PRES: Posterior reversible leukoencephalopathy syndrome.
It usually consists of a constellation of features, including:
AMS or encephalopathy** – in ~¾ of patients
Seizures** – in ~⅔ of patients
Often the presenting symptom
Headache – in ~½ of patients; global, gradual, refractory to meds
Visual changes - in ⅓ of patients
Hypertension - may precede the neurologic syndrome by ~24 hours
Most common key contributing fracture is a rapid increase in blood pressure
In the context of hypertension, PRES is equivalent to hypertensive encephalopathy
BP can related to pre/eclampsia
The BP can be normal in ~20% of patients
Nausea / vomiting
The symptoms typically progress rapidly over hours or days.
Risk factors:
Hypertension – Pre/eclampsia
Renal disease
Immunosuppressive meds, e.g.: tacrolimus and cyclosporine, high dose corticosteroids
Low magnesium
Transplant patient
Pathophysiology:
Usually affects the posterior circulation of the brain
Cerebral endothelial dysfunction
Failure of autoregulation – usually the cerebral arterioles constrict with HTN
If autoregulation fails, the brain experiences high blood pressures
Vasogenic cerebral edema due to decreased integrity of the blood brain barrier
Dx:
MRI will show cerebral edema on the T2-weighted image in the posterior white matter
The edema is typically bilateral
PRES is a diagnosis of exclusion
Ddx:
R/o stroke, ICH, malignancy, eclampsia, meningoencephalitis, metabolic encephalopathy
Tx:
Remove causative factors like immunosuppressive meds
Replete magnesium if hypoMg or pre/eclampsia
Antiepileptics – benzos are firstline; keppra second line
Antihypertensives
Options: nicardipine, clevidipine, labetalol
Goal to reduce BP by 20-30% within 1 hour
Prognosis:
Proper treatment can reduce long term sequelae.
10-44% can have persistent neurologic deficits
Overall mortality: 3-6%
Recovery takes a several days typically
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