Infection Associated Secondary Hemophagocytic Lymphohistiocytosis in Sepsis Syndromes - A Tip of an Iceberg.

BACKGROUND: Hemophagocytic lymphohistiocytosis (HLH) is a rare, underdiagnosed, fatal and devastating hyperinflammatory syndrome that has gained increasing recognition over the past decade. Patients with HLH present with clinical and laboratory evidence of uncontrolled inflammation. Delay in diagnosis and management inevitably leads to a rapidly progressive and fatal course. In this case series, we present 7 cases of secondary HLH (sHLH) in adults with their presentation, course, and outcomes.

MATERIAL AND METHODS: We retrospectively looked at the 7 cases of secondary HLH who were diagnosed and managed in our institute between January 2013 and august 2015. Medical records were retrieved from medical records department and data analyzed and tabulated. The median age at diagnosis was 35 years (age range 26-72 years). Diagnosis was based on HLH 2004 diagnostic criteria.

RESULTS: We report profile of 7 adult patients with sHLH. All patients had a short history of illness (<2 weeks) and presented uniformly with prolonged fever, bi or trilineage cytopenia and multiorgan dysfunction syndrome (MODS) at admission or developed MODS during the course of their illness. None of them had prediagnosed HLH. All patients fulfilled 5 to 6 of 8 criteria as per HLH 2014 diagnostic criteria. The median length of hospital stay was 12 days (range 7-50 days) and the median time to diagnosis was 5 days (range 3 to 21 days). Mortality was 57%.

CONCLUSIONS: HLH is a rare and under-diagnosed clinical syndrome and is rapidly fatal if not diagnosed and managed timely. The cases reported in literature probably represent a tip of an iceberg of large number of undiagnosed cases mostly labeled as sepsis with MODS in critical care units. sHLH should be suspected in any patient who present with persistent and prolonged fever, transaminitis, cytopenia, and high serum Ferritin or dramatically rising serial serum Ferritin. Early diagnosis and prompt aggressive treatment are vital for patients' survival and favorable outcome.