Diagnosis of Cerebral Palsy
Abstract
Cerebral palsy (CP) is the most common cause of physical disability in young children. This article describes the different forms of CP, their differential diagnosis, available interventions, and an algorithm for evaluating children with CP.
CP is the most common cause of physical disability in children and has various underlying causes. Early diagnosis is essential. Therefore, healthcare professionals at every level of care, including pediatricians and pediatric neurologists, must recognize suspected CP and establish the diagnosis promptly.
CP is a developmental disorder that persists throughout a child's life. Early diagnosis enables timely treatment and rehabilitation, helping children adapt to their environment and society.
Etiology of Cerebral Palsy
Cerebral palsy (CP) refers to a group of permanent disorders of movement and posture that limit activity and result from early, nonprogressive injury to the developing, immature brain. There is no universal agreement on what constitutes early injury to the developing brain, but it generally includes injuries occurring before the age of 5–7 years.
In addition to movement disorders, children with CP frequently (approximately 70%) experience disturbances of sensation, cognition, communication, perception, or behavior, as well as epilepsy and other seizures.
CP is the most common cause of physical disability in young children. Its prevalence in developed countries is 2–3.5 per 1,000 live births, increasing to 40–100 per 1,000 live births among very premature infants and those with low birth weight. In Lithuania, CP affects 2–2.5 per 1,000 live births (Prasauskienė, 2009).
CP is a developmental disorder with multiple etiologies. Three main groups of causes are distinguished:
- Prenatal (intrauterine) causes: Factors affecting the fetus before the 28th week of gestation. These include exogenous factors (infectious, chemical, toxic, and others) and endogenous factors (genetic abnormalities and maternal diseases) that cause various brain malformations. The nature of these malformations depends primarily not on the specific etiological factor but on the timing of the injury, particularly which stage of brain development is disrupted.
- Perinatal causes: Factors causing brain injury between the 28th week of gestation and the seventh day of life. These include birth trauma, hypoxic-ischemic brain injury, to which very premature and low-birth-weight infants are particularly susceptible because of immature cerebral circulation, and various pathological conditions occurring during the first days of life, such as hypoglycemia, hyperbilirubinemia, acute neuroinfections, sepsis, and others.
- Postnatal causes: Factors causing brain injury from the seventh day of life until approximately 5–7 years of age. These include traumatic, toxic, infectious, vascular, metabolic, and hypoxic brain injuries.
Studies have shown that brain abnormalities occurring before the 20th week of gestation are most commonly associated with neuronal migration disorders. Brain injuries occurring between 26 and 34 weeks of gestation are predominantly associated with periventricular leukomalacia, while cerebral palsy resulting from injuries between 34 and 40 weeks of gestation is associated with focal and multifocal brain lesions.
Prenatal causes, particularly structural abnormalities of brain development, are the most common and account for approximately 70–80% of all causes. Perinatal causes account for up to 25% and predominate among premature infants. Postnatal causes account for 3–5%, while the etiology remains unexplained in 10–30% of cases.
Diagnosis of Cerebral Palsy
Cerebral palsy (CP) is diagnosed by a pediatric neurologist based on the patient's medical history, developmental assessment, and clinical observation. The evaluation includes a neurological examination, specialized assessment of gross and fine motor skills, functional assessment, and additional investigations aimed at determining the etiology of CP and differentiating it from other disorders of the brain, spinal cord, peripheral nervous system, muscles, and musculoskeletal system.
Brain imaging studies, such as neurosonography, computed tomography (CT), and magnetic resonance imaging (MRI), are recommended to establish the etiology. Brain MRI is recommended for all patients with suspected or diagnosed CP, particularly those born at term, except when neurosonographic examinations performed during the neonatal period or infancy have already identified structural brain damage that fully explains the origin of CP.
Brain CT is less sensitive and is performed in emergencies or when investigating calcifications, such as those associated with phakomatoses, TORCH infections, and other conditions. Spinal MRI is indicated when a spinal origin of paralysis is suspected.
Laboratory investigations are performed to identify intrauterine infections, suspected TORCH infections, HIV, congenital coagulopathies, early stroke, and other conditions. Metabolic and genetic testing is recommended when clinical signs suggest a genetic disease or inherited metabolic disorder, when the clinical presentation or course of CP is atypical or progressive, or when there is a family history of CP, genetic disorders, or inherited metabolic diseases.
Assessment of vision, hearing, and cognitive function is essential for all children with CP. Electroencephalography is performed when seizures occur or epilepsy is suspected.
Spastic Hemiplegic Cerebral Palsy
Spastic hemiplegic CP is characterized by unilateral spastic motor impairment affecting both limbs on one side of the body. The arm is usually more severely affected than the leg, and the right side is affected more frequently than the left.
Impaired arm function usually becomes apparent by 3 months of age. In more severe cases, impaired motor function on one side of the body delays the child's ability to sit independently. When lying prone, the child bears less weight on the affected arm and uses it less frequently for manipulation. When crawling begins, the child moves primarily using the unaffected side, dragging the affected limbs.
Impaired leg movements become apparent considerably later, although external rotation of the affected leg may be observed early. Most children with spastic hemiplegic CP learn to walk by the age of 2 years.
Hemiplegia is characterized by signs of upper motor neuron damage, including spasticity, exaggerated tendon reflexes, pathological reflexes (Babinski sign), muscle weakness, impaired fine motor skills, and synkinesia.
Joint contractures of the upper limbs may develop gradually. A characteristic deformity, known as the flexed-wing posture, develops: the arm is adducted, flexed, and internally rotated; the wrist is flexed and deviated outward; the forearm is pronated; and the thumb is adducted.
Cortical-type disturbances of complex sensation in the affected limbs are characteristic, including impaired sensory discrimination, stereognosis, and perception of textures through touch. Deep sensation is also impaired.
Vasomotor changes are common in the affected limbs, which are frequently cold, with cyanosis and edema of their distal parts.
Cranial nerve involvement is also characteristic. Convergent strabismus, central facial nerve palsy, and optic nerve atrophy may occur. Intellectual impairment is less common than in other forms of CP.
Spastic Quadriplegic Cerebral Palsy
Spastic quadriplegic CP affects all four limbs. The arms may be more severely affected than the legs. Bulbar dysfunction of varying severity, intellectual impairment, microcephaly, and epilepsy are characteristic.
Signs of developmental impairment can be observed during the neonatal period, including difficulties with self-regulation, atypical posture, impaired interaction, and prolonged persistence of neonatal reflexes, such as the Moro reflex, automatic stepping reflex, grasp reflex, tonic neck reflexes, and others. Feeding difficulties are common.
Spastic quadriplegic CP is characterized by spasticity, exaggerated tendon reflexes, clonus, pathological reflexes (Babinski sign), and other neurological abnormalities. Associated manifestations include intellectual impairment, delayed speech development, microcephaly, bulbar symptoms related to cranial nerve involvement, optic nerve atrophy, nystagmus, and strabismus.
Epilepsy is common in these children, and infantile spasms may occur.
Spastic Diplegic Cerebral Palsy
Spastic diplegic CP, also known as Little's disease, is characterized by bilateral motor impairment predominantly affecting the legs. Signs of central paralysis include hypertonia (spasticity), exaggerated tendon reflexes, clonus, pathological reflexes, and absent or reduced voluntary movements.
All four limbs are frequently affected, although impairment is more pronounced in the legs than in the arms.
During the neonatal period, disturbances of self-regulation, feeding difficulties, hypotonia, or increased muscle tone may already be apparent. Neonatal seizures may occur.
Spontaneous movements, particularly of the legs, are limited, and poor head control becomes increasingly evident. Older children have weak trunk muscles, making it difficult to maintain an upright posture.
When attempting to stand, the child bears weight on the toes, with the legs internally rotated and slightly flexed at the knees and hips. A tendency to cross the legs is also observed.
Approximately 70% of children with this form of CP have normal or borderline intellectual functioning.
Ataxic Cerebral Palsy
Ataxic CP is characterized by muscle hypotonia and ataxia and is associated with cerebellar damage.
Movements of the limbs and trunk are uncoordinated, with characteristic asynergia, dysmetria, intention tremor, and marked hypotonia. Tendon reflexes are normal or slightly increased.
Brain imaging reveals cerebellar hypoplasia in more than one-third of these children. Intellectual impairment is identified in approximately half of affected children.
Ataxic CP is also associated with epilepsy, speech impairment, strabismus, nystagmus, and, occasionally, autism.
Dyskinetic Cerebral Palsy
Dyskinetic CP develops as a result of damage to the extrapyramidal nervous system.
Infants are generally quite active and socially responsive. Early signs include hypotonia and postural instability.
Disturbances of muscle tone and involuntary movements usually become apparent only during the second half of the first year of life.
Muscle tone fluctuates, increasing during attempts to perform active movements and decreasing at rest. Dyskinetic hypertonia or rigidity is more pronounced when the child is awake. Muscle tone decreases during sleep.
Involuntary movements of varying amplitude involving the head, neck, and limbs predominate. Hypotonia of the neck and trunk muscles is characteristic.
Worster-Drought Syndrome
Worster-Drought syndrome is a form of CP characterized by impairment of the muscles of the mouth and pharynx (orobuccopharyngeal paralysis).
Brain imaging reveals bilateral perisylvian polymicrogyria.
From birth, affected children have difficulty moving the tongue, lips, and jaw, resulting in feeding and swallowing difficulties that become apparent relatively early.
Speech and cognitive impairments become more pronounced later.
Epilepsy, gastroesophageal reflux disease, behavioral problems, and congenital abnormalities, such as micrognathia, dental fusion, and jaw contractures, are frequently associated with this syndrome.
European Classification of Cerebral Palsy
According to the European classification of cerebral palsy (2000), CP is divided into unilateral and bilateral spastic, ataxic, dyskinetic, dystonic, and choreoathetoid forms.
Spastic Cerebral Palsy
Spastic CP must be characterized by at least two signs: abnormal posture and/or movement, increased muscle tone (which does not necessarily have to be constant), and pathological reflexes, including hyperreflexia and/or other signs of pyramidal tract involvement, such as the Babinski reflex.
In bilateral spastic paralysis, the limbs on both sides of the body are affected, whereas unilateral spastic paralysis involves impaired limb function on one side of the body.
Ataxic Cerebral Palsy
Ataxic CP is characterized by abnormal posture and/or impaired movement and uncoordinated muscle activity. Movements are performed with inappropriate force, rhythm, and precision.
Dyskinetic Cerebral Palsy
Dyskinetic CP is diagnosed when abnormal posture and/or impaired movements are present. These movements are involuntary, uncontrolled, repetitive, and sometimes stereotyped.
Dystonic Cerebral Palsy
Dystonic CP is characterized by hypokinesia (reduced activity and coarse movements) and increased muscle tone.
Choreoathetoid Cerebral Palsy
Choreoathetoid CP is characterized by hyperkinesia (increased activity and excessive movements) and decreased muscle tone.
Authors
Laima Mikulėnaitė Child Development Center, Children's Hospital, Branch of Vilnius University Hospital Santaros Clinics
Jovita Petrulytė Child Development Center, Children's Hospital, Branch of Vilnius University Hospital Santaros Clinics
Source: Pediatrija, No. 2, 2018.
