What are the signs and symptoms of severe hypoxic-ischemic encephalopathy (HIE)?

Updated: Jul 18, 2018
  • Author: Santina A Zanelli, MD; Chief Editor: Dharmendra J Nimavat, MD, FAAP  more...
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Answer

Seizures can be delayed and severe and may be initially resistant to conventional treatments. The seizures are usually generalized, and their frequency may increase during the 24-48 hours after onset, correlating with the phase of reperfusion injury.

As the injury progresses, seizures subside and the electroencephalogram becomes isoelectric or shows a burst suppression pattern. At that time, wakefulness may deteriorate further, and the fontanelle may bulge, suggesting increasing cerebral edema. Other symptoms include the following:

  • Stupor or coma is typical; the infant may not respond to any physical stimulus except the most noxious.

  • Breathing may be irregular, and the infant often requires ventilatory support

  • Generalized hypotonia and depressed deep tendon reflexes are common

  • Neonatal reflexes (eg, sucking, swallowing, grasping, Moro) are absent

  • Disturbances of ocular motion, such as a skewed deviation of the eyes, nystagmus, bobbing, and loss of "doll's eye" (ie, conjugate) movements may be revealed by cranial nerve examination

  • Pupils may be dilated, fixed, or poorly reactive to light

  • Irregularities of heart rate and blood pressure are common during the period of reperfusion injury, as is death from cardiorespiratory failure

An initial period of well-being or mild hypoxic-ischemic encephalopathy may be followed by sudden deterioration, suggesting ongoing brain cell dysfunction, injury, and death; during this period, seizure intensity may increase.

See Clinical Presentation for more detail.


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