Mild hypoxic ischemic encephalopathy [HIE]

This code signifies a mild form of brain dysfunction in a newborn resulting from insufficient oxygen and blood flow around the time of birth. It indicates a less severe neurological injury compared to moderate or severe HIE, often presenting with subtle clinical signs.

Apply this code when documentation explicitly states "mild hypoxic ischemic encephalopathy" or "HIE, mild." This diagnosis is typically made in neonates exhibiting mild neurological signs such as hyperalertness, mild hypotonia, or irritability, without seizures or significant depression of consciousness.

• Ensure the physician's documentation specifies "mild" to differentiate from moderate (P91.62) or severe (P91.63) HIE.
• Do not code based solely on a suspicion of HIE; definitive diagnosis and severity level are required.
• Consider co-occurring perinatal conditions, such as birth asphyxia (P21.-), which may be sequenced before HIE depending on the circumstances.