Posterior reversible encephalopathy syndrome

To see contributor disclosures related to this article, click on this reference: ^[1]

Physicians can earn CME/MOC credit by using this article to address a clinical question and completing a brief evaluation about how they applied the information in their practice.

AMBOSS designates this internet point-of-care activity for a maximum of 0.5 AMA PRA Category 1 Credit(s)™. Physicians should claim only the credit commensurate with the extent of their participation in the activity.

For answers to questions about AMBOSS CME, including how to redeem CME/MOC credit, see “Tips and links” at the bottom of this article.

Posterior reversible encephalopathy syndrome (PRES) is a neurological condition characterized by vasogenic edema predominantly involving the subcortical white matter of the posterior cerebral hemispheres. Causes include acute severe hypertension (e.g., pregnancy-induced hypertension), autoimmune diseases, and certain immunosuppressant or antineoplastic agents. Clinical features typically include altered mental status (AMS), seizures, headache, and/or visual disturbances. Diagnosis relies on neuroimaging (e.g., MRI brain), which typically shows bilateral edema in the parieto-occipital regions. Lumbar puncture may be performed to exclude infectious or inflammatory mimics. Management involves addressing the underlying cause and providing symptomatic support. With early recognition and treatment, most patients achieve complete clinical and radiological recovery.

• Incidence in the general population is unknown and differs in certain patient cohorts, e.g.: ^[2][3]
  • End-stage renal disease and systemic lupus erythematosus (SLE): ∼ 1%
  • Bone marrow transplantation: 2.7–25%
  • Preeclampsia or eclampsia: 20–98%
• Most commonly affects young to middle-aged adults
• ♀ > ♂ ^[3]

Epidemiological data refers to the US, unless otherwise specified.

• Acute severe hypertension (e.g., hypertensive emergency, preeclampsia, eclampsia)
• Renal failure
• Sepsis
• Autoimmune diseases (e.g., SLE)
• Antineoplastic drugs and immunosuppressant drugs (e.g., cyclosporine A, cisplatin, cyclophosphamide)

The exact pathophysiology of PRES is not fully understood, but the following theories have been proposed. ^[3]

• ↑ Blood pressure → loss of cerebrovascular autoregulation → hyperperfusion with endothelial damage and vasogenic edema
• Presence of endogenous or exogenous toxins → endothelial dysfunction

Severity of symptoms may vary. ^[2][3]

• Altered mental status
• Seizures
• Headache (typically moderate to severe and generalized)
• Visual disturbances
• Nausea, vomiting

Diagnosis is based on characteristic clinical features, neuroimaging findings, and risk factors.

Neuroimaging ^[2][3]

• MRI brain (preferred modality)
  • Characteristic finding: bilateral vasogenic edema predominantly in parieto-occipital regions
  • Crucial for differentiating PRES from mimics (e.g., acute ischemic stroke)
• CT brain: less sensitive than MRI for vasogenic edema

Evaluation for the underlying cause ^[2][4]

• Blood pressure monitoring
• Blood tests, e.g.:
  • CBC
  • Renal function tests
  • Liver chemistries, LDH ^[4]
  • Anti-nuclear antibody (ANA) and antigen-specific ANAs
• Urine tests
  • Urinalysis
  • Urine toxicology screen
  • Pregnancy test

Additional studies ^[3]

Consider the following to exclude alternative diagnoses:

• Lumbar puncture
  • Use: to assess for CNS infection or inflammation
  • Findings in PRES: normal or mildly elevated protein concentration
• Electroencephalography: to evaluate encephalopathy and exclude nonconvulsive status epilepticus

Differential diagnoses include: ^[2][3]

• Vascular
  • Cerebral venous thrombosis
  • Reversible cerebral vasoconstriction syndrome
  • Acute ischemic stroke (posterior circulation ischemic stroke, watershed stroke)
• Infectious: infectious encephalitis
• Inflammatory
  • Autoimmune encephalitis
  • Lupus cerebritis
  • Primary CNS vasculitis
• Demyelinating
  • Multiple sclerosis
  • Osmotic myelinolysis
• Neoplastic: primary or secondary brain tumors
• Metabolic and toxic encephalopathies
  • Substance-induced encephalopathy
  • Mitochondrial encephalopathy (see “Mitochondrial myopathies”)
  • Hepatic encephalopathy

The differential diagnoses listed here are not exhaustive.

Management is focused on treating the underlying cause and providing supportive care. ^[2][3][4]

• Provide immediate initial management of AMS or coma.
• Consider admission to ICU. ^[2]
• Identify and manage the underlying cause, which may include:
  • Management of hypertensive emergencies
  • Management of hypertensive pregnancy disorders
  • Reduction or discontinuation of causative medications (e.g., immunosuppressants), under specialist supervision
  • Renal replacement therapy for renal failure
• Management of acute seizures and status epilepticus

• Prognosis is generally favorable, with complete clinical and radiological recovery in the majority of patients. ^[3]
• Poor outcomes include persistent neurological deficits (e.g., epilepsy) and death. ^[2][3]