Untreated, it can lead to neurological complications, and in serious cases, death. It can take several years for pernicious anemia to appear, and the disease often goes unrecognized, as the body becomes used to feeling unwell. The onset may be vague and slow, as the same symptoms are often also present with anemia; in 81.1% of cases of cobalamin deficiency, pernicious anemia is not observed. Pernicious anemia may be present without a person experiencing symptoms at first, over time, feeling tired and weak, lightheadedness, dizziness, headaches, rapid or irregular heartbeat, breathlessness, glossitis (a sore red tongue), poor ability to exercise, low blood pressure, cold hands and feet, pale or yellow skin, easy bruising and bleeding, low-grade fevers, shakiness, cold sensitivity, chest pain, upset stomach, nausea, loss of appetite, heartburn, weight loss, diarrhea, constipation, severe joint pain, feeling abnormal sensations including tingling or numbness to the fingers and toes (pins and needles), and tinnitus, may occur.
Pernicious anemia is a type of vitamin B12 deficiency anemia, a disease in which not enough red blood cells are produced due to the malabsorption of vitamin B12. Malabsorption in pernicious anemia results from the lack or loss of intrinsic factor needed for the absorption of vitamin B12. Anemia is defined as a condition in which the blood has a lower than normal amount of red blood cells or hemoglobin. The disease may come on slowly and insidiously.The most common initial symptoms are tiredness, and weakness. Other signs and symptoms of anemia include breathlessness, dizziness, a sore red tongue, lightheadedness, headaches, poor ability to exercise, cold hands and feet, low blood pressure, pale or yellow skin, chest pain, and an irregular heartbeat. The digestive tract may also be disturbed giving symptoms that can include nausea and vomiting, heartburn, upset stomach and loss of appetite. Pernicious anemia can cause osteoporosis and may lead to bone fractures. Symptoms of severe vitamin B12 deficiency can include tingling or numbness in the hands and feet, memory problems, blurred vision, unsteady walking, poor balance, muscle weakness, impaired sense of taste and smell, poor reflexes, clumsiness, depression, and confusion. Without treatment, some of these problems may become permanent.Pernicious anemia occurs due to an autoimmune response that produces antibodies that attack the parietal cells in the stomach lining and prevents them from creating intrinsic factor.