Vivekanantham Arani, Patel Rikesh, Jenkins Petra, Cleary Gavin, Porter David, Khawaja Fareed, McCarthy Eoghan
The Kellgren Centre of Rheumatology, Manchester Royal Infirmary, Oxford Road, Manchester, UK.
Centre for Epidemiology Versus Arthritis, University of Manchester, Manchester, UK.
BMC Rheumatol. 2022 Mar 25;6(1):16. doi: 10.1186/s41927-022-00248-0.
Culture-negative infective endocarditis (IE) constitutes approximately 10% of all cases of IE. Bartonella endocarditis is a common cause of culture-negative endocarditis and is associated with a high mortality rate. To date, no cases of Bartonella IE has been reported in association with cryoglobulinemia in the UK. We present a unique case of Bartonella IE causing secondary cryoglobulinemia in a young female.
A 17-year-old female with a background of pulmonary atresia and ventricular septal defect repaired with a cardiac conduit at the age of 4, presented with a one-year history of weight loss (from 53 to 39 kg) and poor appetite. She subsequently developed a vasculitic rash and haematoproteinuria with decline in renal function, requiring urgent hospital admission. Initial blood tests showed a near normal creatinine, but a raised cystatin C. Renal biopsy showed focal necrotizing glomerulonephritis with no acute tubular necrosis or chronic change. Subsequent blood tests supported a diagnosis of cryoglobulinaemic vasculitis (high rheumatoid factor, low complement, polyclonal gammopathy, Type 3 cryoglobulin). A weak positive PR3 meant there was some uncertainty about whether this could be a primary ANCA-associated vasculitis (AAV). Initial workup for an infectious cause, including multiple blood cultures, were negative. However, an echocardiogram showed definite vegetations on her surgical conduit. The patient did not respond to empirical antimicrobials and so was referred for surgical revision of her conduit. Tissue samples obtained intra-operatively demonstrated Bartonella species. With targeted antimicrobials post-operatively, she improved with resolution of immunologic abnormalities and at last review had a normal renal profile. On reviewing her social history, she had adopted several stray cats in the preceding year; and thus, the cause of the Bartonella infection was identified.
This is the first reported case of Bartonella endocarditis causing secondary cryoglobulinemia reported in the UK. The key learning points from this case include that Bartonella endocarditis can present as a cryoglobulinaemic vasculitis and should be considered in any differential when the cause of cryoglobulinaemia is not clear and to enquire about relevant exposures especially when culture-negative endocarditis is suspected.
血培养阴性感染性心内膜炎（IE）约占所有IE病例的10%。巴尔通体心内膜炎是血培养阴性心内膜炎的常见病因，且与高死亡率相关。迄今为止，英国尚未有巴尔通体IE合并冷球蛋白血症的病例报道。我们报告一例年轻女性因巴尔通体IE导致继发性冷球蛋白血症的独特病例。
一名17岁女性，4岁时因肺动脉闭锁和室间隔缺损接受心脏导管修复手术，出现体重减轻（从53公斤降至39公斤）和食欲减退1年病史。随后出现血管炎性皮疹和血红蛋白尿，肾功能下降，需紧急住院治疗。初始血液检查显示肌酐接近正常，但胱抑素C升高。肾活检显示局灶性坏死性肾小球肾炎，无急性肾小管坏死或慢性改变。随后的血液检查支持冷球蛋白血症性血管炎的诊断（类风湿因子高、补体低、多克隆丙种球蛋白病、3型冷球蛋白）。蛋白酶3弱阳性意味着对于这是否可能是原发性抗中性粒细胞胞浆抗体相关性血管炎（AAV）存在一些不确定性。包括多次血培养在内的感染病因初步检查均为阴性。然而，超声心动图显示其手术导管上有明确的赘生物。患者对经验性抗菌药物无反应，因此被转诊进行导管手术翻修。术中获取的组织样本显示为巴尔通体属。术后使用针对性抗菌药物治疗后，她的免疫异常得到缓解，病情好转，最后一次复查时肾功能正常。回顾其社会史，她在前一年收养了几只流浪猫；因此，确定了巴尔通体感染的病因。
这是英国首例报道的巴尔通体心内膜炎导致继发性冷球蛋白血症的病例。该病例的关键经验教训包括，巴尔通体心内膜炎可表现为冷球蛋白血症性血管炎，当冷球蛋白血症病因不明时，在任何鉴别诊断中均应考虑，尤其是怀疑血培养阴性心内膜炎时，应询问相关暴露史。
