Summary

Osteoporosis is a systemic skeletal disease characterized by low bone mass and micro-architectural deterioration of bone tissue, leading to increased bone fragility and fracture risk. It is the most common metabolic bone disease, affecting primarily post-menopausal women due to Oestrogen withdrawal. Diagnosis is confirmed by a DEXA Scan T-Score < -2.5 SD. Fractures of the Hip (Neck of Femur), Spine (Vertebral Wedge), and Wrist (Colles') are the classic sequelae. Treatment focuses on inhibiting resorption (Bisphosphonates/Denosumab) or stimulating formation (Teriparatide), alongside Calcium/Vitamin D repletion. [1,2]

Key Facts

• Definition: T-Score < -2.5 (WHO Criteria).
• Osteopenia: T-Score between -1.0 and -2.5.
• Pathology: Uncoupling of bone turnover (Resorption > Formation).
• Symptom: "The Silent Disease". Asymptomatic until a bone breaks.
• Key Fractures: Distal Radius (Colles'), Vertebrae (Kyphosis), Hip (NOF).
• Sign: Loss of height (>4cm). Dowager's Hump (Thoracic Kyphosis).

Clinical Pearls

"The Wrist is the Warning": A Colles' fracture in a 60-year-old woman is the "Canary in the Coal Mine". It predicts a future hip fracture. Treat the osteoporosis NOW.

"It's not just Calcium": Patients think drinking milk fixes it. It doesn't. Once the architecture is lost (trabeculae disconnected), you cannot rebuild it with calcium alone. You need pharmacological agents to stop the osteoclasts.

"The Drug Holiday": Bisphosphonates stay in the bone for years. After 5 years of oral (or 3 years IV), consider a "Holiday" to reduce the risk of Atypical Femoral Fractures, as the bone becomes "frozen" and brittle.

"Secondary Causes": In men, or young women, always look for a cause. Celiac disease (malabsorption), Steroids (Asthma/RA), Alcohol, Myeloma.

        FRAGILITY FRACTURE or HIGH RISK
                    ↓
         DEXA SCAN (T-Score < -2.5)
           OR HIGH FRAX SCORE
                    ↓
    ┌───────────────┴───────────────┐
   FIRST LINE                   SEVERE / FRACTURES
(Bisphosphonate)             (Anabolic Agents)
    ↓                               ↓
Alendronate Oral             Teriparatide / Romo
(Weekly)                     (Daily Injection)
    ↓                               ↓
 intolerance?               Consolidate with
    ↓                        Bisphosphonate
Denosumab (Prolia)
(6 monthly s/c)

1. Lifestyle

• Exercise: Weight bearing/Resistance.
• Supplements: Calcium (1000mg) + Vitamin D (800IU).
• Falls Prevention: Remove rugs, fix eyesight.

2. Anti-Resorptive Agents (Stop the Osteoclasts)

• Bisphosphonates (Alendronate, Risedronate, Zoledronate):
  • Mechanism: Analogues of pyrophosphate. Bind to bone. Ingested by osteoclasts -> Apoptosis.
  • Side Effects: Reflux/Oesophagitis (Oral). Flu-like symptoms (IV).
• Denosumab (Prolia):
  • Mechanism: Monoclonal antibody against RANK-L. Stops osteoclast formation.
  • Note: Rebound effect! If you stop it suddenly, vertebral fractures occur. MUST transition to bisphosphonate if stopping.

3. Anabolic Agents (Build Bone)

• Teriparatide (PTH analogue):
  • Mechanism: Pulsatile PTH stimulates osteoblasts > osteoclasts.
  • Use: Max 24 months. For severe spinal osteoporosis.
• Romosozumab:
  • Mechanism: Sclerostin inhibitor. (Releases the brake on bone formation).

• Indications: Acute painful vertebral compression fracture <6 weeks old, failing analgesia.
• Procedure: Percutaneous injection of PMMA (Bone Cement) into the collapsed vertebra under fluoroscopy.
• Kyphoplasty: Using a balloon first to restore height, then injecting cement.
• Evidence: Controversial. Some sham trials showed no benefit. NICE supports it for selected painful cases.

Key Studies

1. FIT Trial (Fracture Intervention Trial): Alendronate reduces vertebral and hip fractures by 50%.
2. FREEDOM Trial: Denosumab reduces fractures.
3. HORIZON Trial: Zoledronate (Once yearly IV) reduces fractures and mortality after hip fracture.

What is Osteoporosis?

Your bones are living tissue, constantly being demolished and rebuilt. After menopause, the demolition crew works faster than the builders can keep up. The bone becomes full of holes, like an Aero bar, and breaks easily.

Is it painful?

No, not until you break something. It is a silent thief stealing your bone density.

Why do I need to take the tablet upright?

Alendronate is very irritating to the gullet. If it gets stuck, it burns a hole. You must stand up for 30 minutes after taking it with water.

How long on treatment?

Usually 5 years. Then we assess. If we leave you on it forever, the bone becomes too hard and brittle (like chalk) and can snap unexpectedly. We might give you a "holiday".