Clinico-Radiological Correlation of Weber's Syndrome

Abstract

Weber's syndrome, named after Hermann Weber, is characterized by midbrain lesions often caused by strokes, resulting in ipsilateral third nerve palsy, including ptosis and pupillary abnormalities, and contralateral hemiplegia. We discuss a case of a 35-year-old lady with cognitive impairment, right hemiparesis, diplopia, left eye ptosis, and lateral eye deviation. MRI of the brain with contrast suggested an acute infarct in the left-sided paramedian region of the midbrain. The oculomotor nucleus and cerebral peduncle were both affected by an abrupt left-sided paramedian midbrain stroke. The participation of particular midbrain nuclei together with symptoms including drooping eyelids, diplopia, and limb paralysis suggested Weber's syndrome. An MRI study of the brain is the modality of choice in suspected stroke cases and is more sensitive when it comes to the brainstem lesions. A comprehensive neurological examination with a clinical diagnosis of Weber's syndrome before radiological investigations is of great help for localizing brain stem lesions and thus aids in early diagnosis and treatment.

Keywords: brain stem stroke; mri brain; oculomotor nucleus; paramedian mid brain infarct; weber’s syndrome.

Figure 1. MRI Brain; T1, T2 and FLAIR axial images

MRI brain; T1, T2 and fluid-attenuated inversion recovery (FLAIR) images reveal a focal altered signal intensity lesion in the left paramedian region of the midbrain (yellow arrow) appearing hypointense on T1 weighted image (WI) axial plane (B), hyperintense on T2WI in coronal (A); axial (C) and FLAIR axial plane (D).

Figure 2. MRI Brain; DWI and ADC images

MRI Brain; Diffusion weighted (DW) and apparent diffusion coefficient (ADC) images in the axial plane showing restricted diffusion (yellow arrow) appearing bright on DW image  (A) and corresponding loss of signals on ADC image (B).