Cerebral Palsy and Premature Birth

Cerebral palsy is a term used to describe a group of chronic disorders impairing control of movement that appear in the first few years of life and typically do not worsen over time.  The disorders are caused by damage to motor areas in the brain that disrupts the brain’s ability to control movement and posture.

This damage can occur when there is trauma to the infant’s head during the birth process or when there is oxygen deprivation during labor and delivery or shortly after birth.

Symptoms of cerebral palsy include difficulty with fine motor tasks, such as writing or using scissors, and difficulty maintaining balance or walking.  Cerebral palsy also can cause involuntary movements.

The symptoms differ from child to child and may change over time.  Some children with cerebral palsy are also affected by other medical disorders, including seizures or mental impairment, but cerebral palsy does not always cause profound handicap.

Early signs of cerebral palsy usually appear before 3 years of age.  Infants with cerebral palsy are frequently slow to reach developmental milestones, such as learning to roll over, sit, crawl, smile, or walk.

Cerebral palsy may be congenital or acquired after birth.  Several of the causes of cerebral palsy that have been identified through research are preventable or treatable:

• head injury during labor or delivery
• jaundice
• Rh incompatibility
• rubella (German measles)

Doctors diagnose cerebral palsy by testing motor skills and reflexes, looking into medical history, and employing a variety of specialized tests.

When a baby is born prematurely, or before reaching 37 weeks of gestational age, she is at risk for brain damage and cerebral palsy due to a number of reasons.

First of all, premature babies have systems that are not fully developed, such as the liver, kidneys and lungs, and the baby’s blood vessels are more fragile.  This makes premature babies more prone to high bilirubin levels, infection, trauma and oxygen deprivation, all of which can cause cerebral palsy.  It has long been known that the systems of premature infants cannot deal with brain injuries the same way full term infants can.  In addition, when a baby is delivered early, there are associated conditions that increase the risk of birth trauma with resultant brain damage.

For these reasons, it is crucial that physicians follow standards of care that apply to premature infants, and that they prevent or quickly diagnose and treat conditions that are associated with premature birth.  Failure to follow standards of care and to act skillfully and promptly with diagnosis and treatment is negligence.  If this negligence causes the baby to have cerebral palsy, it is medical malpractice.

A delivery before 26 weeks can be very dangerous for the baby.  Since the lungs mature between 32 and 34 weeks, any delivery before 32 weeks presents a risk of very immature lungs. Underdeveloped lungs may then result in lack of oxygen to the brain after delivery without proper treatment.

Often, a baby born before 34 weeks will require some type of mechanical assistance for ventilation, and there are other conditions that physicians and the medical team should be prepared to test for and treat.

Premature birth puts a baby at risk for developing cerebral palsy due to the following issues that can occur at or around the time a premature baby is born.

Premature babies often have underdeveloped lungs and need some kind of assistance from a breathing machine (ventilator).

Sometimes the ventilator can overventilate the baby, which means the baby is getting rid of too much carbon dioxide (CO2).  When CO2 is abnormally low (called hypocarbia), it can cause the vessels in the brain to constrict, which causes decreased flow of oxygen-rich blood to the brain.  This causes the brain to be deprived of sufficient oxygen, and when this condition lasts for a few hours or more, it can cause brain damage, such as cerebral palsy and periventricular leukomalacia (PVL).

Ventilators can cause other problems, such as ventilator acquired pneumonia, which can cause oxygenation problems that lead to cerebral palsy if the condition becomes serious.

Being on a ventilator also can cause too much pressure to build up in the baby’s lungs, which can cause damage to the lung tissue, called volutrauma.  In addition, a condition called a pneumothorax may occur, which is when the baby gets a hole or leak (or multiple holes) in the lung (or lungs).  As air builds up outside and around the baby’s lungs, the lungs have difficulty expanding, which can cause oxygen deprivation and the baby’s blood to become acidic.  Both can cause brain damage and cerebral palsy.  A pneumothorax also may put pressure on the veins that bring blood to the heart, which can cause a lack of blood flow to the brain, with resultant brain injury and cerebral palsy.

It is crucial for physicians to properly monitor a baby on a ventilator to ensure that the baby’s oxygen and CO2 levels remain normal.  Chest x-rays (if performed) and data from the ventilator – especially data that shows the pressure in the baby’s lungs – should be continuously examined to make sure the baby is not being overventilated and that the lungs are not becoming damaged.  Blood gas results should be carefully reviewed so that physicians can determine if the CO2 level is too low, or if the baby needs more or less oxygen.

A premature baby often has difficulty breathing, and one of the common causes of this is respiratory distress syndrome (RDS).  In RDS, the baby’s immature lungs don’t produce enough surfactant.  Surfactant allows the inner surface of the lungs to expand properly.

When a baby is born prematurely, the physician usually administers 3 doses of surfactant within 72 hours.  The first dose is usually given immediately after birth, or shortly after breathing problems are revealed.

Surfactant therapy has been shown to substantially reduce mortality and respiratory morbidity in premature infants, but it does have some risks.  Sometimes lung function greatly improves, but the ventilator is not adjusted for this.  Ventilation injuries can occur, such as over-ventilation and abnormally low CO2 levels (hypocarbia), which can cause brain damage and cerebral palsy.  It therefore is crucial for physicians to closely monitor the baby after surfactant administration.

Premature babies are at risk of developing neonatal hypoglycemia (NH), which is a condition in which the baby’s glucose (blood sugar) falls to unsafe levels shortly after birth.  Babies need glucose for energy, and the baby’s brain depends on a steady supply of it as its main source of fuel.  When brain cells receive insufficient glucose, they start to die and brain damage and cerebral palsy can occur.

NH is easily diagnosed by drawing a small amount of the baby’s blood and testing it.  The blood should be sent to a lab, but a quick bedside test also can be done so that treatment can begin immediately, if necessary.  The bedside result can later be compared to the more accurate lab result.

For the majority of babies, treatment for NH is simple: a baby with NH needs extra feedings with breast milk or formula, or a glucose solution can be given through an IV if the baby is unable to be fed by mouth.  In more serious conditions, the baby may need medication.  In severe cases, surgery to remove part of the pancreas, thereby reducing insulin production, may need to be performed.  Since diagnosis and treatment are usually very easy, there really is no reason for a premature baby in a hospital to suffer from NH.

Jaundice is one of the most common health problems in both premature and term infants.  Jaundice is the yellowing of skin and eyes that happens when red blood cells break down and bilirubin, a byproduct of red blood cell breakdown, floods the baby’s body.

Most babies are able to metabolize bilirubin easily.  In some babies, however, red blood cells break down faster than normal and the body can’t easily metabolize (break down and utilize) the bilirubin.  In these babies, bilirubin builds up to dangerous levels in the blood, a condition that is called hyperbilurubinemia.

Hyperbilirubinemia can cause a type of serious brain damage called kernicterus.  Kernicterus is primarily seen in premature or sick newborns because their liver and kidneys aren’t fully developed and cannot quickly remove extra bilirubin.  Kernicterus is a brain toxin, and when it enters the brain, it causes damage to the gray matter, particularly that in the basal ganglia. Children with kernicterus usually have a dystonic or athetoid form of cerebral palsy.

Hyperbilirubinemia is easily diagnosed with simple blood tests.  It also is easily treatable with phototherapy, a fiberoptic phototherapy blanket, and a blood exchange transfusion.  The underlying condition that is causing the hyperbilirubinemia also should be treated, if possible.  Infections and trauma that causes bleeding under a baby’s scalp are conditions that can cause elevated bilirubin levels.

All babies experience a decrease in circulating red blood cells after birth.  Hemoglobin is the part of the red blood cell that carries oxygen, and anemia means that the hemoglobin level is below normal.

Infants born at term have a response to anemia: their bodies produce more of a hormone called erythropoietin (EPO), which controls red blood cell production.  This response is diminished in premature infants, so they often remain anemic for a much longer period of time. This anemia of prematurity (AOP) often is associated with abnormal clinical signs.

One of the most serious issues that AOP can cause is hypoxemia / hypoxia, or a lack of oxygen in the blood stream to be carried to the tissues.  Although babies have ways of compensating for anemia and hypoxia, reduced hemoglobin means there is a reduction in the ability to transport oxygen to the cells and tissues in the body.  If hemoglobin becomes low enough and goes untreated, the baby will not be getting sufficient oxygen to the cells – including brain cells –  and this could lead to brain damage and cerebral palsy.

One treatment for anemia is a red blood cell transfusion, and this should be performed when the level of anemia becomes symptomatic or is thought to compromise adequate oxygen delivery.

Premature babies need to be closely monitored to ensure that anemia is not present.  If it is, treatment should be initiated immediately when indicated.

In many premature babies, the part of the central nervous system that controls breathing is not yet mature enough to allow non-stop breathing.  This causes regular (or fast and deep) breathing followed by periods of shallow or stopped breathing.  This is called apnea of prematurity, or AOP.

The pauses in breathing typically last for 15 – 20 seconds (sometimes longer), and are often accompanied by a drop in heart rate (bradycardia) and decreased oxygen saturation (hypoxia), as well as pale or bluish color.  Caffeine and theophylline have been used for decades to treat AOP.

In addition, the following devices can be used to help babies with AOP: nasal cannula, nasal CPAP (or non-invasive intermittent positive pressure ventilation) and intubation (breathing tube in baby’s airway) with mechanical ventilation.

If the nasal devices are not significantly helping the baby’s AOP, the baby should, in most cases, be intubated.  Intubation with mechanical ventilation will prevent apneic episodes.  In many cases, the risks associated with being intubated and on a ventilator are much less than the risk of brain damage that can result if a baby has significant apnea and bradycardia that goes untreated.  Indeed, untreated or improperly treated apnea can cause injury to the brain and cerebral palsy.

This is a common lung problem among premature infants.  It is characterized by scarring on the lungs, primarily from the immaturity of the lung tissue coupled with improper ventilator settings.  Bronchopulmonary dysplasia (BPD) is typically diagnosed when a premature infant has been on ventilation /oxygen therapy long-term – more than 28 days.

It is not known what causes this serious condition; however, mechanical over ventilation is known to worsen the condition due to increased pressure exerted on the lungs.  It therefore is crucial that a baby’s lung pressures be carefully monitored while on the ventilator, and that time spent on a ventilator is minimized.

When physicians and the medical team do not pay close attention to blood gases, chest x-rays, and pressures and other data on the ventilator, the baby’s lungs can become severely compromised, and this can cause oxygen deprivation with resultant cerebral palsy.

Premature babies may have low blood pressure (hypotension) due to RDS, heart dysfunction, capillary leak syndrome, and low blood volume (hypovolemia).  Low blood pressure should promptly be treated.  Maintaining a good blood pressure is extremely important because it is absolutely necessary to avoid decreased flow of blood to the vessels in the brain.

Sometimes treatment is simple, and normal saline or blood is given to the baby.  Medications such as Dopamine or Dobutamine also may be used to achieve adequate cardiac output.  A side effect of these drugs is high blood pressure, and it is important that this be avoided as well.  Very low blood pressure can cause decreased blood flow to the brain, which means less oxygen-rich blood is getting to the brain.  If this is prolonged or severe, it can cause brain damage and cerebral palsy.

Thus it is crucial that a baby’s blood pressure be closely monitored, and a low blood pressure must immediately be treated.  Continuous monitoring must take place to ensure that blood pressure doesn’t get too high, which also can cause damage to the baby.

Premature babies are at a higher risk for intracranial hemorrhages.  One type of intracranial hemorrhage to which they are especially susceptible is an intraventricular hemorrhage, which is bleeding into the brain’s ventricular system, where spinal fluid is produced.  It is the most serious type of intracranial bleeding and is usually seen in premature infants because blood vessels in their brains are not fully developed and therefore are weak.

Intraventricular hemorrhages can also result from physical trauma during birth.  If a baby is in a difficult position, such as a breech presentation, the head may get stuck in the birth canal, or the process of maneuvering the baby might injure the head and cause a bleed.  In a difficult birth, physicians may utilize delivery instruments, such as forceps.  When used improperly, these can cause intracranial hemorrhages.

A premature birth makes a breech more likely, and the difficulty of labor can cause the baby to have fetal distress, which can deprive the brain of oxygen and cause cerebral palsy.  When there is bleeding in the baby’s brain, the brain becomes oxygen deprived, and this can cause brain damage and cerebral palsy.

Certain conditions can cause a mother’s membranes to rupture (her water breaks) when the baby is premature.  This is called preterm PROM, or PPROM.  PPROM frequently is the result of an infection in the vagina or uterus, and when the membranes break, the infection ascends and infects the baby, or the baby can become infected as she travels through the birth canal.

Infections that a baby can get when PPROM occurs include the following:

• Chorioamnionits
• Neonatal HSV
• Encephalitis (inflammation of the brain, most often caused by HSV)
• GBS
• Sepsis (from GBS, most commonly)
• Meningitis (from GBS, most commonly)

When prematurity is caused by PPROM, the baby is susceptible to fetal distress and umbilical cord prolapse.   Fetal distress can cause the baby to be oxygen-deprived, and cord prolapse can impede or completely cut the baby off from the oxygen she is receiving from the mother through the placenta.  These  oxygen-depriving conditions can cause brain damage and cerebral palsy.