Hematologic risk factors for stroke in Saudi children

OBJECTIVE: To explore the hematologic risk factors for stroke in a cohort of Saudi children.

METHODS: We evaluated children at the Division of Pediatric Neurology at King Khalid University Hospital, College of Medicine, King Saud University, Riyadh, during the periods July 1992 to February 2001 (retrospective study) and February 2001 to March 2003 (prospective study). Investigations for suspected cases included neuroimaging, transcranial Doppler (TCD) for cases of sickle cell disease (SCD), and Duplex scan. Hemostatic assays included coagulation screening tests, tests of thrombin generation and fibrinolysis, coagulation inhibitors, and activated protein C resistance.

RESULTS: During the study period, 104 Saudi children (aged one month to 12 years) with stroke were seen. The mean age of the cohort was 27.1 months (SD = 39.3 months) and median was 6 months. Ischemic strokes accounted for the majority of cases (76%). A major risk factor was identified in 93 of 104 cases of stroke (89.4%). Hematologic disorders were the most common (46.2%), followed by prothrombic disorders (31.7%); microcytic hypochromic anemia (26%); sickle cell disease (SCD), or SCBetao-thalassemia, (11.5%), and factor IX deficiency (2.9%). Raised anticardiolipin antibodies (13/49, 26.5%) was the most frequent abnormality. Deficiencies of the natural anticoagulants (protein S, protein C and antithrombin III) were as follows: protein S (15/70, 21.4%); protein C (15/70, 21.4%) and combined deficiency of 2 or more inhibitors (9/70, 12.9%). Activated protein C resistance has not been detected. Contrary to the findings of previous studies from Saudi Arabia, SCD is a common risk factor and is severe, as it resulted in multiple strokes. Moyamoya syndrome was diagnosed in 2 patients with SCD, one of whom had revascularization surgery (encephaloduroarterio-synangiosis). Assessment of children with SCD at risk of stroke was helped by the introduction of TCD followed by neuroimaging, using MRI and magnetic resonance angiography.

CONCLUSION: The study strongly highlights the importance of prothrombotic disorders and the severe phenotype of SCD as risk factors for stroke in Saudi children.