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Diagnostic Radiology/Musculoskeletal Imaging/Metabolic Advanced/Cerebral Palsy

< Diagnostic Radiology | Musculoskeletal Imaging | Metabolic Advanced

Cerebral palsy or CP is a group of permanent disorders associated with developmental brain injuries that occur during fetal development, birth, or shortly after birth. It is characterized by a disruption of motor skills, with symptoms such as spasticity, paralysis, or seizures. Cerebral palsy is a form of static encephalopathy. One form of it, spastic diplegia, is sometimes known as Little's disease in the United Kingdom. Properly speaking, the fact that CP does not get better or worse implies that it is a 'condition' (chronic nonprogressive neurological disorder) rather than a 'disease.' The incidence is about 1.5 to 4 per 1000 live births. There is no cure, but therapy has been shown to be helpful in the maintenance of motor functions. While severity varies widely, cerebral palsy ranks among the most costly congenital conditions to manage.

Cerebral palsy develops while the brain is under development. 80% of all cases occur before the baby reaches 1 month old, however this disorder can occur within about the first 5 years of life. It is a nonprogressive disorder; once damage to the brain occurs, no additional damage occurs as a result of this condition. Cerebral palsy neither improves nor worsens, though symptoms may seem to increase with time, likely due to the aging process.

History

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Cerebral palsy, then known as "Cerebral Paralysis", was first identified by a British surgeon named 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 suggested that a difficult birth was not the cause but rather only a symptom of other effects on fetal development. Modern research has shown that asphyxia is not found during birth in at least 75% of cases. Such research also shows that Freud's view was correct, even though during the late 19th century and most of the 20th century Little's view was the traditional explanation. ("Conditions", 9)

Cause

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Since cerebral palsy refers to a group of disorders, there is no exact known cause. Some major causes are asphyxia, hypoxia of the brain, birth trauma or premature birth, genetic susceptibility, certain infections in the mother during and before birth, central nervous system infections, trauma, and consecutive hematomas. In most people with CP, the cause is unknown. After birth, the condition may be caused by toxins, physical brain injury, incidents involving hypoxia to the brain (such as drowning), and encephalitis or meningitis. Despite all of these causes, the cause of many individual cases of cerebral palsy is unknown.

Recent research has demonstrated that asphyxia is not the most important cause as it was once considered to be, though it still plays a role, probably accounting for about 10% of all cases. The research has shown that infections in the mother, even infections that are not easily detected, may triple the risk of the child developing the disorder.

Premature babies have a higher risk because their organs are not yet fully developed. This increases the risk of asphyxia and other injury to the brain, which in turn increases the incidence of cerebral palsy.

Incidence and prevalence

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The incidence is about 1.5 to 4 per 1000 live births. This amounts to approximately 5,000-10,000 babies born with cerebral palsy each year in the United States. Each year, around 1,500 preschoolers are diagnosed with the disorder. In around 70% of all cases, cerebral palsy is found with some other disorder, the most common being mental retardation.

Overall, advances in care of pregnant mothers and their babies has not resulted in a noticeable decrease in cerebral palsy. Only the introduction of quality medical care to locations with less than adequate medical care has shown any decreases. The incidence increases with premature or very low-weight babies regardless of the quality of care. Twins are also four times more likely to develop cerebral palsy than single births, and triplets are more likely still to develop it.

Despite medical advances, the incidence and severity of cerebral palsy has actually increased over time. This may be attributed to medical advances in areas related to premature babies or the increased usage of artificial fertilization techniques.

Types

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Based on the group of muscles involved (typically only used to further describe spastic CP):

  1. Tetraplegia or Quadriplegia : Involvement of the four limbs, the trunk and the head. The great majority of these individuals will not be able to stand up or walk.
  2. Diplegia: The four limbs are affected, but lower limbs are more involved than upper limbs. Some of the people with diplegia will be able to walk alone, with orthosis, or by the use such as crutches or walkers.
  3. Hemiplegia: Only the right side or the left side of the body is involved. People with hemiplegia are the most likely to walk, even though people with the above two types can often walk without assistance, if severity allows.

NOTE: These are not the only 3 types of spastic CP. Occasionally, terms such as monoplegia, paraplegia, triplegia and pentaplegia may be used.

  1. Ataxia: Persons with ataxia have damage to their cerebellum which results in problems with balance, especially while walking. It is the most rare type, occurring in at most 10% of all cases.
  2. Athetoid or dyskinetic: Persons with this type generally have involuntary body movements. The damage occurs to the extrapyramidal motor system and/or pyramidal tract and to the basal ganglia. It occurs in ~20% of all cases.
  3. Spastic: Persons with this type have damage to the corticospinal tract, motor cortex, or pyramidal tract. It occurs in ~70% of all cases.

These three types may be found together. In 30% of all cases of cerebral palsy, the spastic form is found with the one of the other types. There are a number of other minor types of cerebral palsy, but these are the most common.

Presentation (signs and symptoms)

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All types of cerebral palsy are characterized by abnormal muscle tone, posture, reflexes, or motor development and coordination. The classical symptoms are spasticity, paralysis, seizures, unsteady gait, and dysarthria. While mental retardation and cerebral palsy do not cause each other, the two disorders are found together in approximately 20%-30% of all persons with cerebral palsy. CP symptomatology is as diverse as the individuals who have it. Secondary symptoms can include rigidity of limbs, bladder control issues, and impaired tongue movement.

Imaging Findings

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Soft Tissue

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Soft tissue findings consist largely of decreased muscle mass.

Bones

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In order for bones to attain their normal shape and size, they require the stresses from normal musculature. The osseous findings will therefore mirror the specific muscular deficits in a given patient. The shafts (diaphyses) of the bones are often thin (gracile). When compared to these thin shafts, 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 in a given patient, they may exhibit a variety of angular deformities about their joints.

Vertebral bodies also need vertical gravitational loading forces to develop properly. If a patient with cerebral palsy spends a great deal of time horizontal (in bed) during skeletal maturation, their adult vertebral bodies may be somewhat vertically elongated. Since the horizontal spines of quadrupeds normally appear this way, this finding in humans is sometimes referred to as "caninization".

Prognosis

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Cerebral Palsy is not a progressive disorder. A person with the disorder may improve somewhat during childhood, if they receive extensive care from specialists. Some individuals with the disorder will need to stay under the immediate care of another person for their entire lives, while others have a mild enough case to pursue fully independent lives.

Treatment

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There is no cure for cerebral palsy, but various forms of therapy can help a person with the disorder to function more effectively. Nevertheless, there is only some benefit from life-long care. The treatment is usually symptomatic and focuses on helping the person to develop as many motor skills as possible or to learn how to compensate for the lack of them. The disorder does not affect the expected length of life so treatment focuses on quality of life issues. Non-speaking people with cerebral palsy are often successful availing of Augmentative and Alternative Communication systems such as Blissymbols.

Usage of the term "spastic"

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The term "spastic" describes the attribute of spasticity in one type of cerebral palsy. In 1952 a UK charity called The Spastics Society was formed. The term "spastic" was used by the charity as a term for people with cerebral palsy. The word has since been used extensively as a general insult to disabled people, which they see as extremely offensive. It is also frequently used to insult able-bodied people when they seem overly anxious or unskilled in sports. The charity changed its name to SCOPE in 1994.

References

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