A Case of Adult-onset Still’s Disease Diagnosed as Causing Fever of Unknown Origin and Cervical Lymphadenopathy

Abstract

Otorhinolaryngologists often treat infections presenting with the chief complaints of fever, sore throat, and cervical lymphadenopathy, but they rarely include collagen diseases in the initial differential diagnosis. Adult-onset Still’s disease is a condition that is difficult to diagnose, as there are few specific laboratory findings, and it is a typical example of a disease that manifests as fever of unknown origin. We encountered a case of adult-onset Still’s disease in which the patient presents with cervical lymphadenopathy, followed by fever of unknown origin and systemic symptoms, making it difficult to make an accurate diagnosis. A 40-year-old woman visited an otorhinolaryngologist with painful cervical lymphadenopathy. She was diagnosed as having cervical lymphadenitis and prescribed an antibiotic, but was referred to our department when she failed to improve. At the first visit, the patient had no fever, and the throat findings were unclear. However, during follow-up, she developed a rash with fever, followed gradually by easy fatigability, and was hospitalized. Blood tests showed liver dysfunction, increased inflammatory response marker levels, and a mild increase in the serum level of ferritin. Infections and malignant tumors were considered unlikely, and cervical lymph node biopsy proved non-diagnostic. Remittent fever was noted during hospitalization, and joint pains appeared. A dermatologist consultation led to the suspicion of adult-onset Still’s disease, the diagnostic criteria for adult-onset Still’s disease were met, and the skin biopsy results were in agreement. Although it is necessary to make a diagnosis of fever of unknown origin immediately, it is important to carefully carry out a process of diagnosis by exclusion in cooperation with other departments, while keeping in mind the possibility of adult-onset Still’s disease in patients presenting with cervical lymphadenopathy.