Ch. 45 Notes

Chapter 45: Alterations of Musculoskeletal Function in Children

McCance and Huether's Pathophysiology, 9th edition

Chapter Objectives (1 of 4)

  • Discuss the concurrent processes of growth and maturation in the musculoskeletal systems of children.
  • Compare the rates of growth in the appendicular and axial skeletons during childhood.
  • Characterize syndactyly and polydactyly.
  • Describe the structural defects and resulting manifestations associated with developmental dysplasia of the hip (DDH).

Chapter Objectives (2 of 4)

  • Discuss the structural manifestations in metatarsus adductus, equinovarus deformity, idiopathic equinovarus, teratologic equinovarus, and pes planus (flatfoot).
  • Describe the pathophysiology and manifestations of osteogenesis imperfecta (brittle-bone disease).
  • Identify the common causes for rickets; describe the resulting bone malformations.
  • Describe the structural changes, pathophysiology, and treatment for scoliosis.
  • Compare osteomyelitis in adults and children.

Chapter Objectives (3 of 4)

  • Compare the manifestations of rheumatoid arthritis in adults and children.
  • Discuss the osteochondroses using specific examples.
  • Describe the pathophysiology, evaluation, and treatment of Legg-Calvé-Perthes disease and Osgood-Schlatter disease.
  • Relate the cause of cerebral palsy (CP) to the corresponding changes in the musculoskeletal system.
  • Describe the pathophysiology and manifestations of muscular dystrophies.

Chapter Objectives (4 of 4)

  • Describe the benign bone tumors: nonossifying fibroma, simple bone cyst, aneurysmal bone cyst, and osteoid osteoma.
  • Compare and contrast osteosarcomas and Ewing sarcomas.
  • Characterize rhabdomyosarcoma of childhood.

Bone Formation (1 of 2)

  • Bone formation begins in two phases at approximately 6 weeks’ gestation:
      - Delivery of bone cell precursors to sites of bone formation.
      - Aggregation of bone cell precursors at the primary centers of ossification, where they mature and begin to secrete osteoid.
  • Ossification occurs in two long bone centers:
      - Primary center: Diaphysis—long, central portion of the bone.
      - Secondary center: Epiphysis—end portions of the bone.

Bone Formation (2 of 2)

  • Intramembranous formation: Occurs on or within the mesenchyme.
  • Endochondral formation: Involves development of new bone from cartilage, which includes:
      - Cartilage anlage.
      - Perichondrium.
      - Periosteal collar.
      - Secondary centers of ossification.

Bone Growth (1 of 2)

  • Until adult stature is achieved, bone growth occurs at the physeal plate through endochondral ossification.
  • Bone is constantly being destroyed and re-formed.
  • Epiphyseal closure:
      - Unites the metaphysis and the epiphysis.
      - Occurs earlier in girls than in boys due to earlier puberty in girls.

Bone Growth (2 of 2)

  • Factors affecting bone growth include:
      - Growth hormone (secreted by the pituitary).
      - Nutrition.
      - General health.
      - Various growth factors and regulators, e.g., fibroblast growth factor.
  • Peak bone mass is achieved by the middle to late 20s.

Skeletal Development (1 of 2)

  • In the newborn, the entire spine is concave anteriorly (kyphosed).
  • The cervical spine begins to arch (lordotic) in the first 3 months of life.
  • The curve of the lumbar spine develops with sitting.
  • Compared to adults, a newborn has a large head, long spine, and short extremities.
  • By 1 year of age, 50% of the total spinal growth has occurred, and it is more than 70% complete by age 8.

Skeletal Development (2 of 2)

  • Genu varum (bowlegs):
      - Peaks by 30 months and occurs in all newborns due to intrauterine stress.
  • Genu valgum (knock knees):
      - Peaks by ages 5-6.
  • If varum and valgum persist beyond their respective ages, a pathologic cause may be suggested.

Muscle Growth (1 of 2)

  • Between birth and maturity, muscle nuclei increase by approximately:
      - 14 times in boys.
      - 10 times in girls.
  • Composition and size of muscles vary with age.
  • Growth in length occurs at the ends of muscles and is accompanied by an increase in the number of nuclei in the muscle fibers.
  • Muscle fibers increase in diameter as the fibrils become more numerous; however, the fibrils themselves do not increase in diameter.

Muscle Growth (2 of 2)

  • Infants:
      - Muscle constitutes approximately 25% of total body weight (40% in adults).
      - Majority of muscle weight resides in the axial musculature (55% in adult lower limbs).
      - Respiratory and facial muscles are well developed at birth crucial for breathing and sucking.
      - Other muscle groups, such as pelvic muscles, develop over several years.

Syndactyly and Polydactyly

  • Syndactyly:
      - Defined as webbing of the fingers.
      - Involves fusion of the soft tissues of the fingers.
      - Complex syndactyly:
      - Also includes fusion of the bones and nails.
  • Polydactyly:
      - Characterized by the presence of an extra digit.
    Syndactyly and Polydactyly
      - (A) Syndactyly is the fusing together or webbing of two or more fingers or toes.
      - (B) Polydactyly is the presence of extra fingers or toes.

Developmental Dysplasia of the Hip (1 of 5)

  • Also known as congenital dislocation of the hip.
  • It involves an abnormality of the proximal femur, acetabulum, or both.
  • Risk factors include:
      - Family history.
      - Female gender.
      - Metatarsus adductus.
      - Torticollis.
      - Oligohydramnios.
      - First pregnancy.
      - Breech presentation.
  • Subluxated or dislocated hip or acetabular dysplasia can occur.

Developmental Dysplasia of the Hip (2 of 5)

  • Clinical manifestations:
      - Asymmetry of gluteal or thigh folds.
      - Limb length discrepancy: Galeazzi sign.
      - Limitation of hip abduction.
      - Positive Ortolani sign: Hip dislocated but reducible.
      - Positive Barlow maneuver: Hip reduced but dislocatable.
      - Positive Trendelenburg gait: Waddling motion.
      - Pain: Typically very late in presentation.

Developmental Dysplasia of the Hip (3 of 5)

  • Treatment:
      - Earlier treatment is beneficial, ideally before 1 year of age.
      - In children younger than 4 months: Use of the Pavlik harness.
      - Up to 12 months: Closed reduction (without opening the joint), followed by spica or body casting for up to 3 months.

Developmental Dysplasia of the Hip (4 of 5)

  • Continued treatment:
      - After 12 months: Surgical intervention may be required, including opening the joint, and cutting and realigning the femur and/or acetabulum.
      - As the child ages, the likelihood of good outcomes decreases.
      - Up to 70% of children treated surgically after 3 years of age may develop early osteoarthritis.

Developmental Dysplasia of the Hip (5 of 5)

  • Question 1:
      - An infant with a positive Ortolani sign is experiencing which condition?
        - A) Syndactyly
        - B) Developmental dysplasia of the hip
        - C) Genu varum
        - D) Periosteal collar

Deformities of the Foot (1 of 2)

  • Metatarsus adductus (forefoot adduction):
      - Degree of deformity:
        - Mild: Heel bisection line passes medial to the third toe.
        - Moderate: Through the third or fourth toes.
        - Severe: Lateral to the fourth toe.
      - Flexibility: Can be passively correctable or rigid.
      - Treatment: Serial casts during the first 6 months of life.
  • Clubfoot:
      - Defined as equinovarus deformation, where the heel is positioned varus (inwardly deviated) and equinus (plantar flexed).

Deformities of the Foot (2 of 2)

  • Positional equinovarus:
      - The infant’s foot is in the equinovarus position; serial casting may be required.
  • Idiopathic congenital equinovarus:
      - Cast correction followed by surgical intervention for resistant deformities; braces may also be utilized.
  • Teratologic equinovarus:
      - Often requires surgical correction.
  • Pes planus:
      - Flatfoot: If painless, feet are typically normal.

Osteogenesis Imperfecta (1 of 2)

  • Known as “brittle bone disease.”
  • Characterized by a defect in bone and/or vessel collagen production.
  • Sillence classification: Types I through IV, classified based on severity.
  • Results in:
      - Osteoporosis.
      - Increased rate of fractures.
      - Bony deformation.
      - Triangular facies.
      - Vascular weakness.
      - Blue sclera.
      - Poor dental health.

Osteogenesis Imperfecta (2 of 2)

  • Treatment:
      - Prompt fracture care, careful handling and positioning.
      - Use of telescoping rods.
      - Bisphosphonate therapy.
      - Genetic counseling.

Rickets (1 of 2)

  • Disorder leading to mineralization failure, resulting in “soft” bones, and skeletal deformity.
  • Causes of rickets include:
      - Insufficient vitamin D.
      - Insensitivity to vitamin D.
      - Renal wasting of vitamin D.
      - Inability to absorb calcium or vitamin D in the gut.

Rickets (2 of 2)

  • Clinical manifestations:
      - Short stature.
      - Bowing of the limbs accompanied by hypotonia and muscle weakness.
  • Treatment:
      - Levels of calcium, phosphorus, and vitamin D must be optimized before surgical intervention can be considered.

Scoliosis (1 of 3)

  • Defined as rotational curvature of the spine.
  • Can be classified as:
      - Nonstructural: Curvature due to a cause other than the spine.
      - Structural: Curvature with associated vertebral rotation; may arise from various causes including skeletal abnormalities, neuromuscular disease, trauma, extraspinal contractures, bone infections, metabolic bone disorders, joint disease, and tumors.
      - Idiopathic: No known cause; onset can occur in infancy, juvenile, or adolescent phases.

Scoliosis (2 of 3)

  • Clinical manifestations of scoliosis include:
      - Nonstructural scoliosis may present with a mild spinal curvature and hip prominence.
      - Structural scoliosis may show:
        - Asymmetry in hip and shoulder height.
        - Shoulder and scapula prominence.
        - Rib prominence.
  • Treatment:
      - Bracing: Prevents progression but does not cure scoliosis.
      - Surgical fusion of the spine may be necessary for severe cases.

Scoliosis (3 of 3)

  • Question 2:
      - Structural scoliosis may be caused by:
        - A) Neuromuscular disease.
        - B) Postural abnormalities.
        - C) Discrepant leg length.
        - D) Vitamin C deficiency.

Osteomyelitis (1 of 5)

  • Infection in the bone; often associated with septic arthritis due to the structure of an infant’s bone with blood vessels perforating the growth plate.
  • Begins as a bloody abscess in the metaphysis of the bone; vertebrae involvement is more common in adolescents and adults but less frequent than in younger populations.

Osteomyelitis (2 of 5)

  • Infection spreads under the periosteum and along the bone shaft or into the bone marrow.
  • Sequestra: Sections of dead bone resulting from periosteal separation.
  • Involucrum: Periosteal new bone formed in response to infection.
  • Secondary septic arthritis: Occurs when pus from ruptured joints leads to inflammation.

Osteomyelitis (3 of 5)

  • Infection risk decreases significantly after the epiphyseal plates are closed, except in the vertebral body.
  • Infection may occur in any part of the bone; abscesses typically spread slowly.
  • Localized destruction of the cortex can lead to pathologic fractures.

Osteomyelitis (4 of 5)

  • Clinical manifestations:
      - In infants: Fever and failure to move the affected limb (termed pseudoparalysis).
      - In children: Fever with systemic signs of toxicity, swelling, tenderness, and decreasing ability to bear weight or move the affected area, often with an abrupt onset.
      - In adolescents: May present with back pain, which can be the sole complaint.

Osteomyelitis (5 of 5)

  • Treatment:
      - Intravenous (IV) antibiotics, or a combination of IV and oral antibiotics for 6 weeks in reliable children and their families.
      - Drainage and margination of infected bone if abscesses are present.
      - Immobility of the area for pain control.
      - If a joint is infected (septic arthritis), this constitutes a surgical emergency, as lysozymes released from involved neutrophils can damage articular cartilage.

Juvenile Arthritis (1 of 3)

  • Juvenile idiopathic arthritis (JIA): Form of rheumatoid arthritis occurring in childhood.
  • Pathophysiology is fundamentally similar to the adult form.
  • Onset classifications:
      - Pauciarticular: Involving fewer than five joints.
      - Polyarticular: Involving more than five joints.
      - Systemic: Known as Still's disease.

Juvenile Arthritis (2 of 3)

  • Differences between JIA and adult rheumatoid arthritis (RA):
      - Usually affects larger joints.
      - Spinal changes can lead to subluxation and ankylosis of cervical spine.
      - Joint pain in JIA is generally less severe.
      - Antinuclear antibody test is positive in JIA.
      - Chronic uveitis is a common association in JIA but less prevalent in adult RA.

Juvenile Arthritis (3 of 3)

  • Additional differences:
      - Rheumatoid factor is rarely detected in JIA.
      - Rheumatoid nodules, typically found in various organs in adult RA, are uncommon in JIA.
      - Cyclic citrullinated peptide antibody is positive.
  • Treatment:
      - Supportive measures and biologic therapies.

Osteochondroses (1 of 7)

  • Defined as avascular diseases of the bone, resulting from an insufficient blood supply to growing bones.
  • Several types include:
      - Osgood-Schlatter (tibial tubercle).
      - Sinding-Larsen-Johansson (distal patellar pole).
      - Panner (radial head).
      - Kohler (navicular bone of the foot).
      - Sever (calcaneus).

Osteochondroses (2 of 7)

  • Clinical manifestation includes activity-related pain of the affected region that improves with rest.
  • Treatment strategies:
      - Use of anti-inflammatory medications.
      - Modification of activities.
      - Possible immobilization.
      - Reparative correction via revascularization.

Osteochondroses (3 of 7)

  • Legg-Calvé-Perthes disease:
      - Results from interrupted blood supply to the femoral head.
      - It is a self-limiting condition.
      - The ossification center becomes necrotic and collapses, gradually being remodeled by healthy bone.
  • Clinical manifestations include:
      - Knee pain.
      - Muscle spasm on inward rotation of the hip.
      - Limitation of internal rotation, flexion, and abduction.
      - Altered ambulation presenting as Trendelenburg gait or abductor lurch.

Osteochondroses (4 of 7)

  • Continued treatment strategies for Legg-Calvé-Perthes disease:
      - Containment: Maintain the femoral head properly within the acetabulum.
      - Motion: Preserve articular cartilage.
      - Use anti-inflammatory medications and crutches for synovitis; avoid activities that stress the hip during the active phase.
      - Regular monitoring via serial roentgenograms.
      - Consider intraarticular injection of bisphosphonates to decrease osteoclast activity.
      - Surgery may be indicated in some cases.

Osteochondroses (5 of 7)

  • Osgood-Schlatter disease:
      - Defined as tendinitis of the anterior patellar tendon along with osteochondrosis of the tibial tubercle.
      - It can vary in severity from mild tendinitis to complete separation of the anterior extension of the tibial epiphysis.
  • Clinical manifestations include:
      - Pain and swelling in the affected area, tender to direct pressure, particularly post-physical activity.

Osteochondroses (6 of 7)

  • Continued treatment strategies for Osgood-Schlatter disease:
      - Restrict strenuous physical activity for 4-8 weeks.
      - If pain relief is not achieved, a cast or brace may be necessary.
      - A gradual return to unrestricted athletic participation typically occurs at least 8 weeks following treatment.

Osteochondroses (7 of 7)

  • Question 3:
      - A preadolescent presenting with knee pain and swelling after sports activity may be suffering from:
        - A) Rickets
        - B) Osteogenesis imperfecta
        - C) Osgood-Schlatter disease
        - D) Equinovarus

Neuromuscular Disorders

  • This grouping of disorders is inherited and leads to degeneration of skeletal muscle fibers, causing progressive, symmetric weakness and wasting of skeletal muscle groups.

Cerebral Palsy (1 of 2)

  • Nonprogressive disorder of movement and posture, resulting from injury or malformation of the developing CNS.
  • Disease patterns may include:
      - Hemiplegia.
      - Diplegia.
      - Quadriplegia.
  • Clinical manifestations:
      - Delayed or unmet motor milestones.

Cerebral Palsy (2 of 2)

  • Treatment:
      - There is no cure; requires a multidisciplinary approach, including surgical interventions.
      - Interventions might consist of physical and occupational therapies, use of orthotics, and spasticity reduction techniques (such as selected dorsal rhizotomy or baclofen).
      - Botulinum-A (Botox) toxin injections may also be utilized.

Duchenne Muscular Dystrophy (1 of 5)

  • Duchenne muscular dystrophy (DMD): The most common form of muscular dystrophy.
  • It is inherited in an X-linked recessive pattern, affecting males predominantly.
  • The underlying pathology involves a deletion of exons from the DMD gene on the X chromosome or a nonsense mutation resulting in the termination of translation.
  • The dystrophin gene encodes for the dystrophin protein, essential for muscle fiber integrity.

Duchenne Muscular Dystrophy (2 of 5)

  • The dystrophin proteins mediate the anchoring of the actin cytoskeleton of skeletal muscle fibers to the basement membrane.
  • Fibers poorly anchored due to a lack of dystrophin tear apart under repeated contractions, allowing free calcium entry which leads to muscle cell death and necrosis.

Duchenne Muscular Dystrophy (3 of 5)

  • Clinical manifestations of DMD begin around ages 3-4:
      - Gait abnormalities.
      - Progressive weakness in muscles alongside respiratory insufficiency.
      - Cardiomyopathy and development of scoliosis are common issues.
      - Characteristic waddling gait and Gower's sign: Difficulty rising from sitting due to proximal muscle weakness.
      - Cognitive dysfunction may also be present.

Duchenne Muscular Dystrophy (4 of 5)

  • Treatment approaches include:
      - Genetic counseling regarding familial implications.
      - Implementation of range-of-motion exercises, provision of braces, and surgical release of contracture deformities.
      - A multidisciplinary approach is essential for optimal management.

Duchenne Muscular Dystrophy (5 of 5)

  • Question 4:
      - When caring for a child diagnosed with Duchenne muscular dystrophy, the nurse anticipates:
        - A) Weakness of shoulder girdle muscles.
        - B) Diagnosis solely in males.
        - C) Atrophic weakening of calf muscles.
        - D) Decreased levels of creatine phosphokinase (CPK).

Spinal Muscular Atrophy

  • A common autosomal recessive disorder characterized by degeneration of motor neurons in the spinal cord.
  • Clinical manifestations include:
      - Tongue fasciculations.
      - Bell-shaped chest.
      - Progressive weakness.
      - Loss of motor skills.
  • Treatment approaches:
      - Supportive, multidisciplinary care.
      - Nusinersen (Spinraza) treatment.
      - Genetic replacement and gene modification therapies.

Benign Bone Tumors (1 of 2)

  • Nonossifying fibroma:
      - Composed of fibrocytes that have replaced normal bone.
  • Simple bone cysts:
      - Cystic lesions found in the central region of the metaphysics.
  • Aneurysmal bone cysts:
      - Metaphyseal lesions occurring in an older population than those with simple bone cysts.
  • Osteoid osteoma:
      - Painful lesions found in the diaphysis or metadiaphysis of long bones.

Benign Bone Tumors (2 of 2)

  • Osteochondroma:
      - Also referred to as exostosis.
      - Bony protuberance of bone that grows near the growth plate and may occur as solitary lesions or in hereditary multiple exostoses.
  • Fibrous dysplasia:
      - Characterized by bone thinning, growths or lesions that may occur in one (monostotic) or more bones (polyostotic); associated with Albright syndrome triad: polyostotic fibrous dysplasia, precocious puberty, and cutaneous pigmentation.

Malignant Bone Tumors (1 of 3)

  • Osteosarcoma:
      - Originates from bone-producing mesenchymal cells that generate osteoid tissue.
      - Associated genetic deletions on chromosome 13.
      - Commonly presents between ages 10 and 18.
  • Clinical manifestations include:
      - Pain, especially noted at night; potential swelling, warmth, and redness due to tumor vascularity.
      - Respiratory symptoms such as cough, dyspnea, and chest pain may present if lung metastasis occurs.
  • Treatment options:
      - Typically involves surgery along with multi-agent chemotherapy and possible radiation therapy.

Malignant Bone Tumors (2 of 3)

  • Ewing sarcoma:
      - Represents the most lethal malignant bone tumor that may occur during childhood.
      - Primarily arises in the diaphysis of long bones or in flat bones.
  • Clinical manifestations include:
      - Pain, soft tissue mass presentation, fever, malaise, and anorexia.
  • Treatment approach includes:
      - Preoperative chemotherapy followed by surgical resection, radiation, and continuation of chemotherapy for 12-18 months; surgical removal is essential.

Malignant Bone Tumors (3 of 3)

  • Rhabdomyosarcoma:
      - Arises from embryonal rhabdomyoblasts.
  • Clinical manifestation:
      - Characterized by a painless, palpable, and visible mass.
  • Treatment:
      - Approaches typically include surgery, radiation, and chemotherapy.

Nonaccidental Trauma

  • Maltreatment: Must be considered in any long bone injury in a preambulatory child, particularly:
      - Fractures at different stages of healing.
      - “Corner” metaphyseal fractures: Long bone fractures caused by twisting forces.
      - Transverse tibial fractures: Most frequently encountered and often associated with child abuse; however, osteogenesis imperfecta must be ruled out.
  • Mandatory reporting is essential when abuse is suspected.
  • Treatment should include:
      - A nonjudgmental attitude.
      - Emotional support.
      - Involvement of social workers as necessary.

Unit XIII: Musculoskeletal System Case Study (1 of 3)

  • Clinical scenario: A 15-year-old patient is admitted to the pediatric intensive care unit (PICU) due to increased respiratory distress.
      - The adolescent has a history of mild cerebral palsy with associated developmental delays and Duchenne muscular dystrophy (DMD).
      - The patient manifests cough and increases reliance on abdominal muscles for breathing.

Unit XIII: Musculoskeletal System Case Study (2 of 3)

  • Clinical interventions:
      - Due to low muscle tone, the individual is typically positioned side-lying on the left; unable to move lower extremities or turn.
      - Intubation is performed, and the patient is placed on a ventilator to support breathing.

Unit XIII: Musculoskeletal System Case Study Discussion Questions (1 of 2)

  • Regarding Duchenne muscular dystrophy, known for affecting boys primarily, it is acknowledged that the condition results in progressive weakness alongside calf muscle hypertrophy, termed:
      - A) Equinovariant
      - B) Pseudohypertrophic
      - C) Facioscapulohumeral
      - D) Osteochondromatic

Unit XIII: Musculoskeletal System Case Study (3 of 3)

  • The nurse receives an order for the insertion of a Foley catheter to monitor the patient's intake and output.

Unit XIII: Musculoskeletal System Case Study Discussion Questions (2 of 2)

  • What is the primary intention for the catheter insertion?
      - A) The patient exhibits multiple fractures.
      - B) The patient is partially ambulatory.
      - C) The patient has a cognitive disorder.
      - D) The patient is experiencing incontinence.