Cerebral palsy is a non-progressive brain damage syndrome caused by various reasons from before to one month after birth, mainly manifesting as congenital movement disorders and postural abnormalities, including spastic bilateral paresis, tardive dyskinesia and other cone and extrapyramidal symptoms, which may be accompanied by varying degrees of mental retardation, speech disorders and seizures.
I. Etiology and pathogenesis
The etiology of cerebral palsy is complex, including hereditary and acquired. The latter is divided into prenatal, perinatal and postnatal etiologies, and many children cannot find a clear cause. Cerebral palsy in China occurs mostly in infants born prematurely, with low birth weight, hypoxic asphyxia during delivery and postnatal jaundice.
Pre-birth etiology: including malformation of brain development during embryonic period, serious infection (especially viral infection), severe nutritional deficiency, trauma, toxemia of pregnancy, diabetes and radiation exposure during pregnancy, etc., which affect the fetal brain development and cause permanent brain damage.
Perinatal etiology: prematurity is the definite cause of cerebral palsy; prolonged delivery, umbilical cord encirclement, placenta abruptio, placenta praevia causing fetal brain hypoxia; intracranial hemorrhage due to birth injury, emergency delivery, obstructed labor, hemorrhagic disease; kernicterus due to neonatal hyperbilirubinemia caused by mother-child blood type incompatibility or other causes can cause this disease.
Postnatal etiology: including central nervous system infection, poisoning, head trauma, severe asphyxia, cardiac arrest, persistent convulsions, intracranial hemorrhage and acute encephalopathy of unknown origin.
Hereditary factors: Some children with cerebral palsy may have a familial history of hereditary disease. Children with cerebral palsy have a higher chance of developing cerebral palsy if their parents are married to close relatives or if they have cerebral palsy, mental retardation or congenital malformations in the family.
The maintenance of normal muscle tone regulation and postural reflexes depends on the dynamic balance between the inhibitory effect of cortical downstream fibers and the excitatory effect of peripheral afferent fibers of type Ia. When the cortical downstream fiber bundles are damaged due to abnormal brain development, the downstream inhibitory effect is inevitably weakened and the excitatory effect of peripheral afferent fibers is relatively enhanced. Impairment of perceptual abilities such as vision and hearing may aggravate the mental retardation of the child; damage to the basal ganglia may lead to tardive dyskinesia; damage to the cerebellum may lead to ataxia, etc.
Epidemiology High incidence of the disease
Internationally, the incidence of cerebral palsy is 1‰~5‰, and the incidence of cerebral palsy in China is 1.8‰~4‰. The etiology, pathology and symptoms of cerebral palsy are complex and varied, and there are many clinical classification methods.
According to the etiology and pathology, it can be classified as
Stromal (subventricular) hemorrhage in preterm infants: it is a hemorrhage in the area near the caudate nucleus at the level of the monro foramen of the cerebral hemisphere, located in the subventricular cell-generating stroma, often involving bilateral and asymmetric. It is common in low birth weight preterm infants at 20-35 weeks of gestational age. Brain dysfunction, respiratory distress, cyanosis, inability to suck, bulging fontanelle and bloody cerebrospinal fluid are seen rapidly in the first few days after birth, and death often occurs within a few days.
Cerebral spastic bilateral palsy (Little’s disease): Little (1862) introduced the concept of hypoxic-ischemic encephalopathy, which was later called Little’s disease. Cerebral palsy includes types of paraplegia, bilateral palsy, quadriplegia, hemiplegia and pseudobulbar palsy. Of these, bilateral paresis is the more severe quadriplegia of the lower extremities.
Progressive motor abnormalities: can include infantile hemiplegia, paraplegia and tetraplegia, congenital and acquired extrapyramidal syndromes, congenital ataxia, congenital flaccid paralysis, congenital medullary palsy, and other types.
According to the symptoms of muscle tension and abnormal motor posture, they can be classified as
Spastic type: the most common ;
Tonic type ;
Tardive dyskinesia;
Ataxic type;
Tremor;
Hypotonia;
Mixed;
Unable to classify the type.
Pathology
Brain damage in cerebral palsy can involve the brain and cerebellum extensively, with diffuse cortical dysplasia or atrophic lobar sclerosis common, with scattered marble-like lesions scarring the cortex and basal ganglia; followed by limited lesions, including limited white matter sclerosis and giant cerebral penetration malformations. Regardless of the etiology, malformations such as narrowing of the cerebral gyrus and widening of the cerebral sulcus are visible to the naked eye in one-third of cases; in two-thirds of cases, structural abnormalities such as degenerative neuronal cells, reduced number of neuronal cells, white matter atrophy, and proliferation of glial cells in some central structures are visible microscopically at all levels of the cortex.
Pathological changes can be divided into two categories: first, hemorrhagic damage, such as subventricular hemorrhage or intraventricular hemorrhage, mostly seen in immature fetuses less than 32 weeks of gestation, probably due to relatively large cerebral blood flow and imperfect vascular development during this period; second, ischemic damage, such as cerebral white matter softening, cortical atrophy or atrophic lobar sclerosis, mostly seen in infants with hypoxic asphyxia.
V. Clinical manifestations
The etiology is diverse and the clinical manifestations vary. In most cases, the abnormality is detected only when the family tries to pick it up after several months of birth. In severe cases, symptoms such as difficulty in sucking, keratoconus and muscle ankylosis can appear within a few days after birth.
The clinical manifestations of cerebral palsy are motor deficits, mainly due to injury to the pyramidal system, which can be complicated by injury to the cerebellum, brainstem and spinal cord. It is characterized by varying degrees of paralysis, increased muscle tone, hyperactive tendon reflexes and positive pathological signs. Children may have seizures, visual impairment, hearing impairment, behavioral abnormalities and cognitive abnormalities. These signs and symptoms may improve with age are the clinical features of cerebral palsy.
Spastic type: It is the most common and typical type of cerebral palsy, accounting for about 60% to 70% of children with cerebral palsy. It includes paraplegic type, tetraplegic type, hemiplegic type and bilateral palsy type. Most of them are caused by damage to cortical motor areas and cone bundles. The main manifestations are abnormal spasticity of the limbs, such as arcing of the foot when walking, flexion of the foot, inversion and valgus of the foot, knee and hip flexion and contraction, etc. The upper limbs may show abnormal positions such as thumb inversion, finger joint flexion, forearm rotation and elbow flexion. In severe cases, the limbs are tense and the joints are contracted and deformed. It is often accompanied by intellectual, emotional and speech disorders and epilepsy. The spastic type is characterized by a hyperactive detrusor reflex, and the clinical examination is a cone bundle sign.
Tonic type: The limbs are stiff, the detrusor reflex is particularly hyperactive, and there is resistance to the flexion and extension of the limbs when doing passive movements, often accompanied by intellectual, emotional and speech disorders, strabismus and salivation. This type is actually the manifestation of severe spasticity.
Hand-foot tardive dyskinesia: also called involuntary movement type, accounting for about 20% of cerebral palsy. It is characterized by choreiform and tachycardic movements of the limbs, trunk, or face that are difficult to control by will, and is often accompanied by speech disorders when the vocal organs are involved. The lesions are mostly located in the basal ganglia, cerebellar dentate nucleus and other extrapyramidal systems, and are commonly seen in patients with neonatal asphyxia and nucleus accumbens.
Ataxia: It accounts for about 5% of cerebral palsy. It is characterized by cerebellar dysfunction, nystagmus, hypotonia, uncoordinated muscle contractions, unstable gait, and unstable trunk with slightly rhythmic head movements (waddling gait) during walking. It may be accompanied by congenital cataracts, mental retardation, and sensory abnormalities.
Tremor: This type is less common and may occasionally be present in children with tardive dyskinesia.
The flaccid type: also known as hypotonia, is a severe disease in which both random and involuntary movements are lacking. It is characterized by marked hypotonia of the trunk and extremities, excessive joint movement, severe dyskinesia, inability to erect the neck and maintain an upright position, etc. It is often accompanied by intellectual and speech impairment.
Mixed type: Cerebral palsy is called mixed type when the typical symptoms of each type of cerebral palsy exist together. Most of them are mixed with spasticity and involuntary movement symptoms, or three different types of cerebral palsy caused by the mixing of characteristic symptoms.
VI. Examination
Cranial MRI and CT examinations can help to understand whether there are structural abnormalities in the cranium of the child with cerebral palsy. EEG is of special significance to determine whether the child has combined epilepsy and the risk of combined epilepsy; brain evoked potentials can detect abnormalities in the audio-visual function of young children. These tests help to clarify the etiology, provide a basis for confirming the diagnosis, determine the prognosis and guide the treatment.
VII. Diagnosis
At present, there is a lack of specific diagnostic indicators, relying mainly on clinical symptoms and signs.
The diagnostic criteria formulated by the China (1988) Pediatric Cerebral Palsy Conference are
Central palsy appears in infancy;
The presence of mental retardation, speech disorders, convulsions, behavioral abnormalities, perceptual disturbances and other abnormalities;
Central paresis due to progressive disease and transient motor developmental delay in normal children should be excluded.
The possibility of cerebral palsy should be highly suspected in the following cases.
Prematurity, low birth weight, severe hypoxia at birth and during the neonatal period, convulsions, intracranial hemorrhage and nuclear jaundice;
Mental retardation, emotional instability and panic attacks;
Motor retardation, with typical signs of increased muscle tone and spasticity of the limbs and trunk;
Extrapyramidal symptoms with bilateral deafness and superior visual palsy.
Differential diagnosis
In the differential diagnosis, attention should be paid to differentiate from the following diseases.
Hereditary spastic paraplegia: the disease has a family history, starts in childhood, progresses slowly, with increased muscle tone in both lower extremities, hyperactive tendon reflexes, pathological signs, arch foot deformity, and no intellectual impairment;
Ataxia capillaris: also known as Louis-Barr syndrome, autosomal recessive, with a progressive course. In addition to ataxia and extrapyramidal symptoms, there may be specific manifestations such as conjunctival capillary dilation and significant elevation of methemoglobin;
Degenerative cerebellar lesions: ataxic dyskinesia may increase with age to help differentiate;
Infantile muscular dystrophy: progressive muscular atrophy and muscle weakness may be present, and progressive muscular atrophy with tongue hypertrophy and enlarged liver and spleen should be considered glycogen storage disease.
Treatment
There is no particularly effective treatment for cerebral palsy so far. At present, physiotherapy, rehabilitation training, medication and surgery can be used to reduce the muscle tone of spastic muscles and improve motor function. The prognosis is usually better for children with normal intelligence. Frequent seizures may aggravate mental retardation due to cerebral hypoxia, and the prognosis is poor.
Physical therapy and rehabilitation
Family education: including correct lying, holding, motor training, head stability, turning, sitting, crawling, kneeling, standing, walking, and language training.
Special education: In special schools, orphanages and rehabilitation institutions, special forms of education and rehabilitation are provided for children with cerebral palsy who cannot adapt to the normal school teaching environment, integrating medical treatment, rehabilitation, education and upbringing.
Conductive education: It is a collective, playful and comprehensive rehabilitation method in which the affected child receives various stimuli in daily life through awareness and sensory communication, and gradually develops functional movements and motions.
Sensory Integration Training: This is the combination of sensory information from all parts of the human organism, which is integrated by the brain to respond to internal and external body perception.
Music therapy: It can improve the child’s limb coordination, language expression, and interest and motivation in learning.
General treatment: Strengthen the child’s care, pay attention to nutrition and hygiene. The child’s current abilities are identified, and a rehabilitation program is developed and actively trained to achieve maximum functional improvement. For those with speech and language impairment and incomplete intelligence, language and music training will be strengthened to improve intelligence; physical therapy, body therapy and massage will be conducted to improve and enhance the motor function of the affected limbs.
Educational rehabilitation: It is the basis of self-care for children with cerebral palsy. There are five main methods as follows.
Drug therapy: limited efficacy and large adverse effects. The main application of symptomatic drugs, such as epileptic seizures can be given according to different types of appropriate anti-epileptic drugs; lower limb spasms affecting the activity can be tried to reduce muscle tone such as benzhexol, baclofen and other muscle relaxation drugs. The brain nerve cell nutrition drugs that promote brain metabolism can also be applied to facilitate the recovery of neurological function of the child.
Surgical treatment
Selective posterior spinal nerve rhizotomy (SPR): The treatment mechanism is to selectively cut the Ia fibers of the musculocutaneous afferent nerve, blocking the spinal reflex circuit and relieving the muscle spasm without recurrence. The reduction of muscle tone does not affect motor function. The best age for surgery is 2-6 years old, and it is appropriate for those who have spastic cerebral palsy, whose intelligence is close to normal, and whose muscle tone is above grade 3, and who maintain a certain level of muscle strength and motor function. The surgery is not recommended for the tardive dyskinesia and ataxia types. Postoperative rehabilitation is essential for successful treatment.
Continuous subarachnoid infusion of baclofen (CIBI): It is used to treat spastic cerebral palsy. The mechanism is that baclofen binds to GABA-B receptors in the gray matter cells of the spinal cord to block the release of excitatory neurotransmitters, thereby reducing the release of excitatory impulses from motor nerves, inhibiting spinal reflexes, and eliminating myospasm. CIBI treatment can be applied to those who are not suitable or do not receive SPR surgery.
Orthopedic surgery: For joint deformity and limb spasm that cannot be easily changed due to joint capsule contracture, orthopedic surgery such as tendonotomy, grafting or lengthening is feasible for those with little improvement in locomotion after long-term treatment, in order to restore muscle balance, loosen spastic soft tissues and stabilize joints.