Internal Medicine Resident Physician Vassar Brothers Medical Center
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Introduction: Anaplasmosis is tick-borne illness endemic to the Northeastern United States. Most infections are self-limiting; however, it can trigger severe life threatening complications include Hemophagocytic Lymphohistiocytosis (HLH). HLH is a sepsis-mimic hyper-inflammatory disorder presenting with cytopenia and multi-organ dysfunction. We present three cases of HLH induced by anaplasmosis requiring intensive care management.
Description: Case 1: 68-year-old patient with metastatic lung cancer admitted with septic shock thought to be secondary to pneumonia. Workup was positive for anaplasmosis. Despite initiating doxycycline, he developed worsening pancytopenia and multiorgan dysfunction. Ferritin was noted to be >20,000. calculated H-score: 210; HLH-2004: 5/8 criteria met. Case 2: 80-year-old male patient admitted to the ICU for ischemic stroke, and septic shock. Tick panel returned positive for anaplasmosis. Despite appropriate antibiotics, his condition worsened, rendered investigations for complications of underlying infection. Ferritin, triglycerides and IL-2 were noted to be elevated. H-score >190, and HLH 2004 score of 5/8. Case 3: 70-year-old woman admitted after a mechanical fall. Shortly after, Patient developed fever and hypotension requiring ICU upgrade. Labs showed worsening pancytopenia. Tick-borne panel was positive for anaplasmosis. Elevated ferritin, triglyceride levels, and interleukin-2 receptor levels along side transaminitis were noted. H-score was 186 referencing a 70 to 80% chance of HLH. Patient was started on anakinra, dexamethasone, and IVIG, with rapid clinical improvement.
Discussion: HLH, although rare, causes significant increase in mortality rates if not diagnosed and treated promptly. Blood smear examination, serology with PCR do provide a great diagnostic tool for anaplasmosis. Failure to improve following initiation of doxycycline should raise the question of a complication induced by anaplasmosis or a concurrent undiagnosed medical condition. Ordering ferritin levels, triglycerides, interleukin-2 receptor levels, and LFTs as well as maintaining a high index of clinical suspicion is important to rule in/out a rare, yet life threatening, diagnosis. Key treatment including immunomodulatory therapy with early initiation of IVIG, anakinra, and corticosteroids.
