INTRODUCTION
Cerebral palsy refers to a group of neurological disorders that appear in infancy or early childhood and permanently affect body movement and muscle coordination Cerebral palsy (CP) is caused by damage to or abnormalities inside the developing brain that disrupt the brain’s ability to control movement and maintain posture and balance.
The word “Cerebral” refers to Cerebellum — the brain part that usually gets damaged in CP. “Palsy” refers to the resulting movement disorder. Cerebral palsy affects the motor area of the brain’s outer layer (called the cerebral cortex), the part of the brain that directs muscle movement. In some cases, the cerebral motor cortex hasn’t developed normally during fetal growth. In others, the damage is a result of injury to the brain either before, during, or after birth. In either case, the damage is not repairable and the disabilities that result are permanent.
Thus, Cerebral Palsy can cause locomotor disability i.e. it can hamper voluntary movement of muscles. Locomotor disability can range from muscular weakness to complete lack of movement in muscles. People affected with CP are also likely to have other types of impairment.
TYPES OF CEREBRAL PALSY
The specific forms of cerebral palsy are determined by the extent, type, and location of a child’s abnormalities. Doctors classify CP according to the type of movement disorder involved -- spastic (stiff muscles), athetoid (writhing movements), or ataxic (poor balance and coordination) -- plus any additional symptoms, such weakness (paresis) or paralysis (plegia). For example, hemiparesis (hemi = half) indicates that only one side of the body is weakened.Quadriplegia (quad = four) means all four limbs are afffected.
Spastic cerebral palsy is the most common type of the disorder. People have stiff muscles and awkward movements. Forms of spastic cerebral palsy include:
· Spastic hemiplegia/hemiparesis typically affects the arm and hand on one side of the body, but it can also include the leg. Children with spastic hemiplegia generally walk later and on tip-toe because of tight heel tendons. The arm and leg of the affected side are frequently shorter and thinner. Some children will develop an abnormal curvature of the spine (scoliosis). A child with spastic hemiplegia may also have seizures. Speech will be delayed and, at best, may be competent, but intelligence is usually normal.
· Spastic diplegia/diparesis involves muscle stiffness that is predominantly in the legs and less severely affects the arms and face, although the hands may be clumsy. Tendon reflexes in the legs are hyperactive. Toes point up when the bottom of the foot is stimulated. Tightness in certain leg muscles makes the legs move like the arms of a scissor. Children may require a walker or leg braces. Intelligence and language skills are usually normal.
· Spastic quadriplegia/quadriparesis is the most severe form of cerebral palsy and is often associated with moderate-to-severe intellectual disability. It is caused by widespread damage to the brain or significant brain malformations. Children will often have severe stiffness in their limbs but a floppy neck. They are rarely able to walk. Speaking and being understood are difficult. Seizures can be frequent and hard to control.
Dyskinetic cerebral palsy (also includes athetoid, choreoathetoid, and dystonic cerebral palsies) is characterized by slow and uncontrollable writhing or jerky movements of the hands, feet, arms, or legs. Hyperactivity in the muscles of the face and tongue makes some children grimace or drool. They find it difficult to sit straight or walk. Some children have problems hearing, controlling their breathing, and/or coordinating the muscle movements required for speaking. Intelligence is rarely affected in these forms of cerebral palsy.
Ataxic cerebral palsy affects balance and depth perception. Children with ataxic CP will often have poor coordination and walk unsteadily with a wide-based gait. They have difficulty with quick or precise movements, such as writing or buttoning a shirt, or a hard time controlling voluntary movement such as reaching for a book.
Mixed types of cerebral palsy refer to symptoms that don’t correspond to any single type of CP but are a mix of types. For example, a child with mixed CP may have some muscles that are too tight and others that are too relaxed, creating a mix of stiffness and floppiness.
CLASSIFICATION
Cerebral palsy is classified according to the Gross Motor Function Classification System (GMFCS). The World Health Organization (WHO) and the Surveillance of Cerebral Palsy in Europe developed the GMFCS as a universal standard for determining the physical capabilities of people with CP.
The system focuses on:
The five levels of the GMFCS increase with decreasing mobility:
Level 1 CP is characterized by being able to walk without limitations.
A person with level 2 CP can walk long distances without limitations, but they can’t run or jump.
They may need assistive devices, such as leg and arm braces, when first learning to walk. They also may need to use a wheelchair to get around outside of their home.
A person with level 3 CP can sit with little support and stand without any support.
They need handheld assistive devices, such as a walker or cane, while walking indoors. They also need a wheelchair to get around outside of the home.
A person with level 4 CP can walk with the use of assistive devices.
They’re able to move independently in a wheelchair, and they need some support when they’re sitting.
A person with level 5 CP needs support to maintain their head and neck position.
They need support to sit and stand, and they may be able to control a motorized wheelchair.
Intellectual disability. Approximately 30 – 50 percent of individuals with CP will be intellectually impaired. Mental impairment is more common among those with spastic quadriplegia than in those with other types of cerebral palsy.
Seizure disorder. As many as half of all children with CP have one or more seizures. Children with both cerebral palsy and epilepsy are more likely to have intellectual disability.
Delayed growth and development. Children with moderate to severe CP, especially those with spastic quadriparesis, often lag behind in growth and development. In babies this lag usually takes the form of too little weight gain. In young children it can appear as abnormal shortness, and in teenagers it may appear as a combination of shortness and lack of sexual development. The muscles and limbs affected by CP tend to be smaller than normal, especially in children with spastic hemiplegia, whose limbs on the affected side of the body may not grow as quickly or as long as those on the normal side.
Spinal deformities and osteoarthritis. Deformities of the spine—curvature (scoliosis), humpback (kyphosis), and saddle back (lordosis) -- are associated with CP. Spinal deformities can make sitting, standing, and walking difficult and cause chronic back pain. Pressure on and misalignment of the joints may result in osteoporosis (a breakdown of cartilage in the joints and bone enlargement).
Impaired vision. Many children with CP have strabismus, commonly called “cross eyes,” which left untreated can lead to poor vision in one eye and can interfere with the ability to judge distance. Some children with CP have difficulty understanding and organizing visual information. Other children may have defective vision or blindness that blurs the normal field of vision in one or both eyes.
Hearing loss. Impaired hearing is also more frequent among those with CP than in the general population. Some children have partial or complete hearing loss, particularly as the result of jaundice or lack of oxygen to the developing brain.
Speech and language disorders. Speech and language disorders, such as difficulty forming words and speaking clearly, are present in more than a third of persons with CP. Poor speech impairs communication and is often interpreted as a sign of cognitive impairment, which can be very frustrating to children with CP, especially the majority who have average to above average intelligence,
Drooling. Some individuals with CP drool because they have poor control of the muscles of the throat, mouth, and tongue.
Incontinence. A possible complication of CP is incontinence, caused by poor control of the muscles that keep the bladder closed.
Abnormal sensations and perceptions. Some individuals with CP experience pain or have difficulty feeling simple sensations, such as touch.
Learning difficulties. Children with CP may have difficulty processing particular types of spatial and auditory information. Brain damage may affect the development of language and intellectual functioning.
Infections and long-term illnesses. Many adults with CP have a higher risk of heart and lung disease, and pneumonia (often from inhaling bits of food into the lungs), than those without the disorder.
Contractures. Muscles can become painfully fixed into abnormal positions, called contractures, which can increase muscle spasticity and joint deformities in people with CP.
Malnutrition. Swallowing, sucking, or feeding difficulties can make it difficult for many individuals with CP, particularly infants, to get proper nutrition and gain or maintain weight.
Dental problems. Many children with CP are at risk of developing gum disease and cavities because of poor dental hygiene. Certain medications, such as seizure drugs, can exacerbate these problems.
Inactivity. Childhood inactivity is magnified in children with CP due to impairment of the motor centers of the brain that produce and control voluntary movement. While children with CP may exhibit increased energy expenditure during activities of daily living, movement impairments make it difficult for them to participate in sports and other activities at a level of intensity sufficient to develop and maintain strength and fitness. Inactive adults with disability exhibit increased severity of disease and reduced overall health and well-being.
Gastroesophageal reflux disease (GERD) is common among those with cerebral palsy. GERD is a digestive disease in which stomach acid is regurgitated into the esophagus. Children who have difficulty swallowing and/or GERD are at risk for aspiration, which is when food, liquids, saliva or vomit are inhaled into the lungs. Frequent aspiration can lead to respiratory problems, like aspiration pneumonia, and may be life-threatening.
CAUSES
Cerebral palsy is caused by abnormal development of part of the brain or by damage to parts of the brain that control movement. This damage can occur before, during, or shortly after birth. The majority of children have congenital cerebral palsy CP (that is, they were born with it), although it may not be detected until months or years later. A small number of children have acquired cerebral palsy, which means the disorder begins after birth. Some causes of acquired cerebral palsy include brain damage in the first few months or years of life, brain infections such as bacterial meningitis or viral encephalitis, problems with blood flow to the brain, or head injury from a motor vehicle accident, a fall, or child abuse.
In many cases, the cause of cerebral palsy is unknown. Possible causes include genetic abnormalities, congenital brain malformations, maternal infections or fevers, or fetal injury, for example. The following types of brain damage may cause its characteristic symptoms:
Damage to the white matter of the brain (periventricular leukomalacia, or PVL). The white matter of the brain is responsible for transmitting signals inside the brain and to the rest of the body. Damage from PVL looks like tiny holes in the white matter of an infant’s brain. These gaps in brain tissue interfere with the normal transmission of signals. Researchers have identified a period of selective vulnerability in the developing fetal brain, a period of time between 26 and 34 weeks of gestation, in which periventricular white matter is particularly sensitive to insults and injury.
Abnormal development of the brain (cerebral dysgenesis). Any interruption of the normal process of brain growth during fetal development can cause brain malformations that interfere with the transmission of brain signals. Mutations in the genes that control brain development during this early period can keep the brain from developing normally. Infections, fevers, trauma, or other conditions that cause unhealthy conditions in the womb also put an unborn baby’s nervous system at risk.
Bleeding in the brain (intracranial hemorrhage). Bleeding inside the brain from blocked or broken blood vessels is commonly caused by fetal stroke. Some babies suffer a stroke while still in the womb because of blood clots in theplacenta that block blood flow in the brain. Other types of fetal stroke are caused by malformed or weak blood vessels in the brain or by blood-clotting abnormalities. Maternal high blood pressure (hypertension) is a common medical disorder during pregnancy and is more common in babies with fetal stroke. Maternal infection, especially pelvic inflammatory disease, has also been shown to increase the risk of fetal stroke.
Severe lack of oxygen in the brain. Asphyxia, a lack of oxygen in the brain caused by an interruption in breathing or poor oxygen supply, is common for a brief period of time in babies due to the stress of labor and delivery. If the supply of oxygen is cut off or reduced for lengthy periods, an infant can develop a type of brain damage called hypoxic-ischemic encephalopathy, which destroys tissue in the cerebral motor cortex and other areas of the brain. This kind of damage can also be caused by severe maternal low blood pressure, rupture of the uterus, detachment of the placenta, or problems involving the umbilical cord, or severe trauma to the head during labor and delivery.
RISK FACTORS
A number of factors are associated with an increased risk of cerebral palsy.
Certain infections or toxic exposures during pregnancy can significantly increase cerebral palsy risk to the baby. Infections of particular concern include:
· Cytomegalovirus. This common virus causes flu-like symptoms and can lead to birth defects if a mother has her first active infection during pregnancy.
· German measles (rubella). This viral infection can be prevented with a vaccine.
· Herpes. This can be passed from mother to child during pregnancy, affecting the womb and placenta. Inflammation triggered by infection can damage the unborn baby's developing nervous system.
· Syphilis. This is a sexually transmitted bacterial infection.
· Toxoplasmosis. This infection is caused by a parasite found in contaminated food, soil and the feces of infected cats.
· Zika virus infection. Infants for whom maternal Zika infection causes their head size to be smaller than normal (microcephaly) can develop cerebral palsy.
· Other conditions. Other conditions that can increase the risk of cerebral palsy include thyroid problems, intellectual disabilities or seizures, and exposure to toxins, such as methyl mercury.
Illnesses in a newborn baby that can greatly increase the risk of cerebral palsy include:
· Bacterial meningitis. This bacterial infection causes inflammation in the membranes surrounding the brain and spinal cord.
· Viral encephalitis. This viral infection similarly causes inflammation in the membranes surrounding the brain and spinal cord.
· Severe or untreated jaundice. Jaundice appears as a yellowing of the skin. The condition occurs when certain byproducts of "used" blood cells aren't filtered from the bloodstream.
· Bleeding into the brain. This condition is commonly caused by the baby having a stroke in the womb.
While the potential contribution from each is limited, additional pregnancy or birth factors associated with increased cerebral palsy risk include:
· Breech presentation. Babies with cerebral palsy are more likely to be in this feet-first position at the beginning of labor rather than being headfirst.
· Low birth weight. Babies who weigh less than 5.5 pounds (2.5 kilograms) are at higher risk of developing cerebral palsy. This risk increases as birth weight drops.
· Multiple babies. Cerebral palsy risk increases with the number of babies sharing the uterus. If one or more of the babies die, the survivors' risk of cerebral palsy increases.
· Premature birth. Babies born fewer than 28 weeks into the pregnancy are at higher risk of cerebral palsy. The earlier a baby is born, the greater the cerebral palsy risk.
PREVENTION
Most cases of cerebral palsy can't be prevented, but you can lessen risks. If you're pregnant or planning to become pregnant, you can take these steps to keep healthy and minimize pregnancy complications:
· Make sure you're vaccinated. Getting vaccinated against diseases such as rubella, preferably before getting pregnant, might prevent an infection that could cause fetal brain damage.
· Take care of yourself. The healthier you are heading into a pregnancy, the less likely you'll be to develop an infection that results in cerebral palsy.
· Seek early and continuous prenatal care. Regular visits to your doctor during your pregnancy are a good way to reduce health risks to you and your unborn baby. Seeing your doctor regularly can help prevent premature birth, low birth weight and infections.
· Practice good child safety. Prevent head injuries by providing your child with a car seat, bicycle helmet, safety rails on beds and appropriate supervision.
· Avoid alcohol, tobacco and illegal drugs. These have been linked to cerebral palsy risk.
Most children with cerebral palsy are diagnosed during the first 2 years of life. But if a child’s symptoms are mild, it can be difficult for a doctor to make a reliable diagnosis before the age of 4 or 5.
Doctors will order a series of tests to evaluate the child’s motor skills. During regular visits, the doctor will monitor the child’s development, growth, muscle tone, age-appropriate motor control, hearing and vision, posture, and coordination, in order to rule out other disorders that could cause similar symptoms. Although symptoms may change over time, CP is not progressive. If a child is continuously losing motor skills, the problem more likely is a condition other than CP—such as a genetic or muscle disease, metabolism disorder, or tumors in the nervous system.
Lab tests can identify other conditions that may cause symptoms similar to those associated with CP.
Neuroimaging techniques that allow doctors to look into the brain (such as an MRI scan) can detect abnormalities that indicate a potentially treatable movement disorder. Neuroimaging methods include:
· Cranial ultrasound uses high-frequency sound waves to produce pictures of the brains of young babies. It is used for high-risk premature infants because it is the least intrusive of the imaging techniques, although it is not as successful as computed tomography or magnetic resonance imaging at capturing subtle changes in white matter—the type of brain tissue that is damaged in CP.
· Computed tomography (CT) uses x-rays to create images that show the structure of the brain and the areas of damage.
· Magnetic resonance imaging (MRI) uses a computer, a magnetic field, and radio waves to create an anatomical picture of the brain's tissues and structures. MRI can show the location and type of damage and offers finer levels of details than CT.
Another test, an electroencephalogram, uses a series of electrodes that are either taped or temporarily pasted to the scalp to detect electrical activity in the brain. Changes in the normal electrical pattern may help to identify epilepsy.
Some metabolic disorders can masquerade as CP. Most of the childhood metabolic disorders have characteristic brain abnormalities or malformations that will show up on an MRI.
Other types of disorders can also be mistaken for CP or can cause specific types of CP. For example, coagulation disorders (which prevent blood from clotting or lead to excessive clotting) can cause prenatal or perinatal strokes that damage the brain and produce symptoms characteristic of CP, most commonly hemiparetic CP. Referrals to specialists such as a child neurologist, developmental pediatrician, ophthalmologist, or otologist aid in a more accurate diagnosis and help doctors develop a specific treatment plan.
Children and adults with cerebral palsy require long-term care with a medical care team. Besides a pediatrician or physiatrist and possibly a pediatric neurologist to oversee your child's medical care, the team might include a variety of therapists and mental health specialists.
Medications that can lessen muscle tightness might be used to improve functional abilities, treat pain and manage complications related to spasticity or other cerebral palsy symptoms.
To treat tightening of a specific muscle, your doctor might recommend injections of onabotulinumtoxinA (Botox, Dysport) or another agent. Your child will need injections about every three months.
Side effects can include pain at the injection site and mild flu-like symptoms. Other more-serious side effects include difficulty breathing and swallowing.
Drugs such as diazepam (Valium), dantrolene (Dantrium), baclofen (Gablofen, Lioresal) and tizanidine (Zanaflex) are often used to relax muscles.
Diazepam carries some dependency risk, so it's not recommended for long-term use. Side effects of these drugs include drowsiness, blood pressure changes and risk of liver damage that requires monitoring.
In some cases, baclofen is pumped into the spinal cord with a tube. The pump is surgically implanted under the skin of the abdomen.
Your child might also be prescribed medication to reduce drooling — possibly Botox injections into the salivary glands.
A variety of therapies play an important role in treating cerebral palsy:
· Physical therapy. Muscle training and exercises can help your child's strength, flexibility, balance, motor development and mobility. You'll also learn how to safely care for your child's everyday needs at home, such as bathing and feeding your child.
For the first one to two years after birth, both physical and occupational therapists provide support with issues such as head and trunk control, rolling, and grasping. Later, both types of therapists are involved in wheelchair assessments.
Braces or splints might be recommended for your child to help with function, such as improved walking, and stretching stiff muscles.
· Occupational therapy. Occupational therapists work to help your child gain independence in daily activities and routines in the home, the school and the community. Adaptive equipment recommended for your child can include walkers, quadrupedal canes, seating systems or electric wheelchairs.
· Speech and language therapy. Speech-language pathologists can help improve your child's ability to speak clearly or to communicate using sign language. They can also teach the use of communication devices, such as a computer and voice synthesizer, if communication is difficult.
Speech therapists can also address difficulties with eating and swallowing.
· Recreational therapy. Some children benefit from regular or adaptive recreational or competitive sports activities, such as therapeutic horseback riding or skiing. This type of therapy can help improve your child's motor skills, speech and emotional well-being.
Surgery may be needed to lessen muscle tightness or correct bone abnormalities caused by spasticity. These treatments include:
· Orthopedic surgery. Children with severe contractures or deformities might need surgery on bones or joints to place their arms, hips or legs in their correct positions.
Surgical procedures can also lengthen muscles and tendons that are shortened by contractures. These corrections can lessen pain and improve mobility. The procedures can also make it easier to use a walker, braces or crutches.
· Cutting nerve fibers (selective dorsal rhizotomy). In some severe cases, when other treatments haven't helped, surgeons might cut the nerves serving the spastic muscles in a procedure called selective dorsal rhizotomy. This relaxes the muscle and reduces pain, but can cause numbness.