Hypoglossal nerve palsy due to internal carotid artery dissection
Cranial nerve palsy is an infrequent manifestation of internal carotid artery dissection with the hypoglossal nerve being the most frequently affected (< 10% of cases 1) 2)) , this symptom, especially when occurring in young patients and/or in association with head or neck pain, should prompt a search for ICA dissection, ideally by MRI of the neck 3).
ICAD frequently occurs associated to focal cerebral ischemic deficits, Horner's syndrome, tinnitus or together with the involvement of other cranial nerves 4).
The underlying mechanism of hypoglossal nerve involvement in ICAD is attributed to mechanical compression or stretching of the cranial nerve below the jugular foramen by the expanded or aneurysmal formation of the ICAD. Nevertheless, many arterial dissections have not been clearly associated with aneurysm formation. Other possible mechanism to explain the hypoglossal involvement is related to the blood supply to this cranial nerve. Ischemic injury from nutrient vessels as a result of its anatomic location adjacent to the internal carotid artery mural hematoma might occur by mechanical, embolic or hemodynamic phenomenon 5) 6) 7) 8) 9) 10).
Case reports
Transient left hypoglossal nerve palsy caused by mechanic compression from intramural hematoma in higher extracranial portion of internal carotid artery dissection confirmed in MRI and CT scans 11).
Isolated hypoglossal nerve palsy due to internal carotid artery dissection 12).
Hypoglossal Nerve Palsy Due to Internal Carotid Artery Dissection 13).
Unilateral isolated hypoglossal nerve palsy associated with internal carotid artery dissection 14).
In 2012 A 57-year-old man presented with dysarthria and left-sided headache lasting 4 days. Neurologic examination revealed deviation of the tongue to the left. MRI demonstrated the left carotid artery dissection and its anatomic juxtaposition with the left hypoglossal nerve. Tongue deviation returned to normal after 4 weeks of treatment with aspirin 15).
In 2009 Hypoglossal nerve palsy as the sole manifestation of spontaneous internal carotid artery dissection 16).
A 43-year-old man presented with a 3-week history of mild dysarthria. There was no history of craniocervical trauma. The physical examination revealed an isolated left hypoglossal nerve paresis. Magnetic resonance imaging and angiography findings were consistent with a left skull base ICAD. The patient was successfully treated with anticoagulation therapy. The current rate of cranial nerve involvement is estimated at 10% of all ICADs. This is the second report of isolated hypoglossal nerve palsy without hemicrania in a case of atraumatic ICAD 17).
In 2001 Isolated hypoglossal nerve palsy due to internal carotid artery dissection 18).
In 1998 Boukobza et al., published a case of unilateral XIIth nerve palsy due to the dissection of the internal carotid artery. They described the clinical and radiological features. In this patient, cranial nerve palsy is probably the result of compression by an enlarging carotid artery due to mural hematoma. Diagnosis is discussed with emphasis on magnetic resonance imaging findings. Magnetic resonance imaging is also useful for follow-up of arterial lesions 19).