Posterior reversible encephalopathy syndrome is a neurological disorder characterized by swelling or inflammation in the brain. It’s often treatable if diagnosed quickly.

Posterior reversible encephalopathy syndrome (PRES) has previously gone by several other names, including:

  • reversible posterior leukoencephalopathy syndrome
  • reversible posterior cerebral edema syndrome
  • reversible occipital parietal encephalopathy

Many underlying conditions can trigger PRES, including high blood pressure or drug overdose. Autoimmune disease and epilepsy are risk factors for PRES, and PRES can also increase the risk of these conditions.

Read on to learn more about PRES, including potential symptoms, causes, and treatment options.

PRES is a rare condition that causes neurological symptoms, such as seizures or headaches. These symptoms are caused by swelling, inflammation, and damage in the brain, particularly in the posterior (back) region.

Several underlying risk factors, including high blood pressure and autoimmune disease, may increase the chance of developing PRES.

It’s unclear exactly how the condition develops. Some theories suggest that fluid or inflammatory cells may leak from small blood vessels in the brain, causing an accumulation of buildup in the posterior region of the brain.

This can also affect the brainstem, which is below the posterior area of the cerebral cortex of the brain.

Symptoms of PRES are nonspecific, which means that different medical conditions can cause the same symptoms. Usually, symptoms develop over hours to days. With treatment, symptoms resolve within days to weeks.

Common signs and symptoms include:

Some people can develop life threatening complications such as status epilepticus or coma. Status epilepticus is a medical term for seizures that are prolonged or that occur quickly in succession.

It’s not entirely clear what causes PRES, but it has been associated with many health conditions, such as eclampsia.

Eclampsia is a dangerous medical complication of pregnancy that causes severe high blood pressure, seizures, and strokes.

The average age of PRES development is about 45, and it mainly affects young or middle-aged adults. PRES is more common in middle-aged females, even when eclampsia is excluded as a potential cause.

Health conditions that have been associated with the development of PRES

Some of the health conditions that have been associated with the development of PRES include:

Autoimmune disorders

PRES has been associated with autoimmune conditions such as:

Toxin exposure

PRES may develop in some people after exposure to toxic substances. Potential exposures include:

Medications

Many types of medications can potentially trigger PRES, including many used to treat cancer or autoimmune conditions. Potential triggering medications used to treat these conditions include:

  • azathioprine
  • bortezomib
  • capecitabine, 5-fluorouracil
  • chemotherapy
  • corticosteroids
  • cyclophosphamide
  • cytarabine
  • cyclosporin
  • daunorubicin
  • etoposide
  • gemcitabine
  • hydroxydaunorubicin/adriamycin
  • interferon therapy
  • intravenous contrast
  • intravenous immunoglobulin
  • linezolid
  • lithium
  • methotrexate
  • mycophenolate mofetil
  • platinum-containing chemotherapy drugs such as cisplatin or oxaliplatin
  • rituximab
  • sirolimus
  • tacrolimus
  • tyrosine kinase inhibitors
  • vinblastine/vincristine

Diagnosing PRES can be difficult since its symptoms have multiple causes. A diagnosis can only be made once a doctor sees characteristic swelling in your brain with imaging.

During the diagnostic process, you may receive the following to help confirm PRES and rule out other conditions:

You may also receive other tests such as:

  • blood test to look for conditions like electrolyte imbalances or infections
  • electroencephalogram (EEG) to monitor seizure activity
  • urine tests

The main treatment for PRES is treating the underlying cause. For example, if high blood pressure is suspected to be contributing, you’ll likely receive medications to bring your blood pressure into a safe range.

Other treatments you might need include:

  • supportive treatment with fluids and electrolytes administered through an IV
  • antiseizure medications
  • maternal and fetal management during labor and delivery
  • dialysis for kidney failure
  • corticosteroids and immunosuppressant medications for people with autoimmune conditions

Receiving prompt treatment for PRES reduces your chances of developing severe complications, such as neurological problems caused by a lack of blood flow to the brain.

What makes PRES unique is that although neurological symptoms are significant, PRES is reversible when treated promptly and effectively.

Even though the majority of people recover, some people have permanent brain damage. Brain damage in the posterior area of the brain causes long-term effects such as vision problems, epilepsy, or cognitive changes.

The outlook is usually worse when the brainstem is affected.

Some people may develop PRES more than once. This has been reported in some people undergoing dialysis for kidney failure.

PRES is a group of symptoms that are characterized by swelling and inflammation in the posterior region of the brain. It’s usually reversible, but if not treated promptly, swelling can lead to permanent damage to your brain.

It’s important to seek medical attention if you or somebody you’re with develops concerning neurological symptoms, such as the new development of seizures or sudden vision changes.

The quicker you’re diagnosed, the better your odds of recovering without long-term complications.