Stroke among sickle cell disease patients in Madina Maternity and Children's Hospital

Moyamoya Syndrome in Children With Sickle Cell Disease in Saudi Arabia: A Single-Center Experience

Background Sickle cell disease (SCD) is relatively common in Saudi Arabia. Its neurologic complications such as stroke and Moyamoya syndrome (MMS) can be severe and devastating. Such complications can be minimized by modern investigative tools such as transcranial Doppler (TCD) ultrasound, which is unavailable in many high-risk places. Our aim is to investigate the prevalence and characteristics of these complications in children with SCD in our center where TCD is not available. Methods We conducted a retrospective record review of children with SCD admitted to the pediatric ward and visited the pediatric hematology outpatient clinic of King Fahad Military Medical Complex, Dhahran, Saudi Arabia, from January 2010 to December 2021. The target population was children aged six months to 14 years with SCD and a history of stroke or transient ischemic attacks (TIAs). Their magnetic resonance imaging/magnetic resonance angiography (MRI/MRA) of the brain radiographic features were reviewed. A descriptive analysis was used to summarize the demographic characteristics and clinical features of patients with and without MMS. Results Twenty-six children (out of 385 with sickle cell anemia, originating mainly from the southwestern and eastern provinces of Saudi Arabia) experienced an overt stroke with an overall prevalence of 6.7%. All patients with stroke were originally from the Southwestern province. Their genotype was SS, and the median age at the onset of the first stroke was six years (IQR: 5.5). The main presenting symptoms were seizures (57.7%), motor weakness (42.3%), headache (15.3%), cranial nerve palsies (11.5%), cognitive deficit (7.6%), and dysphasia (3.8%). The majority of strokes were ischemic (92.3%). MMS was detected in 61.5% and was seen at the onset of the first stroke in all patients with this MRA abnormality. Seven children with moyamoya (43.8%) had recurrent strokes. Conclusion In this study, the prevalence of overt stroke is 9% in children with SCD originating from the southwestern region of Saudi Arabia (26/286), and 61.5% of them (16/26) had MMS. It is absent in the children of Eastern origin (99 children). In places lacking TCD facilities, further studies are required to determine if MRA brain screenings of children with SCD may detect MMS before the onset of stroke and help start protective therapy.

Epidemiology of Stroke in Sickle Cell Disease

Sickle cell disease is the most common cause of stroke in childhood, both ischaemic and haemorrhagic, and it also affects adults with the condition. Without any screening or preventative treatment, the incidence appears to fall within the range 0.5 to 0.9 per 100 patient years of observation. Newborn screening with Penicillin prophylaxis and vaccination leading to reduced bacterial infection may have reduced the incidence, alongside increasing hydroxyurea prescription. Transcranial Doppler screening and prophylactic chronic transfusion for at least an initial year has reduced the incidence of stroke by up to 10-fold in children with time averaged mean of the maximum velocity >200 cm/s. Hydroxyurea also appears to reduce the incidence of first stroke to a similar extent in the same group but the optimal dose remains controversial. The prevention of haemorrhagic stroke at all ages and ischaemic stroke in adults has not yet received the same degree of attention. Although there are fewer studies, silent cerebral infarction on magnetic resonance imaging (MRI), and other neurological conditions, including headache, epilepsy and cognitive dysfunction, are also more prevalent in sickle cell disease compared with age matched controls. Clinical, neuropsychological and quantitative MRI screening may prove useful for understanding epidemiology and aetiology.

Sickle cell disease subphenotypes in patients from Southwestern Province of Saudi Arabia

Sickle cell disease (SCD) is common in the Eastern and Southwestern (SW) Provinces of Saudi Arabia. We studied 159 patients with SCD to better characterize its phenotype in the SW Province, where patients usually have a HBB haplotype of African origin. All cases had history and examination, chart review, and laboratory testing. Blood tests were obtained during steady state and included: complete blood count, reticulocytes, hemoglobin electrophoresis, lactate dehydrogenase, and G6PD level. HBB haplotype and presence of α-thalassemia were also determined. Frequency of various SCD complications was as follows: painful episodes of variable severity occurred in majority of patients (98%), osteonecrosis (14%), acute chest syndrome (22%), splenic sequestration (23%), gallstones (34%), stroke (7.5%), priapism (2.6%), serious infections (11.5%), and persistent splenomegaly (11%) beyond 5 years of age. No patient had leg ulcer. History of asthma and high steady state white blood cells count were associated with increased risk of acute chest syndrome. Coinheritance of α-thalassemia was associated with a lower frequency of gallstones. Higher fetal hemoglobin level was associated with persistent splenomegaly but not with other complications. Splenic sequestration was more common among males and was associated with lower steady state hemoglobin. SCD phenotype in the SW Province is variable and comparable with African Americans except for the rarity of priapism and the absence of leg ulcers. Fetal hemoglobin level was not associated with SCD vaso-occlusive complications. New genetic modifiers and environmental factors might modulate the phenotype of SCD in Saudi Arabia.