Overview
Definition:
Spasticity is a motor disorder characterized by a velocity-dependent increase in tonic stretch reflexes with exaggerated tendon jerks, resulting from hyperexcitability of the stretch reflex
In pediatrics, it is often associated with conditions like cerebral palsy, traumatic brain injury, and spinal cord injuries.
Epidemiology:
Cerebral palsy (CP) is the most common cause of spasticity in children, affecting approximately 2-3 per 1000 live births
The prevalence of spasticity varies widely depending on the underlying neurological insult and its severity.
Clinical Significance:
Spasticity significantly impacts a child's motor function, potentially leading to contractures, joint deformities, pain, difficulties with feeding, communication, and overall participation in daily activities
Effective management is crucial for improving quality of life and functional independence.
Clinical Presentation
Symptoms:
Increased muscle tone and stiffness
Difficulties with voluntary movement control
Exaggerated reflexes
Involuntary muscle spasms
Pain associated with muscle tightness and positioning
Difficulty with gait, fine motor skills, and self-care activities
Potential for secondary complications like scoliosis or hip dysplasia.
Signs:
Hypertonia (spasticity) assessed using scales like the Modified Ashworth Scale (MAS)
Increased deep tendon reflexes (hyperreflexia)
Clonus
Scissoring gait
Equinovarus foot deformities
Contractures
Joint range of motion limitations
Abnormal posturing.
Diagnostic Criteria:
Diagnosis is primarily clinical, based on history, neurological examination, and identification of the underlying neurological insult
No specific laboratory or imaging criteria define spasticity itself, but investigations aim to identify the cause and associated comorbidities.
Diagnostic Approach
History Taking:
Detailed birth history (prematurity, birth asphyxia)
Developmental milestones
History of neurological insults (e.g., meningitis, stroke, trauma)
Family history of neurological disorders
Current functional abilities and limitations
History of pain and sleep disturbances
Previous treatments and their efficacy.
Physical Examination:
Comprehensive neurological examination including assessment of muscle tone (proximal and distal), reflexes, voluntary motor control, coordination, and presence of involuntary movements
Musculoskeletal examination to assess joint range of motion, contractures, and deformities
Functional assessment of gait, posture, and activities of daily living.
Investigations:
Neuroimaging (MRI brain, CT scan) to identify the underlying cause (e.g., periventricular leukomalacia, hypoxic-ischemic encephalopathy, stroke)
Genetic testing may be considered for specific etiologies
Electromyography (EMG) and nerve conduction studies (NCS) can help differentiate spasticity from other causes of hypertonia
Developmental assessments and functional outcome measures.
Differential Diagnosis:
Other causes of increased muscle tone include rigidity (e.g., Parkinsonism), dystonia, myotonia, and spastic pseudoparesis
Differentiating these from spasticity is crucial for appropriate management
Conditions to consider include neurodegenerative disorders, metabolic myopathies, and peripheral neuropathies.
Management
Initial Management:
Multidisciplinary approach involving neurologists, physiatrists, physical therapists, occupational therapists, orthopedic surgeons, and social workers
Early identification and intervention are key.
Medical Management:
Oral pharmacotherapy: Baclofen is a first-line agent acting as a GABA-B agonist
Typical starting dose for children is 0.75-2 mg/kg/day divided into 3-4 doses, titrating up to 5 mg/kg/day or a maximum of 80-100 mg/day for older children
Diazepam is another option, useful for sedation and muscle relaxation, but carries risk of sedation and tolerance
Tizanidine, an alpha-2 adrenergic agonist, can also be used
Dantrolene sodium acts peripherally on skeletal muscle but has significant hepatotoxicity concerns in children
Intrathecal baclofen pump (ITB) for severe generalized spasticity unresponsive to oral agents
Dosage is highly individualized, starting at low doses and titrating based on response and side effects
Botulinum toxin type A (BoNT-A) injections for focal spasticity, targeting specific muscle groups
Dosing varies by muscle group, patient weight, and toxin type (e.g., Dysport, Botox)
Typical doses range from 1-6 units/kg per muscle, with a maximum total dose per session of 10-20 units/kg or 400-600 units for older children
Repeat injections are usually needed every 3-6 months.
Surgical Management:
Selective Dorsal Rhizotomy (SDR) for spastic diplegia/quadriplegia with disabling lower extremity spasticity and positive sensory root findings
Orthopedic surgery for management of contractures, deformities (e.g., tendon lengthening, osteotomies), and scoliosis
Baclofen pump implantation for ITB therapy.
Supportive Care:
Intensive physical and occupational therapy to maintain range of motion, improve strength, and enhance functional skills
Orthotics and assistive devices (e.g., braces, walkers, wheelchairs)
Speech therapy for communication and feeding difficulties
Pain management strategies
Psychosocial support for the child and family
Management of bowel and bladder dysfunction.
Comparison Baclofen Vs Botulinum Toxin
Baclofen Oral:
Systemic effects, potential for sedation, fatigue, and cognitive impairment
Effective for generalized spasticity
Titration required
Dosing can be challenging to optimize across different muscle groups.
Baclofen Intrathecal:
Targeted delivery to the spinal cord, bypassing the blood-brain barrier
Highly effective for severe generalized spasticity
Requires surgical implantation of a pump
Risk of infection, catheter issues, and pump malfunction.
Botulinum Toxin A:
Focal effect on injected muscles, minimal systemic absorption
Effective for localized spasticity contributing to functional deficits
Provides temporary relief, requiring repeat injections
Can be used in conjunction with therapy and orthotics
Potential for muscle weakness, pain at injection site, and rare systemic effects.
Indication Differences:
Oral baclofen is a good starting point for diffuse spasticity
ITB is reserved for severe, generalized spasticity unresponsive to oral medications
BoNT-A is ideal for focal spasticity impacting specific movements or causing significant joint issues, often used to improve function prior to or in conjunction with orthopedic interventions.
Complications
Early Complications:
Baclofen: Drowsiness, dizziness, muscle weakness, nausea, vomiting
BoNT-A: Local pain, bruising, transient muscle weakness in adjacent non-target muscles, systemic spread (rare).
Late Complications:
Baclofen: Tolerance, dependence, withdrawal syndrome if stopped abruptly
Hepatotoxicity (rare with baclofen, more with dantrolene)
Chronic pain due to spasticity, contractures, joint deformities, scoliosis, hip dislocation, pressure sores, respiratory compromise, bowel and bladder dysfunction.
Prevention Strategies:
Gradual titration of oral baclofen, careful monitoring for side effects
Proper injection technique for BoNT-A, targeting appropriate muscles
Regular physical therapy to prevent contractures
Early orthopedic intervention for deformities
Comprehensive care plan addressing all aspects of the child's needs.
Prognosis
Factors Affecting Prognosis:
Severity and location of the initial brain lesion
Age of onset
Extent of spasticity and associated neurological impairments (cognitive, sensory)
Timeliness and comprehensiveness of intervention
Family support and adherence to treatment plan.
Outcomes:
Goals of management are to improve function, reduce pain, enhance mobility, and improve quality of life
Complete resolution of spasticity is rare
Management aims to optimize the child's potential for independence and participation
Long-term prognosis varies greatly and requires ongoing care and adaptation of treatment strategies.
Follow Up:
Regular follow-up with the multidisciplinary team is essential
Frequency depends on the child's age, severity of spasticity, and treatment modalities used
Ongoing assessment of motor function, pain, functional abilities, and the need for adjustments in medication, therapy, or surgical interventions.
Key Points
Exam Focus:
DNB/NEET SS candidates should understand the mechanisms of action, indications, contraindications, typical dosing ranges (pediatric), and common side effects of baclofen (oral and ITB) and botulinum toxin in pediatric spasticity
Differentiate indications for focal vs
generalized spasticity management.
Clinical Pearls:
Always start oral baclofen at a low dose and titrate slowly
Monitor for CNS side effects
Consider BoNT-A for specific focal deficits to improve gait or function prior to orthopedic surgery
ITB is a significant intervention for severe, refractory generalized spasticity
Multidisciplinary care is paramount.
Common Mistakes:
Underestimating the impact of spasticity on overall function and quality of life
Inadequate pain assessment and management
Delaying orthopedic or surgical interventions when indicated
Using systemic medications without considering their potential for sedation and cognitive effects in children
Incorrect dosing of baclofen or botulinum toxin.