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:

Kumar P, Clark M. Kumar & Clark's clinical medicine.
Walker B, Colledge N, Ralston S, Penman I. Davidson's principles and practice of medicine.
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
Agabegi S, Agabegi E, Ring A. Step-up to medicine. Philadelphia: Wolters Kluwer/Lippincott Williams &

Wilkins; 2013.
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).
Pennmedicine.org. Kyphosis [Internet]. 2016 [cited 24 January 2016]. Available from:

http://www.pennmedicine.org/encyclopedia/em_PrintArticle.aspx?gcid=001240 (Figure 2).
Wikipedia. Colles' fracture [Internet]. 2016 [cited 24 January 2016]. Available from:

https://en.wikipedia.org/wiki/Colles%27_fracture (Figure 3).
"Osteoporosis And Arthritis: Two Common But Different Conditions". N.p., 2015. Web. 18 Dec. 2015.
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