Differential Diagnosis
- Single most likely diagnosis
- Pernicious anemia: This is the most likely diagnosis given the patient's low iron, low iron saturation, and positive parietal cell antibody test. Pernicious anemia is an autoimmune disorder that leads to the destruction of parietal cells in the stomach, resulting in a deficiency of intrinsic factor and subsequent vitamin B12 deficiency. The positive parietal cell antibody test supports this diagnosis, as it is a common finding in pernicious anemia.
- Other Likely diagnoses
- Iron deficiency anemia due to chronic disease: This diagnosis is possible, as chronic diseases such as rheumatoid arthritis, chronic kidney disease, and chronic infections can lead to iron deficiency anemia. However, the positive parietal cell antibody test makes pernicious anemia a more likely diagnosis.
- Celiac disease: Celiac disease is an autoimmune disorder that can lead to iron deficiency anemia due to malabsorption of iron. While it is possible, the positive parietal cell antibody test is more specific for pernicious anemia.
- Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
- Gastric cancer: Although less likely, gastric cancer can cause iron deficiency anemia and a positive parietal cell antibody test. It is essential to rule out gastric cancer, as it can be life-threatening if left untreated.
- Whipple's disease: This rare bacterial infection can cause malabsorption of iron and other nutrients, leading to iron deficiency anemia. While unlikely, it is crucial to consider Whipple's disease, as it can be fatal if left untreated.
- Rare diagnoses
- Autoimmune gastritis: This rare condition is characterized by autoimmune destruction of the stomach lining, leading to iron deficiency anemia. While possible, it is less likely than pernicious anemia.
- Zollinger-Ellison syndrome: This rare disorder is caused by a gastrin-producing tumor, leading to excessive acid production and iron deficiency anemia. However, it is unlikely given the patient's presentation and the positive parietal cell antibody test.