Atypical Adult Still's Disease Complicated by Hemophagocytic Syndrome in an Older Patient: A Case Report.

Hyperferritinemia can occur in various diseases, making the differential diagnoses diverse and often fatal. The macrophage-activated syndrome (MAS) is a differential diagnosis of hyperferritinemia in which systemic macrophages are activated and cause various symptoms. Many cases are complicated by hemophagocytic syndrome, causing pancytopenia, which can be fatal. Furthermore, it is challenging to diagnose hyperferritinemia in elderly patients, and the disease may develop into a fever of unknown origin. We report the case of a 93-year-old man with aspiration pneumonia, followed by intermittent prolonged fever complicated by abnormal hyperferritinemia and leukopenia. Based on his general condition, he was diagnosed with atypical adult Still's disease and treated with steroid pulses and tocilizumab, temporarily relieving his symptoms. However, the patient eventually developed sepsis and could not be saved. Diagnosis of hyperferritinemia in the elderly population is complex and requires immediate attention. However, invasive intervention may lead to the deterioration of an elderly patient's condition. In the context of medical care for the elderly at a community hospital, it is necessary to provide comprehensive care for those in critical condition, considering the degree of invasiveness of examinations and procedures.