Hypoxic ischemic encephalopathy, or HIE, is a serious problem at birth. In fact, it is one of the scariest injuries that happens to full-term infants. A staggering 40-60% of infants with HIE die before they turn 2 years old or they become severely disabled. Shockingly, there are fewer babies who survive from HIE than there are babies who survive from extreme prematurity. However, new treatment methods are being explored to mitigate the long-term effects of HIE, so there is hope for these precious children.
This post will discuss the causes, symptoms, and treatment of hypoxic ischemic encephalopathy, as well as how to determine if a doctor’s mistake may have caused your baby’s birth injury.
What is hypoxic ischemic encephalopathy?
HIE is a brain injury that affects blood flow to the baby’s brain after damage that occurs before, during, or after birth. HIE injuries can be complex and evolve over time, but are generally the result of impaired cerebral blood flow and oxygen to the brain. Ischemia refers to an insufficient amount of blood for baby’s needs, while hypoxia relates to asphyxia, or oxygen deprivation.
Although new technology such as fetal monitoring has been put in place to reduce such birth injuries, the incidence of HIE still remains the same, occurring in between 1 to 8 per 1,000 live births in developed countries. Many infants who suffer from HIE develop cerebral palsy, epilepsy, or mental retardation.
What causes neonatal asphyxia?
An exact cause isn’t always identified, but HIE can occur after cord prolapse, uterine rupture, placental abruption, placenta previa, maternal hypotension, breech presentation, or shoulder dystonia. Babies with HIE may have low Apgar scores, abnormal fetal heart rate tracings, presence of meconium, poor umbilical gases, or need respiratory support right after birth.
An HIE injury starts as an initial reduction of cerebral blood flow, or primary energy failure. Blood flow issues lead to an increase in both oxygen and glucose, which impairs baby’s energy and eventually affects his cells. Glutamate, an excitatory neurotransmitter, also is released at this stage and increases intracellular calcium and sodium, which can lead to cerebral edema and ischemia. Cells can swell, rupture, and die in cases of severe hypoxia and ischemia. Inflammation can make things worse, but cell death overall can decrease brain function.
Six to 48 hours after the initial injury, secondary energy failure occurs. Cell death also leads to oxidative stress, which is particularly difficult for newborns due to their low level of antioxidants and how much oxygen they consume up to birth. They also have more free radicals in their body, of which they are unable to eliminate with decreased brain function from primary energy failure, leading to neuronal tissue damage.
Babies who have very mild HIE may have some behavioral abnormalities, but symptoms typically resolve within 24 hours. More moderate cases may manifest in slow reflexes and seizures, but babies recover within a couple of weeks.
Then, there are the symptoms of babies with severe HIE:
- Irregular breathing, heart rate, and blood pressure
- Dilated or fixed pupils, and/or reacting poorly to light
- Eye motion is disturbed
- No neonatal reflexes, such as sucking and grasping
- Depressed deep tendon reflexes and hypotonia (or floppy baby syndrome)
- Not reacting to any physical stimuli, as evidence of stupor or coma
Long-term effects for survivors of HIE include:
- Vision or hearing loss
- Seizures — more than half of babies with HIE also have seizures, and 10% will be diagnosed with epilepsy by age 3.5
- Head circumference and growth — this is associated with when the injury occurred, as smaller heads may indicate problems before birth
- Severe cerebral palsy is detected by age 1, while less severe cases are diagnosed by age 2
- Developmental delay or other cognitive deficits may be noticeable by school age
Although children can rebound from mild HIE, they also can suddenly deteriorate because of ongoing brain cell dysfunction, so it’s important to seek treatment and regular assessment by your medical team.
Hypoxic ischemic encephalopathy is diagnosed through lab and imaging studies, as well as additional studies such as hearing and eye tests. Proper management of HIE includes prompt resuscitation, preventing hyperthermia and hypoglycemia, and treating seizures.
Many babies with HIE are treated using moderate hypothermia, which can reduce free radicals, decrease the need for oxygen, and decrease cell death. While hypothermia on purpose may sound a little odd, babies are cooled either by their head or whole body for 48 to 72 hours, then slowly rewarmed to prevent things like hypotension. One systemic review of 13 clinical trials found the use of hypothermia after HIE to significantly reduce the risk of death, severe cerebral palsy, cognitive delay, and other complications by the time the babies were 1 year old. However, 30% of babies who receive hypothermia treatment after HIE still have major developmental disabilities at age 18 months.
Other treatment methods for hypoxic ischemic encephalopathy include administering the hormone erythropoietin, stem cell transplants from umbilical cord blood, and anti-epileptic medications. Xenon, an anesthetic gas, also is used to reduce neurotransmitters and excess glutamate.
As a possible preventative for hypoxic ischemic encephalopathy, a maternal diet rich in the long-chain fatty acid docosahexaenoic acid (DHA) may reduce oxidative stress and inflammation in the fetus. Research also is being done on cannabinoid agonists and how they can reduce brain damage after HIE.
Doctors will generally use a few different approaches in treating HIE, such as combining hypothermia with a glutamate receptor antagonist or antioxidants to increase the amount of time to respond to the brain damage and effectively reduce it.
During early assessments for hypoxic ischemic encephalopathy at 4-8 months, doctors will focus on baby’s head growth and motor neurodevelopment as well as overall health. Cognitive skills and language development are the focus at 12 and 24 months. A little later in life, children may need early intervention at school and/or ongoing treatment for cerebral palsy and epilepsy as a result of HIE.
Get Help with Your Baby’s Birth Injury
Hypoxic ischemic encephalopathy can have several causes, but one of those is birth trauma. If your baby’s asphyxia was due to breech birth or shoulder dystonia, for example, you may have a legal claim for a birth injury.
Responding to hypoxic ischemic encephalopathy quickly and accurately is important for any medical team, but sometimes doctors make mistakes. At Safe Birth Project, we can help. Contact us today for a free case evaluation and get the compensation you deserve.