Diazoxide-related Hyperglycemic Hyperosmolar State in a Child With Kabuki Syndrome

Diazoxide is a commonly used first-line medication for the treatment of hyperinsulinism. Hyperglycemia may occur with diazoxide use. However, hyperglycemic hyperosmolar state (HHS) secondary to diazoxide is an exceedingly rare but potentially life-threatening adverse effect. We present a case of a 2-year-old with Kabuki syndrome and hyperinsulinism on diazoxide. She presented with 4 days of fever, respiratory symptoms, and lethargy. She was influenza B positive. Initial workup indicated HHS, with an elevated serum glucose (47.1 mmol/L [847.8 mg/dL]; reference range 3.9-6.0 mmol/L; 70-108 mg/dL), serum osmolality (357 mmol/kg H₂O; reference 282-300 mmol/kg H₂O) but absent urine ketones and no metabolic acidosis (venous pH 7.34). Her course was complicated by an acute kidney injury. Management in the hospital included discontinuation of diazoxide and intravenous fluid resuscitation, following which hyperglycemia and hyperosmolarity resolved. No insulin therapy was required. She remained normoglycemic without diazoxide for 2 weeks but subsequently required restarting of diazoxide for hypoglycemia. This case highlights the need for early recognition and prompt management of diazoxide-related HHS to reduce negative outcomes. We present the first case report of a child with Kabuki syndrome and hyperinsulinism with diazoxide-induced HHS.