Hypoxic-ischemic Encephalopathy (HIE)

Hypoxic-ischemic encephalopathy (HIE) is a condition that occurs when an infant’s brain experiences both a lack of oxygen and blood flow, often during or shortly after birth. This lack of oxygen may cause brain injury as well as neurological and developmental challenges.

Symptoms of HIE can vary from infant to infant, but common signs include:

• Lethargy or decreased responsiveness
• Abnormal muscle tone (hypotonia or hypertonia)
• Seizures
• Reflex changes

Several factors can cause HIE, including problems that occur before, during, and after delivery:

Problems during pregnancy

• Conditions affecting the pregnant person, such as blood pressure abnormalities or preeclampsia
• Infections affecting the pregnant person or fetus
• Problems with blood flow to the placenta or from the placenta to the fetus
• Drug and alcohol abuse during pregnancy
• Cardiac disease in the fetus
• Fetal lung abnormalities

Problems during labor and delivery

• Problems with the umbilical cord, particularly compression that leads to oxygen deprivation
• Prolonged labor
• Placental or uterine rupture

Problems after delivery

• Respiratory distress or lung disease
• Heart disease
• Infections such as meningitis or sepsis
• Trauma to the brain or skull
• Very low blood pressure

Doctors can often detect HIE shortly after birth if they observe signs such as low muscle tone, breathing difficulty, or abnormal reflexes. If your care team suspects your child has HIE, they may recommend brain imaging and monitoring, such as an EEG, to evaluate your child’s brain function and structure. A diagnosis of HIE is primarily based on these exams, blood work results, a review of the pregnancy and delivery, and monitoring of your child’s oxygen levels and other vital signs.

Treating HIE in infants depends on several factors, including the infant’s age and symptoms. One common approach to treatment is therapeutic hypothermia, also known as cooling therapy, which helps protect brain cells, improving the chances of healthy brain development. To be effective, therapeutic hypothermia must be started shortly after delivery.

Supportive care is critical for managing symptoms of HIE, such as seizures and feeding difficulties. Physical therapy and occupational therapy can improve mobility and daily functioning.

The long-term outlook for HIE can vary greatly. Some infants with HIE grow to lead healthy lives; others may face challenges such as:

• Cognitive impairments
• Epilepsy or seizures
• Hearing loss
• Motor skill difficulties
• Speech delays
• Visual impairment

At Boston Children’s, we provide specialized care for infants with HIE through a multidisciplinary team that includes neurologists and neonatologists, as well as physical therapy, occupational therapy, speech and language, and developmental specialists. Our personalized approach addresses each infant’s unique needs and includes the latest diagnostic and treatment options, and family-centered support, education, and resources to help navigate the challenges of HIE.