A Case Report of Classical eight-and-a-Half Syndrome and Etiology Analysis

Eight-and-a-half syndrome is one-and-a-half syndrome plus ipsilateral seventh (facial) cranial nerve palsy, which was first reported by Eggenberger in 1998. This syndrome is caused by a lesion (most often vascular or demyelinating) in the dorsal tegmentum of the caudal pons. It involves the para pontine reticular formation and the medial longitudinal fasciculus, as well as the nucleus and the fasciculus of the facial nerve. We describe a case of a 56-year-old man presented with eight-and-a-half syndrome. We also discuss the vascular pathology and etiology of this syndrome through the literature review. Most eight-and-a-half syndrome cases are caused by occlusions of the perforating branches of the pons. The pathology can be transparent lipid-like changes at the perforator arteries. It can also be thrombosis at the orifice of the main or perforator arteries. BAH could be a very important factor in perforator artery infarction at the pontine. The etiology is closely related to hyperglycemia. An effective intervention is to avoid bad habits and control the hyperglycemia.