A 44‐year‐old previously healthy male presented with 3 weeks of severe sore throat, spiking fevers up to 103F, chills, and night sweats. A course of amoxicillin for presumed strep throat had failed. He then developed swelling of his wrists followed by knees and ankles. He had generalized malaise and reported a 30‐pound weight loss over 5 weeks. He was a lean male without abnormal cardiopulmonary findings, organomegaly, or active synovitis. WBC count was 17,000 (78% neutrophils) with mild normocytic anemia, CRP of 13, and ESR of 83. An inpatient workup including blood and urine cultures, CXR, Echo, PPD, HIV. smear for parasites, CT abdomen, RF, and ANA panel failed to reveal a source. He was empirically treated with doxycycline and levaquin. A sleroid taper for possible seronegative arthritis slightly improved his arthralgias. However, persistent high fevers prompted transfer to our hospital. He was watched off antibiotics and steroids, while a workup for less common causes of FUO was undertaken including bartonella, coxiella, viral illnesses (EBV, CMV), and histoplasmosis, which was negative. LDH and CT chest ruled out lymphoma. He had mild transaminilis to the 80s but negative hepatitis panel. At thai time, his iron studies revealed a ferritin level of 34,282 ng/mL (normal: 20‐320 ng/mL), On specific questioning, he revealed that 5 weeks back he had had intermittent self‐limited maculopapular rashes on his shoulders and amis. The combination of high fevers, sore throat, arthralgias, hepalopathy, and evanescent rash along with leukocytosis and the elevated ferritin led to a clinical diagnosis of systemic‐onset juvenile inflammatory arthritis (adult Still's disease). By this time the fevers had defervesced. Since he had previously failed steroids, anakinra was considered to prevent recurrences.
ASD is a diagnosis of exclusion that is usually based on a combination of clinical and laboratory findings. The most common symptoms are fever, arlhralgia/arthritis, and myalgia. The fever most often exceeds 39°C (97%) with usually 1 spike (quotidian pattern). ESR is invariably elevated with frequent neutrophilic leukocytosis, which may result in the use of antibiotics. In 1 series, ASD was the cause of FUO in nearly 5% of patients. Hyperferritinemia is common (70%); however, levels above 4000 are noted in fewer than 50% of patients. ASD is among a few conditions associated with very high ferritin levels. Moreover, glycosylated ferritin levels are usually less than 20% in patients with ASD. It is suggested that a combination of ferritin levels above 3000 ng/mL along with glycosylated ferritin less than 20% has 97% specificity for diagnosing ASD.
Hospitalists should consider adult Still's disease in the differential diagnosis of FUO, especially when other suggestive symptoms are present. Very high ferrilin levels makes the diagnosis very likely after excluding infectious and malignant etiologies.
M. Patel, none; G. Noaiseh, none.