9.4 Pediatric Brachial Plexopathy & Congenital Disorders

Obstetric Brachial Plexus Palsy (OBPP)

Obstetric Brachial Plexus Palsy (OBPP) occurs in 0.5-3 per 1,000 live births, caused by traction applied to the fetal head/neck during delivery. Risk factors include shoulder dystocia, birth weight >4,000 g, maternal diabetes, and breech presentation.

Clinical Subtypes and Postural Deformities

Erb-Duchenne Palsy (Upper Trunk Injury)

• Nerve Roots: C5 and C6 (± C7).
• Paralyzed Muscles: Deltoid, supraspinatus, infraspinatus, biceps brachii, brachialis, supinator.
• Deformity Posture: "Waiter's Tip" posture — shoulder adducted and internally rotated, elbow extended, forearm pronated, wrist flexed.
• Reflexes & Hand Function: Biceps reflex absent; hand grasp and finger movement are completely intact (C8-T1 spared).

Klumpke Palsy (Lower Trunk Injury)

• Nerve Roots: C8 and T1.
• Paralyzed Muscles: Hand intrinsics (interossei, lumbricals, thenar, hypothenar), wrist flexors, long finger flexors.
• Deformity Posture: Claw hand deformity — supination of forearm, MCP joint hyperextension, IP joint flexion.
• Horner Syndrome: Preganglionic sympathetic fiber involvement at T1 causes ipsilateral Horner syndrome (ptosis, miosis, anhidrosis). Indicates severe T1 root avulsion.

Total Brachial Plexus Palsy

• Nerve Roots: C5 through T1. Complete flaccid limb paralysis, total sensory loss, Horner syndrome.

Rehabilitation and Secondary Orthopedic Deformities

Spontaneous recovery occurs in 80-90% of infants within 3 months. Physical therapy uses daily passive range of motion (PROM) starting at 3 weeks to prevent shoulder internal rotation contractures (subscapularis contracture leading to glenohumeral dysplasia and posterior humeral head subluxation). Secondary reconstructive procedures for established joint deformities include latissimus dorsi or teres major to infraspinatus tendon transfers and humeral derotation osteotomies.

Surgical Decision-Making for Primary Nerve Repair

The definitive clinical indication for surgical referral (nerve grafting or Oberlin biceps nerve transfer) is absence of active biceps recovery (elbow flexion against gravity) by 3 to 6 months of age.

Osteogenesis Imperfecta (OI)

Osteogenesis Imperfecta (OI) ("brittle bone disease") is a genetic disorder of connective tissue marked by bone fragility, recurrent fractures, low bone mass, and short stature.

Molecular Etiology

Over 85-90% of cases are autosomal dominant mutations in COL1A1 or COL1A2 genes encoding Type I collagen—the primary structural protein of bone, dentin, sclera, and ligaments.

Sillence Classification (Types I through IV)

• Type I (Mild, Non-Deforming): Most common form. Quantitative reduction in normal Type I collagen. Features near-normal height, blue sclerae (thin scleral collagen showing choroidal veins), childhood fractures, joint hypermobility, conductive hearing loss, ± dentinogenesis imperfecta (DI).
• Type II (Perinatal Lethal): Most severe. Intrauterine fractures, crumpled ribs ("beaded ribs"), accordion femurs. Death occurs perinatally from respiratory insufficiency.
• Type III (Severe, Progressively Deforming): Most severe non-lethal form. Fractures present at birth, severe progressive limb deformities, marked short stature, triangular facies, kyphoscoliosis. Sclerae are blue at birth, turning white in childhood.
• Type IV (Moderate, Deforming): Moderate fragility/deformation. Sclerae are normal (white). Short stature, recurrent fractures, DI common.

Multidisciplinary Management

• Bisphosphonate Pharmacotherapy: Intravenous pamidronate or zoledronic acid is standard of care. Inhibits osteoclasts, increases cortical bone density, reduces fracture frequency, and relieves bone pain.
• Orthopedic Surgery: Intramedullary rodding with telescoping rods (Fassier-Duval rods) that elongate during growth to realign bones and prevent fractures.
• Rehabilitation Precautions: Avoid rotational/torsional forces. Hydrotherapy provides low-impact strengthening without fracture risk.

Juvenile Idiopathic Arthritis (JIA)

Juvenile Idiopathic Arthritis (JIA) is chronic inflammatory arthritis lasting >6 weeks in a child under 16 years.

Clinical Subtypes

• Oligoarticular JIA: Affects ≤4 joints in the first 6 months (~50% of cases). Presents in young girls (<6 years) affecting large joints (knees, ankles). High ANA positivity (70-80%).
  • Complication: Chronic Asymptomatic Anterior Uveitis. Risk of blindness without ocular pain or redness. Mandatory screening: Slit-lamp ophthalmologic exam every 3 to 4 months.
• Polyarticular JIA: Affects ≥5 joints in the first 6 months. RF-positive or RF-negative. Symmetrical involvement of small and large joints.
• Systemic JIA (Still Disease): High-spiking (quotidian) fevers, evanescent salmon-pink maculopapular rash, lymphadenopathy, hepatosplenomegaly, serositis.
  • Complication: Macrophage Activation Syndrome (MAS)—life-threatening hyperinflammation with cytopenias, coagulopathy, extreme hyperferritinemia, and hepatosplenomegaly. Treated urgently with high-dose corticosteroids and IL-1 blockade (anakinra).

Rehabilitation Management

• Medications: NSAIDs, intra-articular steroid injections (triamcinolone hexacetonide), DMARDs (Methotrexate), biologics (anti-TNF etanercept/adalimumab; anti-IL-1/IL-6 for systemic JIA).
• Rehab Interventions: Resting wrist extension splints, active-assisted ROM during flares, resistive strengthening in remission, joint protection, low-impact exercise (swimming).