[Pontine reversible leucopathy in an AIDS patient associated with highly active antiretroviral therapy (HAART): Report of one case]

Posterior reversible encephalopathy syndrome (PRES) and infection: a systematic review of the literature

Posterior reversible encephalopathy syndrome (PRES) is an encephalopathy characterized by a rapid onset of symptoms including headache, seizures, confusion, blurred vision, and nausea associated with a typical magnetic resonance imaging appearance of reversible subcortical vasogenic edema prominent and not exclusive of parieto-occipital lobes. Vasogenic edema is caused by a blood-brain barrier leak induced by endothelial damage or a severe arterial hypertension exceeding the limits of cerebral blood flow autoregulation. Although the exact pathophysiological mechanism is still unclear, frequent conditions that may induce PRES include severe hypertension, eclampsia/pre-eclampsia, acute kidney diseases and failure, immunosuppressive therapy, solid organ, or bone marrow transplantation. Conversely to other conditions, which may induce PRES, the link between severe infection or sepsis and PRES, often associated with gram-positive bacteria, is still poorly understood and less well known. Clinicians from multiple disciplines, such as neurologists and internists, may encounter during their profession patients with severe infection or sepsis and should consider the possible association between PRES and these conditions. We systematically reviewed the literature about this association in order to provide a helpful clinical insight of such complex pathophysiological mechanism, highlighting the importance of recognizing PRES in such a complex clinical scenario.

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