Rosh Emergency Medicine Practice Test

What is the suspected diagnosis in a patient presenting with fatigue and low blood cell counts after starting carbamazepine?

1. Drug-induced aplastic anemia

2. Glucose-6-phosphate dehydrogenase deficiency

3. Megaloblastic anemia

4. Myelodysplastic syndrome

The correct answer is: Drug-induced aplastic anemia

The suspected diagnosis of drug-induced aplastic anemia in a patient presenting with fatigue and low blood cell counts after starting carbamazepine is supported by the understanding of how certain medications can affect bone marrow function. Carbamazepine is known to be associated with the development of aplastic anemia, a condition in which the bone marrow fails to produce sufficient blood cells, leading to a decrease in red blood cells, white blood cells, and platelets. This occurs as a result of an immune-mediated reaction, where the body mistakenly attacks the hematopoietic stem cells in the bone marrow, leading to profound cytopenias and associated symptoms such as fatigue, weakness, and susceptibility to infections due to low white blood cell counts. The timing of the symptom onset following the initiation of carbamazepine therapy also strengthens the likelihood of the drug being a contributing factor. Other possible conditions, such as glucose-6-phosphate dehydrogenase deficiency, megaloblastic anemia, and myelodysplastic syndrome, do not correlate as directly with the recent introduction of carbamazepine. For example, glucose-6-phosphate dehydrogenase deficiency typically presents with hemolytic anemia rather than aplastic anemia, and megaloblastic anemia is often