Blood Disorder: Pernicious Anemia (Vitamin B12 Deficiency)

Pernicious Anemia is not a cancer but blood disorder.  This disorder is treated by a hematologist oncologist or a family physician.

Above an image of a patient's blood smear that has been stained showing classic pernicious anemia


Pernicious anemia is a disease that begins slowly and make take several years to realize what is happening in your body. This disease is classified as autoimmune.  The definition of autoimmune arise from an overactive immune response of the body against substances and tissues normally present in the body. In other words, the immune system mistakes some part of the body as a pathogen and attacks its own cells. This may be restricted to certain organs (e.g. in autoimmune thyroiditis) or involve a particular tissue in different places (e.g. Goodpasture's disease which may affect the basement membrane in both the lung and the kidney). The treatment of autoimmune diseases is typically with immunosuppression—medication which decreases the immune response.

Pernicious anemia is a decrease in red blood cells that occurs when the body cannot properly absorb vitamin B12 from the gastrointestinal tract. Vitamin B12 is necessary for the proper development of red blood cells.
Pernicious anemia is a type of megaloblastic anemia. Megaloblastic anemia is a blood disorder in which there is anemia with larger-than-normal red blood cells.

The body needs vitamin B12 to make red blood cells. To provide vitamin B12 to your blood cells, you need to eat enough foods containing vitamin B12, such as meat, poultry, shellfish, eggs, and dairy products.To absorb vitamin B12, your body uses a special protein called intrinsic factor, which is released by cells in the stomach. The combination of vitamin B12 bound to intrinsic factor is absorbed in the last part of the small intestine.
When the stomach does not make enough intrinsic factor, the intestine cannot properly absorb vitamin B12.
Very rarely, infants and children are born without the ability to produce enough intrinsic factor, or the ability to absorb the combination of intrinsic factor and vitamin B12 in the small intestine. Pernicious anemia that occurs at birth (congenital) is inherited. You need the defective gene from each parent to get it.
Common causes of pernicious anemia include:

• Weakened stomach lining (atrophic gastritis)
• The body's immune system attacking the cells that make intrinsic factor (autoimmunity against gastric parietal cells) or intrinsic factor itself

 RISK FACTORS

 

• Family history of the disease
• History of autoimmune endocrine disorders, including:
  
  • Addison's disease
  • Chronic thyroiditis
  • Graves disease
  • Hypoparathyroidism
  • Hypopituitarism
  • Myasthenia gravis
  • Secondary amenorrhea
  • Type 1 diabetes
  • Testicular dysfunction
  • Vitiligo
• Scandinavian or Northern European descent
  
  SYMPTOMS
  
  People with mild anemia may have no symptoms or very mild symptoms. More typical symptoms of vitamin B12 deficiency anemia include:
• Diarrhea or constipation
• Fatigue, lack of energy, or light-headedness when standing up or with exertion
• Loss of appetite
• Pale skin
• Problems concentrating
• Shortness of breath, mostly during exercise
• Swollen, red tongue or bleeding gums
• Nerve damage caused by vitamin B12 deficiency that has been present for a longer time may cause:
  
  • Confusion or change in mental status (dementia) in severe or advanced cases
  • Depression
  • Loss of balance
  • Numbness and tingling of hands and feet
    
    LAB TESTING
     1. Complete blood count which is where blood is drawn and the lab tech will process the specimen through an analyzer that will measure the blood counts which include white counts,red counts,hemoglobin,hematocrit,platelets and indices .
    2. Serum holotranscobalamin II 
            Circulating homocysteine is a risk factor of cardiovascular and cerebrovascular events.    Hyperhomocysteinemia may be an early indicator for vitamin B12 disorders because cobalamin is a cofactor in the remethylation process of homocysteine. Serum holotranscobalamin (holoTC II) becomes decreased before the development of metabolic dysfunction. In this study, we assessed circulating holoTC II to estimate the diagnosis of vitamin B12 deficiency in the first ischemic cerebrovascular attack.       

                  3. Reticulocyte Count measures the amount of red cells that are being produced from the bone 
                       marrow. 


                 4.  Schilling test is a medical investigation used for patients with vitamin B₁₂ deficiency. The                        patient is given radiolabeled B12 to drink. An intramuscular B12 injection an hour later.
                     24 hours later a urine sample is collected and is measured for B12 absorption.
                 
                5.  Methylmalonic Acid level is a blood test that is performed by gas chromotographic Mass
                     spectrometry. An elevated level may indicate a Vitamin B12 deficiency.


Treatment
 The treatment for pernicious anemia requires a monthly injection of vitamin B12 . This treatment brings great relief for the patient.  Fatigue and other symptoms are relieved.

For more information:  
http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0001595/