Osteoporosis 4.29/5 (14)

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Osteoporosis

Normal bone tissue and osteoporosis (right). Gtirouflet (CC BY SA 3.0, from Wikimedia Commons

Definition

In osteoporosis, low bone mass is present and the construction (architecture) in the bone tissue is weakened. Thus, there is an increased risk of bone fractures. In the skeleton there is a continuous build-up and breakdown of bone tissue. Low bone mass occurs when the degradation exceeds the build-up over time.

Definitions

  • Osteoporosis occurs when a DEXA measurement shows "T-score" for bone density / bone mass at -2,5 or lower
  • In the case of "severe osteoporosis" osteoporotic bone fractures should be included
  • Osteopenia involves T-scores between -1.0 and -2.5 (between normal bone density and osteoporosis)
  • Among children, osteoporosis is defined by comparing the bone mass with that which is normal for the corresponding age ("Z-score")

Disease Causes

There are various causes of osteoporosis.

  • In autoimmune rheumatic diseases of the joints (Arthritis) connective tissue (connective tissue disorders) and blood vessels (Vasculitis) may require treatment with cortisone (Prednisone) cause osteoporosis as a side effect
  • Elderly women in particular (estrogen deficiency) have an increased risk of taking prednisolone or other cortisone preparations over time
  • Gestation osteoporosis
  • A rare cause is Mastocytosis, which can be suspected among younger people with striking fractures in the back
  • Osteoporosis is separated osteopenia which is a precursor (see more below), and from osteomalacia which is limited to reduced mineralization (most often calcium deposits) in the skeleton
(A) Sagittal fat-suppressed contrast-enhanced T2 weighted MRI of the spine shows spondylitis of T8, 9, 10 with left paraspinal and anterior subligamentous abscesses (arrow head) and compression fractures at T8 through L5. (B) Low bone mineral density at lumbar spine and left femur is demonstrated, indicating & quot; osteoporosis & quot ;. AP, anteroposterior; BMD, bone mineral density.

Osteoporosis triggered by cortisone. Many spinal vertebral fractures seen on MRI examination (left) and low bone mass in bone density measurement (right). Ko SH, 2012. CC BY NC 3.0

Symptoms

Osteoporosis produces no symptoms before a fracture occurs. Such fractures are usually painful and can occur almost spontaneously. Fractures in vertebrae (compression fracture), bone fractures, femoral neck, ribs and other parts of the skeleton, even at low load or injury, are typical.

Risk Factors

  • Age
    • Older women (long time since menopause / terminated menstrual periods)
  • Hyper Para-thyreoidose (high calcium and high PTH (parathyroid hormone) in the blood
  • Cholesterol-lowering drugs (statins) may increase the risk of osteoporosis, but it is only shown at high doses.
    • It is unclear whether the cause is the drug or that lower cholesterol is associated with an increased risk of osteoporosis (reference: Leutner M, 2019)
  • Cortisone use (prednisolone) over a long time
  • Diet with low intake of Calcium and D vitamins
  • Low body weight
  • Little physical activity
  • Low sun exposure (low Vitamin D)
  • Metabolic disease (hyperthyroidism)
  • Pregnancy and breastfeeding (Pregnancy Osteoporosis)
  • Reduced intestinal uptake (for example in intestinal disorders)
  • Smoking and high alcohol consumption

Risk of fracture- calculator (FRAX)

Prevention

Preventive measures should be implemented among people with significant risk factors. Threshold to do Measurement of bone density should also be low.

  • Together with long-term use of prednisolone or other cortisone preparations should Calcium and Vitamin D (eg Calcigran Forte chewable tablets 1000 mg / day or Kalcipos which can be swallowed)
  • With strikingly low bone mass is often supplemented with alendronate or another bisphosphonate for a period of time

Diagnosis

Osteoporosis is usually detected by bone density / bone mass measurement. The measurement uses a small dose of X-rays, called dual energy X-ray absorptiometry (DEXA measurement). The result provides good evidence for future breach risk. Many rheumatic and x-ray departments have such machines and receive referrals from GPs / GPs.

Interpretation of measurement values ​​at DEXA

  • At normal bone density, T-score -1,0 or higher
  • By osteopenia (precursor of osteoporosis) is T-score lower, that is, between -1,0 and -2,5
  • Osteoporosis is defined by T-score -2,5 or less
  • Z-scores are also often reported and show bone density in percent compared to results from healthy in the same age group
  • Although the bone mass usually correlates well with the risk of fracture, the measurement values ​​do not show how the architecture of the bone substance is. A weak bone structure may occur even though bone density / bone mass is good
  • Some DEXA machines may additionally consider (sidepictures of the spinal cord) if compression fractures of vertebrae are present
  • Control of bone density is often done after approx. 2 years to see if there is improvement (after treatment) or development to the worse and then indication for supplemental treatment

Cursor for the formation of new bone tissue (bone markers)

  • Bone markers are rarely used in clinical routine, but are relevant if the treatment does not work as expected
  • N-terminal Propeptide of Collagen Type I (PINP) is considered the best marker
  • Reference values
    • Postmenopausal female 16-96 mcg / L
    • Premenopausal female 19-83 mcg / L
    • Adult man 22-87 mcg / L
  • PINP should be measured before treatment start and after 6 months
    • An increase of 21% or more indicates treatment effect
  • PINP is not suitable for screening or diagnosis of osteoporosis
  • In severe hepatic disease, the test can not be used (metabolism of PINP through liver)

Other blood samples that can be taken in the investigation of osteoporosis

  • Lowering reaction (SR), CRP, hemoglobin (Hgb), white blood cells (leukocytes), platelets (platelets), calcium, albumin, creatinine, ALAT, alkaline phosphatase (ALP), TSH, 25 (OH) vitamin D, phosphate, parathyroid hormone ( PTH) and electrophoresis. Testosterone in men.

Treatment

First, risk factors (see above) are reduced as far as possible

  • Reduce possible cortisone dose (prednisolone)
  • Custom physical activity
  • Sun exposure (increases vitamin D)
  • Calcium and vitamin D (for example Calcigran Forte 1000mg / day)

Drugs that reduce bone mass degradation (anti-resorptive drugs)

  • Bisphosphonates, for example Alendronate tablets
    • It is essential that Alendronate is taken with water as described in the package leaflet. Otherwise, the treatment has no effect
    • Alternatively, bisphosphonate may be given intravenously, for example with Alclasta once a year.
      • Some people get a fever reaction after the infusion.
      • Attack of chondrocalcinosis occurs after intravenous treatment
      • Blood too low in the blood occurs and should be checked before treatment. Pain in joints and muscles is also possible side effect
      • If bisphosphonates have been used for longer than 5 years, the indication must be carefully considered. Damage to the bone tissue in the jaw and drug-related bone fractures are very rare side effects, mostly at high drug doses
      • Often the bone mass retains over several years after discontinuation of treatment, otherwise, change to another type of treatment (please see below)
      • Reduces risk of new fractures with 40-70%
    • If osteoporosis fractures occur during alendonate treatment, bone mass building (anabolic), PTH analogue drugs are relevant
  • Teriparatide, Forsteo
    • An injection (with "pen") daily for a maximum of 2 years
    • Excessive calcium in blood and kidney stones development may occur during treatment
    • The treatment should not be given by cancer where metastases to the skeleton may be present
  • RANKL antibody, Prolia (densunumab) can be given as injections under the skin every 6. month. Calcium in blood may become low and should be controlled.
  • SERM (estrogen receptor regulators), Evista (raloxifene)
    • For women under the age of 65
  • Estrogen
  • Testosteron can be used in osteoporosis among men with hormone deficiency

Related diseases in the skeleton

Osteomalacia (among adults) and rickets (In children)

  • Lack of calcium and other mineralization of the skeleton
  • Causes are most often lacking
    • Vitamin D (too low intake), calcium and / or phosphate
  • Investigation: Measurement of 25 (OH) vitamin D, calcium, phosphate, parathormone (PTH), alkaline phosphatase and creatinine (renal function)
  • Leading to "soft bones"
  • Can overlap with osteoporosis, but bone mass need not be reduced

Osteopenia

  • Low bone mass (T-score between -1,0 and -2,5)

Osteitis fibrosis cystica

  • Loss of bone mass and skeletal structure changes
  • Caused by hyperparathyroidism
  • In blood tests, parathymone, usually also calcium and alkaline phosphatase, is elevated

Osteopetrosis

  • Too high bone density. Rare, hereditary disease
  • In the blood test alkaline phosphatase is elevated

Paget's disease (Osteitis deformans)

  • Adults (over the age of 55 years), most often men
  • Gradual rebuilding and thickening of the skeleton, mostly in the pelvis, thighs, vertebrae and skull
  • Alkaline phosphatase in blood is often elevated

Literature


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