Cerebral palsy
Cerebral palsy (CP) is an umbrella term encompassing a group of non-progressive, non-contagious conditions that cause physical disability in human development.
Cerebral refers to the cerebrum, which is the affected area of the brain (although the disorder most likely involves connections between the cortex and other parts of the brain such as the cerebellum), and palsy refers to disorder of movement. CP is caused by damage to the motor control centers of the developing brain and can occur during pregnancy (about 75 percent), during childbirth (about 5 percent) or after birth (about 15 percent) up to about age three. Further research is needed on adults with CP as the current literature is highly focused on the pediatric patient.
It is a non-progressive disorder, meaning the brain damage does not worsen, but secondary orthopedic difficulties are common. For example, onset of arthritis and osteoporosis can occur much sooner in adults with cerebral palsy. In addition, motor disorder(s) may be accompanied by "disturbances of sensation, cognition, communication, perception, and/or behavior, and/or by a seizure disorder".
There is no known cure for CP. Medical intervention is limited to the treatment and prevention of complications arising from CP's effects.
In another study, the incidence in six countries surveyed was 2.12–2.45 per 1000 live births, indicating a slight rise in recent years. Improvements in neonatal nursing have helped reduce the number of babies who develop cerebral palsy, but the survival of babies with very low birth weights has increased, and these babies are more likely to have cerebral palsy.
Classification
CP is divided into three major classifications to describe different movement impairments. These classifications also reflect the areas of the brain that are damaged. The three major classifications are:
Spastic
Spastic cerebral palsy is by far the most common type, occurring in 70% to 80% of all cases. Moreover, spastic CP accompanies one of the other types in 30% of all cases. People with this type are hypertonic and have a neuromuscular condition stemming from damage to the corticospinal tract or the motor cortex that affects the nervous system's ability to receive gamma amino butyric acid in the area(s) affected by the disability. Spastic CP is further classified by topography dependent on the region of the body affected; these include:
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Spastic hemiplegia (one side being affected). Generally, injury to the left side of the brain will cause a right body deficit, and vice versa. Typically, people that suffer from this type of cerebral palsy are the most ambulatory, although they generally have dynamic equinus on the affected side and are primarily prescribed ankle-foot orthoses to prevent said equinus.
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Spastic diplegia (the lower extremities are affected more than the upper extremities). Most people with disabled diplegia do eventually walk. The gait of a person with Cerebral Palsy diplegia is typically characterised by a crouched gait. Toe walking and flexed knees are common. Hip problems, dislocations, and side effects like strabismus (crossed eyes) are common. Strabismus affects three quarters of people with spastic diplegia. This is due to weakness of the muscles that control eye movement. In addition, these individuals are often nearsighted. In many cases the intelligence of a person with spastic diplegia is unaffected by the condition.
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Spastic quadriplegia (Whole body affected; all four limbs affected equally). Some children with quadriplegia also have hemiparetic tremors; an uncontrollable shaking that affects the limbs on one side of the body and impairs normal movement. A common problem for children with quadriplegia is fluid buildup. Diuretics and steroids are medications administered to decrease any buildup of fluid in the spine that is caused by leakage from dead cells. Hardened feces in a quadriplegia patient are important to monitor because it can cause high blood pressure. Autonomic dysreflexia can be caused by hardened feces, urinary infections, and other problems, resulting in the overreaction of the nervous system and can result in high blood pressure, heart attacks, and strokes. Blockage of tubes inserted into the body to drain or enter fluids also needs to be monitored to prevent autonomic dysreflexia in quadriplegia. The proper functioning of the digestive system needs to be monitored as well.
Occasionally, terms such as monoplegia, paraplegia, triplegia, and pentaplegia may also be used to refer to specific manifestations of the spasticity.
Ataxic
Ataxia type symptoms can be caused by damage to the cerebellum. Forms of ataxia are less common types of Cerebral Palsy, occurring in at most 10% of all cases. Some of these individuals have hypotonia and tremors. Motor skills like writing, typing, or using scissors might be affected, as well as balance, especially while walking. It is common for individuals to have difficulty with visual and/or auditory processing of objects.
Athetoid/dyskinetic
Athetoid or dyskinetic is mixed muscle tone—sometimes hypertonia and sometimes hypotonia (Hypotonia will usually occur before 1 year old; the muscle tone will be increased with age and progress to Hypertonia). People with athetoid CP have trouble holding themselves in an upright, steady position for sitting or walking, and often show involuntary motions. For some people with athetoid CP, it takes a lot of work and concentration to get their hand to a certain spot (like scratching their nose or reaching for a cup). Because of their mixed tone and trouble keeping a position, they may not be able to hold onto objects (such as a toothbrush or pencil). About one quarter of all people with CP have athetoid CP. The damage occurs to the extrapyramidal motor system and/or pyramidal tract and to the basal ganglia. It occurs in 40% of all cases.
Incidence and prevalence
In the industrialised world, the incidence of cerebral palsy is about 2 per 1000 live births. The incidence is higher in males than in females; the Surveillance of Cerebral Palsy in Europe (SCPE) reports a M:F ratio of 1.33:1. Variances in reported rates of incidence across different geographical areas in industrialised countries are thought to be caused primarily by discrepancies in the criteria used for inclusion and exclusion. When such discrepancies are taken into account in comparing two or more registers of patients with cerebral palsy (for example, the extent to which children with mild cerebral palsy are included), the incidence rates converge toward the average rate of 2:1000.
In the United States, approximately 10,000 infants and babies are diagnosed with CP each year, and 1200–1500 are diagnosed at preschool age.
Overall, advances in care of pregnant mothers and their babies has not resulted in a noticeable decrease in CP. This is generally attributed to medical advances in areas related to the care of premature babies (which results in a greater survival rate). Only the introduction of quality medical care to locations with less-than-adequate medical care has shown any decreases. The incidence of CP increases with premature or very low-weight babies regardless of the quality of care.
Prevalence of cerebral palsy is best calculated around the school entry age of about six years, the prevalence in the U.S. is estimated to be 2.4 out of 1000 children
The SCPE reported the following incidence of comorbidities in children with CP (the data are from 1980–1990 and included over 4,500 children over age 4 whose CP was acquired during the prenatal or neonatal period):
- Mental retardation (IQ < 50): 31%
- Active seizures: 21%
- Mental retardation (IQ < 50) and not walking: 20%
- Blindness: 11%
The SCPE noted that the incidence of comorbidities is difficult to measure accurately, particularly across centers. For example, the actual rate of mental retardation may be difficult to determine, as the physical and communicational limitations of people with CP would likely lower their scores on an IQ test if they were not given a correctly modified version.
Apgar scores have sometimes been used as one factor to predict whether or not an individual will develop CP.
Symptoms
All types of CP are characterized by abnormal muscle tone(i.e. slouching over while sitting), reflexes, or motor development and coordination. There can be joint and bone deformities and contractures (permanently fixed, tight muscles and joints). The classical symptoms are spasticities, spasms, other involuntary movements (e.g. facial gestures), unsteady gait, problems with balance, and/or soft tissue findings consisting largely of decreased muscle mass. Scissor walking (where the knees come in and cross) and toe walking (which can contribute to a gait reminiscent of a marionette) are common among people with CP who are able to walk, but taken on the whole, CP symptomatology is very diverse. The effects of cerebral palsy fall on a continuum of motor dysfunction which may range from virtually unnoticeable to "clumsy" and awkward movements on one end of the spectrum to such severe impairments that coordinated movements are almost impossible on the other end of the spectrum.
Babies born with severe CP often have an irregular posture; their bodies may be either very floppy or very stiff. Birth defects, such as spinal curvature, a small jawbone, or a small head sometimes occur along with CP. Symptoms may appear, change, or become more severe as a child gets older. Some babies born with CP do not show obvious signs right away.
Secondary conditions can include seizures, epilepsy, speech or communication disorders, eating problems, sensory impairments, mental retardation, learning disabilities, and/or behavioral disorders.
Causes
Despite years of debate, the cause of the majority of cases of CP is uncertain.
Some contributing causes of CP are asphyxia, hypoxia of the brain, birth trauma, premature birth, central nervous system infections and certain infections in the mother during and before birth. CP is also more common in multiple birth.
Between 40% and 50% of all children who develop cerebral palsy were born prematurely. Premature infants are vulnerable, in part because their organs are not fully developed, increasing the risk of hypoxic injury to the brain that may manifest as CP. A problem in interpreting this is the difficulty in differentiating between CP caused by damage to the brain that results from inadequate oxygenation and CP that arises from prenatal brain damage that then precipitates premature delivery.
Recent research has demonstrated that intrapartum asphyxia is not the most important cause, probably accounting for no more than 10 percent of all cases; rather, infections in the mother, even infections that are not easily detected, may triple the risk of the child developing the disorder, mainly as the result of the toxicity to the fetal brain of cytokines that are produced as part of the inflammatory response. Low birthweight is a risk factor for CP—and premature infants usually have low birth weights, less than 2.0 kg, but full-term infants can also have low birth weights. Multiple-birth infants are also more likely than single-birth infants to be born early or with a high birth weight.
After birth, other causes include toxins, severe jaundice, lead poisoning, physical brain injury, shaken baby syndrome, incidents involving hypoxia to the brain (such as near drowning), and encephalitis or meningitis. The three most common causes of asphyxia in the young child are: choking on foreign objects such as toys and pieces of food; poisoning; and near drowning.
Some structural brain anomalies such as lissencephaly may present with the clinical features of CP, although whether that could be considered CP is a matter of opinion (some people say CP must be due to brain damage, whereas these people never had a normal brain). Often this goes along with rare chromosome disorders and CP is not genetic or hereditary.
Diagnosis
The diagnosis of cerebral palsy has historically rested on the patient's history and physical examination. Once diagnosed with cerebral palsy, further diagnostic tests are optional. The American Academy of Neurology published an article in 2004 reviewing the literature and evidence available on CT and MRI imaging. They suggested that neuroimaging with CT or MRI is warranted when the etiology of a patient's cerebral palsy has not been established - an MRI is preferred over CT due to diagnostic yield and safety. When abnormal, the neuroimaging study can suggest the timing of the initial damage. The CT or MRI is also capable of revealing treatable conditions, such as hydrocephalus, porencephaly, arteriovenous malformation, subdural hematomas and hygromas, and a vermian tumor (which a few studies suggest are present 5 to 22%). Furthermore, an abnormal neuroimaging study indicates a high likelihood of associated conditions, such as epilepsy and mental retardation.
Source: Wikipedia