Susac syndrome with a unique involvement of the thoracic spinal cord

Abstract

A woman in her late 20s presented with headaches and subacute encephalopathy. MRIs showed multiple punctate subcortical and periventricular white matter hyperintensities with diffusion restriction, infratentorial lesions, leptomeningeal enhancement of the cervical spinal cord, brainstem and cerebellum and two areas of high-signal abnormality at T4 and T6 raising suspicion for multiple sclerosis or acute disseminated encephalomyelitis.Further studies and evolution of her symptoms during her hospital stay confirmed the clinical triad of encephalopathy, branch retinal artery occlusions and hearing loss pathognomonic for Susac's syndrome.While cervical spinal cord and cauda equina involvement have been reported in Susac's syndrome previously, no thoracic spinal cord involvement has been reported.We report the novel MRI finding of thoracic spinal cord involvement in Susac's syndrome. In order to avoid misdiagnosis, neurologists and neuroradiologists should be aware that any part of the spinal cord can be involved in Susac's syndrome.

Keywords: immunology; neuroimaging; neuroopthalmology; spinal cord.

Figure 1

(A) Brain MRI sagittal T2 FLAIR showing an ‘icicle’ lesion in the superior genu of the corpus callosum (solid red arrow), a central corpus callosum ‘Snowball’ lesion at the posterior midbody (Dashed red arrow). T2 hyperintensities are seen at the splenium (light blue arrow), tectum (orange arrow) and within the vermis, just posterior to the fourth ventricle (dark blue arrow). (B) Axial diffusion-weighted imaging (DWI) sequence showing three splenial corpus callosum lesions with restricted diffusion (dashed light blue arrows). (C) Axial DWI demonstrating multiple punctate areas of restricted diffusion in the subcortical areas (pink arrows) and posterior periventricular area (Dashed green arrow). (D) Axial DWI demonstrating multiple punctate areas of restricted diffusion.

Figure 2

MRI of the cervical and thoracic spine: (A) sagittal T1 postcontrast of the cervical spine showing areas of leptomeningeal enhancement at the anterior pons/medulla and posterior vermis (green arrows). (B) Axial T2 of the thoracic spine at the level of T4 showing area of T2 intensity at the anterior right spinal cord (red arrows). (C) Sagittal T2 stir thoracic spine showing corresponding arrows for the T2 hyperintensities seen at T4 (red arrow) and T6 (yellow arrow). (D) Axial T2 of the thoracic spine at the level of T4 showing area of T2 intensity at the anterior right spinal cord (red arrows).

Figure 3

Audiogram showing a moderately severe sensorineural hearing loss in the right ear and a moderate to severe down sloping left sided sensorineural hearing loss. Speech discrimination 0% for the right ear and 80% for the left ear.

Figure 4

Colourfundus photographs of the right (A) and left (B) eyes showing patchy areas of retinal whitening due to ischaemia (arrows). Fluorescein angiography of the right (C) and left (D) eyes demonstrating branch retinal artery occlusions (dashed arrows).