Adult-Onset Still’s Disease Masquerading as Candida Sepsis

Background: Adult Onset Still’s Disease (AOSD) is a rare systemic inflammatory disorder characterized by daily fever, polyarthritis, and transient salmon-pink rash typically at the peak of fever. It is hypothesized to be a reactive syndrome triggered by an infectious process. However, the etiology is still unknown. The Yamaguchi diagnostic criteria is commonly used to classify AOSD. Although there is not a specific laboratory or imaging study used to diagnose AOSD, a serum ferritin > 1000 ng/mL is typically seen.

Case presentation: Here we present a case about a 66 year old male with a past medical history of hypertension, hyperlipidemia, uncontrolled type II diabetes mellitus (DMT2), atrial fibrillation, hypothyroidism, chronic knee pain, and tobacco abuse who presented to the hospital with subjective fevers, myalgias, and generalized weakness for 2 weeks. The patient also had a pruritic, erythematous rash in the bilateral lower abdominal region which extended to the inguinal folds over the last 15 days. Physical exam revealed oral thrush covering his tongue. The patient also had chronic, bilateral knee swelling, erythema, and warmth without formal diagnosis of arthritis in the past. The patient was febrile, tachycardic, and hypotensive on admission. Complete blood count was remarkable for leukocytosis with a white blood cell count of 12.35 K/mm3. Based on his initial presentation, the patient was diagnosed with sepsis secondary to candida infection. The patient’s history of DMT2, Jardiance use, and tobacco abuse further elevated suspicion of candidiasis. However, his fever was non-responsive to antifungals, antibiotics, or antivirals. Given his bilateral knee, elbow, and wrist swelling, we investigated possible rheumatologic processes. Further workup revealed an elevated erythrocyte sedimentation rate (ESR) of 106 mm/Hr, elevated C-reactive protein (CRP) of 353 mg/L, and elevated ferritin of 29125 ng/mL suggestive of severe inflammation. The patient’s daughter later revealed he had an erythematous rash most notable at the height of his fever. The Yamaguchi criteria were used to diagnose AOSD. Patient presentation was positive for four major criteria and two minor criteria. His elevated ferritin > 1000 ng/mL solidified the diagnosis. His fever ultimately improved after corticosteroid treatment.

Discussion: Diagnosis of AOSD still remains a challenge because it is a diagnosis of exclusion. Although the Yamaguchi criteria are the most sensitive criteria for identifying AOSD, cases do not always present classically. Sepsis is an exclusion criteria for AOSD. The patient’s initial presentation was highly suggestive of sepsis, which initially delayed identification of AOSD. Also the salmon-pink rash that is classically presented with AOSD masqueraded as candida infection in addition to his oral thrush. This case illustrates the diagnostic challenges of AOSD. Delay in diagnosis remains a problem with AOSD, because delay can lead to increased risk of complications including disseminated intravascular coagulopathy (DIC), thrombotic thrombocytopenic purpura (TTP), macrophage activation syndrome, pulmonary hypertension, and diffuse alveolar hemorrhage. Further investigation is critical for understanding the etiology of AOSD as well as diagnostic protocols to expedite management and prevent life-threatening complications.