Diseases Info

Osteomalacia

Overview | Symptoms | Treatment | Prevention | Mechanical Stress | Diseased Hip Joint

Overview

Definition

A softening of the bones in adults caused by a failure of the normal calcification (calcium deposits).

Causes and Risks

There are numerous causes of osteomalacia. In children, the condition is called rickets and is usually caused by a deficiency of vitamin D. Conditions that may result in osteomalacia include inadequate dietary intake of vitamin D, inadequate exposure to sunlight (ultraviolet radiation), which forms vitamin D in the body, and malabsorption of vitamin D by the intestine. Other conditions include hereditary or acquired disorders of vitamin D metabolism, kidney failure and acidosis, phosphate depletion associated with low dietary intake or kidney disease, and side effects of medications used to treat seizures. Risk factors are related to the causes. In the elderly, there is an increased risk for those who tend to remain indoors and who avoid milk because of lactose intolerance.

The incidence is 1 in 1000 people.

Symptoms

• diffuse bone pain, especially in the hips
• muscle weakness
• symptoms associated with low calcium
• numbness around the mouth
• numbness of extremities
• spasms of hands or feet

Treatment

Medications

Oral supplements of vitamin D, calcium, and phosphorus may be given depending on the underlying cause of the disorder. Larger doses of vitamin D combined with exposure to ultraviolet light may be indicated in people with intestinal malabsorption. Monitoring of blood levels of phosphorus and calcium may be indicated with some underlying conditions.

Prognosis

Improvement in the condition of the bones, evidenced by bone X-rays, can be seen within a few weeks in some people with vitamin deficiency disorders. Complete healing with treatment takes place in 6 months.

Complications

• recurrence of symptoms

Call Your Health Care Provider If:

Call for an appointment with your health care provider if you have symptoms of osteomalacia, or if you think that you may be at risk for this disorder.

Prevention

An adequate dietary intake of dairy products that are fortified with vitamin D and exposure of the body to sunlight can prevent osteomalacia caused by vitamin D deficiency in adults.

Use of very strong sunscreen, limited exposure of the body to sunlight, short days of sunlight, and smog are factors that decrease formation of vitamin D within the body.

Mechanical Stress

Mature bone is always responding to mechanical stress. It is effectively plastic, indicated by the ability of soft tumours or brain cortical sulci to indent the skull vault, for example. A minor change in mechanical strain will stimulate osteoclast and then osteoblast activity as the bone microstructure is altered to respond to the stress. The lack of vitamin Dprevents the ossification. The stress is unchanged, but the bone is effectively weaker. The mechanical stress continues with greater effect. A continuation of this process will cause a widening fissure filled with un-ossified matrix, the Looser zone or Milkman's fracture so characteristic of osteomalacia.

One should look for the Looser zones in those areas which are most subject to mechanical stress. For example; the architecture of the pelvis reflects its mechanical loads.

• Comparison of the gothic architecture with the pelvis makes it easy to see where the lines of mechanical stress might go and this is where the Looser zones can be seen. Elsewhere, there might be, for example, Looser zones in the ribs at the points of attachment of the accessory muscles of respiration in those patients who combine osteomalacia and, say, chronic obstructive airways disease

• Looser zone left hip
• Knee close-up
• Looser zone in pelvis
• Upper ribs
• 

Diseased Hip Joint

Hip-joint replacement (or total hip replacement) substitutes all or part of the hip joint with an artificial device (prosthesis) that restores joint movement. Hip-joint replacement is mostly performed in older people. It is usually not recommended for younger people because of the strain they will most likely put on the artificial hip.

Hip-joint replacement is performed in patients who have:

• hip pain that has failed to respond to conservative therapy (for six months or more)
• hip osteoarthritis or arthritis confirmed by X-ray
• inability to work, sleep, or move because of hip pain
• loose hip prosthesis
• some hip fractures
• hip-joint tumors

Hip-joint replacement is not recommended for:

• current hip infection
• poor skin coverage around hip
• paralysis of the quadriceps muscles
• severe diseases of the blood vessels in the leg and foot (peripheral vascular disease)
• nerve diseases (neuropathy) affecting the hip
• severe, limiting mental dysfunctions
• serious physical diseases (such as metastatic disease)
• morbid obesity (over 300 pounds)

This table shows a list of causes of osteomalacia and some of the biochemical abnormalites that can be seen.