Introduction: Congenital toxoplasmosis (CTox) is common in Malaysia and classically presents with brain and eye involvement, causing hydrocephalus, intracranial calcifications, cataract, chorioretinitis, blindness, epilepsy, and psychomotor or mental impairment. Cranial diabetes insipidus (CDI) and panhypopituitarism rarely complicate its clinical course. Case: From 2024 to 2026, we had encountered three cases of CTox infants, of whom 2 (C1, C2) had a stormy neonatal period and passed away by 3 months old due to refractory seizures, while the 3rd (C3) survived. C1 (2.2 kg) was diagnosed antenatally from fetal ultrasound brain with severe ventriculomegaly, whereas C2 (2.47 kg) had multiple syndromic features, cleft lip, palate and anopthalmos. C3 (2.6 kg) was only diagnosed later by 1-month-old when she had afebrile seizures. C1 and C2 had severe hypernatremia (Na >150 mmol/L) within 1st week of life, but C3 had hypernatremia after surgical drainage of her hydrocephalus and administration of steroids. All were diagnosed with CDI and fulfilled the triad of polyuria, hypernatremia and inappropriate paired osmolality. During acute period, they were managed with IV vasopressin infusion with intensive monitoring. At low dose (0.1–0.3 mcg/kg/hour), all achieved eunatremia and euvolemia within 12 hours with no inadvertent hyponatremia. They also had central hypothyroidism and received L-thyroxine, with prior oral hydrocortisone, except C1. Their CDI persisted with highest Na 165 mmol/L in C1. They were started on tab hydrochlorothiazide (HCTZ) alongside low renal solute load formula (LRSL) and EBM. HCTZ dose was titrated gradually from 0.5 to 1.0 mg/kg/dose and further to 1.5 mg/kg/dose. In between, subcutaneous desmopressin (DDAVP) 0.02–0.04 mcg were given during breakthrough DI. All cases responded to HCTZ at 1.5 mg/kg/dose, with varying intervals (daily to TDS). C3 went home after 6 weeks with HCTZ, L-thyroxine and hydrocortisone, together with oral anti-toxoplasmosis and anticonvulsants. Conclusion CTox with CDI presents a challenge during infancy, and a combination of LRSL with thiazide diuretics is an acceptable alternative, prior to definitive DDAVP therapy later.
oxoplasmosis, Congenital ; Hydrochlorothiazide ; Diabetes Insipidus