Central‐Variant Posterior Reversible Encephalopathy Syndrome With Brainstem Involvement

A 31-year-old woman with untreated hypertension presented with a progressively worsening occipital headache for 3 months. In the last 4 days, she developed a pulsating holocranial headache that awakened her nocturnally and worsened with Valsalva maneuver. Neurological examination revealed no focal deficits. The patient reported decreased visual acuity, and fundoscopic examination demonstrated grade III hypertensive retinopathy, but no optic disc edema. Blood pressure was 230/160 mmHg and laboratory analysis showed elevated serum creatinine (3.42 mg/dL). Autoimmune and infectious markers were negative. A brain magnetic resonance imaging (MRI) (Figure 1) was performed, which revealed T2/FLAIR hyperintensity predominantly involving the brainstem and both middle cerebellar peduncles, extending to cerebellar hemispheres, and mild involvement of the insular cortex and deep white matter of the corona radiata. The diffusion-weighted imaging (DWI) sequence showed no restriction, and the corresponding apparent diffusion coefficient map confirmed vasogenic edema. Susceptibility-weighted imaging (SWI) showed microbleeds in the inferior vermis and right cerebellar hemisphere. The angio-MR showed normal arteries of the circle of Willis (not shown). These findings were compatible with vasogenic edema in the context of central-variant posterior reversible encephalopathy syndrome (PRES). Brain MRI after 2 days of adequate control of arterial hypertension. Axial FLAIR slices from inferior to superior revealed hyperintensity predominantly in the central region including the brainstem, middle cerebellar peduncles, cerebellar hemispheres (arrows) and to a lesser extent supratentorial involvement of the insular cortex (arrowheads) and corona radiata (circles). The DWI sequence showed no diffusion restriction, and the corresponding ADC map confirmed vasogenic edema. SWI sequence revealed microbleeds in the inferior vermis and right cerebellar hemisphere (dotted arrows). The occipito-parietal regions had normal appearance. ADC, apparent diffusion coefficient; DWI, diffusion-weighted imaging; FLAIR, fluid attenuated inversion recovery; SWI, susceptibility-weighted imaging. The patient also developed acute renal failure and received 2 months of treatment with ravulizumab alongside antihypertensive therapy. This led to a normalization of both creatinine levels and blood pressure. She improved clinically and became asymptomatic. On the 2-month follow-up MRI (Figure 2), there was a resolution of signal hyperintensities, although with persistent microbleeds. Control brain MRI at 2 months. FLAIR sequences showed significant resolution of the vasogenic edema, with only a minimal focus of hyperintensity persisting in the left corona radiata (arrows). SWI sequence confirmed persistence of microbleeds in the inferior vermis and right cerebellar hemisphere (dotted arrows). FLAIR, fluid attenuated inversion recovery. SWI, susceptibility-weighted imaging. PRES is an uncommon clinico-radiological syndrome arising from endothelial dysfunction due to diverse triggers. Patients typically present with persistent headaches that may advance to visual disturbances or seizures. Although its pathophysiology is not fully understood, two main mechanisms are proposed: disrupted vascular autoregulation and direct endothelial injury. Most cases follow one of three classic MRI patterns—posterior, superior frontal sulcus, or holohemispheric watershed—marked by reversible vasogenic edema appearing hyperintense on T2/FLAIR (fluid attenuated inversion recovery), often centered in subcortical white matter. Microbleeds occur in up to 60% of patients and do not indicate severity, whereas 15%–30% show small diffusion-restricted foci without clear prognostic impact. Central-variant PRES is less common, affecting basal ganglia, thalamus, cerebellum, or brainstem while sparing parieto-occipital regions, usually in the setting of severe hypertension or renal failure. A crucial diagnostic clue is the clinico-radiological mismatch: mild symptoms contrasted with prominent imaging abnormalities. This distinction aids recognition and appropriate management in clinical practice. Zhao Hui Chen Zhou: writing – original draft, conceptualization. Ana Ramos González: supervision. The authors have nothing to report. The authors have nothing to report. The authors have nothing to report. Informed consent was obtained from the patient. The authors declare no conflicts of interest. The data that support the findings of this study are available on request from the corresponding author. The data are not publicly available due to privacy or ethical restrictions.