Osteomalacia

Definition

Osteomalacia involves softening of the bones caused by a deficiency of vitamin D or problems with the metabolism of this vitamin.

Causes, incidence, and risk factors

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 lead to osteomalacia include:

• Inadequate dietary intake of vitamin D
  
• Inadequate exposure to sunlight (ultraviolet radiation), which produces vitamin D in the body
  
• Malabsorption of vitamin D by the intestines
  

Other conditions that may cause osteomalacia include:

• Hereditary or acquired disorders of vitamin D metabolism
  
• Kidney failure and acidosis
  
• Phosphate depletion associated with low dietary intake of phosphates
  
• kidney disease or cancer (rare)
  
• Side effects of medications used to treat seizures
  

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.

Risk factors for osteomalacia are related to the causes. In the elderly, there is an increased risk among people who tend to remain indoors and those who avoid milk because of lactose intolerance.

Symptoms

• Diffuse bone pain, especially in the hips
  
• Muscle weakness
  
• Bone fractures with minimal trauma
  

Symptoms associated with low calcium including:

• Numbness around the mouth
  
• Numbness of extremities
  
• Spasms of hands or feet
  
• Abnormal heart rhythms
  

Signs and tests

• A bone biopsy shows osteomalacia.
  
• Serum vitamin D level may be low.