Hypoxic-ischemic encephalopathy (HIE) is a type of brain damage that could occur in infants due to insufficient oxygen and blood reaching the brain during pregnancy or delivery. The severity of HIE may vary depending on the duration of oxygen deprivation.
HIE may result in cerebral palsy, severe cognitive and motor impairment, and developmental delay in some babies. Although there is no cure, several treatment options may improve the baby’s quality of life.
Read this post to know about the symptoms, causes, risk factors, long-term effects, treatment, and prevention of hypoxic-ischemic encephalopathy in babies.
Signs And Symptoms Of HIE
The signs and symptoms of HIE are usually seen immediately after birth and may vary depending on the severity of the brain damage.
Mild HIE signs and symptoms may resolve within a week in many babies and may include the following (1).
- Abnormal reflexes
- Stiff muscles
- Feeding issues
- Excessive crying
- Excessive sleeping
Moderate HIE may cause the following signs and symptoms(1).
- Floppy baby syndrome or hypotonia (reduced or lack of muscle tone)
- Sporadic apnea (sudden pause in breathing)
- Seizures within the first day of life
- Absence of reflexes
- Unable to grasp and often has a poor sucking reflex
Severe HIE couldbe life-threatening and may cause the following signs and symptoms(1).
- Irregular breathing
- Increased frequency of seizures across two days
- Hypotonia, extreme lack of muscle tone may make the baby like a rag doll
- Dilated pupils
- Abnormal eye movement and control
- No reflexes
- Abnormal blood pressure
- Changes in heart rate
- Cardiorespiratory failure
The severity of brain damage may vary based on the time of hypoxia (oxygen deprivation). HIE before 35 weeks of gestation (premature) may result in periventricular leukomalacia (PVL). This condition causes the death of small areas of brain tissue around the brain’s ventricles (fluid-filled cavities).
The extent of brain damage in full-term infants may depend on the severity of hypoxia. Mild hypoxia may affect the white matter of the brain, while severe hypoxia may involve more complex brain structures, such as the thalamus.
Causes And Risk Factors Of HIE In Newborns
Hypoxia(insufficient oxygen reaching tissues) and ischemia (inadequate blood flow to the tissues) cause encephalopathy (brain damage), leading to hypoxic-ischemic encephalopathy in babies. Loss of blood and poor oxygen supply to the brain during the birth process may result in HIE in babies. The incidence and severity of HIE may vary based on the duration of oxygen deprivation.
The following factors may increase the risk of hypoxia and ischemia in newborns (2).
- Preeclampsia (high blood pressure)
- Cardiac problems
- Umbilical cord complications and cord prolapse
- Poor lung function
- Breathing interruptions
- Blood clotting abnormalities
- Fetal stroke
- Head injury during delivery
- Pressure on cranium due to molding during delivery
- Medical negligence during delivery, such as inappropriate use of forceps or vacuum-assisted delivery
- Intrapartumhemorrhage that is bleeding from onset of labor to the end of the third stage of labor
- Insufficient bloodflow to the brain during birth
- Placental abnormalities such as placental abruption
- Rupture of vasa previa (blood vessels trapped between the fetus and birth canal)
- Uterine rupture during the gestation period
- Fetal trauma
- Stress during labor and delivery
- Maternal infections, such as pelvic inflammatory disease
HIE is more common in full-term babies than in preemies. Full-term infants are more likely to develop hypoxic-ischemic encephalopathy during labor and delivery than pregnancy. Pregnancy-related complications could be a reason for HIE in preterm babies.
Long-Term Effects Of HIE In Babies
HIE may result in long-term physical and cognitive damage consisting of the following problems (3).
- Cerebral palsy
- Seizure disorders or epilepsy
- Hearing and vision loss or impairments
- Learning disabilities
- Speaking problems
- Walking and coordination problems
- Autism and autism spectrum disorders
Low mental development index (MDI) and psychomotor development index (PDI) due to HIE could also occur in some babies.
Diagnosis Of HIE
Neuroimaging, such as MRI scans, can diagnose hypoxic-ischemic encephalopathy. Other techniques, such as diffusion-weighted imaging and MR spectroscopy, could also be conducted (4).
The HIE diagnostic tests are often ordered if the birth was traumatic or there are significant risk factors for fatal stroke. Visible signs and symptoms, such as seizures, within 24 hours of life, organ dysfunctions shortly after birth, growth and developmental delay, and impaired motor function are also indications to do an MRI scan.
The severity of HIE is usually diagnosed at an age when the cognitive function can be assessed adequately. HIE can be mild, moderate, or severe. Some additional tests are often ordered to exclude the diagnosis of other metabolic and neurodegenerative disorders in babies.
Treatment Of HIE In Babies
There is no specific cure for HIE. Treatment options aim to relieve or ease symptoms of brain injury. Therapeutic hypothermia or cooling the body and head immediately after birth is one of the recent treatments for HIE. Cooling down the body temperature may reduce brain cell damage and death (5).
Although it’s relieved, oxygen deprivation may reoccur in some cases. The blood glucose levels and blood pressure are kept in normal range with medications to avoid further brain injuries and complications. Cerebral edema and seizures are also controlled or prevented with medications.
Physical and occupational therapies are often required to improve the quality of life. Babies with HIE may require medical support for a long time. The type of therapy and long-term support may depend on several factors, including the extent of brain damage, response to other treatments, and prognosis of complications.
Prevention Of Hypoxic-ischemic Encephalopathy
Prevention of hypoxia and ischemia during pregnancy and delivery could prevent HIE in babies. The following factors may help to avoid HIE in babies.
- Parents and caregivers must be educated about the risk factors and early signs and symptoms of HIE.
- Adequate prenatal checkups and testing in case of problems should be conducted.
- Discuss any pregnancy-related or delivery-related risk factors and their resolution extensively with your healthcare provider.
- Electronic fetal monitoring during delivery by the doctor may help understand fetal distress and use interventions to enhance the delivery process.
HIE is a rare condition but may cause lasting problems. It is a severe type of brain injury that may also result in permanent brain damages, such as cognitive impairment and physical disabilities, in most survivors. Appropriate management could help babies with mild and moderate HIE recover without long-term effects. You may discuss the risk factors with your doctor for timely diagnosis and prevention of complications.
2. Hypoxic Ischemic Encephalopathy: Pathophysiology and Experimental Treatments; US National Library of Medicine
3. Long-Term Outcomes of HIE; HIE Help Center
4. Hypoxic-Ischemic Encephalopathy; CerebralPalsy.org
5. HIE – Hypoxic Ischemic Encephalopathy; Birth Injury Help Center