Gitelman Syndrome in a Toddler With Normal Blood Test Findings Except on Sick Days.

A 3-year-old, male, Japanese patient with a history of seizure clusters was urgently admitted for febrile status epilepticus. Blood tests found metabolic and respiratory acidosis linked to the seizures and poor oral intake along with unexplained hypokalaemia, hypomagnesaemia and elevated corrected bicarbonate. These abnormalities resolved with fluid therapy, and follow-up testing after discharge found no electrolyte or acid-base disturbances. A review of the previous episodes of seizure clusters revealed similar findings, including hypokalaemia and metabolic alkalosis, raising suspicion of Gitelman syndrome (GS), which was later confirmed by genetic testing. The present case demonstrated that some patients with GS may present electrolyte or acid-base abnormalities only on sick days. Whenever a blood test performed for any pathological condition reveals unexplained hypokalaemia and metabolic alkalosis, the possibility of GS should be considered even if the blood test results are normal except on sick days.