Approach to Pancytopenia in a Deployed Service Member
Background: Pancytopenia is a result of increased destruction or decreased production of bone marrow cells and has a broad differential. Pernicious anemia commonly presents as a macrocytic anemia and is typically autoimmune in nature and the result of vitamin B12 deficiency. Pancytopenia is a rare presentation of this disorder especially in the setting of hemolysis. Testing in the deployed setting may be limited and/or challenging.
Case Presentation: A 24-year-old female patient with a history of Hashimoto thyroiditis presented during an overseas deployment with a witnessed syncopal episode and was found to be pancytopenic with a mild transaminitis and laboratory tests demonstrating hemolysis. Though initially she was hypotensive, tachycardic, and febrile, her vitals improved after multiple transfusions, but she had persistent cytopenia with transfusion dependence, concerning for aplastic anemia or acute leukemia.
Conclusions: Testing for B12 deficiency is crucial in symptomatic, patients with pancytopenic to either diagnose or exclude pernicious anemia and conserve resources by preventing costly workup and transfer/escalation of medical care, especially in the deployed setting. A predeployment screening in those with history of autoimmune disorders may be warranted.
Conclusions
This rare case of pernicious anemia presenting as pancytopenia illustrates the challenge in working up pancytopenia, especially in austere military environments with limited testing capabilities. Screening for chronic dietary and nutritional deficiency is important in a service member, raising the question of what role predeployment screening may have and what dietary accommodations may be available during overseas deployments, which can potentially dampen inflammation of the gastrointestinal tract, especially for those with preexisting autoimmune gastrointestinal conditions. Also, newer technology allows portable, low-cost testing of cobalamin and may aid in its diagnosis. In patients who are anemic with low vitamin B12, HCPs can begin vitamin B12 supplementation while continuing the workup (eg, antibody testing, endoscopy). If the patient responds appropriately, further workup becomes less urgent, therefore, decreasing resource use and increasing military readiness. When hemolysis is present, a low reticulocyte count can be beneficial to help differentiate this condition from TTP, a life-threatening condition that must also be ruled out or treated. Pernicious anemia should be on the differential in any patients with autoimmune conditions presenting with cytopenias, especially in those with a history of autoimmune thyroid disorders.
