Central-variant posterior reversible encephalopathy syndrome: more than meets the eye

Isolated pons involvement in Posterior Reversible Encephalopathy Syndrome: Case report and review of the literature

Background

Posterior Reversible Encephalopathy Syndrome (PRES) is a clinical-radiological syndrome, usually reversible and with a favorable prognosis, which recognizes a variety of etiologies and clinical patterns and is likely due to an impairment in cerebral blood flow autoregulation. It is typically characterized by subcortical, predominantly parieto-occipital, vasogenic brain oedema in patients with acute-subacute neurological symptoms. Infratentorial oedema on neuroimaging has been mostly described in association with the typical supratentorial pattern and seldom as isolated.

Case report

We report a case of PRES with isolated pons involvement on MRI. A woman affected by Turner syndrome, epilepsy, slight mental deficiency, obesity and hypothyroidism, experienced a progressive gait and standing impairment, worsening in the last 2 weeks. At admission blood pressure was 220/110 mmHg. Brain MRI showed a wide FLAIR signal hyperintensity on T2-weighted sequences affecting the entire pons, without contrast enhancement. Clonidine, doxazosine, furosemide and telmisartan were effective in restoring normal blood pressure. Pons hyperintensity completely resolved on MRI 3 weeks later, together with return to normal neurological examination.

Conclusions

Though isolated infratentorial involvement in PRES recognizes several causes, hypertension, which is a common feature in Turner syndrome, would have played a key role in our case with solely pons MRI T2-hyperintensity.

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Clinical and radiological findings of PRES are heterogeneous with possible atypical presentations: in this regard an accurate differential diagnosis is mandatory in order to provide prompt intervention.

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Isolated pons involvement has been rarely described. A key feature may be poor clinical presentation in spite of a radiological pattern of severity.

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Severe hypertension acts as the more frequently reported predisposing factor for isolated pontine PRES