[A case of pernicious anemia with type A gastritis in an extremely elderly patient with dementia and heart failure].

A 90-year-old woman was referred and admitted to our hospital because of progressing dementia, decreased appetite, and general fatigue. Blood tests on admission disclosed: white cell count, 2,900 /mm(3); hemoglobin 5.6 g/dl; mean corpuscular volume; 139.7 microm(3). Based on the presence of pancytopenia, macrocytic anemia, and elevated lactate dehydrogenises, we suspected pernicious anemia. We administered vitamin B12, which improved the blood test results and the signs of dementia. Gastrointestinal tract examination showed type A gastritis. Tests for anti-intrinsic factor antibody and anti-gastric parietal cell antibody were positive, which help confirm a diagnosis of pernicious anemia. Pernicious anemia is an autoimmune disease common among those aged 50-60 years. Cases aged over 90 years are rare. However, the numbers of extremely elderly patients are expected to increase with the growth of the elderly population. Fortunately, pernicious anemia is easy to treat. We need to make an appropriate diagnosis of pernicious anemia in the oldest elderly patients.