A case report of reversible leukoencephalopathy associated with cerebral amyloid angiopathy
We report the case of a 68 year old female with cerebral amyloid angiopathy (CAA) presenting as a leukoencephalopathy. She presented following a witnessed complex partial seizure whilst having home peritoneal dialysis. Following this she developed marked expressive dysphasia. CT head showed bilateral hypodensities, in the left temporo- occipital white matter, right temporal lobe, and both frontal lobes. She was commenced on steroids and referred for brain biopsy as there was concern that the CT changes represented metastatic malignancy. Inflammatory markers, vasculitic screen, CSF, and anti-neuronal antibodies were all normal. MRI showed corresponding bilateral deep white matter and subcortical white matter FLAIR hyperintensities, most evident in the left temporo-occipital region. There was no enhancement nor restricted diffusion. There were multiple gradient echo (GE) hypointensities consistent with microhaemorrhages. Resolution of her dysphasia was accompanied by dramatic resolution of the white matter T2 FLAIR abnormality on repeat MRI three months later. Susceptibility weighted imaging (SWI) on the follow up MRI showed extensive microhaemorrahage scattered through both cerebral hemispheres involving both cortex and subcortical white matter. In the appropriate clinical context, the MRI finding of leukoencephalopathy with evidence of prior haemosiderin deposition should alert the clinician to the possibility of reversible CAA leukoencephalopathy (1). The recognition of CAA presenting as a leukoencephalopathy is important to consider in order to avoid invasive investigations such as brain biopsy.

References:
1. Oh U., Gupta R. et al. Reversible leukoencephalopathy associated with cerebral amyloid angiopathy. Neurology. 2004; 62: 494-497.