Adult-onset Still disease (AOSD) is an uncommon clinical entity that predominantly affects young adults. One of the most common presentations of the disease is fever of unknown origin. Early diagnosis can be difficult because fever of unknown origin is more commonly seen with other conditions such as malignancy or infection. Ambiguity in presentation and lack of serologic markers make diagnosis difficult.We describe here an 18-year-old African-American man who presented with fever, sore throat, and arthritis at initial admission, with serology positive for both Mycoplasma pneumonia and Epstein-Barr infection. The patient was discharged without improvement. He was then readmitted with persistence of initial symptoms and, at that stage, he fulfilled the proposed diagnostic criteria of AOSD. The purpose of this case report is to describe the triggering infections that can initially mislead diagnosis and to review the literature about AOSD from a primary care perspective.
Case PresentationAn 18-year-old African-American man presented to the emergency department with complaints of having had sore throat, joint pain, and a spiking fever for 5 days. The rest of the review of the systems was negative. He had no significant medical history, was not taking any medication, and had no significant family history. He smoked marijuana approximately 2 to 3 times a week. Vital signs at admission were a temperature of 38.8°C, heart rate of 92 beats per minute, respiratory rate of 20 breaths per minute, and blood pressure of 126/74 mm Hg. Physical examination showed shotty cervical lymphadenopathy bilaterally. Cardiovascular and respiratory systems were normal. The abdominal examination showed mild hepatosplenomegaly and the genitourinary examination was normal. A moderate left knee joint effusion was noted, and tenderness was elicited in the shoulder, knee, elbow and wrist joints. Total white blood cell count, bands, C-reactive protein level, erythrocyte sedimentation rate (ESR), and liver function test were elevated. See Table 1 for further details about the laboratory results of the patient during the initial admission.Transthoracic echocardiogram revealed a small pericardial effusion, with no valve vegetation. A chest radiograph showed a left lower lobe consolidation with minimal pleural effusion. Radiographs of the left knee revealed a moderate effusion. Left knee joint fluid study was normal. Urinalysis, urine culture, and 3 sets of blood cultures were negative. Based on the chest radiograph findings and increased white blood cell count, a diagnosis of community-acquired pneumonia was made and the patient was started on ceftriaxone and azithromycin. Mycoplasma and Epstein-Barr virus serologies This article was externally peer reviewed.