludrocortisone, and levothyroxine. The patient remained under pediatric endocrinology follow-up and showed well progression.

Thombare AS, Maine G, Sykes E. Nausea, Vomiting, Fatigue, and Hyponatremia in a 7-Year-Old Boy. Clinical Chemistry. 2020;66(10):1272–1275. https://doi.org/10.1093/clinchem/hvaa141