Neuromuscular Disorders in Children

Cerebral Palsy - Brainy Body Bends

• Non-progressive Upper Motor Neuron (UMN) disorder affecting movement & posture. Results from brain injury or malformation before, during, or shortly after birth (typically before age 2-3 years).
• Etiology: Prenatal factors most common (~80%); perinatal (e.g., birth asphyxia, prematurity), postnatal (e.g., meningitis, trauma) insults.
• Types:
  • Spastic (~75%): Most common. Increased muscle tone. Subtypes: diplegia, hemiplegia, quadriplegia.
  • Dyskinetic (Athetoid/Dystonic): Involuntary movements. Basal ganglia damage.
  • Ataxic: Shaky movements, balance problems. Cerebellar damage.
  • Mixed: Combination of types.
• Clinical Features: Delayed motor milestones, abnormal muscle tone (spasticity or hypotonia), persistence of primitive reflexes (e.g., Moro reflex beyond 6 months), characteristic gaits (e.g., scissoring in spastic diplegia).
• GMFCS (Gross Motor Function Classification System): Levels I (walks without limitations) to V (severely limited, transported in manual wheelchair).
• Management: Multidisciplinary approach. Includes physiotherapy, occupational therapy, speech therapy, orthotics, medications (e.g., Botulinum toxin for spasticity), and surgical interventions (e.g., Selective Dorsal Rhizotomy (SDR), tendon lengthening).

⭐ Spastic diplegia is the most common pattern in preterm infants, often linked to periventricular leukomalacia (PVL).

Neural Tube Defects - Spine's Twisty Tales

• Failure of neural tube closure during embryogenesis (3rd-4th week gestation).
• Folic acid deficiency is a key preventable risk factor.
• Types:
  • Spina Bifida Occulta: Vertebral arch defect, cord/meninges normal. Often asymptomatic; skin dimple/hair tuft.
  • Meningocele: Meninges herniate through defect, cord normal. Sac contains CSF.
  • Myelomeningocele (MMC): Meninges & neural tissue herniate. Most common & severe.
• Orthopedic Issues (MMC):
  • Lower limb paralysis/paresis (level-dependent).
  • Foot deformities (clubfoot, vertical talus).
  • Hip dysplasia/dislocation.
  • Spinal deformities (scoliosis, kyphosis).
  • Tethered cord syndrome.
  • Hydrocephalus (often associated, requires shunting).
• Management: Multidisciplinary; orthotics, physiotherapy, surgical correction of deformities.

⭐ Arnold-Chiari II malformation (hindbrain herniation) is almost universally present in patients with myelomeningocele.

• 📌 Spinal Abnormalities Lead To Motor Issues (SALTMI) for MMC manifestations (Scoliosis/Kyphosis, Arthrogryposis-like changes, Lower limb paralysis, Talipes, Muscle imbalance, Instability of hips).

MD & SMA - Muscle Power Plunge

• Muscular Dystrophies (MD): Progressive muscle weakness, degeneration.
  • Duchenne (DMD):
    • X-linked; dystrophin absent. Onset 2-5 yrs.
    • Proximal weakness. 📌 Gower's sign (climbs self). Calf pseudohypertrophy.
    • ↑ CK. Wheelchair by ~12 yrs. Scoliosis.
    • Cardiomyopathy, respiratory failure.
  • Becker (BMD):
    • Milder X-linked; dystrophin abnormal/reduced.
    • Later onset (>7 yrs); ambulant >15 yrs.
• Spinal Muscular Atrophy (SMA):
  • Autosomal recessive; SMN1 gene defect (Chr 5q).
  • Anterior horn cell loss → LMN signs.
  • Symmetric proximal weakness, hypotonia ("floppy baby").
  • ↓/Absent DTRs, tongue fasciculations.
  • Types:
    • Type I (Werdnig-Hoffmann): <6 mo; severe, never sit. Death <2 yrs (respiratory).
    • Type II: 6-18 mo; sit, never walk.
    • Type III (Kugelberg-Welander): >18 mo; walk, later weakness.

⭐ DMD vs BMD: Both X-linked dystrophinopathies. DMD: absent dystrophin, earlier onset, rapid progression. BMD: abnormal/reduced dystrophin, milder.

Ortho Rx - Movement Masters

• Core Goals: Maximize function, prevent/correct deformity, pain relief. Emphasizes a multidisciplinary team.
• Management Strategies:
  • Gait Disturbances: Analysis, physiotherapy, orthotics (AFOs, KAFOs). Surgery for fixed issues.
  • Contractures: Prevention (stretching, splinting). Treatment (serial casting, Botulinum toxin, tenotomy).
  • Hip Dysplasia/Dislocation: Regular X-ray screening. Rx: soft tissue releases, osteotomies.

    ⭐ Hip surveillance (exam & X-rays) is vital in Cerebral Palsy to detect hip displacement early; GMFCS level indicates risk.

  • Scoliosis: Bracing for flexible curves < 40°. Spinal fusion for curves > 40-50° or functional decline.
  • Foot Deformities: Stretching, serial casting (e.g., Ponseti), surgical correction.
• General Therapeutic Pillars:
  • Physiotherapy & Occupational Therapy.
  • Orthotics for support & alignment.
  • Medications for spasticity (e.g., Baclofen).

High‑Yield Points - ⚡ Biggest Takeaways

• Cerebral Palsy: Most common motor disability; spastic diplegia common. Key concern: hip subluxation.
• DMD: X-linked; Gower's sign, calf pseudohypertrophy, progressive scoliosis.
• SMA: Autosomal recessive; proximal muscle weakness (legs > arms). Scoliosis frequent.
• Myelomeningocele: Presents with clubfoot, hip dislocation, scoliosis. Function by lesion level.
• Erb's Palsy (C5-C6): Characteristic "waiter's tip" deformity.
• CMT: Features pes cavus, "stork leg" appearance, foot drop.
• Early intervention & multidisciplinary care vital for all_neuromuscular_disorders_in_children_