• symptoms and signs

• laboratory findings

• about the disease

• prevention

• treatment

• prognosis

Symptoms and signs.  usual signs and symptoms associated with anemia (pallor, fatigue, weakness, dyspnea) plus symptoms that stem from the physiologic changes in the gastrointestinal tract (e.g., glossitis, gingivitis, indigestion, epigastric pain, loss of appetite, diarrhea, constipation, weight loss). Peripheral neurologic changes occur, with paresthesia in the hands and feet

Laboratory findings. peripheral blood smear will show oval macrocytes, hypersegmented neutrophils, enlarged platelets; on Schilling test - Radioactive-tagged vitamin B12 is not excreted in urine; complete blood count may reveal decreased Hgb, leukocytes, erythrocytes, and thrombocytes; hyperplasia, increased large-cell megaloblasts on bone marrow aspiration; lack of free hydrochloric acid on gastric analysis

About the disease.  Pernicious anemia is a chronic, progressive anemia characterized by the production of megaloblasts, which are enlarged red blood cells with an immature nucleus. It is caused by a deficiency in or underutilization of vitamin B12. It is a fairly common anemia in adults over 50 years of age who are of Scandinavian origin. Most commonly, the gastric mucosa develops a defect caused by an unknown factor and atrophies. This inhibits the secretion of intrinsic factor (IF), which binds and transports dietary vitamin B12 to the ileum for absorption. The lack of IF prevents vitamin B12 from entering the body, and existing stores of the vitamin are depleted, leading to the production of enlarged, immature RBCs. 

Prevention.  lifelong vitamin B12 replacement

Treatment.  treatment of underlying cause of gastric atrophy, if possible; oxygen to increase arterial levels; oral hygiene; orientation if confused; safety precautions for neurologic effects; instruction about lifelong parenteral vitamin B12 replacement (dietary vitamin B12 replacement is not effective); oral iron if Hgb does not rise

Prognosis.  if the condition goes untreated, the neurologic changes become more profound, with involvement of the spinal cord and loss of vibratory sense, ataxia, spasticity, and disturbances in bowel and bladder function; depression, paranoia, and delirium may follow; splenomegaly and hepatomegaly occur, as well as organ failure, neurologic degeneration, or infection, eventually causing death