Osteoporosis

Definition:

  • An acquired condition characterized by low bone density that leads to bone fragility and high risk of fractures.

  • Bone density < 2.5 standard deviations of the mean for healthy matched controls.

Epidemiology:

  • Majority of osteoporotic patients are postmenopausal women and elderly men.

  • Estimated that over 200 million people globally suffer from this disease.

  • In Saudi Arabia an epidemiological analysis showed that 34% of healthy Saudi women, and 30.7% of men, 50-79 years of age are osteoporotic.

Pathophysiology:

  • Normally, bones are constantly being remodeled and replaced by the balanced
    activities of osteoclasts (bone resorption) & osteoblasts (bone deposition).

  • On osteoporosis, the activity of osteoclasts is increasing while the activity of
    osteoblasts is decreasing leading to a decrease in bone mass or failure to
    attain the peak of bone mass before the age of 30.

Types & Classification:

Study guide:

Risk Factors:

  • Depletion of estrogen:

    • Postmenopausal state.

    • Eating disorder, oligomenorrhea, or athletic
      amenorrhea.

    • Premature menopause.

  • Female gender.

  • Vitamin D & Calcium deficiency .

  • Prolonged immoblity.

  • Low testosterone.

  • Hyperthyroidism.

Signs & Symptoms:

  • Osteoporosis is a silent disease!

    • Most patients are asymptomatic until fractures occur.

  • Vertebral body compression:

    •  Especially in the middle & lower thoracic, and

      upper lumbar spine.

    •  Back pain, restricted spinal movement, and deformity (kyphosis, or hunch-back
      deformity).

    •  Always suspect osteoporosis in an elderly patient who is suffering from loss of
      height and back pain.

  • Colles’ fracture:

    • When falling on outstretched hand.

    • Postmenopausal women.

  • Hip fracture:

    • Either femoral neck, or intertrochanteric.

  • Long bone fracture: femur, humerus, and tibia.

  • Smoking & alcohol.

  • Medications: steroids, & long-term use of heparin.

  • Others: family history, Asian or European origin, thin built, and delayed peak bone mass.

 

Diagnosis:

  • Plain X-ray:

    • To check the presence of any fracture.

  • DEXA (dual energy x-ray absorptiometry) Scan:

    • Gold standard for measuring the bone density.

    • T-scores according to the WHO classification (see table)

    • To rule out secondary causes (usually normal):

      • Check serum chemistry for calcium, phosphate, and alkaline phosphatase.

      • TSH and thyroid function tests.

      • Serum free PTH.

      • Vitamin D.

      • Serum creatinine.

      • CBC.

 

Screening:

  • Every woman (with no previous known fractures or secondary
    causes of osteoporosis) should be screened using DEXA
    scan at the age of 65 Y/O.

  • If DEXA scan is normal and no risk factors, repeat the screening in 3-5 years.

Treatment:

  • Non-pharmacological:

    • Adequate calorie intake, and supplemental calcium.

    • Avoid malnutrition.

    • Weight bearing exercise 30 minutes, at least 3 times a week.

    • Smoking cessation:

      • Smoking accelerates bone loss.

    • Reduce alcohol intake.

    • Hip protectors in elderly patients.

  • Pharmacological:

    • Vitamin D and calcium are the best initial therapy in cases of osteopenia.

    • Bisphosphonate:

      • First- line treatment for osteoporosis.

      • Mechanism:

        • Decrease the osteoclastic activity through binding to hydroxyapatite & lowers the risk of fractures (inhibit the bone resorption).

      • Usually oral (alendronate, or risedronate) or IV (zoledronic acid).

      • Side-effects:

        • Reflux, gastric ulcers, and esophageal irritation “Pill Esophagitis” (mainly for oral).

        • Flu-like symptoms (mainly with IV form).

        • Rarely, osteonecrosis of the jaw.

  • PTH therapy (Teriparatide):

    • Increase bone mineral density (anabolic effect) & lowers the risk of fractures.

    • Safety is not fully known on the long run.

    • Used in severe osteoporosis patient, who are not tolerating bisphosphonate.

    • Used for 24 months maximally, because of the risk of osteosarcoma and hypercalcemia.

  • Calcitonin nasal spray:

    • Increase bone mineral density (anabolic effect).

    • Useful for short-term therapy, and decreases the risk of vertebral fractures.

    • Used in elderly women with vertebral fracture.

  • Estrogen-progestin therapy:

    • Not a first line therapy.

    • Risk of coronary artery disease, stroke, thromboembolism, and breast cancer.

Prevention:

  • Non-pharmacologic:

    • Adequate calcium & vitamin D intake, and weight-bearing exercises.

  • Pharmacologic:

    • Raloxifene and bisphosphonates should be considered as first-line agents for the prevention of osteoporosis.

References:

  1. Kumar P, Clark M. Kumar & Clark's clinical medicine.

  2. Walker B, Colledge N, Ralston S, Penman I. Davidson's principles and practice of medicine.

  3. Aafp.org. U.S. Preventive Services Task Force: Screening for Osteoporosis: Recommendation Statement -

    American Family Physician [Internet]. 2016 [cited 24 January 2016]. Available from:

    http://www.aafp.org/afp/2011/0515/p1197.html

  4. Agabegi S, Agabegi E, Ring A. Step-up to medicine. Philadelphia: Wolters Kluwer/Lippincott Williams &

    Wilkins; 2013.

  5. Czarny D. Tell Me About: Osteoporosis | SAGE [Internet]. SAGE. 2015 [cited 24 January 2016]. Available from:

    https://www.sage.care/blog/tell-me-about-osteoporosis/ (Figure 1).

  6. Pennmedicine.org. Kyphosis [Internet]. 2016 [cited 24 January 2016]. Available from:

    http://www.pennmedicine.org/encyclopedia/em_PrintArticle.aspx?gcid=001240 (Figure 2).

  7. Wikipedia. Colles' fracture [Internet]. 2016 [cited 24 January 2016]. Available from:

    https://en.wikipedia.org/wiki/Colles%27_fracture (Figure 3).

  8. "Osteoporosis And Arthritis: Two Common But Different Conditions". N.p., 2015. Web. 18 Dec. 2015.

  9. Melton III LJ, Chrischilles EA, Cooper C, Lane AW, Riggs BL: Perspective: How many women have

    osteoporosis? J Bone Miner Res 1992;7:1005-10

First Author:      Sarah Alsadun

Second Author: Roaa Amer

Reviewed by:     Mneera Khaled

                           Khairiah Nassri

Format Editor:   Roaa Amer

Audio recording:
- Read by: Ghada Saleh Ashamed
​- Directed by: Tariq Jawadi
- Audio production: Bayan Alzomaili