Annual stroke incidence in Nigerian children with sickle cell disease and elevated TCD velocities treated with hydroxyurea.

BACKGROUND: Elevated transcranial Doppler (TCD) velocities accurately predict stroke risk in children with sickle cell disease (SCD). Chronic blood transfusion, the gold standard for primary stroke prevention, is faced with numerous challenges in Africa. Hydroxyurea (HU) has been shown to reduce elevated TCD velocities in children with SCD. AIM: To determine the effectiveness of HU in reducing the risk of primary stroke in a cohort of Nigerian children with SCD and elevated velocities treated with HU. METHODS: Children with SCD and TCD velocities ≥170 cm/sec treated with HU were prospectively followed with 3-monthly TCD and neurological evaluations for ≥12 months to determine the incidence of primary stroke. RESULTS: One hundred and four children, 53 males, and 51 females were enrolled into the study. Their ages ranged from 2 to 16 years with a mean of 6 years. At first TCD examination, velocities ranged from 173 to 260 cm/sec with conditional and abnormal risk velocities in 60 (57.7%) and 44 (42.3%) children, respectively. Follow up ranged from 1 to 8 years with a mean of 3.6 years. Mean TCD velocities showed a significant decline from 198.2 (standard deviation [SD] = 15.6) cm/sec to 169.3 (SD = 21.4) cm/sec (P < 0.001). One stroke event occurred in the cohort, giving a stroke incidence of 0.27/100 person years. CONCLUSION: HU significantly reduces TCD velocities in Nigerian children with SCD and elevated TCD velocities, with a corresponding reduction in the incidence of primary stroke. HU may represent a potential alternative for primary stroke prevention in low and middle income countries where the burden of SCD resides.

Chronic blood transfusion for primary and secondary stroke prevention in Nigerian children with sickle cell disease: a 5-year appraisal.

BACKGROUND: Chronic blood transfusion (CBT) diminishes the risk of primary and secondary stroke in sickle cell disease (SCD). We appraised CBT and assessed its feasibility as an option for stroke prevention in a setting of limited resources. METHODS: All new cases of SCD seen in the Paediatric Hematology/Neurology units of the University College Hospital, Ibadan, Nigeria over a 5-year period were screened and followed up to identify those who had an indication for CBT for stroke prevention. Caregivers were counseled and offered CBT when indicated. Children of caregivers who accepted chronic transfusion were carefully followed up and outcomes documented. RESULTS: Five (10%) of the caregivers of the 50 children who had an indication for CBT for stroke prevention consented to the treatment. They all had homozygous sickle cell anemia and had suffered a stroke. None of the children with abnormal TCD velocities consented to CBT. Two children experienced transfusion reactions, fatal in one. The mean annual cost of chronic transfusion (without chelation) was $3,276 (SD = 1,168). Major reasons given for declining CBT were high costs of blood transfusion, unavailability of blood, the need to regularly seek for blood donors, and the indefinite duration of blood transfusions. CONCLUSION: High economic costs, unavailability of blood, need to regularly seek for blood donors, cultural beliefs, and high frequency of transfusion reactions are major challenges to a successful CBT program in Nigeria. There is a need for government subsidy on blood transfusions and improved efforts towards provision of safe and affordable blood.

Stroke recurrence in Nigerian children with sickle cell disease treated with hydroxyurea.

AIMS AND OBJECTIVES: To compare the outcome after a first clinical stroke, following treatment with and without hydroxyurea (HU). SUBJECTS AND METHODS: A retrospective review of a cohort of Nigerian children with SCD, who had suffered a first stroke, was carried out. Outcomes in the group of children who received and did not receive HU were compared. RESULTS: Thirty two children presented with stroke and one died of haemorrhagic stroke at presentation. All the children had haemoglobin SS phenotype, and ischaemic stroke was the predominant form seen. Mean age at first clinical stroke was 7 years, 7 months (SD=2 years, 4 months). Thirteen children received HU while 18 declined HU therapy. Maximum dose of HU ranged from 20-25 mg/kg/ day. The secondary stroke incidence of 7/100 person years in the HU group was significantly lower than the 28/100 person years in the non-HU group (P=0.001, OR 3.808, 95% CI 1.556, 9.317). Children who did not receive HU were more likely to drop out of school and to have moderate-severe motor disabilities requiring caregiver assistance for daily living. CONCLUSION: In settings where facilities for chronic blood transfusion are not accessible or feasible, HU therapy should be considered for secondary stroke prevention in children with SCD.

Associated morbidities in children with sickle-cell anaemia presenting with severe anaemia in a malarious area.

A prospective study of 104 consecutive cases of patients with sickle-cell anaemia (SCA) presenting with severe anaemia (packed cell volume < or = 15%) was carried out in the Children's Emergency Ward of the University College Hospital, Ibadan, in 1991. The patients were classified according to the type of anaemic crisis, by physical findings, serum bilirubin and reticulocyte counts. Other investigations included a blood film for malaria parasites, blood culture, radiological investigation and lumbar puncture when necessary. The most common problems associated with SCA patients in anaemic crisis were malaria and bacterial infections--68 (66%) and 18 (17.3%) of cases, respectively. Acute chest syndrome was significantly more frequent in patients with hyperhaemolytic and acute splenic sequestration crisis compared with aplastic crisis (P < 0.05). Conjugated hyperbilirubinaemia was also significantly more frequent among patients with hyperhaemolytic crisis compared with all other anaemic crises (chi2 = 13.18, P = 0.001). The overall case fatality was 86.5/1,000 SCAs, with no fatalities in those with aplastic crisis. There were complications in six of the nine mortalities. Co-existing bacterial infections and conjugated hyperbilirubinaemia were associated with increased morbidity and mortality in patients with anaemic crisis. Patients with SCA crisis should have early evaluation and prompt treatment for associated infections.