Isolated brainstem congestion caused by craniocervical junction arteriovenous fistula.

Abstract

Although arteriovenous fistulas (AVFs) at the craniocervical junction (CCJAVFs) are rare, they often develop into a subarachnoid haemorrhage when they have an ascending venous drainage, or cause venous congestion of the spinal cord with descending venous drainage. Isolated brainstem lesions due to CCJAVF are extremely rare, and, to our knowledge, the vascular architectural features that could cause such lesions are unknown. We present a case of CCJAVF manifesting as isolated brainstem congestion and review the literature on the vessel architecture of these rare lesions. A 64-year-old man was admitted to our hospital with gradually worsening nausea, dysphagia, double vision, grogginess, and gait disturbances. On admission, the patient showed dysarthria, horizontal ocular nystagmus to the left, paresis of cranial nerves IX and X, and ataxia on the right side. Magnetic resonance imaging (MRI) revealed an isolated lesion in the medulla. Cerebral angiography (CAG) showed a CCJAVF with the coexistence of intradural AVF and dural AVF, fed by the right first cervical radiculomedullary, right vertebral, and intradural posterior inferior cerebellar arteries, which were drained by the anterior spinal vein in an ascending direction. The patient underwent direct surgery to occlude dural and intradural fistulas. Postoperatively, the patient returned to work with full recovery from the neurological deficits via rehabilitation. MRI revealed vanishing brainstem congestion, and CAG revealed complete disappearance of the AVF. CCJAVFs with venous drainage around the brainstem, regardless of their direction (ascending or descending), can cause isolated brainstem congestion, although this condition is rare.