Hypoxic ischemic encephalopathy (HIE) is one of the most grievous birth complications that a full-term infant can face. It describes a deprivation of blood and oxygen to the young nervous system which may occur at any phase of the birth process, and it is sadly accompanied by a host of medical complications that, when not fatal, leave a large number of victims with lifelong brain-related challenges.
If you are worried your child has been affected by HIE, our experienced brain injury attorneys are prepared to help.
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Hypoxic Ischemic Encephalopathy Resources in this Article:
- What is Hypoxic Ischemic Encephalopathy (HIE)?
- Symptoms of Hypoxic Ischemic Encephalopathy
- Long Term Effects of Hypoxic Ischemic Encephalopathy
- Rehabilitation Following Hypoxic Ischemic Encephalopathy
- Compensation & Liability For Hypoxic Ischemic Encephalopathy
What is Hypoxic Ischemic Encephalopathy (HIE)?
Hypoxic ischemic encephalopathy, or HIE for short, is a rare birth complication and brain injury caused by decreased oxygen to the central nervous system. Hypoxic refers to a lack of oxygen, while ischemic signifies a lack of blood flow and encephalopathy means brain disorder. It may also be referred to as neonatal HIE because it primarily occurs in babies during birth, and is considered to be one of the most problematic birth complications that can affect full term infants.
Although HIE can occur in any age group, such as when it occurs due to cardiac arrest, it is predominantly associated with very young babies. It can occur to infants before (pregnancy), during (labor), and after birth (post-natal), and its severity is determined by how long the lack of oxygen or blood flow lasts. Brief HIE may result in no long-term consequences, while its moderate and severe forms may result in disabilities ranging from mild developmental delays or cognitive impairments to conditions such as epilepsy and cerebral palsy.
In this section:
- How Hypoxic Ischemic Encephalopathy is Diagnosed
- Causes of Hypoxic Ischemic Encephalopathy
- The Impact of HIE on Neurodevelopment
How Hypoxic Ischemic Encephalopathy is Diagnosed
Medical professionals may suspect HIE due to complications during labor and delivery, or the newborn’s accompanying symptoms such as seizures. It is usually diagnosed within the first six hours of life, and is confirmed with one or more tests:
- Blood tests – An HIE-diagnosing blood test examines the amount of oxygen in the blood, as well as the levels of electrolytes, enzymes, and nutrients such as calcium.
- Umbilical or placental tests – Examination and blood testing of the umbilical cord and placenta may indicate the previously-unknown cause of HIE.
- Lumbar puncture – Infection is confirmed or ruled out by taking a sample of cerebrospinal fluid from the lower back.
- Ultrasound of the head – Such an ultrasound can spot blood or other fluid buildup in the baby’s brain.
- EEG – Electroencephalography checks the electrical activity of the brain, and is usually conducted on the baby’s first day.
- Brain MRI – Magnetic resonance imaging can indicate which specific areas of the brain sustained damage, and is typically done late in the baby’s first week.
When neonatal HIE is not diagnosed early on, it may cause motor function issues or other developmental delays. In such cases, medical professionals will examine the child’s health history and symptoms and perform a physical exam in order to potentially diagnose HIE.
Causes of Hypoxic Ischemic Encephalopathy
The exact cause of HIE is not always identified, but issues that may cause HIE during pregnancy include:
- Obstructed blood flow to the placenta
- Congenital fetal infections
- Severe fetal anemia
- Pre-eclampsia (high blood pressure)
- Maternal diabetes with vascular disease
- Maternal drug or alcohol abuse
Issues during labor and delivery can include:
- Umbilical cord problems
- Excessive bleeding of the placenta
- Low maternal blood pressure
- Abnormal fetal positions, such as the breech position
- Anesthetic negligence
The problems after delivery that can cause HIE may include:
- Severe prematurity
- Infections
- Lung or heart disease
- Head trauma
The Impact of HIE on Neurodevelopment
HIE can have a profound impact on the developing brain. Our nervous systems follow a complex and intricate set of steps as they grow, and any injury that occurs during that time can interrupt the development of essential neurological regions and the connections between them.
For instance, research has shown that HIE can lead to abnormal brain development, such as cerebral atrophy (the loss of brain cells) and reduced myelination (myelin provides an insulating layer around the axons of our nerve cells, allowing electrical impulses to be transmitted rapidly), as well as impaired synaptic plasticity. Synaptic plasticity can be best thought of as the process through which our brains grow and develop in response to new information, and it plays an important part in learning and memory.
These impairments can radically alter an individual’s life. If the HIE event that brought about such neurodevelopmental impairments was caused by another person’s negligence, that person may be held liable for causing a traumatic brain injury. In these situations, it is important to understand your legal rights and the rights of your child. Contact one of our experienced brain injury attorneys to find out what options may be available to you.
Symptoms of Hypoxic Ischemic Encephalopathy
HIE can result in a host of symptoms, including impaired reflexes, breathing problems, and seizures.
In this section:
Impaired Reflexes
Infants affected by HIE may present with weak muscles and poor reflexes, such as little or no grasping or swallowing ability. This may also manifest as hypotonia or low muscle tone, meaning the infant’s muscles exhibit abnormally low resistance and may even exhibit ragdol-like movements.
Cognitive Symptoms
Breathing Problems
HIE may also manifest as breathing problems, ranging from apnea or brief pauses in breathing, to irregular breathing that necessitates a breathing tube.
Seizures
HIE-caused seizures typically occur within the first 24 hours or few days after infant’s birth. However, HIE seizures can also recur later in life when the underlying brain injury persists, such as in the first two years of life or even 10+ years later. HIE seizures are often quite subtle and may need to be confirmed with an electroencephalogram (EEG) to detect abnormal brain waves.
Motor & Attention Deficits
Children who survive HIE may suffer from motor deficits such as difficulties with balance and impaired manual dexterity, and attention deficits such as ADHD.
Emotional Disorder
Sadly, there is also a correlation between HIE and the development of childhood mood disorders and disturbances. In one study, young HIE survivors consistently scored higher than a non-HIE peer group for anxious or depressive symptoms and aggressive behaviors (even after ruling out potential genetic and environmental factors such as maternal mental health or parental education and income). Animal testing has even suggested that there may be a relationship between prenatal hypoxia and the development of schizophrenia.
Long Term Effects of Hypoxic Ischemic Encephalopathy
The long term effects of HIE are considerable and varied. One study of children three years or older estimated that death, cerebral palsy, or motor/cognitive impairment occurred in 47% of the cases. Other estimated outcomes in early childhood included 10-12% developing post-neonatal epilepsy, 9% developing hearing loss or deafness, and 26% developing impaired vision or blindness.
It is also important to note that cerebral palsy at times comes with a host of secondary impairments, such as problems with eating and digesting, scoliosis, osteoporosis, sensory and cognitive impairments, and disorders affecting communication and memory. Evidence suggests that children with even mild and moderate HIE score significantly lower on tests involving attention, verbal reasoning, and sensory-motor ability, when compared to non-HIE peers.
Levels of Severity of Hypoxic Ischemic Encephalopathy
HIE has three stages of severity:
- Mild – symptoms last less than 24 hours
- Moderate – symptoms last between two days and two weeks
- Severe – symptoms last several weeks or more
Roughly 20-25% of all infants with HIE die during the neonatal period, or the first four weeks of the child’s life. Another 25-30% of infant HIE survivors are left with lifelong neurodevelopmental challenges. Mild to moderate hypoperfusion (restricted bloodflow leading to lack of oxygen) as in HIE typically causes a specific brain hemorrhage and injury to the white matter surrounding the brain’s ventricles, while severe hypoperfusion damages the deep grey matter where the neural cell bodies are highly concentrated.
Because the newborn brain is generally quite resistant to injury (due to factors such as lower cerebral metabolic rate, central nervous system plasticity, and immature development of balance in functional neurotransmitters), it is possible for HIE to go unnoticed during its earliest phases, leaving the child susceptible to compounding injury in the following hours.
Rehabilitation Following Hypoxic Ischemic Encephalopath
Pediatric neurologists utilize several sophisticated treatments to mitigate HIE injury after it is detected. These may include therapeutic hypothermia, or using a special cooling blanket for whole-body cooling to bring the baby’s temperature down and protect the brain by lessening the thermogenic heat it produces for energy. During such treatment, an EEG can also be used to constantly monitor the baby’s brain activity and detect any seizures. Post-acute care in infant critical care units (ICCU) usually follows such initial treatments.
Compensation & Liability For Hypoxic Ischemic Encephalopathy
Our team stands ready to help you or your loved one get the compensation and closure they deserve in the aftermath of an HIE injury. For more information on the legal implications of brain injuries, visit our brain injury page.
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Banner image from Unsplash
ARTICLE BY
ARMEN AKARAGIAN
Admitted to practice in 2006, Armen has arbitrated, tried, and settled several cases which have resulted in multi-million dollar verdicts and settlements.
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- Hypoxic Ischemic Encephalopathy: Pathophysiology and Experimental Treatments – NIH
- Neonatal Hypoxic-Ischemic Encephalopathy – Nationwide Children’s
- Neonatal hypoxic ischemic encephalopathy – USCF Benioff Children Hospital
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