Residency · Residency · Pediatrics

Cerebral Palsy and Spasticity Management

Overview

Cerebral palsy (CP) is the most common cause of motor disability in childhood, with a prevalence of approximately 2-3 per 1,000 live births. It is defined as a group of permanent disorders of movement and posture causing activity limitation, attributed to non-progressive disturbances in the developing fetal or infant brain. Motor impairment is often accompanied by epilepsy, sensory impairment, cognitive disability, communication difficulties, and behavioral issues. CP is a clinical diagnosis; the underlying brain injury is static, but functional manifestations evolve with growth.

Etiology and Risk Factors

Prenatal (Most Common -- 70-80%)

Prenatal causes include periventricular leukomalacia (PVL, the white matter injury of prematurity), congenital brain malformations, intrauterine infection (CMV, toxoplasmosis, Zika), placental insufficiency and IUGR, genetic and metabolic disorders (increasingly recognized), and maternal substance abuse or trauma.

Perinatal (10-20%)

Perinatal causes include hypoxic-ischemic encephalopathy (HIE), prematurity and IVH, perinatal stroke, and neonatal sepsis or meningitis.

Postnatal (<10%)

Postnatal causes include traumatic brain injury (accidental or non-accidental), CNS infection (meningitis, encephalitis), near-drowning or cardiac arrest, and kernicterus.

Classification

By Motor Type

Spastic CP (80% of cases) follows an upper motor neuron pattern with velocity-dependent increased muscle tone, hyperreflexia, and clonus, resulting from corticospinal tract injury. Dyskinetic CP (10-15%) involves involuntary movements and is subdivided into dystonia (sustained or intermittent muscle contractions causing abnormal postures) and choreoathetosis (writhing, flowing movements). It is often caused by basal ganglia injury from kernicterus or HIE. Ataxic CP (5%) involves cerebellar dysfunction with poor coordination, intention tremor, and wide-based gait. Mixed CP combines features of the above types.

By Topography

Hemiplegia affects one side of the body (arm usually more affected) and is often related to perinatal stroke or PVL. Diplegia affects the legs more than the arms and is classically associated with prematurity and PVL. Quadriplegia affects all four limbs severely and is often associated with severe HIE.

By Function -- GMFCS (Gross Motor Function Classification System)

The GMFCS has five levels: Level I (walks without limitations), Level II (walks with limitations and may use assistive devices outdoors), Level III (walks with a handheld mobility device indoors), Level IV (self-mobility with limitations using a powered wheelchair), and Level V (transported in a manual wheelchair with severely limited head and trunk control).

<image>Classification of cerebral palsy showing motor types (spastic, dyskinetic, ataxic) with associated brain lesion patterns on MRI, topographic distribution (hemiplegia, diplegia, quadriplegia), and the five-level GMFCS functional classification system with representative illustrations of mobility at each level</image>

Diagnosis

CP is a clinical diagnosis based on history and neurological examination, usually made by 12-24 months of age, though it may be earlier in severe cases or later in mild ones. The General Movements Assessment (GMA) at 3-5 months is highly predictive of CP, with absent fidgety movements being particularly significant. MRI of the brain is recommended for all children with CP and identifies the etiology in approximately 85% of cases; common findings include PVL (most common in preterm CP), perinatal stroke, brain malformations, and basal ganglia injury. Genetic testing should be considered if MRI is normal, there is a family history of neurological disease, or the course appears progressive (which may not be CP). Metabolic workup is indicated if symptoms are progressive, since CP is non-progressive and progression suggests an alternative diagnosis.

Associated Comorbidities (Multisystem)

Epilepsy occurs in 25-45% of patients (highest in spastic quadriplegia). Intellectual disability affects 30-50%. Visual impairment includes cortical visual impairment, strabismus, and refractive errors. Hearing impairment occurs especially in dyskinetic CP from kernicterus. Speech and language disorders include dysarthria and limited communication. Feeding difficulties and dysphagia carry aspiration risk and may necessitate gastrostomy. GERD is very common. Drooling (sialorrhea) can be managed with glycopyrrolate, botulinum toxin to the salivary glands, or surgical options. Orthopedic complications include hip subluxation and dislocation, scoliosis, contractures, and osteoporosis with fractures. Constipation is almost universal. Pain is often underrecognized and is multifactorial. Behavioral and emotional comorbidities include anxiety, depression, and sleep disorders.

Spasticity Management

Non-Pharmacologic

Physical therapy with stretching, strengthening, and range of motion exercises is the cornerstone of management. Occupational therapy focuses on fine motor skills, activities of daily living, and hand function. Serial casting provides progressive stretching of spastic muscles (ankle, wrist). Orthoses (AFOs, SMOs) support alignment, prevent contractures, and improve gait. Constraint-induced movement therapy (CIMT) is used for hemiplegic CP, constraining the unaffected limb to force use of the affected side. Hippotherapy and aquatic therapy are complementary approaches with emerging evidence.

Pharmacologic

Oral Medications

Oral baclofen (a GABA-B agonist at 5-80 mg/day divided three to four times daily) can cause sedation, weakness, and a lowered seizure threshold. Diazepam (a GABA-A agonist) has sedation that limits daytime use but is useful for nighttime spasticity. Tizanidine (an alpha-2 agonist) requires hepatotoxicity monitoring. Dantrolene acts at the muscle level but carries a risk of hepatotoxicity requiring liver function monitoring and may cause weakness.

Botulinum Toxin (Chemodenervation)

OnabotulinumtoxinA (Botox) is injected into specific spastic muscles, blocking acetylcholine release at the neuromuscular junction to reduce focal spasticity for 3-6 months. Commonly targeted muscles include the gastrocnemius, hamstrings, hip adductors, and biceps. Dosing is 1-6 units/kg per muscle with a total body dose maximum of 16-20 units/kg (or 400 units total). It should be combined with stretching, casting, and physical therapy for maximum benefit. Risks include weakness, pain at the injection site, and rare systemic spread causing dysphagia or respiratory compromise.

Intrathecal Baclofen (ITB) Pump

A surgically implanted pump delivers baclofen directly to the intrathecal space, achieving high CSF concentrations with minimal systemic side effects. It is indicated for generalized spasticity (GMFCS IV-V) refractory to oral medications. Benefits include reduced tone, improved comfort, and easier caregiving. Risks include pump malfunction, infection, catheter complications, and baclofen withdrawal, which is a medical emergency presenting with fever, seizures, rhabdomyolysis, and potentially death.

Surgical Interventions

Selective Dorsal Rhizotomy (SDR)

SDR involves selective division of dorsal (sensory) nerve rootlets at the L1-S1 level and permanently reduces spasticity in the lower extremities. The best candidates have spastic diplegia, GMFCS II-III, good strength underlying the spasticity, and are aged 3-8 years. Intensive post-operative rehabilitation (12 or more months) is required. Long-term outcomes include improved gait and reduced need for orthopedic surgery.

Orthopedic Surgery

Hip surveillance requires regular hip X-rays (every 6-12 months in high-risk children), as hip subluxation and dislocation occur in 35-60% of children with CP (highest in GMFCS IV-V). Soft tissue lengthening procedures address hamstring, Achilles tendon, and adductor tightness. Bony procedures include femoral or pelvic osteotomy for hip dysplasia and spinal fusion for scoliosis. Single-event multilevel surgery (SEMLS) addresses multiple contractures and deformities in one surgical session.

<image>Spasticity management pyramid showing foundational interventions (physical therapy, stretching, orthoses) at the base, followed by focal chemodenervation (botulinum toxin), oral medications (baclofen, tizanidine), intrathecal baclofen pump, selective dorsal rhizotomy, and orthopedic surgery at the top, with GMFCS level and spasticity distribution guiding treatment selection</image>

Hip Surveillance

All children with CP should undergo regular hip surveillance with AP pelvis X-ray. The frequency is based on GMFCS level: every 6 months for GMFCS III-V and annually for GMFCS I-II. The migration percentage (Reimers index) quantifies lateral displacement of the femoral head: less than 30% warrants monitoring, 30-40% warrants consideration of soft tissue surgery, and greater than 40% often requires bony surgery. The goal is to prevent painful hip dislocation through early intervention. The Australian Hip Surveillance Guidelines provide a systematic protocol that has been adopted internationally.

Transition to Adulthood

A planned transition to adult services should occur by age 16-18 and should address vocational planning, independent living, reproductive health, and long-term orthopedic care. Many adults with CP experience functional decline and increased pain with aging. Lifetime multidisciplinary care coordination is essential.

Clinical Pearls

CP is a clinical diagnosis of a non-progressive motor disorder; if there is progressive neurological deterioration, the diagnosis should be reconsidered (neurodegenerative disease or metabolic disorder). Hip surveillance with regular X-rays is mandatory in all children with CP because hip displacement is common and preventable with early intervention. Baclofen withdrawal from an intrathecal pump is a life-threatening emergency, and any child with an ITB pump presenting with fever, increased spasticity, and altered mental status should be evaluated urgently. The General Movements Assessment at 3-5 months is the most accurate early predictor of CP, with absence of fidgety movements having greater than 95% sensitivity. Botulinum toxin should be combined with stretching, casting, and therapy because injection alone has limited lasting benefit. Drooling in CP is primarily due to poor oral motor control (not overproduction of saliva), and glycopyrrolate and botulinum toxin to the salivary glands are effective treatments.

Key Controversy: Selective Dorsal Rhizotomy Patient Selection and Outcomes

SDR can dramatically reduce spasticity, but patient selection is critical. The ideal candidate has spastic diplegic CP, GMFCS II-III, adequate underlying strength, and good cognition and motivation for intensive rehabilitation. The controversy centers on the age at surgery (some centers advocate as young as 2-3 years while others prefer 4-8 years) and whether to use a single-level (L1) or multi-level approach. Most long-term studies show sustained benefit at 10-20 years, but some patients develop weakness, sensory changes, or spinal deformities. SDR is not appropriate for dystonic CP, GMFCS IV-V (where an ITB pump is preferred), or significant underlying weakness. Compared with an ITB pump, SDR is permanent and avoids device complications but is irreversible, whereas ITB is adjustable and reversible but requires lifelong device management.

References

• Rosenbaum P, et al. A Report: The Definition and Classification of Cerebral Palsy (April 2006). Dev Med Child Neurol. 2007;49(s109):8-14.
• Novak I, et al. Early, Accurate Diagnosis and Early Intervention in Cerebral Palsy. JAMA Pediatr. 2017;171(9):897-907.
• Novak I, et al. A Systematic Review of Interventions for Children with Cerebral Palsy: State of the Evidence. Dev Med Child Neurol. 2013;55(10):885-910.
• Graham HK, et al. Cerebral Palsy. Nat Rev Dis Primers. 2016;2:15082.
• Hägglund G, et al. Prevention of Hip Dislocation in Children with Cerebral Palsy: The First Ten Years of a Population-Based Prevention Programme. J Bone Joint Surg Br. 2005;87(1):95-101.
• McLaughlin J, et al. Selective Dorsal Rhizotomy: Efficacy and Safety in an Investigator-Masked Randomized Clinical Trial. Dev Med Child Neurol. 1998;40(4):220-232.

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