Hypereosinophilic syndrome with central nervous system involvement: Two case reports and literature review.

OBJECTIVE: To report two cases of hypereosinophilic syndrome (HES) with central nervous system involvement and explore its possible pathogenesis.

METHODS: We have analysed the clinical data and relevant features of two patients who presented themselves to The Affiliated Hospital of Xuzhou Medical University between 2012 and 2015. We have reviewed the relevant literature, elaborated the possible pathogenesis, and discussed the treatment options.

RESULTS: Both patients had consistently high levels of absolute eosinophil count which led to multiple cerebral infarcts in the arterial border zone and small-vessel disease. Blood tests were taken several times during their course of disease showing elevated eosinophils. Both patients underwent head computed tomography (CT), magnetic resonance imaging, and magnetic resonance angiography, which indicated small-vessel disease and watershed infarction. Glucocorticoids, improvement cycle, and neuro-nutrition treatments resulted in a significant improvement of their clinical state.

CONCLUSION: HES can involve central nervous system by causing small-vessel disease and watershed infarction, which can be its presenting features. Repeated blood tests should be done to rule out HES in central nervous system lesion.