Treatment of a Newborn with Urea-Cycle-Disorder and Cerebral Edema with Venovenous Hemodiafiltration and Therapeutic Hypothermia

Abstract

We report about a term newborn with urea-cycle disorder with severe cerebral edema in which the pharmacological treatment was combined with venovenous hemodiafiltration (VVHDF) and therapeutic hypothermia. A 50h old boy was admitted at a NICU in an external hospital because of convulsions and respiratory failure. Initial metabolic workup showed ammonia 2320µmol/l and the boy was transferred to our hospital. Initial examination showed a ventilated newborn with hepatomegalia and severe hypotension and ammonia concentrations of 2391µmol/l under treatment with Arginin-HCL and Na-Benzoat. Cranial ultrasound (CUS) showed a cerebral edema with systolic peaks and a pulsatility index (PI) of 3.0. After placing of a dual lumen catheter in the right jugularian vein VVHDF was started. In addition neuroprotection was performed by cooling the boy to a rectal temperature of 33°C for the first 24h using CritiCool cooling therapy system. Then the boy was rewarmed stepwise to 36°C over the next 48h. Ammonia concentration was decreased during the first 3h to 830.4µmol/l by VVHDF and CUS showed a significant improvement of the cerebral blood flow. VVHDF was stopped 3h later at ammonia 224.3µmol/l. There was no rebound of hyperammonemia and CUS showed regular findings. The metabolic investigation revealed an Argininosuccinate lyase deficiency. After Extubation at day 10, the boy was discharged at day 38. The 2 months follow up showed an adequate neurological development despite the classic signs of metabolic stroke in MRI. Conclusion: Life-threatening cerebral edema in newborns with inborn urea-cycle defects can be treated effectively by the combination of VVHDF with therapeutic hypothermia.