Pernicious anemia is a subtype of vitamin B12 deficiency anemia. Pernicious anemia is a type of anemia where there is a low production of red blood cells due to lack of intrinsic factor. Intrinsic factor is a glycoprotein that is produced by the stomach parietal cells. It is required for vitamin B12 absorption in the ileum of the small intestine. The lack of intrinsic factor is usually caused by an autoimmune attack on the parietal cells of the stomach. It can also be due to an inherited disorder, surgical removal of part of the stomach, folic acid deficiency, lack of B12 complex absorption in the terminal ileum, and altered pH in the small intestine. Pernicious anemia should be distinguished from other disorders that cause issues with the metabolism and absorption of vitamin B12. In adults, pernicious anemia is most commonly seen among those who are of Irish, English, Scottish, or Scandinavian origin with 10 to 20 cases per 100,000 individuals annually. It is less commonly seen in other races. It is typically seen in those aged 40 to 70 years old. In children, congenital pernicious anemia usually manifests in those younger than 2 years old.
Early recognition and treatment usually result in a normal and uncomplicated lifespan. Delayed treatment can cause progression of neurological complications that may be permanent. Severe anemia can also lead to congestive heart failure or coronary insufficiency. Treatment involves the administration of cobalamin and possibly folic acid as well. While vitamin B12 therapy resolves the pernicious anemia, it does not help the atrophic gastritis which may progress to cancer. It has been shown that gastric adenocarcinoma incidence is 2 to 3 times higher in patients with pernicious anemia. Patients should be educated that they require lifelong vitamin B12 orally or by injection to avoid the relapse of pernicious anemia.
Symptom #1: Fatigue and General Weakness
Fatigue is a gradual feeling of tiredness that can be alleviated by rest. Fatigue can be divided into physical fatigue where it refers to the temporary inability of the muscles to maintain peak physical performance while mental fatigue is the transient inability to reach maximal cognitive function.
It is a non-specific and common symptom that is seen in various diseases such as viral, bacterial, or parasitic infections, overworking, inadequate sleep, stress, nutritional deficiency, and many others.