Secondary hemophagocytic syndrome in adults: a case series of 18 patients in a single institution and a review of literature.

Hemophagocytic lymphohistiocytosis (HLH) is rare in adults and is usually fatal without treatment. We present a consecutive series of 18 adults with HLH diagnosed at our institution between 2004 and 2009. All diagnoses were confirmed by pathology. The median age at diagnosis was 56 years (range: 18-73 years), with a male: female ratio of 2:1. Patients uniformly presented with fever. Fifty-five per cent of the patients presented with evidence of hepatomegaly or splenomegaly. All of the patients had at least a bi- or trilineage cytopenia. Elevated liver enzymes, hyperferritinemia, hypertriglyceridemia and hyperfibrinogenemia were seen in 50, 100, 40 and 50% of patients, respectively. The presumed causes were as follows; haematological malignancies (n = 4), post-autologous stem cell transplant (n = 2), infection (n = 2), rheumatologic illness (n = 2), sickle cell disease (n = 1), post-orthotopic liver transplant (n = 1) and idiopathic (n = 3). The median time from suspicion to diagnosis was 5 days (1-27 days). Corticosteroids and/or cyclosporine were the most frequently used treatment regimen. Other agents used were etoposide, IVIG, cyclophosphamide and chemotherapy. The mortality rate was 72%, with multi-system organ failure being the most common cause of death. Median survival time from diagnosis was 35 days. Six patients are alive to date. In a univariate analysis, the presence of fever was the only factor that was statistically significant for predicting a poor prognosis (early mortality) (p = 0.05). In conclusion, a high index of suspicion is the critical factor for early diagnosis. Early treatment with immunosuppressant is warranted, and a thorough diagnostic evaluation to identify the underlying cause should be undertaken.