Hemilingual edema as a warning sign for internal carotid artery dissection-a case report and literature review.

Background: Internal carotid artery dissection (ICAD) is a rare but important cause of ischemic stroke in young adults. Its clinical presentation is highly variable, and atypical symptoms can delay recognition. Unilateral tongue (hemilingual) edema is an exceptionally uncommon manifestation. This case highlights its diagnostic relevance and explores potential pathophysiological mechanisms. Case presentation: A 23-year-old male presented with a four-day history of left-sided tongue swelling, occipital headache, and pulsatile tinnitus. Examination revealed left hemilingual edema and mild dysarthria, without motor or sensory deficits. Diagnostic workup included non-contrast cerebral CT, Doppler ultrasonography, MRI with contrast, CT angiography, and additional ENT, ophthalmological, laboratory, and cardiac evaluations. MRI demonstrated a subintimal hematoma of the left internal carotid artery extending from the distal C1 segment to the carotid canal, producing up to 80% stenosis, along with a small subacute ischemic lesion in the left centrum semiovale. The patient received antiplatelet therapy, resulting in symptomatic improvement within days. Follow-up MRI at 3 months confirmed complete arterial healing and minimal residual tongue swelling. The clinical picture suggested mild hypoglossal nerve involvement with sympathetic dysfunction but no motor impairment. Conclusion: Asymmetric tongue swelling may serve as an early and underrecognized sign of ICAD, particularly when accompanied by ipsilateral headache or cranial neuropathy. Early identification and appropriate imaging are essential to ensure timely diagnosis and reduce the risk of ischemic complications. Hemilingual edema likely results from sympathetic dysfunction due to local neurovascular involvement.