[The use of hydroxyurea in severe forms of sickle cell disease: study of 47 Tunisian paediatric cases]

Abstract

Introduction: The Sickle Cell Disease (SCD) is a serious illness considering its complications. For the children seriously affected, three therapeutic options are currently validated: transfusion therapy, hydroxyurea and bone-marrow transplantation.

Objectives: To see the contribution of hydroxyurea therapy on severe forms of SCD in affected Tunisian children.

Material and methods: This investigative study lasted over 6 years and 9 months, (September 2000-May 2007), enrolling 47 patients including 27 homozygous SCD and 20 double heterozygote SCD-S/beta thalassemia. The median age was 12 years and a half. The average dosage were 20mg/kg/d (14-30 mg/kg/d). The average duration of treatment was 52 months (18-81 months).

Results: The main indication for hydroxyurea treatment was prevention of recurrence of an acute chest syndrome in seven cases; episodic vaso-occlusive crises exceeding three events per year in 38 cases and prevention of deterioration of cerebral vascular accident in two cases. We observed a fast and sustained improvement of the clinical expression of the disease with a significant decrease of the number of days of hospitalization per patient and per annum from 29.3 d (10-84 d) to 3.2 d/(p<0.01). Treatment was well tolerated. We observed a significant increase of haemoglobin fetus (HbF) rates from 3 to 30% (p<0.01), hemoglobin from 7.8 to 9.6g/dl (p<0.05), average blood cells volume from 79.1 to 100.3 fl (p<0.05) and a significant fall of the white blood cells rates from 14,914 to 8464 per millimetre cube (p<0.05), polynuclear neutrophils from 6799 to 3486 per millimetre cube (p<0.05) and platelets from 508,666 to 293,500 per millimetre cube (p<0.05).

Conclusions: Hydroxyurea represents a privileged choice of treatment in the severe forms of SCD in children, for homozygous SCD-SS as well as for double heterozygote SCD-S/beta thalassemia. Used carefully, with frequent monitoring, it appeared as a safe treatment in short and medium term, but studies of long-term tolerance should be undertaken.