Fall at mountain hiking resulting in acute rupture of traumatic posterior inferior cerebellar artery aneurysm and hypoglossal nerve palsy.

Background: Traumatic posterior inferior cerebellar artery (PICA) aneurysms are rare. Fractures of the occipital condyles (OCs) have been reported to cause delayed hypoglossal nerve (HN) palsy possibly. Case Description: A 67-year-old man fell while hiking on a mountain. On initial presentation at a local hospital, the patient exhibited right abducens nerve palsy and hoarseness. Cranial computed tomography (CT) revealed multiple intracranial air densities, with no remarkable hemorrhages detected in the cerebral cisterns. In addition, fractures involving both the OCs and clivus were identified, along with a collapsed left hypoglossal canal. Three days later, the patient developed a severe headache and coma. CT showed an extensive subarachnoid hemorrhage in the perimedullary and basal cisterns. After conservative management, the patient was transferred to our hospital. On examination, no instability in the craniocervical region was found; however, marked atrophy was noted in the left tongue. Cerebral angiography revealed a fusiform aneurysm in the proximal PICA. Stent-assisted coil embolization was successfully performed. The patient was eventually transferred to a rehabilitation facility. Conclusion: Traumatic PICA aneurysms may be complicated by HN palsy. A thorough evaluation with clinical and radiological examinations is essential for correct diagnosis and appropriate treatment.