Cerebral Palsy
Cerebral palsy is a common developmental
disability first described by William Little in the 1840s. The condition poses
considerable diagnostic and therapeutic challenges to the physician with degree
of involvement ranging from mild with minimal disability to severe, associated
with several co morbid conditions. It is one of the most common lifelong
developmental disabilities causing considerable hardship to affected
individuals and their families.
Cerebral palsy is primarily a disorder of
movement and posture. It is defined as an “umbrella term covering a group of
non-progressive, but often changing, motor impairment syndromes secondary to
lesions or anomalies of the brain arising in the early stages of
its development”. It may be stated as a static encephalopathy in which,
even though the primary lesion, anomaly or injury is static, the clinical
pattern of presentation may change with time due to growth and developmental
plasticity and maturation of the central nervous system.
CP is a common problem, the worldwide
incidence being 2 to 2.5 per 1000 live births When Little first described CP,
he attributed the cause of CP to birth trauma and this view has persisted for
several decades. Recent advances in neonatal management and obstetric care have
not shown a decline in the incidence of CP. On the contrary, with a decline in
infant mortality rate, there has actually been an increase in the incidence and
severity of CP. The incidence in premature babies is much higher than in term
babies. For the vast majority of term infants who develop CP, birth asphyxia or
obstetric complications cannot be ascribed as the cause.
Etiology and Risk Factors for CP
The etiology of CP is very diverse and
multifactorial. The causes are congenital, genetic, inflammatory, infectious,
anoxic, traumatic and metabolic. The injury to the developing brain may be
prenatal, natal or postnatal. As much as 75% - 80% of the cases are due
to prenatal injury with less than 10% being due to significant birth trauma or
asphyxia. The most important risk factor seems to be prematurity and low birth
weight with risk of CP increasing with decreasing gestational age and
birth weight. Cerebral palsy is seen in 10 – 18 % of babies in 500–999 grams
birth weight. CP occurs more commonly in children who are born very prematurely
or at term. Although term infants are at relatively low absolute risk, term
births constitute the large majority of all births, as well as approximately
half of all births of children with cerebral palsy. Prenatal maternal chorioamnionitis
is also a significant risk factor accounting for as much as 12% of cerebral
palsy in term infants and 28% in premature infants. 7, 8 Cystic periventricular
leukomalacia (CPVL) is a risk factor with 60%-100% of patients with CPVL
developing CP.
Prenatal risk factors include intrauterine infections, teratogenic exposures,
placental complications, multiple births, and maternal conditions such as
mental retardation, seizures, or hyperthyroidism. The incidence of CP is higher
among twins and triplets than singletons. Perinatal risk factors are
infections, intracranial hemorrhage, seizures, hypoglycemia,
hyperbilirubinemia, and significant birth asphyxia. Perinatal arterial ischemic
stroke has been identified as another probable cause which leads to hemiplegic
CP in many infants.
Postnatal causes include toxic, infectious meningitis, encephalitis, traumatic
such as drowning. There is also a relation between coagulopathies causing
cerebral infarction and particularly hemiplegic type of CP. Postnatal events
account for 12% – 21% of CP. But in a large number of cases, the cause of CP
remains unknown.
There are several types of cerebral palsy,
each with its own features. Using the American Academy of Cerebral Palsy
classification these are the spastic form, athetosis, rigidity, ataxia, tremor,
atonic form and mixed types.
The diagnosis is greatly complicated by the
wide range of levels of intelligence, and particularly by the frequency with
which mental sub normality is found. Mental sub normality alone has a profound
effect on the developmental pattern.
There is also delay appearance of signs of
cerebral palsy, particularly signs of athetosis where, as children grow older,
certain signs become more obvious.
The child at risk of cerebral palsy:
- Family history of cerebral palsy
- Prematurity, especially extreme
- Multiple pregnancies
- Low birth weight in relation to the duration
of gestation
- Mental sub normality
- Severe hypoxia, convulsion,
hyperbilirubinaemia or cerebral hemorrhage in the newborn period.
Diagnosis of any form
of cerebral palsy:
The
diagnosis must be made, as always, on the basis of history, the examination,
and the interpretation of one’s findings.
The
mother herself may notice that the baby feels stiff, or is stiff on one side,
or keeps one hand clenched when the other is open, or does not kick the legs
properly. She may notice that the child constantly refuse to use one
hand. For instance, she may say that the child can readily pick up a bead
between the tip of the forefinger and the tip of the thumb, but cannot nearly
sit unsupported. This would immediately suggest an abnormality of muscle tone-
hypotonia or hypertonia.
Spastic
form:
The diagnosis is made
on the developmental examination; the following are the essential
considerations:
First 3 months
· In
newborn, note the quantity of his movement, for the spastic child tends to be
relatively immobile. If he has spastic quadriplegia he may lie with his limbs
unduly extended, and his hands unusually tightly closed. After about 3months
the hands should be predominantly loosely open. A hemiplegic child would be
likely to have one hand tightly closed and the other open, and there will be asymmetry
of movement.
· Observe the child, his head size and shape,
his facial expression, his alertness and interest in his surroundings. A small
head circumference in relation to the weight is common because of the frequency
of associated mental sub normality. Because of the frequent mental sub
normality, there is often a lack of normal alertness and responsiveness.
· Hold the child up with your hands holding his
underarms. There may be abnormal extension of the hip and knees (or asymmetry),
and the legs may cross.
· Hold in ventral suspension. There is usually
delayed motor development and so there will be excessive head lag. The arms and
legs commonly hang down lifelessly without the flexion of the elbows and knees
and slight hip extension seen in the normal child.
Some
infants show apparently good or even advanced head control in ventral
suspension and in the prone position, due to excessive extensor tone, and so
give the wrong impression of having advanced motor development: but on pulling
the child to the sitting position from the supine, the gross head lag is
obvious. It is incorrect to term the head lag ‘hypotonic’.
· Place him in the prone position, in order to
assess maturation. The spastic infant commonly assumes an immature position
owing to the mental sub normality and may show excessive extensor tone.
· Place him in the supine position. Note the
symmetry or asymmetry of the kick. Note whether the hands are equally open or
closed. Assess muscle tone by feeling the muscles, assessing the resistance to
passive movement, assessing the range of movement, and shaking the limbs
(for passivity), when holding the arm below the elbow and leg below the knee.
Assess the range of movement especially in the hips (after flexing them to
the right angle) and in dorsiflexion of the ankle. When doing this, test
for ankle clonus. Test the knee jerks, ankle jerks, biceps jerks: for when they
are exaggerated, the area over which the reflex is obtained is greatly
increased.
· Pull him to sitting position in order to
assess head lag. Sway him gently from side to side in order to determine the
degree of head control (positive). When he is being pulled up into the sitting
position, have the hand in the popliteal space in order to detect spasm of the
hamstrings. When a child is spastic one feels a resistance to pulling him up to
the sitting position and the knees may flex: one can see his and feel the spasm
of the hamstrings. When leaned forward he repeatedly falls back, because of spasm
of the erector spinae, glutei and hamstrings. When he is pulled up to the
sitting position, he may rise to his feet, because of excessive extensor tone,
and give the wrong impression of advanced weight bearing. The true diagnosis is
revealed by the other signs of excessive tone, mentioned above, the exaggerated
knee jerks, the ankle clonus, and reduced abduction of the hip and ankle
dorsiflexion, with head lag when he is pulled up.
· Measure his head circumference and relate this
to his weight.
At the end of this period, persistent of the Moro reflex, grasp reflex and
asymmetrical tonic reflex, point to the diagnosis. They should have disappeared
by 2 to 3 months.
Four to 8 months
· Observe the child, as in the case of the
younger infant, noting the quality, quantity and symmetry of movement.
· Give the child a 1-inch cube to go for. This
may reveal the typical spastic approach, unilateral if he has hemiplegia, with
the slow characteristic dorsiflexion of the wrist with splaying out of the
fingers as he approaches the object, often with ataxia and tremor. In a mild
case this may be missed, but careful observation of the two hands shows the
difference in the two sides in a hemiplegic child. It is different from the ataxic
approach of the athetoid child, who does not show the wrist dorsiflexion and
splaying out of the fingers.
· Hold the child up with your hands in his
axilla, in order to determine whether there is excessive extension of the legs.
Test in vertical suspension and the prone position.
· Place him in supine position. Note the
symmetry of kick. Test the knee jerks, the degree of hip abduction and ankle
dorsiflexion, and test for ankle clonus. Elicit the plantar response which in a
normal child (or in an athetoid or ataxic child) is flexor. One must test with
the thumb, and never with a pin or a key, which hurt. When in doubt squeeze the
calf muscles (Gordon’s sign) or stroke firmly down the tibia (Oppenheim’s
sign): these signs depend merely on the fact that in disease of the pyramidal
tract the area over which the reflex is obtained is increased. Pull him to the
sitting position, note the resistance to pulling him up (because of spasm of
the erector spinae and glutei) and the repeated falling back when placed
sitting forward. Note shortening of the limb if there is hemiplegia. See that
the child is lying flat and straight on the couch, and bring the malleoli
together, to see if one leg is shortened. From the end of the couch note
whether the heels are parallel- or whether one is higher up the couch than the
other because of shortening. The foot of the hemiplegic foot limb may be
smaller than the normal foot. Unless the child and room are warm, the
hemiplegic limb is cold as compared with the normal one: feel with the palm of
the hand.
· Note signs of general retardation.
· Measure the head circumference.
· Check the hearing.
Nine months onwards:
· Observe for the same signs above.
· Offer the child a pellet of paper and 1-inch
cubes and if he is old enough, get him to build a tower. In trivial cases the
ataxia or tremor may be slight and readily missed: there may be merely slight
clumsiness in building the tower. Give him beads to thread: a timed bead
threading test may reveal slight neurological involvement. As before, pull him
up, and to the sitting position feel for the resistance when he is pulled up,
and to feel the spasm of the hamstrings.
· If the child is standing or walking, note toe
walking and note the gait. Note shoe wear.
· If old enough (over 3) get him to stand on one
foot. This is a sensitive test, in the case of hemiplegia immediately showing
the difference in the two sides.
· Note signs of general retardation. Measure the
head circumference.
These are the basic
signs of the spastic form of cerebral palsy. It would take perhaps 2 or 3
minutes to carry out the tests described.
Athetosis:
It
is virtually impossible to make a definite diagnosis of athetosis until the
athetoid movements are seen, and these may be delayed for some years. The
condition may be suspected because of one of the conditions known to place the
child at risk of athetosis – particularly severe hypoxia or
hyperbilirubinaemia. When those ‘risk’ conditions occurred, it is easy to
imagine that the child has athetoid movements, when the movements are the
normal arm and leg movements.
The signs of kernicterus appear not later than the sixth day in a
full-term baby, or the tenth day in a preterm baby; the signs are a high
pitched cry, rolling of the eyes, opisthotonus, refusal of feeds, hypertonia,
tightly clenched fists, loss of the Moro reflex and possibly fits or apnoeic
attacks. The infant may characteristically extend the elbows and pronate the
wrists. There may be excessive extensor tone, so that there is severe head lag
when the child is pulled from the supine to sitting position, while there is
apparently good head control in the prone or ventral suspension. Rhythmical tongue
thrusting is often an early feature, and sucking and swallowing difficulties
are common. In the early weeks there are usually signs of delayed motor
development, sometimes with the attacks of opisthotonus. Athetoid movements may
be observed anytime after the first 6months (and possibly sooner), but more
often after the first year. As they are difficult to be certain about, opinions
as to when they first appeared are open to doubt. The earliest suspicious sign
of the development of athetosis is ataxia on reaching out for objects- a
movement quiet different from the splaying out of the hands when a specific
child reaching for a toy. After the first year there is usually difficulty in
vertical gaze, enamel hypoplasia of the deciduous teeth and high tone deafness.
The plantar responses and knee jerks are normal in athetosis, because the
pyramidal tract is not involved.
Not
all athetosis had hyperbilirubinaemia. The signs after the newborn period are
mainly developmental delay, followed by ataxia on reaching out for objects,
followed by the development of athetoid movements.
Rigidity:
The rigid form is diagnosed by the extreme rigidity of all limbs, in the
absence of signs of disease of the pyramidal tract, such as increased tendon
jerks, ankle clonus, positive stretch reflex, and extensor plantar response. It
is almost always associated with a severe degree of mental sub normality.
Ataxia:
The ataxic form is diagnosed by the ataxia in the child’s approach to an
object, and ataxia in sitting and walking.
Hypotonic form of
cerebral palsy:
This is a very rare form of cerebral palsy which can readily be confused with
the hypotonia that persists beyond 2 to 3 yrs of age that does not result
from a primary disorder of muscle or peripheral nerve. Almost all infants with
this condition are mentally subnormal. The deep tendon reflexes are normal
or hyperactive, and the electrical reactions of muscle and nerve are
normal. The circumference of the skull is likely to be small. There is an
increased range of movement. Fits occur in a third.
The Gross Motor Function Classification System
(GMFCS)
This is a recently developed system which has
been found to be a reliable and valid system that classifies children with
cerebral palsy by their age-specific gross motor activity. The GMFCS describes
the functional characteristics in five levels, from I to V, level I being the
mildest in the following age groups: up to 2 yrs, 2 – 4 yrs, 4 – 6 years and
between 6 to 12 years. For each level, separate descriptions are provided.
Children in level III usually require orthotics and assisting mobility devices,
while children in level II do not require assisting mobility devices after age
4. Children in level III sit independently, have independent floor mobility,
and walk with assisting mobility devices. In level IV, affected children
function in supported sitting but independent mobility is very limited.
Children in level V lack independence even in basic antigravity postural
control and need power mobility.
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