Alterations in Musculoskeletal Function: Trauma, Infection, and Disease

Alterations in Musculoskeletal Function

• Disorders of the Musculoskeletal System:
  • Bone Diseases
  • Diseases of Skeletal Muscle
  • Soft Tissue Injuries

Infections of the Bone: Osteomyelitis

• Definition: Severe pyogenic infection of bone and local tissue.
• Pathways of Infection:
  • Bloodstream (hematogenous)
  • Infectious agents reach bone through blood from elsewhere in the body.
  • Adjacent soft tissue
  • Common origins: burns, sinus disease, trauma, malignant tumor necrosis, periodontal infection, infected pressure ulcer.
  • Direct introduction
  • Occurs due to open fractures, penetrating wounds, surgical contamination, or prosthesis insertion.

Risk Factors

• Common Among:
  • Children under 16 years old (mean age 6)
  • Elderly patients
  • IV drug users
  • indwelling intravascular catheter users
  • Diseases: sickle cell anemia and chronic granulomatous disease.
• Most common pathogen: Staphylococcus aureus, followed by Streptococcus pneumoniae.

Clinical Manifestations

• In Children:
  • High fever
  • Localized pain at the bone site
• In Adults:
  • Fever, malaise, anorexia, night sweats, weight loss.

Healing Complications

• If untreated:
  • Necrotic bone separates from healthy bone leading to dead segments.
  • Possible outcomes: abscess or chronic infection (Involucrum).

Treatment

• Duration: 4 to 6 weeks of IV antibiotic therapy.
• Possible interventions for abscess:
  • Debridement or amputation.
  • Management of chronic osteomyelitis.

Alterations in Bone Mass and Structure: Scoliosis

• Definition: Lateral curvature of the spine, often S- or C-shaped.

Etiology and Pathogenesis

• Possible Causes:
  • Idiopathic
  • Congenital disorders
  • Connective tissue disorders
  • Neuromuscular disorders.

Clinical Manifestations and Classifications

• Symptoms:
  • Asymmetrical shoulders, hips, chest wall.
  • Possible respiratory problems and gastrointestinal dysfunction.

Types of Scoliosis

• Nonstructural Scoliosis:

  • Resolves when the patient bends to the affected side.
  • No vertebral rotation present.
  • Causes include postural problems and inflammation.

• Structural Scoliosis:

  • Fails to correct on forced bending.
  • Involves vertebral rotation and deformity.

Key Indicators of Scoliosis

• Symptoms:
  • Uneven shoulders
  • Rib hump
  • Scapular prominence
  • Uneven hips
  • Lateral deviation of the spine.

Treatment

• Options:
  • Bracing
  • Exercises
  • Surgical interventions for spinal alignment.

Alterations in Bone Mass and Structure: Osteoporosis

• Definition: Most common metabolic bone disease; greater bone resorption than formation.

Key Characteristics

• Disruption in osteoblastic/osteoclastic balance.
• Decreased mineral and protein matrix results in fragile bones.
• Factors influencing rate of bone loss:
  • Age
  • Genetics
  • Estrogen.

Risk Factors

• Common Factors:
  • Family history.
  • Estrogen deficiency.
  • Small body frame.
  • Caucasian or Asian race.
  • Menopause and various diseases.

Clinical Manifestations

• Symptoms include shortened stature, muscle wasting, back spasms, and kyphosis.

Diagnosis

• Based on Bone Mineral Density (BMD) by dual energy x-ray absorptiometry (DXA):
  • T score < -2.5 indicates osteoporosis.
  • T score between -1.0 and -2.5 indicates osteopenia.

Treatment Options

• Calcium and vitamin D supplements.
• Exercise.
• Medications:
  • Bisphosphonates
  • Recombinant human parathyroid hormone.

Alterations in Bone Mass and Structure: Rickets and Osteomalacia

• Definition: Vitamin D deficiency affecting bone matrix mineralization leading to soft osteopenic bone.

Clinical Manifestations

• Symptoms:

  • Kyphosis
  • Genu valgum (knock knees)
  • Genu varum (bow legs)
  • Bone pain in adults.

• Rickets: Affects growing skeleton in children.

• Osteomalacia: Affects mature skeleton in adults.

Etiology

• Causes include:
  • Inadequate vitamin D, calcium, or phosphorus.
  • Poor vitamin D metabolism.
  • Renal disease.

Treatment

• Supplementation with vitamin D, calcium, and phosphorus.

Bone Tumors: Multiple Myeloma

• Most common primary bone tumor, a slowly growing malignancy of bone marrow.

Pathogenesis

• Neoplastic proliferation of a single clone of plasma cells.
• Commonly affects kidneys and the immune system.

Clinical Manifestations

• Symptoms:
  • Predominantly bone pain.
  • Pathologic fractures.
  • Kidney dysfunction and neurologic symptoms.

Diagnosis

• Presence of homogeneous immunoglobulin in urine and serum.
• Confirmed by:
  • Bone marrow aspiration and biopsy.
  • Imaging tests.

Treatment

• Aggressive combination chemotherapy and local radiation.

Diseases of Skeletal Muscle: Muscular Dystrophy

• Group of genetically determined myopathies characterized by:
  • Progressive muscle weakness.
  • Replacement of muscle tissue with fat and fibrous tissue.
• Classified by the pattern of inheritance, age of onset, and muscular weakness distribution.

Duchenne Muscular Dystrophy

• Most common and severe type, inherited as X-linked trait.

Pathogenesis

• Muscle cells lack dystrophin, leading to muscle necrosis and degeneration.

Clinical Manifestations

• Symptoms often appear by age 3:
  • Enlarged calf muscles due to fat infiltration.
  • Proximal muscle weakness leading to frequent falls by 5-6 years old.
  • Most patients are wheelchair-bound by age 12-14 and may die by 20.

Treatment

• Education for patients and families, corticosteroid therapy, and preservation of function.

Myasthenia Gravis

• Chronic autoimmune disease affecting voluntary muscles.
• Mechanism: Antibodies block or destroy acetylcholine receptors at the neuromuscular junction, causing muscle weakness.

Risk Factors

• More common in women than men, peak onset at ages 20-30.

Clinical Manifestations

• Initial symptoms include painless muscle weakness affecting ocular and cranial muscles and proximal limb muscles; usually improves with rest but worsens with repeated use.

Treatment Options

• Anticholinesterase inhibitors, corticosteroids, IV immune globulin, plasmapheresis, immunosuppressive agents, and thymectomy if unresponsive to treatment.

Myasthenic Crisis vs. Cholinergic Crisis

• Myasthenic Crisis: Insufficient medication causing sudden increases in BP and pulse.
• Cholinergic Crisis: Excessive medication leads to muscle fasciculations, especially around the mouth.

"If you fell down yesterday, stand up today."
H. G. Wells