Vitamin B-12 is also known as cobalamin. It is responsible for the formation of blood normal functioning of the nervous system and cell metabolism, particularly of DNA, fatty acids and the production of energy. Vitamin B-12 deficiency can cause anemia, or low red blood cell counts, and nerve problems such as degenerative myelopathy. It is important to consult with a physician regarding vitamin deficiencies and the diagnosis and treatment of health concerns.
Causes
According to a 2003 article in "American Family Physician," causes of vitamin B-12 deficiency can be divided into malabsorption syndromes and other gastrointestinal causes. Meat, dairy and fortified foods are sources of B-12, so a diet low in these foods can lead to deficiency. Malabsorption syndromes are problems with the gastrointestinal tract in which B-12 can no longer be absorbed. Other GI problems include bacterial overgrowth and parasitic infections. The nerves, particularly at the back of the spinal cord, degenerate. This is because their insulation, called myelin, cannot be maintained or formed. The mechanism for this is not known.
Signs and Symptoms
The anemia caused by B-12 deficiency can lead to tiredness, fatigue, weakness and pale skin color. The nerve problems can cause psychiatric symptoms such as confusion, irritability and depression. Damage to the back of the spinal cord in degenerative myelopathy causes problems in the extremities, with the legs being affected more than the arms. It tends to start with numbness, tingling, difficulty walking, loss of your sense of position, as well as vibration. It can progress to an inability to move the extremities and incontinence.
Diagnosis
The diagnosis of B-12 deficiency is made by a medical history that includes the symptoms above, as well as physical exam and laboratory findings. Physical exam findings may include pale skin and the loss of sensation, particularly position and vibration. Lab tests are generally done on the blood levels of vitamin B-12, and compounds involved in overlapping biochemical pathways, including folic acid, homocysteine and methylmanonic acid.
Treatment
The treatment of B-12 deficiency involves the administration of B-12 under the supervision of a physician as well as addressing the underlying causes. Mild degenerative myelopathy may be reversible, but past a point, the nerve problems will not be treatable.
References
- "American Family Physician"; "Vitamin B12 Deficiency"; David Brown, M.D.; March 2003
- "UpToDate"; "Etiology and clinical manifestations of vitamin B12 and folic acid deficiency"; Stanley L Schrier, MD; January 2011
- "Robbins and Cotran Pathologic Basis of Disease"; Vinay Kumar, et al.; 8th Ed 2009
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