Prolonged brain retention of contrast agent in neonatal herpes simplex encephalitis.

A neonate with herpes simplex encephalitis type 2 manifested progressively increasing density of the gray matter on serial computed tomographic scans. Postmortem examination of the brain proved the cause of the increased density to be a high concentration of iodine that had been retained following the intravenous administration of sodium diatrizoate 25 and 16 days previously. This demonstrates that a water-soluble iodinated contrast agent or its iodine component may be retained in the brain for a prolonged period of time. It is recommended that such agents be avoided when possible in neonates with herpes simplex encephalitis.