What causes neonatal encephalopathy?

See below:: In ne, it is not always possible to document a significant hypoxic-ischemic insult. There are potentially several other etiologies, specifically, it is important to exclude metabolic disease, infection, drug exposure, nervous system malformation and neonatal stroke as possible causes of the encephalopathy. The nature of brain injury causing neurologic impairment in a newborn is poorly understood.