Posterior reversible encephalopathy syndrome after COVID-19 in a patient with chronic renal failure

A 61-year-old man with chronic renal failure had an embolic stroke of undetermined source that was treated with warfarin. Five weeks later, the patient contracted coronavirus disease (COVID-19). Six days after the onset of COVID-19, high blood pressure (>200 ‍mmHg) and consciousness disturbance were reported. CT demonstrated symmetrical hypodensity areas in the bilateral cerebellar hemispheres. MRI revealed hyperintensity lesions in the bilateral cerebellar hemispheres and pons on the T₂-weighted and fluid-attenuated inversion recovery images. Moreover, cerebellar lesions appeared as hyperintensity areas on apparent diffusion coefficient mapping. Based on these findings, a diagnosis of posterior reversible encephalopathy syndrome (PRES) was made. The patient was treated with antihypertensive drugs, and the consciousness level improved gradually. MRI after one month showed that the lesions had disappeared. PRES should be considered if the brain CT of patients with COVID-19 shows a low-density lesion, especially in patients with risk factors for PRES such as chronic renal failure or hypertension.