Moyamoya syndrome associated with hereditary spherocytosis: pathogenesis, management, and an illustrative case with rapid radiological progression.

The association between moyamoya syndrome and hereditary spherocytosis is exceedingly rare, with only nine pediatric cases reported in the literature including the present case.

• Only eight pediatric cases had been reported prior to this case report.
• The current case represents the ninth reported pediatric case of MMS associated with HS.
• All reported cases occur in the pediatric population.

A 13-year-old boy with known hereditary spherocytosis presented with acute left limb weakness and imaging-confirmed moyamoya syndrome.

• The patient had a pre-existing diagnosis of hereditary spherocytosis.
• Presenting symptom was acute left limb weakness.
• Diagnosis of MMS was confirmed via imaging including MRI and digital subtraction angiography (DSA).
• Serial MRI and DSA over a 3-year follow-up demonstrated significant progression of cerebrovascular steno-occlusive disease.

The patient's management required a stepwise multidisciplinary approach including anemia correction, antiplatelet therapy, splenectomy, and revascularization surgery.

• Management included chronic anemia correction and aspirin therapy as initial interventions.
• Laparoscopic splenectomy was subsequently performed.
• Ultimately, unilateral encephaloduroarteriosynangiosis (EDAS) revascularization surgery was performed due to symptomatic progression.
• The integrated roles of splenectomy and revascularization surgery are discussed as complementary interventions.

Chronic hemolysis and anemia in hereditary spherocytosis are proposed to potentiate rapid progression of moyamoya syndrome.

• The case demonstrates significant radiological progression over a 3-year follow-up period.
• The paper describes this as 'rapid radiological progression' in the context of the dual pathology.
• Pathophysiological theories linking chronic hemolysis and anemia to cerebrovascular steno-occlusive disease progression are explored.
• The paper characterizes this as a 'pathophysiological' intersection between the two conditions.

The paper advocates for maintaining hemoglobin levels above 110 g/L in hereditary spherocytosis patients with moyamoya syndrome to mitigate stroke risk.

• A specific hemoglobin threshold of greater than 110 g/L is recommended.
• This recommendation is framed in the context of reducing cerebrovascular disease progression.
• The recommendation is presented alongside the necessity of vigilant neurological monitoring in HS patients.
• Early recognition and a multidisciplinary treatment strategy are described as 'crucial to mitigating stroke risk in this unique patient population.'