Globus Pallidus & Thalami Brain Injury

A common cause of brain injury in babies is a lack of oxygen to the brain, called birth asphyxia. Birth asphyxia occurs at or near the time of birth when something affects the amount of oxygen-rich blood flowing to the baby. When the baby is in the womb, it receives all of its its oxygen from the mother. This blood travels through vessels that run between the uterus and placenta. The blood then travels to the baby through the umbilical cord.

Flow of blood to the baby takes the following path: maternal circulation –> utero-placental circulation and placenta –> umbilical vein –> fetal circulation.

Anything that hinders this blood flow can cause birth asphyxia. Common causes of asphyxia include umbilical cord problems, such as the cord being wrapped around the baby’s neck (nuchal cord), placental abruption, and uterine rupture. When a baby begins to experience oxygen deprivation, a series of events starts to occur that can severely injure brain cells. Birth asphyxia results in reduced oxygen in the baby’s blood and decreased flow of blood to the baby’s brain. The brain injury caused by this is called hypoxic-ischemic encephalopathy (HIE), which usually involves damage to the basal ganglia, thalami, cerebral cortex and watershed regions of the brain, but sometimes also includes periventricular damage.

When a baby experiences severe asphyxia during birth and is diagnosed with HIE, parents are often told that their child has basal ganglia, globus pallidus, thalami, or sensorimotor cortex injury. These types of brain injury are characteristic of a central pattern of injury involving the deep gray matter of the brain.

“Deep” brain structures include the basal ganglia, thalamus, and brain stem. The basal ganglia are gray matter structures that are located just underneath the cerebral cortex, on both sides of the thalamus. These structures play a central role in motor function (movement), and when the basal ganglia are damaged, the child can have a wide variety of motor impairments.

The globus pallidus is a major component of the basal ganglia and is involved in the regulation of voluntary movement. Many serious problems are associated with basal ganglia, thalami, and globus pallidus injury.

Cerebral palsy (CP) is a motor disorder often caused by damage to the motor centers of the brain, such as the thalami, basal ganglia, and globus pallidus. Children with cerebral palsy have certain limitations in motor function.

Birth asphyxia typically causes hypoxic-ischemic encephalopathy (HIE), which often involves damage to the basal ganglia and globus pallidus. When this area of the brain is damaged from asphyxia, the child is frequently diagnosed with spastic cerebral palsy, the most common form of CP. This type of cerebral palsy causes constant muscle tightness, which interferes with normal movement. Children with spastic cerebral palsy – or any type of cerebral palsy – often have seizures as well.

Globus pallidus injury is also associated with dyskinetic or athetoid cerebral palsy. The globus pallidus appears as a single mass, but it can be divided into two distinct parts. When a baby has elevated bilirubin (jaundice) for too long, the bilirubin can enter the brain and cause a form of brain damage called kernicterus. Bilirubin is toxic to the brain. When kernicterus occurs, there is often bilateral globus pallidus injury, which means that both parts of the globus pallidus show damage.

Birth asphyxia is usually caused by a problem with the uterus, placenta, or umbilical cord. Severe asphyxia and HIE often cause injury to the basal ganglia, globus pallidus, thalamus, and brain stem.

Common causes of birth asphyxia & hypoxic-ischemic encephalopathy (HIE) include:

• Failure to quickly deliver a baby in the presence of oxygen deprivation (delayed emergency C-section)
• 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
• Placental abruption (placenta separates from uterine wall (womb)
• Preeclampsia / eclampsia
• Placenta previa
• Anesthesia mistakes, which can cause low blood pressure in the mother, including a hypotensive crisis.
• Oligohydramnios (low amniotic fluid)
• Premature rupture of the membranes (PROM) / premature birth
• Prolonged and arrested labor
• Hyperstimulation caused by Pitocin and Cytotec
• Fetal stroke
• Postmaturity syndrome

During labor and delivery, the baby is supposed to be closely monitored with a fetal heart rate monitor. If a baby becomes oxygen-deprived, it will be reflected on the fetal heart monitor as nonreassuring heart tracings. When nonreassuring tracings occur, the medical team must quickly deliver the baby to get him or her out of the oxygen depriving conditions. Failure to quickly deliver a baby experiencing birth asphyxia can cause brain damage in important structures such as the basal ganglia (including the globus pallidus), thalamus, and cerebral cortex. There also may be injury to the watershed and periventricular regions of the brain.

Birth asphyxia and HIE can cause permanent brain damage, leaving children with long-term conditions such as:

• Cerebral palsy
• Seizure disorders
• Developmental delays
• Intellectual (cognitive) disabilities
• Motor disorders
• Hydrocephalus
• Learning disabilities
• Speech delays and disorders