Infectious Disease Division, Winthrop-University Hospital, Mineola, New York 11501, USA.
Heart Lung. 2012 Mar-Apr;41(2):177-80. doi: 10.1016/j.hrtlng.2011.01.002. Epub 2011 Mar 30.
Fever of unknown origin (FUO) has been defined as a fever of ≥101°F that persists for 3 weeks or more. It is not readily diagnosed after 1 week of intensive in-hospital testing or after intensive outpatient or inpatient testing. Fevers of unknown origin may be caused by infectious diseases, malignancies, collagen vascular diseases, or a variety of miscellaneous disorders. The relative distribution of causes of FUOs is partly age-related. In the elderly, the preponderance of FUOs is attributable to neoplastic and infectious etiologies, whereas in children, collagen vascular diseases, neoplasms, and viral infectious disease predominate. The diagnostic approach to FUOs depends on a careful analysis of the history, physical findings, and laboratory tests. Most patients with FUOs exhibit localizing findings that should direct the diagnostic workup and limit diagnostic possibilities. The most perplexing causes of FUOs involve those without specific diagnostic tests, e.g., juvenile rheumatoid arthritis (JRA) or adult Still's disease. In a young adult with FUO, if all of the cardinal symptoms are present, JRA may present either a straightforward or an elusive diagnosis, if key findings are absent or if the diagnosis goes unsuspected.
We present a 19-year-old man with a recurrent FUO. His illness began 3 years before admission and has recurred twice since. In the past, he did not manifest arthralgias, arthritis, or a truncal rash. On admission, he presented with an FUO with hepatosplenomegaly, aseptic meningitis, and pericarditis. An extensive diagnostic workup ruled out lymphoma and leukemia. Moreover, a further extensive workup eliminated infectious causes of FUO appropriate to his clinical presentation, ie, tuberculosis, histoplasmosis, brucellosis, Q fever, typhoid fever, Epstein-Barr virus, infectious mononucleosis, cytomegalovirus, human herpes virus (HHV)-6, babesiosis, ehrlichiosis, viral hepatitis, and Whipple's disease.
The diagnosis of JRA was based on the exclusion of infectious and neoplastic disorders in a young adult with hepatosplenomegaly, aseptic meningitis, pericarditis, and a double quotidian fever. With JRA, tests for rheumatic diseases are negative, as they were in this case. The only laboratory abnormalities in this patient included elevated serum transaminases, a mildly elevated erythrocyte sedimentation rate, and a moderately elevated level of serum ferritin.
Diagnostic fever curves are most helpful in cases where the diagnosis is most elusive, as was the case here. Relatively few disorders are associated with a double quotidian fever, ie, visceral leishmaniasis, mixed malarial infections, right-sided gonococcal acute bacterial endocarditis, and JRA. Because the patient received antipyretics during the first week of admission, fever was not present. After infectious disease consultation during week 2 of hospitalization, antipyretics were discontinued, and a double quotidian fever was present, which provided the key diagnostic clue in this case.
不明原因发热（FUO）被定义为持续 3 周或以上的体温≥101°F 的发热。在住院 1 周后或门诊或住院 intensive 检测后仍无法明确诊断。FUO 可能由传染病、恶性肿瘤、胶原血管疾病或多种其他疾病引起。FUO 的病因分布在一定程度上与年龄有关。在老年人中，FUO 的主要病因是肿瘤和感染性疾病，而在儿童中，胶原血管疾病、肿瘤和病毒性传染病更为常见。FUO 的诊断方法取决于对病史、体格检查和实验室检查的仔细分析。大多数 FUO 患者都有局部表现，这些表现应指导诊断，并限制诊断的可能性。最令人困惑的 FUO 病因是那些没有特异性诊断试验的病因，例如幼年特发性关节炎（JRA）或成人斯蒂尔病。对于患有 FUO 的年轻成年人，如果所有主要症状都存在，JRA 可能表现为直接或隐匿的诊断，如果关键表现缺失或诊断未被怀疑。
我们介绍了一位 19 岁的男性复发性 FUO 患者。他的疾病始于入院前 3 年，此后已复发两次。过去，他没有出现关节痛、关节炎或躯干皮疹。入院时，他出现 FUO 伴有肝脾肿大、无菌性脑膜炎和心包炎。广泛的诊断性检查排除了淋巴瘤和白血病。此外，进一步广泛的检查排除了适合他临床表现的 FUO 的感染性病因，即结核病、组织胞浆菌病、布鲁氏菌病、Q 热、伤寒、EB 病毒、传染性单核细胞增多症、巨细胞病毒、人疱疹病毒（HHV）-6、巴贝斯虫病、埃立克体病、病毒性肝炎和 Whipple 病。
JRA 的诊断基于排除年轻成年人肝脾肿大、无菌性脑膜炎、心包炎和双日热时的感染性和肿瘤性疾病。在这种情况下，JRA 的风湿性疾病检测结果为阴性。该患者唯一的实验室异常包括血清转氨酶升高、红细胞沉降率轻度升高和血清铁蛋白中度升高。
诊断性发热曲线在最难以诊断的情况下最有帮助，本例就是如此。与双日热相关的疾病相对较少，即内脏利什曼病、混合疟疾感染、右侧淋球菌急性细菌性心内膜炎和 JRA。由于患者在入院第一周接受了退热治疗，因此没有发热。在住院第 2 周接受传染病会诊后，停止了退热治疗，出现了双日热，这为该病例提供了关键的诊断线索。
