ABSTRACT NUMBER: ESOC2026A1264 MIDBRAIN INFARCTION WITH OVERLAPPING WEBER AND REVERSECLAUDE SYNDROME FEATURES: A CLINICO-RADIOLOGICAL CASE

Abstract Background and aims Midbrain infarctions produce characteristic syndromes depending on the anatomical structures involved. Weber syndrome results from involvement of the cerebral peduncle and oculomotor fascicles, producing ipsilateral third cranial nerve palsy with contralateral weakness. Claude syndrome arises from involvement of the midbrain tegmentum and oculomotor fascicles, typically sparing the cerebral peduncle. Reverse Claude syndrome represents a rare variation in which the pattern of crossed findings differs due to selective midbrain involvement. This report describes a paramedian midbrain infarction with overlapping Weber and reverse Claude syndrome. Methods A 71-year-old woman with vascular risk factors presented with acute dysarthria. Examination revealed pupil-sparing right 3rd nerve palsy, mild left facial and upper/lower limb weakness, and right unilateral(ipsilateral) ataxia. Results MRI demonstrated discrete acute infarctions involving the right paramedian midbrain and right cerebral peduncle, showing restricted diffusion on DWI /ADC.(figure) This accounted for the pattern of ipsilateral oculomotor nerve involvement and contralateral motor weakness due to cerebral peduncle involvement, alongside features consistent with reverse Claude syndrome arising from adjacent midbrain tegmental involvement. In reverse Claude’s syndrome, there is ipsilateral ataxia contrary to contralateral ataxia of Claude’s syndrome. This can be explained by the lesion involving ipsilateral cerebellar connections while sparing crossed cerebellar pathways. Conclusions This case demonstrates a rare midbrain stroke producing overlapping Weber and reverse Claude syndrome features. To our knowledge, this combination has not been previously reported. The case adds to the reported spectrum of complex presentations of midbrain stroke and emphasizes the importance of accurate clinical neurological examination. Conflict of interest Md Aziz Mazumdar: nothing to disclose. Ramachandran Sivakumar: nothing to disclose. Joseph Ngeh: nothing to disclose. Rajesh Saksena: nothing to disclose. Figure 1 - belongs to Results