Mild Hypoxic Ischemic Encephalopathy: Causes and Long Term Effects

Babies that don’t receive enough oxygen around the time of labor and delivery risk developing a dangerous brain injury called hypoxic ischemic encephalopathy (HIE). HIE is caused by decreased blood flow and oxygen in the brain. HIE can cause permanent brain damage, leaving a child with lifelong conditions, such as seizures, cerebral palsy (CP), developmental disabilities and motor disorders.

A new study found that even mild hypoxic-ischemic encephalopathy can cause long-term problems in a child, such as intellectual disabilities, developmental delays, learning disorders, behavioral difficulties, speech delays, autism, attention deficit disorder and dyspraxia (1). This research is significant to note because there is only one treatment for HIE, and if a child is diagnosed with a mild form of HIE, they usually will not qualify for the critical treatment. The treatment is hypothermia, or brain cooling, and it must be given within 6 hours of the time the baby was deprived of oxygen. This usually means the treatment must be given within 6 hours of delivery (2). Hypothermia treatment for HIE has been shown to stop almost every injurious process that starts to occur when the brain experiences a lack of oxygen. The treatment can significantly decrease the likelihood that HIE will cause permanent brain damage, which may prevent a child from developing CP, or it may reduce the severity of the CP.

Causes of Mild HIE

Hypoxic ischemic encephalopathy (HIE) is the most common type of birth injury. It is often caused by oxygen deprivation (birth asphyxia) that occurs during or near the time of birth. During labor and delivery, problems with the umbilical cord, placenta or uterus can cause birth asphyxia. Listed below are conditions that can occur during or near the time of birth that can lead to HIE

Umbilical cord problems, such as a nuchal cord (cord wrapped around baby’s neck), umbilical cord prolapse, short umbilical cord and cord in a true knot
Ruptured uterus
Preeclampsia / eclampsia
Placental abruption
Placenta previa
Anesthesia mistakes, which can cause blood pressure problems in the mother, including a hypotensive crisis. This can greatly decrease the supply of oxygen-rich blood going to the baby, causing birth asphyxia.
Oligohydramnios (low amniotic fluid)
Premature rupture of the membranes (PROM) / premature birth
Prolonged and arrested labor
Intracranial hemorrhages (brain bleeds), which can be caused by a traumatic delivery. Forceps and vacuum extractors can cause brain bleeds. Sometimes intense contractions caused by labor induction drugs (Pitocin and Cytotec) can cause head trauma. Mismanagement of cephalopelvic disproportion (CPD), abnormal presentations (face or breech presentation), and shoulder dystocia also put the baby at risk for brain bleeds.
Hyperstimulation caused by Pitocin and Cytotec can also cause oxygen deprivation that gets progressively worse.
Fetal stroke
Postmaturity syndrome
Placental insufficiency and intrauterine growth restriction (IUGR)
An infection that travels from the mother to the baby at birth, such as chorioamnionitis, Group B Strep, urinary tract infections (UTI) and bacterial vaginosis (BV), which can cause sepsis and/or meningitis.
Failure to quickly deliver a baby when fetal distress is evident on the fetal heart rate monitor (delayed emergency C-section).
Mismanaged breathing problems after birth, such as failing to properly intubate and place baby on a breathing machine (ventilator); untreated apnea or respiratory distress; improper settings on the ventilator, which can cause overventilation injuries, such as prolonged hypocarbia.

Requirements for hypothermia treatment

Many hospitals use criteria from HIE and brain cooling research trials to determine whether a baby is eligible for hypothermia treatment. The eligibility requirements for hypothermia treatment in many hospitals are (1):

Gestational age greater than 36 weeks
Their pH is less than 7, or base deficit is 16 or greater in umbilical cord arterial blood
If pH is 7.01 – 7.15, base deficit is 10 – 15.9, or a blood gas sample is not available, these additional criteria are required:
- A sudden event during labor such as…
  - non-reassuring fetal heart tones (late or variable decelerations)
  - umbilical cord prolapse or rupture
  - uterine rupture
  - maternal trauma, hemorrhage or cardio-respiratory arrest
- AND either…
  - a 10 minute Apgar score of 5 or less
  - OR assisted ventilation (baby is on a breathing machine or is being bagged) at birth that lasts 10 minutes or more
Evidence of seizures or neonatal encephalopathy (global brain injury) by a standard neurological exam

Some hospitals use criteria such as the following from the American Academy of Pediatrics in Virginia (3):

Infants greater than 35 weeks gestation with ONE of the following:

Apgar score of less than 5 at 10 minutes after birth
Continued need for resuscitation, including endotracheal or mask ventilation, at 10 minutes after birth
Acidosis defined as either umbilical cord pH or any arterial pH within 60 minutes of birth less than 7.00
Base deficit greater than 16 mmol/L in umbilical cord blood sample or any blood sample within 60 minutes of birth (arterial or venous blood)

If the infant meets criteria A then assess for neurological abnormality:

Moderate to severe encephalopathy (Sarnat 2 or 3) consisting of an altered state of consciousness (as shown by lethargy, stupor, or coma) and at least one or more of the following:

Hypotonia
Abnormal reflexes including oculomotor or pupillary abnormalities
Absent or weak suck

Physicians at different hospitals may use varying methods for diagnosis of HIE. The key is for them to recognize the signs, quickly diagnose the condition, and begin hypothermia treatment. If the baby meets the criteria for hypothermia treatment listed above, the therapy should be started right away. Hypothermia treatment is very easy to give and as of yet, researchers have not seen harmful effects of the therapy when it is properly implemented.

Legal help for children with HIE

If you are seeking the help of an HIE attorney, it is very important to choose a lawyer and firm that focus solely on birth injury cases. ABC Law Centers (Reiter & Walsh, P.C.) is a national birth injury law firm that has been helping children with birth injuries for almost three decades.

Attorney Jesse Reiter, president and founder of ABC Law Centers, has been focusing solely on birth injury cases for over 28 years, and most of his cases involve HIE and cerebral palsy. Jesse and firm partner Rebecca Walsh have been consistently recognized in Best Lawyers for Plaintiffs – Medical Malpractice and Plaintiffs – Personal Injury in Troy, Michigan, by U.S. News and World Report, which also consistently recognizes ABC Law Centers in Best Law Firms.

Contact our birth injury attorneys and legal nurses in any of the following ways with any questions you may have. We do not charge any fees for our legal processes unless we win!

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Video: Michigan HIE Attorney Discusses Birth Asphyxia and Neonatal Seizures

Watch a video of attorney Jesse Reiter discussing how birth asphyxia can cause HIE, which often results in seizures. Most neonatal seizures are caused by hypoxic ischemic encephalopathy.