Atypical MRI presentation of posterior reversible encephalopathy syndrome with predominant brainstem involvement

Extensive Brainstem Posterior Reversible Encephalopathy Syndrome in a Hemodialysis Non-Adherent Patient

Posterior reversible encephalopathy syndrome (PRES) refers to a disorder of reversible vasogenic edema caused by rapid hyperperfusion of the brain that classically involves areas supplied by the posterior circulation such as the parieto-occipital region. It may present with atypical features such as brainstem and spinal cord involvement. Common causes include renal failure, pre-eclampsia/eclampsia among pregnant women, rapid changes in systemic blood pressure, and autoimmune diseases. The most prevalent presenting signs and symptoms are encephalopathy, seizures and headache. A 64-year-old female presented to a dialysis unit after missing several sessions with twitching in her extremities and elevated blood pressure. Additionally, she recently terminated clonidine use and was likely experiencing rebound hypertension. The continuous electroencephalogram (EEG) demonstrated generalized, non-convulsive seizures. MRI findings were notable for hyperintensities in the pons, middle cerebellar peduncles, cerebellar hemispheres, and periventricular and subcortical matter with medulla and proximal spinal cord involvement. A notable clinical sequela of PRES in this patient was coma. Aggressive blood pressure control led to significant improvement and return to her neurologic baseline. PRES can present with extensive brainstem involvement with a clinical sequela of coma. Multiple underlying causes such as dialysis non-adherence and rebound hypertension following clonidine discontinuation contributed to the development of this condition in this patient.

Tumour-like presentation of atypical posterior reversible encephalopathy syndrome with prominent brainstem involvement

Typical posterior reversible encephalopathy syndrome (PRES) is a clinical-neuroradiological entity characterised by bilateral white matter oedema, which is usually symmetrical and totally reversible in 2-3 weeks. A 46-year-old man presented with a persistent headache and visual blurring in the right eye. On admission, the clinical examination revealed minimal unsteadiness of gait and elevated blood pressure. A brain MRI showed a hyperintense signal on T2-weighted sequences in the whole brainstem, extended to the spinal cord (C2-C6), the left insula and the right cerebellum. When his blood pressure was controlled, his symptoms gradually improved. The follow-up MRI scan at 3 weeks revealed a dramatic regression of the hyperintense lesions on T2-weighted sequences. The differential diagnosis of PRES is very wide, especially in the case of conspicuous brainstem involvement. Treatable causes of white matter oedema should be always kept in mind to avoid misdiagnosis and prevent complications, such as intracranial haemorrhage.