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Monday, November 5, 2007

Cerebral palsy (CP) -- Causes, Signs and Symptoms

  • Cerebral refers to the affected area of the brain, the cerebrum (however the centres have not been perfectly localised and the disease most likely involves connections between the cortex and other parts of the brain such as the cerebellum)

  • Palsy refers to disorder of movement.

Cerebral palsy (CP) is a group of disorders that hinder control of movement. It is caused by an injury to the brain during pregnancy, around the time of birth, or shortly after birth. This brain damage may be caused by several factors depending on the type, the onset, and the health history of mother and child. CP is either congenital (present at birth) or acquired after birth.

CP is caused by damage to the motor control centers of the young 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. Eighty percent of causes are unknown; for the small number where cause is known this can include infection, malnutrition, and/or head trauma in very early childhood.

Cerebral Paralysis was first identified by English surgeon William Little in 1860. Little raised the possibility of asphyxia during birth as a chief cause of the disorder. It was not until 1897 that Sigmund Freud, then a neurologist, suggested that a difficult birth was not the cause but rather only a symptom of other effects on fetal development. Research conducted during the 1980s by the National Institute of Neurological Disorders and Stroke (NINDS) suggested that only a small number of cases of CP are caused by lack of oxygen during birth.

Causes

The causes of CP remain unclear,with debate over the years giving no obvious answers. The incidence in developed countries is approximately 2.12–2.45 per 1000 live births. Incidence has not declined over the last 60 years despite medical advances (such as electro-fetal monitoring) because these advances allow extremely low birth weight and premature babies to survive. It can result from a variety of conditions:

Infection During Pregnancy

Rubella, cytomegalovirus, and toxoplasmosis can cause severe damage to the nervous system of the fetus and result in cerebral palsy. The central nervous system infections, trauma, consecutive hematomas, and placenta abruptio can cause it too.

Premature birth

Between 40% and 50% of all children who develop cerebral palsy were born prematurely. Premature infants are at higher risk in part because their organs are not yet fully developed, increasing the risk of asphyxia and other injury to the brain, which in turn increases the incidence of CP. Periventricular leukomalacia is an important cause of CP.

Asphyxia, hypoxia of the brain, birth trauma, toxins, lead poisoning, physical brain injury, shaken baby syndrome, incidents involving hypoxia to the brain (such as near drowning), and encephalitis or meningitis --

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 2.0kg, 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 low birth weight.

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.

Lissencephaly

Some structural brain anomalies such as lissencephaly cause symptoms 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).

Jaundice severe jaundice can result in brain damage. After birth, other causes include.

Rh Incompatibility – can cause jaundice This is a condition where the mother's immune system attacks the fetus

Oxygen Shortage – a shortage of oxygen during birth can cause brain damage to the child.

Stroke
– a stroke in the fetus can occur if the mother suffers from coagulation disorders

Toxicity
– drug or alcohol use can result in brain damage

Bleeding
– bleeding in the brain of the infant after birth can cause brain damage

Kidney/Urinary Tract Infections
– can also lead to brain damage

Rare chromosome
-- Often this goes along with rare chromosome disorders and CP is not genetic or hereditary.

Signs and Symptoms

The Characteristic

All types of CP are characterized by abnormal muscle tone, posture (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

The classical symptoms are spasticity, 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 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.

The Bone

In order for bones to attain their normal shape and size, they require the stresses from normal musculature. Osseous findings will therefore mirror the specific muscular deficits in a given person with CP. The shafts of the bones are often thin (gracile).

When compared to these thin shafts (diaphyses) the metaphyses often appear quite enlarged (ballooning). With lack of use, articular cartilage may atrophy, leading to narrowed joint spaces. Depending on the degree of spasticity, a person with CP may exhibit a variety of angular joint deformities. Because vertebral bodies need vertical gravitational loading forces to develop properly, spasticity and an abnormal gait can hinder proper and/or full bone and skeletal development.

People with CP tend to be shorter in height than the average person because their bones are not allowed to grow to their full potential. Sometimes bones grow at different lengths, so the person may have one leg longer than the other.

The Secondary Conditions

Secondary conditions can include :

  • seizures,
  • epilepsy,
  • speech or communication disorders,
  • eating problems,
  • sensory impairments,
  • mental retardation,
  • learning disabilities,
  • and/or behavioral disorders.

From Many Sources

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