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.

Impaired Firing Behavior of Individually Tracked Paretic Motor Units During Fatiguing Contractions of the Dorsiflexors and Functional Implications Post Stroke.

Introduction: This study quantified stroke-related changes in the following: (1) the averaged discharge rate of motor units (individually tracked and untracked) identified from high-density electromyography (HD-EMG) recordings, (2) global muscle EMG properties of the dorsiflexors during a fatiguing contraction, and the relationship between task endurance and measures of leg function. Methods: Ten individuals with chronic stroke performed a sustained sub-maximal, isometric, fatiguing dorsiflexion contraction in paretic and non-paretic legs. Motor-unit firing behavior, task duration, maximal voluntary contraction strength (MVC), and clinical measures of leg function were obtained. Results: Compared to the non-paretic leg, the paretic leg task duration was shorter, and there was a larger exercise-related reduction in motor unit global rates, individually tracked discharge rates, and overall magnitude of EMG. Task duration of the paretic leg was more predictive of walking speed and lower extremity Fugl-Meyer scores compared to the non-paretic leg. Discussion: Paretic leg muscle fatigability is increased post stroke. It is characterized by impaired rate coding and recruitment and relates to measures of motor function.