Introduction Hemophagocytic lymphohistiocytosis (HLH) is a life-threatening hyperinflammatory syndrome, its diagnosis being based on fulfilment of five out of eight clinical and laboratory parameters (fever, splenomegaly, cytopenia, hemophagocytosis, ferritin>500 ng/ml, hypertrygliceridemia and/or hypofibrinogenemia, low or absent NK cell activity, increased of soluble receptor for IL2) or a molecular diagnosis of a disease conferring a high risk of developing HLH. The differentiation between primary and secondary HLH (infections, autoimmune and metabolic diseases, malignancy) is very important for treatment decision.

Aim To identify the cause of HLH, clinical and laboratory parameters, to analyse the treatment and the evolution.

Material and method 13 patients between 2 months and 8 years of age were diagnosed based on mentioned criteria (at least 5 of 8 ) with HLH in the period 1995–2017.

Results 6 of them (46%) had primary HLH (1 Griscelli and 1Chediak-Higashi syndrome, 1 case FHLH2 and 3 cases with probability of FHLH) and 7 (54%) had secondary HLH (2 cases with leishmaniosis, 2 EBV induced, 1 BCG-itis, 1 Kawasaki and 1 leukaemia). HLH 2004 protocol treatment (dexamethasone, etoposide, cyclosporine) was used in 8 patients (61%) – in 5 cases complete schema and in 3 cases partial treatment. One patient was bone marrow transplanted. The mortality rate was 53,7%, 4/6 (66,6%) in primary HLH and 3/7 (42,8%) in secondary HLH. Also the mortality rate was 60% in patients not HLH treated, 60% in patients with complete schema and 66,6% in patients with partial schema.

Conclusions HLH is a potential fatal syndrome sometimes with fulminant evolution, an earlier diagnosis being crucial for an earlier treatment. In secondary HLH the etiologic treatment is often insufficient, needing also HLH treatment for life saving. In primary HLH bone marrow transplantation is the curative treatment, HLH protocol being obligatory but insufficient for survival.