Recurrent fever of unknown origin (FUO): aseptic meningitis, hepatosplenomegaly, pericarditis and a double quotidian fever due to juvenile rheumatoid arthritis (JRA).
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.