The primitive hypoglossal artery is one of the embryological vessels that connect the carotid and basilar arteries. It persists occasionally after birth, but the persistent primitive hypoglossal artery (PPHA) is an uncommon vascular anomaly. In this paper, we describe a case of acute vertigo with PPHA.
A 54-year-old man complained of vertigo when he turned his head while riding the train. A few minutes later, he lost consciousness for 2 hours. He was treated with medication at a local hospital, and there was improvement of his symptoms. However, he remained concerned about the sensation of dizziness, and presented to the neurotological clinic at Takarazuka City Hospital on March 18, 1999.
Spontaneous rightward tortional and horizontal nystagmus was present. Severe canal paresis was detected on caloric test. Mild cerebellar signs were noted. Eye tracking test, optokinetic pattern test and auditory brain stem response were normal. Vestibular dysfunction with a cerebellar lesion was suggested. Brain MRI did not indicate any intracranial lesions except for apparent absence of the left vertebral artery. MRA failed to show the vertebral arteries bilaterally, but detected the anastomotic artery that communicated between the right internal carotid artery and the basilar artery. Carotid angiography indicated similar findings. MRA indicated that the vessel ran through the hypoglossal canal. These findings demonstrated that the anastomotic artery was the PPHA.
In this case, the basilar artery was only perfused via the right carotid artery. Insufficiency of the carotid artery might occur when the patient turned his head, resulting in basilar insufficiency, syncope and vertigo.
