Osteoporosis Lecture Notes

Introduction

• Lecturer: Sarah Thresh Turner
• Topic: Osteoporosis
• Part of In-Depth Review Series on the Musculoskeletal System
• Free quiz available at the end of the lecture

What is Osteoporosis?

• Disease that thins bones to a point where they can't withstand normal everyday stress
• Results in fractures
• Common misconception: Falls cause fractures, but in osteoporosis, bones may break first, leading to falls
• Common types of fractures:
  • Colles fracture: Lower part of the radius at the wrist
  • Common sites: Wrist, hips, spine

Pathophysiology

• Spongy Bone: Normally porous; becomes more porous over time due to osteoporosis
  • Decreased bone density; bones become weak
• Osteoclasts vs Osteoblasts: Balance disrupted in osteoporosis
  • Osteoclasts: Break down bone (consume bone, release calcium and phosphorus)
  • Osteoblasts: Build up bone (use calcium and phosphorus)
• Peak bone density achieved at age 30; Osteoclast activity surpasses Osteoblast activity post-30
• Symptoms often absent until a fracture occurs

Functions of Bones

• Provide support and protection for internal organs
• Allow movement: Muscles and ligaments attach to bones
• Shape giving: Determines body shape (tall, short, etc.)
• Bone marrow: Produces red/white blood cells and platelets, stores calcium, phosphorus, and lipids

Bone Structure

• Compact bone: Hard, outer structure
• Spongy bone: Porous, inner structure filled with proteins and minerals (calcium, phosphorus)
• Cells within spongy bone:
  • Osteoclasts: Consume bone, release calcium into blood
  • Osteoblasts: Build up bone, utilize calcium

Hormonal Regulation

• Parathyroid Gland: Secretes parathyroid hormone (PTH) when calcium levels drop
  • PTH increases Osteoclast activity indirectly
  • Influences small intestine (reabsorbs calcium) and kidneys (minimizes calcium loss)
• Thyroid Gland: Releases calcitonin when calcium levels are high
  • Calcitonin decreases Osteoclast activity
• Sex Hormones:
  • Estrogen: Regulates Osteoclast and Osteoblast activity, decreases Osteoclast lifespan
  • Testosterone: Decreases with age, converts to estrogen in men, affects bone density

Risk Factors (Mnemonic: CALCIUM)

• C: Calcium and Vitamin D intake low
• A: Age (peak bone density at 30, decreases afterward)
• L: Lifestyle (sedentarism, smoking, alcohol use)
• C: Caucasian/Asian women more at risk
• I: Inherited (genetics)
• U: Underweight (BMI < 19)
• M: Medications (e.g., glucocorticoids, anticonvulsants)

Signs and Symptoms (Mnemonic: FRAIL)

• F: Fractures (hips, spine, wrists)
• R: Rounding of upper back (Dowager's Hump)
• A: Asymptomatic until fracture
• I: Inches of height lost (2-3 inches)
• L: Lower back, neck, hip pain

Diagnostic Testing

• Bone Density Test: DEXA or DX scan
  • Measures calcium and other minerals in the bones
  • No special prep: Avoid calcium supplements 24 hours prior

Nursing Interventions

• Assess Risk Factors: Use CALCIUM mnemonic
• Educate about DEXA scan: No calcium 24 hours before
• Safety: Fall prevention (call light, non-slip socks, clutter-free environment, assist with mobility)
• Prevention: Weight-bearing exercises, diet rich in calcium and Vitamin D, avoid smoking and excessive alcohol

Medications

• Calcium and Vitamin D Supplements: Aid in bone formation and calcium absorption
• Bisphosphonates: Decrease bone breakdown, prolong Osteoblast activity (e.g., Alendronate, Ibandronate)
• Calcitonin: Decreases Osteoclast activity
• Hormone Replacement Therapy (HRT): For postmenopausal women, short-term use
  • Alternatives: Selective estrogen receptor modulators (e.g., Raloxifene)
• Teriparatide (Forteo): Severe osteoporosis, stimulates Osteoblasts for new bone formation

Summary

• Osteoporosis: Significant impact on bone health
• Prevention and treatment include lifestyle changes, proper diet, medication adherence
• Nurses play a crucial role in patient education and safety management