We here report the case of isolated hypoglossal nerve paralysis. Magnetic resonance imaging demonstrated characteristic findings of internal carotid artery dissection that should be considered as one of the differential diagnosis of ipsilateral pure hypoglossal nerve paralysis. Key Words: Internal—carotid artery—dissection— hypoglossal nerve—paralysis—palsy. Ó 2014 by National Stroke Association
Internal carotid artery dissection can occur in patients of all ages with or without cardiovascular risk factors. Isolated unilateral hypoglossal nerve paralysis is a rare manifestation of internal carotid artery dissection. In cases where internal carotid artery dissection occurs in the higher extracranial portion, the expanded dissected arterial wall could directly compress only the hypoglossal nerve, resulting in pure hypoglossal nerve paralysis. We here report the case of isolated unilateral hypoglossal nerve paralysis caused by internal carotid artery dissection.
Case Report A previously healthy 42-year-old man complained of retro-orbital pain that radiated to the left occiput and had difficulty in moving his tongue, speaking, and swallowing 4 days after treatment in the supine position for periodontal disease. On neurologic examination, his tongue on protrusion deviated toward the left, indicating From the *Department of Neurology, Hiroshima University Hospital, Hiroshima; and †Stroke Center, Kinki University Hospital, Osaka, Japan. Received February 20, 2014; revision received March 3, 2014; accepted March 5, 2014. Address correspondence to Hiroki Fujii, MD, Department of Neurology, Hiroshima University Hospital, 1-2-3, Kasumi, MinamiKu, Hiroshima 734-8551, Japan. E-mail: [email protected] 1052-3057/$ - see front matter Ó 2014 by National Stroke Association http://dx.doi.org/10.1016/j.jstrokecerebrovasdis.2014.03.004
left hypoglossal nerve palsy. Phonation and deglutition were not impaired. Additional neurologic deficits were not detected. There were no cervical bruits. Routine hematologic and biochemical tests were all normal. T1- and T2-weighted magnetic resonance imaging revealed a crescentic high signal of the left internal carotid artery that suggested intramural hematoma (Fig 1, A,B). There was no invasive mass in the base of the skull and no fresh infarcts in the brainstem. Computed tomography angiography revealed the presence of the double lumen sign (Fig 1, C) and the fusiform dissecting aneurysm of the left internal carotid artery located beneath the foramen lacerum, approximately 6-8 cm distal to the bifurcation (Fig 1, D). From the close anatomic relation of structures, T2 revealed that the dissecting and dilated carotid artery may directly compress the hypoglossal nerve beneath the orifice of the hypoglossal canal (Fig 1, E). A week after the first visit, atrophy of the left side of the tongue appeared. The patient’s left-sided neck pain as well as deviation and atrophy of the tongue disappeared within a couple of weeks. Six months after first visit, a second computed tomography angiography showed partial improvement in the expanded dissected arterial wall of the left internal carotid artery (Fig 1, F).
Discussion Internal carotid artery dissection can occur in patients of all ages with or without cardiovascular risk factors.
Journal of Stroke and Cerebrovascular Diseases, Vol. 23, No. 8 (September), 2014: pp e405-e406
H. FUJII ET AL.
Figure 1. (A) T1- and (B) T2-weighted magnetic resonance imaging showed a crescentic high signal, suggesting intramural hematoma. (C) Computed tomography angiography revealed the double lumen sign and (D) the fusiform dissecting aneurysm. (E) T2 revealed that the dissecting and dilated carotid artery (arrowhead) directly compressed the hypoglossal nerve (arrow) beneath the orifice of the hypoglossal canal (asterisks). (F) Follow-up computed tomography angiography 6 months after first visit showed partial improvement in the expanded dissected arterial wall of the left internal carotid artery.
Possible reasons for internal carotid artery dissection include trauma such as falling and hitting the head, lifting a heavy object, chiropractic neck manipulations, or congenital tissue defects.1 In the present case, treatment for periodontal disease in the supine position is thought to have contributed to internal carotid artery dissection. Isolated unilateral hypoglossal nerve paralysis is a rare manifestation of internal carotid artery dissection. The hypoglossal nerve leaves the skull through its own canal and descends into the retrostyloid space along with cranial nerves IX, X, and XI, the sympathetic chain, jugular vein, and carotid artery.2 In cases where internal carotid artery dissection occurs in the higher extracranial portion, as in the present case, the expanded dissected arterial
wall could directly compress only the hypoglossal nerve resulting in pure hypoglossal nerve paralysis. Carotid artery dissection should be considered as one of the differential diagnosis of isolated unilateral hypoglossal nerve paralysis.
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