Association Between Pernicious Anemia and Orthostatic Hypertension
Pernicious Anemia and its association to orthostatic hypertension
Pernicious anemia is the major form of vitamin B12 deficiency. It is caused by serum antibodies against intrinsic factor which leads to B12 deficiency rather than by B12 deficiency itself. Absorption of vitamin B12 requires intrinsic factor which is secreted by parietal cells. Pernicious anemia is marked by autoimmune attack on gastric mucosa and a loss in parietal cells. Approximately 75% of the affected patients have type I antibody that blocks the binding on vitamin B12 to the intrinsic factor. These antibodies are found in plasma and gastric juice. A large percent expresses Type II antibodies. Type II antibodies prevent the binding of intrinsic factor-Vitamin B12 complex to the ileal cell receptors. About 85% to 90% of patients have Type III antibodies. Type III antibodies recognize the alpha and beta subunits of the gastric proton pump which is found on parietal cells.1
It is also thought that an auto reactive CD4+ T-cell response causes gastric mucosal injury and this results in the formation of autoantibodies which makes the injury worse. Anemia develops when intrinsic factor falls below the threshold level and vitamin B12 stores are depleted. This theory is backed up by experiments in animal models. This type of anemia can also be caused by achlorhydria and loss of pepsin secretion which is more common in elderly individuals.1
Pernicious anemia occurs in all racial group but is somewhat more prevalent in Scandinavian and Caucasian populations. It is usually a disease of older adults with the median age of diagnosis at 60 and the incidence in people younger than 30 is rare. There might be genetic predisposition to pernicious anemia but no specific genetic pattern has been observed yet.1
Some of the characteristics of pernicious anemia include atrophy of fundic glands, deficiency of parietal cells or achlorhydria, intestinalization, and shiny or glazed tongue known as strophic
Pernicious anemia is the major form of vitamin B12 deficiency. It is caused by serum antibodies against intrinsic factor which leads to B12 deficiency rather than by B12 deficiency itself. Absorption of vitamin B12 requires intrinsic factor which is secreted by parietal cells. Pernicious anemia is marked by autoimmune attack on gastric mucosa and a loss in parietal cells. Approximately 75% of the affected patients have type I antibody that blocks the binding on vitamin B12 to the intrinsic factor. These antibodies are found in plasma and gastric juice. A large percent expresses Type II antibodies. Type II antibodies prevent the binding of intrinsic factor-Vitamin B12 complex to the ileal cell receptors. About 85% to 90% of patients have Type III antibodies. Type III antibodies recognize the alpha and beta subunits of the gastric proton pump which is found on parietal cells.1
It is also thought that an auto reactive CD4+ T-cell response causes gastric mucosal injury and this results in the formation of autoantibodies which makes the injury worse. Anemia develops when intrinsic factor falls below the threshold level and vitamin B12 stores are depleted. This theory is backed up by experiments in animal models. This type of anemia can also be caused by achlorhydria and loss of pepsin secretion which is more common in elderly individuals.1
Pernicious anemia occurs in all racial group but is somewhat more prevalent in Scandinavian and Caucasian populations. It is usually a disease of older adults with the median age of diagnosis at 60 and the incidence in people younger than 30 is rare. There might be genetic predisposition to pernicious anemia but no specific genetic pattern has been observed yet.1
Some of the characteristics of pernicious anemia include atrophy of fundic glands, deficiency of parietal cells or achlorhydria, intestinalization, and shiny or glazed tongue known as strophic
References: 1Kumar et al. Red blood cell & bleeding disorders. In: Kumar et al. Robbins and Cotran Pathologic basis of disease. Philadelphia, PA: Saunders Elsevier; 2004: 639-675. 2White W, Reik L, Cutlip D. Pernicious anemia seen initially as orthostatic hypotension. JAMA. 1981; 141(2): 198-200. http://jama.jamanetwork.com/article.aspx?articleid=333407#qundefined. Published October 13, 1962. Accessed January 23, 2013. 3Ganjehei L, Massumi A, Razavi M, and Wilson JM. Orthostatic hypotension as a manifestation of vitamin B12 deficiency. Tex Heart Inst J. 2012;39(5):722-3.