= (PRES) = REVERSIBLE POSTERIOR LEUKOENCEPHALOPATHY SYNDROME = HYPERTENSIVE ENCEPHALOPATHY

= heterogeneous collection of disorders associated with a breakdown in cerebral autoregulatory perfusion mechanisms

• Emergency condition as patient may proceed to cerebral infarction and death if untreated!

Cause: acute rise in systemic blood pressure, preeclampsia or eclampsia, hemolytic uremic syndrome, cryoglobulinemia, SLE, following immunosuppressive treatment with cyclosporine A, cisplatin, tacrolimus (= Tsukuba macrolide immunosuppressan = FK-506)

Pathophysiology: vasogenic edema related to sparse sympathetic innervation in posterior circulation

• headache, nausea, vomiting, visual changes
• decreased alertness, seizures

Location: white matter of posterior half of brain

• hypodense white matter on NECT
• lesion hypointense on T1WI + hyperintense on T2WI ← vasogenic edema (= fluid extravasation into interstitium)
• lesion hypo- to isointense on DWI + hyperintense on ADC map (due to a net effect of elevated diffusion coefficient from vasogenic edema + T2 shine-through effect)
• NO contrast enhancement

Cx: infarction (lesions develop high DWI signal + normal ADC signal)

Rx: rapid control of blood pressure / withdrawal of offending drug