Brainstem transient ischemic attacks due to compression of pons from a persistent primitive trigeminal artery

摘要

Sir, Persistent primitive trigeminal artery (PPTA) is the most common type of persistent carotid-basilar arterial anastomosis.[1] Most cases have been incidentally detected1121 but can present with brainstem symptoms.^1 Possible mechanisms of brain-stem ischaemia are low perfusion pressure in the vertebrobasilar system and embolisation from the stenotic carotid lesions.121 Hemodynamic factors and dysautoregulation could also play a part in the pathogenesis of vertebrobasilar territory ischaemic attacks.A 17-year old girl noted sudden onset numbness of right side of her face and left hand for 15 min. Two months later she had a similar episode; this time it was associated with difficulty in walking, slipping of footwear from left foot which lasted for 45 min. On admission, neurological examination was essentially normal. Blood biochemistry and complete blood picture were normal. Brain magnetic resonance imaging (MRI) revealed indentation of the right ventral pons by an anomalous vessel [Figure la]. Magnetic resonance angiography (MRA) showed right PPTA (Saltzman type 1) with hypoplastic ipsilateral vertebral artery and basilar artery below PPTA [Figure lb and c]. The postrerigL communicating arteries were absent bilaterally. The posterior fossa circulation was almost independent from circle of Willis. Cerebral digital subtraction angiography (DSA) and therapeutic interventions were refused by the patient's relatives. She was treated with clopidogrel plus aspirin. She did not suffer from any transient ischemic attacks (TIAs) or stroke at 3-months follow-up.