McCance 46 Book. Musculoskeletal Alterations in Children

Alterations of Musculoskeletal Function in Children

• Musculoskeletal alterations in children are common, arising from congenital, hereditary, or acquired causes.
• Some conditions are acute and resolve completely, while others are chronic or terminal.
• Understanding the pathophysiology is crucial for optimal patient care.

Musculoskeletal Development in Children

• Bone formation starts around the sixth week of gestation, with two phases: delivery of bone cell precursors to sites of formation and aggregation into osteoblasts.
• Two main types of fetal tissue are involved: mesenchymal tissue (forming flat bones) and cartilage (forming most other bones).
• Intramembranous bone formation occurs within mesenchyme, while endochondral bone formation involves cartilage models that transform into bone.
• Bone growth at the physeal plate, the cartilage between the metaphysis and epiphysis, continues until skeletal maturity.
• Skeletal growth in the length of long bones happens at the physeal plate.
• Muscle growth includes increase in fiber size, number of muscle nuclei, and connective tissue components.
• Muscle growth is stimulated by the separation of muscle attachments as the skeleton grows.

Abnormal Density or Modeling of the Skeleton

• Osteogenesis Imperfecta (OI) / Brittle Bone Disease: Characterized by defects in collagen production, leading to bone fragility and fractures.
• OI severity varies, with some cases resulting in stillbirth or early death.
• OI is often diagnosed by clinical presentation (fractures, skeletal deformities) and radiographs, supported by genetic testing.

Bone Infection: Osteomyelitis

• Osteomyelitis is a bone infection typically caused by bacteria that enter the bone through the bloodstream, lodging in the medullary cavity or beneath the epiphyseal plate.
• The microorganism responsible varies by age; Staphylococcus aureus is prevalent in newborns/infants, with other bacteria more common in older children and adolescents.
• Early diagnosis is key for successful treatment involving intravenous antibiotics and, in some cases, surgical intervention.

Rheumatologic Disorders

• Juvenile Idiopathic Arthritis (JIA): The most common rheumatologic condition in children, impacting connective tissues and often accompanied by systemic symptoms.
• JIA's onset can appear in various ways, including arthritis in few or several joints, or with systemic involvement.

Avascular Diseases of the Bone

• Osteochondroses are a range of conditions characterized by avascular necrosis of bone due to inadequate blood supply. Examples include Osgood-Schlatter disease, Legg-Calvé-Perthes disease, Sinding-Larsen-Johansson syndrome, Panner disease, and Kohler disease.
• Typically, these conditions manifest as activity-related pain that improves with rest.

Cerebral Palsy

• Cerebral palsy (CP) is a nonprogressive group of movement and posture disorders stemming from damage to the developing central nervous system.
• CP can range in severity from mild spasticity to severe disability requiring lifelong support.

Neuromuscular Disorders

• Duchenne Muscular Dystrophy (DMD): A severe X-linked recessive disorder leading to progressive muscle weakening and loss of ambulation.
• Spinal Muscular Atrophy (SMA): An autosomal recessive disorder causing progressive loss of motor neurons in the spinal cord.
• Facioscapulohumeral Muscular Dystrophy (FSHD): Autosomal dominant form of muscular dystrophy impacting facial and shoulder muscles and causing slow progression.

Musculoskeletal Tumors in Children

• Bone Tumors: These include benign conditions such as nonossifying fibroma, osteochondroma, and simple bone cysts as well as malignant conditions such as osteosarcomas and Ewing sarcoma
• Soft Tissue Tumors: Rhabdomyosarcoma is the most common malignant soft tissue tumor of childhood, often originating from skeletal muscle precursor cells.
• Early diagnosis and treatment are imperative for favorable prognosis

Nonaccidental Trauma

• Nonaccidental trauma (NAT) should be considered in any patient with long bone fractures in non-ambulatory children.
• Suspicion for NAT includes pattern injuries, multiple injuries at different stages of healing , and radiographic findings.