Vitamin B12 deficiency

Vitamin B12 deficiency

Vitamin B12 deficiencyis a low blood level of vitamin B₁₂. It can cause permanent damage to nervous tissue if left untreated longer than 6 months.^[1]Vitamin B₁₂ itself was discovered through investigation of pernicious anemia, which is an autoimmune disease that destroys parietal cells in the stomach that secrete intrinsic factor. Pernicious anemia, if left untreated, is usually fatal within three years.

Causes

Inadequate dietary intake of vitamin B₁₂.

Selective impaired absorption of vitamin B₁₂.

 Surgical removal of the small bowel (for example in Crohn's disease).

Long-term use of ranitidine hydrochloride

Coeliac disease may also cause impaired absorption of this vitamin

Malnutrition.

Sign and symptoms

Anemia (megaloblastic anemia)

Gastrointestinal symptoms effect on mucosal tissue in stomach.

Neurological symptoms : Sensory or motor deficiencies (absent reflexes, diminished vibration or soft touch sensation)may occur  Dementia and depression.

Ataxia of dorsal chord type

 Decrease muscle-tendon reflexes or irritability

shortness of breath and increased pallor

Diagnosis

Serum B₁₂ levels are often low in B₁₂ deficiency.

the lowest acceptable level for vitamin B₁₂ in blood has been about( 200 pg/ml to 550 pg/mL).

Serum homocysteine and methylmalonic acid levels are considered more reliable indicators of B₁₂ deficiency than the concentration of B₁₂ in blood.

Treatment

B₁₂ can be supplemented in healthy subjects by oral sublingual pill, liquid, or strip; intranasal spray; transdermal patch or by injection. B₁₂ is available singly or in combination with other supplements. B₁₂ supplements are available in forms including cyanocobalamin, hydroxocobalamin, methylcobalamin, and adenosylcobalamin (sometimes called "cobamamide" or "dibencozide"). Oral treatments involve giving 250 µg to 1 mg of B₁₂ daily.

Vitamin B₁₂ can be given as intramuscular or subcutaneous injections of hydroxycobalamin, methylcobalamin, or cyanocobalamin.