A form of anaemia resulting from deficiency of vitamin B 12. This in turn results either from failure to produce the substance (intrinsic factor) that facilitates absorption of B12 from the bowel or from dietary deficiency of the vitamin. Pernicious anaemia is characterized by defective production of red blood cells and the presence of megaloblasts in the bone marrow. In severe forms the nervous system is affected (see subacute combined degeneration of the cord). The condition is treated by injections of vitamin B12.
Subjects: Medicine and Health.