Tongue Denervation Changes From Acute Hypoglossal Nerve Palsy Secondary to Internal Carotid Artery Dissection and Pseudoaneurysm

A 43-year-old female presented with acute onset of left frontoparietal headache, intractable vomiting, and mastication difficulties. Neurological examination demonstrated isolated left-sided tongue deviation with intact taste and sensation. CT angiography demonstrated a 6 × 4 × 9 mm luminal outpouching of the distal left cervical internal carotid artery (ICA). MRI revealed left ICA dissection from C2 vertebral level to the skull base and pseudoaneurysm in the path of the left hypoglossal nerve after traversing hypoglossal canal, accompanied by increased FLAIR signal within the nerve in and just beyond the canal with minimal enhancement. (Figure 1A–D). Left hemi-tongue demonstrated contrast enhancement suggestive of denervation edema but no evidence of diffusion restriction (Figure 1E). At 4 months follow-up, tongue deviation resolved despite persistent pseudoaneurysm following conservative treatment with a statin and 3 months of aspirin and clopidogrel. The pseudoaneurysm demonstrated preserved luminal patency and evolving signal characteristics of the intramural hematoma in the false lumen, without progression in size or flow-limiting stenosis. There was interval improvement in the ipsilateral tongue (with no evidence of denervation atrophy) and hypoglossal nerve signal changes, with minimal change in the degree of enhancement of the latter, suggesting a reduction in local compressive inflammatory effect rather than complete anatomical resolution. This case highlights the importance of considering vascular causes in isolated cranial neuropathies and the critical anatomical relationship between the ICA and the hypoglossal nerve [1]. Future studies are needed to clarify the role of interventional therapy [2]. The authors have nothing to report. The authors did not receive any form of funding for this study. All authors report no disclosures relevant to the manuscript. The authors declare no conflicts of interest. Data supporting the study is available upon request.