What Is the Main Cause of Cerebral Palsy?

The main cause of cerebral palsy, a disorder affecting a person’s movement, balance, and posture, is abnormal development of the brain prior to birth. For some children, the condition develops early in life while the brain is still developing. Risk factors can include low birth weight, premature birth, multiple birth, infection, brain injury, and others.

Cerebral palsy (CP) is a disorder that affects a person’s movement, balance, and posture. Cerebral means having to do with the brain and palsy means weakness with the muscles. Damage to the brain causes people with CP to have problems using their muscles. 

The main cause of cerebral palsy is abnormal development of the brain prior to birth. Babies are generally born with CP (it is congenital — from birth), though in some children the condition develops early in life while the brain is still developing. About 85 to 90 percent of cases of cerebral palsy are congenital. 

Risk factors for congenital cerebral palsy include:

• Low birth weight, weighing less than 5-1/2 pounds at birth, and especially weighing less than 3 pounds, 5 ounces at birth 
• Premature birth, before the 37th week of pregnancy, especially before the 32nd week of pregnancy
• Multiple birth (twins, triplets, and other multiple births)
• Children conceived using assisted reproductive technology (ART) infertility treatments
• Infections during pregnancy, such as chickenpox, rubella (German measles), and cytomegalovirus (CMV), and bacterial infections such as infections of the placenta or fetal membranes, or maternal pelvic infections
• Jaundice and kernicterus
• Maternal medical conditions such as thyroid problems, intellectual disability, or seizures 
• Birth complications such as detachment of the placenta, uterine rupture, or problems with the umbilical cord during birth 

In a small percentage of patients, cerebral palsy is caused by brain damage that occurs more than 28 days after birth (acquired cerebral palsy). Some causes of acquired CP include:

• Infection, including brain infections such as meningitis or encephalitis during infancy
• Brain injuries, such as head injuries caused by motor vehicle crashes or child abuse
• Problems with blood flow to the brain, such as stroke or bleeding in the brain associated with a blood clotting problem, blood vessels that didn’t form properly, a heart defect that was present at birth, or sickle cell disease

Symptoms of cerebral palsy vary widely and some children have mild impairment while others can have severe disability. Symptoms of CP last throughout a person’s life, but the condition does not worsen with age. 

Symptoms of cerebral palsy involve movement disorders including:

• Stiff muscles (spasticity)
• Uncontrollable movements (dyskinesia)
• Poor balance and coordination (ataxia)

There are four main types of CP and symptoms depend on the type of CP that is present.

• Spastic cerebral palsy
  • The most common type, affects about 80% of people with CP
  • Causes increased muscle tone (stiff muscles)
  • Awkward movements
    • Spastic diplegia/diparesis
      • In this type of CP, muscle stiffness is mainly in the legs and patients may have difficulty walking because tight hip and leg muscles cause their legs to pull together, turn inward, and cross at the knees (“scissoring”)
    • Spastic hemiplegia/hemiparesis
      • This type affects only one side of a person’s body
      • Usually the arm is more affected than the leg
    • Spastic quadriplegia/quadriparesis
      • The most severe form of spastic CP 
      • Affects all four limbs, the trunk, and the face
      • Patients usually cannot walk and often have other developmental disabilities such as intellectual disability; seizures; or problems with vision, hearing, or speech.
• Dyskinetic cerebral palsy (also includes athetoid, choreoathetoid, and dystonic cerebral palsies)
  • Muscle tone can change (from too tight to too loose) not only from day to day, but even during one day
  • Causes problems controlling the movement of their hands, arms, feet, and legs, making it difficult to sit and walk
  • Movements are uncontrollable and can be slow and writhing or rapid and jerky
  • Face and tongue may be affected and the person has a hard time sucking, swallowing, and talking
• Ataxic cerebral palsy
  • Problems with balance and coordination.
  • Unsteadiness when they walking
  • Difficulty with quick movements or movements that need a lot of control, such as writing
  • Difficulty controlling hands or arms when reaching for things
• Mixed cerebral palsy
  • Symptoms of more than one type
  • The most common type of mixed CP is spastic-dyskinetic CP

Children with cerebral palsy may also have other symptoms, including:

• Problems drinking or eating 
  • May lead to lack of weight gain 
  • Choking
• Acid reflux 
• Lung infections
• Difficulty thinking and learning
• Problems with hearing and speaking
• Trouble seeing 
• Seizures
• Scoliosis
• Bladder control problems 
• Constipation 
• Dislocation of the hip joints
• Pain, which can be related to issues like muscle stiffness, problems with the hip joints, or constipation

Cerebral palsy is diagnosed with a patient history of symptoms, and a physical examination, however it is not always apparent if a child has cerebral palsy at birth. Children develop at different rates during the first two years of life so they may need to be monitored. 

• Developmental monitoring (also called surveillance) involves tracking a child’s growth and development over time
• Developmental screening involves a test to see if a child has specific developmental delays, such as motor or movement delays
  • Some developmental screening tests are interviews or questionnaires completed by parents while others are tests that a doctor administers to the child
  • The American Academy of Pediatrics recommends all children be screened for developmental delays during regular well-child office visits at 9 months, 18 months, and 24 or 30 months
  • If the screening tests raise any cause for concern, a child may need:
    • Developmental and medical evaluations to diagnose the specific disorder that is affecting the child
      • Tests may include 
        • X-ray
        • Computed tomography (CT) scan
        • Magnetic resonance imaging (MRI)
        • Electroencephalogram (EEG)
        • Genetic testing
        • Metabolic testing

Treatment for cerebral palsy usually involves an “early intervention” program to teach parents and caretakers how to help a child do everyday activities that they might have trouble with such as eating, speaking, walking, and learning. 

There is no single treatment for CP, and treatments are individualized based on a child’s symptoms. Treatments for cerebral palsy may include:

• Medications to help treat symptoms such as stiff muscles, unusual body movements, or seizures
• Equipment which may include devices such as leg braces, walkers, or a wheelchair to help a child get around
• Physical, occupational, and speech therapy
• Nutrition 
  • Some children need special diets so they can gain a healthy amount of weight
  • Some may need a “gastrostomy tube” or “g-tube,” to bring nutrition directly into the stomach
• Surgery 
  • For very severe symptoms, surgery may be needed to put the child's legs or arms into the correct position