Haemophagocytic lymphohistiocytosis in Hong Kong children.

Haemophagocytic lymphohistiocytosis is a rare but potentially fatal disease. Diagnosing this disease may be difficult and is often delayed because the clinical presentation mimics other conditions like severe sepsis, hepatic failure and malignancies. We reviewed the clinical presentations, response to treatment, and outcomes of children diagnosed with haemophagocytic lymphohistiocytosis from 1991 to 2006 in a Hong Kong tertiary paediatric haematology centre. All patients had typical presentations with prolonged fever, organomegaly, and pancytopaenia. Six children had hepatic dysfunction and two had neurological symptoms. The median time from disease onset to diagnosis was 21 days. Elevated serum ferritin levels and evidence of haemophagocytosis in bone marrow examinations aided diagnosis. The overall mortality was 57%. Three patients who presented in the first few years studied had relatively long lag times between disease onset and definitive treatment; all died of active disease. Three patients diagnosed more recently were given timely treatment using the haemophagocytic lymphohistiocytosis-94 protocol of etoposide and dexamethasone, with or without cyclosporin. All three achieved remission, but two had a recurrence and one died during the recurrence.