In this report, the authors describe a unique presentation ofventriculomegaly in the setting of diabetic ketoacidosis (DKA). A 15-year-old male, with a history of shunt placement for hydrocephalus and repair of a myelomeningocele, presented to the emergency room with DKA and was found to have ventriculomegaly. At the time of presentation, the patient had a 24- to 48-hour history of lethargy, nausea, vomiting, fever (102.2°F), and polydipsia. A computed tomographic (CT) scan of the head indicated increased ventricular size compared with previous studies, thus prompting a neurosurgical evaluation. Blood glucose level at admission was found to be 1,551 mg/dl, bicarbonate level was 9 mmol/l, and pH was 7.08. The patient was treated for DKA; his fever, lethargy, nausea, and vomiting subsequently resolved. A repeat CT scan obtained 24 h after admission revealed a return of the ventricular system to its baseline size. On the basis of radiographic and laboratory evaluations, the authors hypothesize that the transient ventriculomegaly was directly related to extreme hyperglycemia. Copyright © 2009 S. Karger AG.