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. The presence of parietal cell antibodies is a hallmark of pernicious anemia, which is an autoimmune disorder that leads to atrophic gastritis and impaired iron absorption. The negative intrinsic factor antibody test does not rule out pernicious anemia, as some patients may have parietal cell antibodies without intrinsic factor antibodies.
- Other Likely diagnoses
- Iron deficiency anemia due to chronic blood loss: The patient's 15-year history of low iron suggests a chronic process, and iron deficiency anemia due to chronic blood loss is a possible cause. However, the presence of parietal cell antibodies and low iron saturation makes pernicious anemia a more likely diagnosis.
- Celiac disease: Celiac disease is an autoimmune disorder that can lead to malabsorption of iron and other nutrients. The patient's low iron and iron saturation could be consistent with celiac disease, but the presence of parietal cell antibodies makes pernicious anemia a more likely diagnosis.
- Do Not Miss diagnoses
- Gastric cancer: Gastric cancer can cause atrophic gastritis and impaired iron absorption, leading to low iron and iron saturation. While the patient's positive parietal cell antibody test is more suggestive of pernicious anemia, gastric cancer is a potentially deadly diagnosis that should not be missed.
- Whipple's disease: Whipple's disease is a rare bacterial infection that can cause malabsorption of iron and other nutrients. While it is unlikely, Whipple's disease can present with similar symptoms to pernicious anemia, and a diagnosis of Whipple's disease would require prompt antibiotic treatment.
- Rare diagnoses
- Autoimmune hemolytic anemia: This is a rare autoimmune disorder that can cause anemia due to hemolysis. While it is unlikely, autoimmune hemolytic anemia could present with low iron and iron saturation, and a diagnosis would require further testing.
- Gastric bypass or other surgical causes of malabsorption: If the patient has had gastric bypass surgery or other surgical procedures that can cause malabsorption, this could lead to low iron and iron saturation. However, this would be a rare cause of the patient's symptoms, and a thorough medical history would be necessary to consider this diagnosis.