Contents
Acute neurotoxic syndrome that is characterized by a spectrum reversible neurological and radiological feature from various risk factors.
History:
The syndrome was first described in 1996 by Hinchey and colleagues who reported on a series of 15 patients with neurological signs and symptoms including headache, seizures, visual disturbance and other focal neurological deficits. Moreover, computed tomographic (CT) or magnetic resonance imaging (MRI) alterations suggestive of cerebral edema were observed predominantly in the posterior regions. Since this first description of PRES numerous case reports and case series, as well as retrospective observational studies describing the syndrome have been published.
Aetiology
Associated conditions:
Symptoms present acutely or subacutely in the setting of other conditions:
- Accelerated hypertension
- Eclampsia
- Autoimmune disease
- Immunosuppressive treatment
- Cancer chemotherapy

Pathophysiology
Rapidly developing hypertension
↓
Breakdown in cerebral autoregulation
(breakdown of blood-brain barrier + endothelial dysfunction)
↓
Hyperperfusion
(protein and fluid extravasation)
↓
Focal vasogenic edema
Clinical features
Symptoms are reversible, provided that the syndrome is recognized and treated promptly.
- Headache
- Visual impairment (e.g., binocular diplopia, vision loss, no light perception vision, hemianopia, or quadrantanopia)
- Seizures
- Mental status changes

Physical examination:
- Ophthalmic examination: Hemianopia, quadrantanopia, visual neglect, cortical blindness, horizontal gaze palsy with intact vestibulo-ocular reflex, papilledema
- Oral trauma (tongue biting seen during a seizure)
- Brisk reflexes
- Active convulsions
- Urinary and fecal incontinence
Complications:
Cases can develop life-threatening complications, if prompt treatment is not initiated.
- Transforaminal cerebellar herniation
- Focal neurologic deficits
Diagnosis
Non-contrast MRI:
GOLD STANDARD
- Reversible cerebral vasogenic oedema (hyperintense T2/hypointense T1 signal), predominantly affecting the parieto-occipital regions (TYPICAL FINDING)
- Atypical imaging features:
- Involvement of anterior brain/brainstem
- Coexistence of ischemia/hemorrhage

Magnetic resonance angiography (MRA) or magnetic resonance venography (MRV):
Typically normal findings
- Exclude CNS vasculitis (MRA)
- Exclude sagittal sinus thrombosis (MRV)
Differential diagnosis:
- Intracranial hemorrhage
- Subdural hemorrhage
- Subarachnoid hemorrhage
- Cerebral sinus venous thrombosis
- Posterior circulation ischemic or hemorrhagic stroke
- thrombosis of the basilar artery
- Vasculitis of the central nervous system
- Herpes simplex encephalitis
- Autoimmune encephalitis
- Uremic encephalopathy
- Hypoglycemia
Management
Treatment of hypertension and seizures, and withdrawal of causative agents are the mainstays of therapy in PRES.
- Protect the airway (in obtunded patients)
- Aggressive blood pressure management
- Withdrawal of the offending drug
- Immediate delivery (in eclampsia)
- Antiepileptics (to treat seizures)
- Anesthesia and ventilation (in generalized status epilepticus)