Pernicious anemia

Pernicious anemia is a disease where not enough red blood cells are produced due to a deficiency of vitamin B₁₂. Those affected often have a gradual onset. The most common initial symptoms are feeling tired and weak. Other symptoms may include shortness of breath, feeling faint, a smooth red tongue, pale skin, chest pain, nausea and vomiting, loss of appetite, heartburn, numbness in the hands and feet, difficulty walking, memory loss, muscle weakness, poor reflexes, blurred vision, clumsiness, depression, and confusion. Without treatment, some of these problems may become permanent.

Pernicious anemia refers to a type of vitamin B₁₂ deficiency anemia that results from lack of intrinsic factor. Lack of intrinsic factor is most commonly due to an autoimmune attack on the cells that create it in the stomach. It can also occur following the surgical removal of all or part of the stomach or small intestine; from an inherited disorder or illnesses that damage the stomach lining. When suspected, diagnosis is made by blood tests initially a complete blood count, and occasionally, bone marrow tests. Blood tests may show fewer but larger red blood cells, low numbers of young red blood cells, low levels of vitamin B₁₂, and antibodies to intrinsic factor. Diagnosis is not always straightforward and can be challenging.

Because pernicious anemia is due to a lack of intrinsic factor, it is not preventable. Pernicious anemia can be treated with injections of vitamin B₁₂. If the symptoms are serious, frequent injections are typically recommended initially. There are not enough studies that pills are effective in improving or eliminating symptoms. Often, treatment may be needed for life.