PRES (Posterior Reversible Encephalopathy Syndrome)

Other names:

• RPLS/RPLE (Reversible Posterior LeukoEncephalopathy Syndrome)

• Better name?: Subcortical Vasogenic Cerebral Oedema Syndrome

Definition:

• Syndrome of:

o Reversible

o Subcortical vasogenic cerebral oedema with

o Acute neurological symptoms

o Usually with

The clinical syndrome of subacute:

o Headaches

o Decreased level of consciousness

o Confusion

o Seizures

o Cortical blindness

• Combined with characteristic radiological findings of:

o Posterior cerebral (usually white matter) oedema

• Frequently occurring in setting of hypertension

Aetiology/Pathology

• Thought to be due to endothelial injury with breakdown of blood-brain barrier and subsequent brain oedema

• Hypertension and cytokines have been implicated – the relative role of each is debatable

• Hypertension

o Seen to some extent in 80-85% of patients

- Usually before neurological symptoms

o Rapid and severe rise may be more important than absolute level

o Cerebral autoregulation is achieved by sympathetic nervous system as well as local cytokine release. The latter could link in with apparent cytokine triggers.

o Argument against:

- 15-20% of patients have no HTN and less than 50% have MAP above the upper limit of cerebral blood flow autoregulation (>140-150mmHg)

- Hypertension could be a reaction to insufficient brain perfusion

Associated factors (?tiggers)

Pregnancy	Preeclampsia/eclampsia
Post-transplantation	Allo-BMT
Immune suppression	Cyclosporine Tacrolimus
Infection	SIRS/MOD
Autoimmune disease (up to 50% of pts)	SLE Hypothyroidism TTP Systemic sclerosis IBD GPA (Wegener’s) PAN Rheumatoid arthritis NMO
Chemotherapy	Cytarabine, Cisplatin etc. Bevacizumab, sunitinib, sorafenib
Renal failure (up to 55% of pts)	?associated with above conditions or independent risk factor

Clinical features:

	%
Encephalopathy	50-80%	Mild confusion to deep stupor
Seizures	60-75	Focal to BLTCS
Status epilepticus	5-15
Headache	50
Visual disturbance	33	Decreased VA Visual field deficits Cortical blindness Hallucinations
Focal neurological deficit	10-15
Myelopathy	Rare	Case reports of spinal cord involvement

Investigations

Imaging – MRI

• T2 hyperintense lesions consistent with oedema

• White matter predominantly but cortex may also be involved.

• Often symmetrical (at least nearly always bilateral)

• Generally resemble watershed regions

• Regions affected (in order)

o Parietal and occipital lobes most commonly affected – usually with sparing of calcarine and paramedian regions

o Frontal lobes

o Inferior temporal-occipital junction

o Cerebellum

• Lesions with restricted diffusion (infarction) occur in 11-30 %

• Contrast enhancement in 20%

• Haemorrhage is seen in 10-25%

o Intraparenchymal or subarachnoid

o Microhaemorrhage in 58% using SWI

• There may be poor correlation between clinical severity and imaging severity

Angiography

• Blood vessel irregularities consistent with vasoconstriction may be common

• Across studies - 15-30% (up to 85% in one study)

• Particularly common in posterior arteries

EEG

• Bilateral occipital sharp waves

• 11-40/100,000 per year

• 1/60 persons in a lifetime

• Associated with presence of HSV 1 but causal link not proven