Iyer Ajay, D'Anna Mattias, Verma Shruti, Pritchard Thomas, Begilman Vladimir, Bajracharya Himal, Naemi Kaveh
University of Missouri-Columbia School of Medicine, Columbia, MO.
Centerpoint Medical Center, Independence, MO.
HCA Healthc J Med. 2024 Dec 1;5(6):701-706. doi: 10.36518/2689-0216.1639. eCollection 2024.
Hemophagocytic lymphohistiocytosis (HLH) is an immunologic syndrome characterized by excessive inflammation and tissue injury due to uncontrolled activation of the phagocytic system. The underlying mechanism is a lack of downregulation of activated macrophages and lymphocytes by natural killer and T cells. Unfortunately, the diagnosis is often delayed or missed due to the rarity of the disease, decreased awareness, and clinical picture variability. Ehrlichiosis is becoming a more prevalent tick-borne illness in endemic regions and a relatively uncommon but increasingly considered cause of HLH.
We describe the cases of 2 patients diagnosed with secondary HLH as per the 2004 HLH criteria, with the trigger secondary to ehrlichiosis. Our first patient presented with a febrile illness and a remarkably elevated blood ferritin concentration. He ended up meeting HLH criteria despite having a negative bone marrow biopsy. Patient 1 had significant clinical improvement in vitals and had a down-trending ferritin with steroids, doxycycline, and intravenous immunoglobulin. The second patient presented with severe systemic involvement and hemodynamic instability. She was found to have HLH with a positive bone marrow biopsy and a positive Ehrlichia PCR. Patient 2 had significant improvement in her hemodynamic instability with the use of anakinra and doxycycline.
Raising awareness about HLH is imperative for early diagnosis and trigger-directed treatment, which can help in preventing the disease's severe complications. There are an increased number of reports of Ehrlichiosis progressing to HLH. Early identification and treatment with doxycycline, with the use of immunomodulatory treatment in severe cases, has shown favorable outcomes.
噬血细胞性淋巴组织细胞增生症（HLH）是一种免疫综合征，其特征是由于吞噬系统不受控制的激活导致过度炎症和组织损伤。潜在机制是自然杀伤细胞和T细胞对活化的巨噬细胞和淋巴细胞的下调作用缺乏。不幸的是，由于该疾病罕见、认识不足以及临床表现多变，诊断往往延迟或漏诊。埃立克体病在流行地区正成为一种更普遍的蜱传播疾病，并且是HLH相对少见但越来越受关注的病因。
我们描述了2例根据2004年HLH标准诊断为继发性HLH的患者病例，其诱因继发于埃立克体病。我们的首例患者表现为发热性疾病且血铁蛋白浓度显著升高。尽管骨髓活检结果为阴性，但最终他符合HLH标准。患者1的生命体征有显著临床改善，使用类固醇、强力霉素和静脉注射免疫球蛋白后铁蛋白呈下降趋势。第二例患者表现为严重的全身受累和血流动力学不稳定。她被发现患有HLH，骨髓活检阳性且埃立克体PCR检测阳性。患者2使用阿那白滞素和强力霉素后血流动力学不稳定情况有显著改善。
提高对HLH的认识对于早期诊断和针对诱因的治疗至关重要，这有助于预防该疾病的严重并发症。有越来越多关于埃立克体病进展为HLH的报告。早期识别并用强力霉素治疗，在严重病例中使用免疫调节治疗，已显示出良好的效果。
