Hemophagocytic Lymphohistiocytosis in Adults: Associated Diagnoses and Outcomes, a Ten-Year Experience at a Single Institution

BACKGROUND: Hemophagocytic lymphohistiocytosis (HLH) is a syndrome of excessive systemic inflammation which causes tissue damage due to abnormal immune system activation and has a high fatality rate even with treatment. HLH continues to be a difficult diagnosis to make because of lack of awareness and its overlap with other illnesses. This disorder is well defined in pediatric patients under the age of 18, but there is also a paucity of data in the adult population. The goals of this study were to describe associated disorders, clinical course and outcomes, and to determine if additional clinical criteria can be used to help with the diagnosis of HLH in adult patients. METHODS: Patients’ electronic medical records from 2007 to 2017 (who were ≥ 18 years old at the time of the search) were screened by ICD 9 and ICD 10 codes which contain the diagnosis of HLH or hemophagocytic syndrome, infection-associated. We identified 41 adult cases of HLH that were treated at our medical center over the course of 10 years and assessed these patients using both the historical and newly proposed diagnostic criteria. We also identified underlying diagnoses related to the development of HLH and fatality rates. RESULTS: Median age at diagnosis was 55 years old (18 - 87 years old) and 22 were male. Twenty-two had an infection, 16 with malignancy, seven had an autoimmune disorder and one with Sweet syndrome. Fifteen patients were treated with steroids alone, 18 with steroids and chemotherapy, three with steroids and antiviral agents, and two with chemotherapy alone. Sixteen (39%) died and 25 (60%) survived discharge. Seven patients died after discharge. Median survival of all patients was 1,095 days. CONCLUSIONS: Our data show that HLH is primarily associated with infections and malignancies. Newly proposed diagnostic criteria are not as specific, but can be helpful in making the diagnosis of HLH. We also showed that the fatality rate at our institution was lower than currently published rates of adult HLH.