What are PRES and RCVS?

These are two similar stroke-like conditions, but unlike stroke they may get resolved with no or minimal long-term consequences. Both initially presents with stroke-like symptoms. PRES stands for posterior reversible encephalopathy syndrome, and RCVS for reversible cerebral vasoconstriction syndrome. Because of the similarities of presentation and mechanisms, these conditions are frequently discussed together.

 

What are symptoms of PRES and RCVS?

Both PRES and RCVS share similar symptoms. Some have suggested that they are on the same spectrum and differ due to the extent of symptoms. PRES typically presents with visual disturbances (typically cortical blindness – patient seems to be oblivious of blindness) and confusion. RCVS on the other hand, may present with sudden severe headache, seizure and other stroke like symptoms including confusion and visual disturbances. Frequently, patients have features of both PRES and RCVS.

 

What is the real problem in PRES or RCVS?

To comprehend the problem in PRES and RCVS, two concepts are important to understand: a. The size of medium to large-size brain blood vessels is controlled by the autonomic nervous system, which maintains their internal diameter to provide enough blood supply to the brain, and b. In comparison to the rest of the body, walls of the capillaries (the smallest blood vessels) of the brain differ in design. Their walls are particularly sealed well with special structures to avoid flow of material from blood vessels to the brain. This designing is noted in brain and some other structures in the body, which are called “special organs.”

In both PRES and RCVS, there is malfunction of the autonomic control resulting in excessive constriction of blood vessels. This results in deficiency or lack of blood supply to the areas of the brain they supply, resulting in stroke like condition. The impact depends upon the level and extent of this problem. At capillary level, the structures keeping the capillary wall tightly closed malfunction, leading to leakage of fluid in the brain, the brain edema. These changes can happen without any prior problem with blood vessels or narrowing, infection, inflammation or anything else blocking them. As there is no underlying disease of blood vessels and there are no blood clots causing the blockage, after some time (usually hours to days), they open again, and the affected areas of brain may go back to normal. Most patients recover most of the symptoms but in some there may be permanent stroke like effects, especially if the condition is severe or not managed well. In such cases, patients can have both ischemic and hemorrhagic strokes. While similar in many ways, the main issue in PRES is the leaky capillaries causing brain edema, and in RCVS is the constriction of blood vessels.

 

How is the diagnosis for PRES or RCVS is made?

In patients presenting with symptoms described above, brain imaging (preferably with MRI) helps to make the diagnosis. MRI may show stroke like abnormal signal. To some, it may suggest combination of ischemic and hemorrhagic strokes. But, unlike strokes, which follow a particular pattern or vascular territory, based upon the blood vessel involved, findings in these conditions may not follow a vascular territory. Also, unlike typical strokes, one may see the resolution of these lesions by repeating the MRI scan in 2-4 weeks. MRA or CTA of brain can reveal abnormal tightening or stenosis of blood vessels, which looks different from the tightening seen with cholesterol build-up, and unlike that it resolves in days to weeks.

 

How to differentiate between PRES vs RCVS?

It is based upon symptoms as described above, and MRI brain findings. In PRES, MRI abnormalities are mostly in the back of the brain, or the occipital regions, where visual images are comprehended, so is the reason for visual disturbances. In RCVS, similar abnormalities are not particularly localized to the back of brain, and there may be findings suggestive of combination of ischemic and hemorrhagic strokes.

 

What are different causes of PRES or RCVS?

Following are some known causes of PRES and RCVS and the list is not all inclusive

1. Very high blood pressure from any cause, especially its sudden rise, but not every patient with PRES and RCVS has high BP
2. Pre-eclampsia or eclampsia
3. Kidney disease
4. Auto-immune diseases
5. Organ transplantation
6. Antidepressants: Prozac, Paxil, Zoloft
7. Migraine drugs: Like triptans, ergot compounds, Midrin
8. Immunosuppressants: Like Cytoxan, tacrolimus
9. Drugs to prevent bleeding from childbirth
10. Anti-Parkinson’s drugs: Bromocriptine and lisuride
11. Nasal decongestants: Pseudoephedrine, phenylpropanolamine
12. Nicotine patches
13. Caffeine-containing energy drinks
14. Ginseng, Ephedra, licorice, khat leaves, eucalyptus, Chinese herbal remedies
15. Drugs of abuse: Marijuana, cocaine, Ecstasy, LSD, amphetamine derivatives
16. MS drugs: Like interferons, fingolimod
17. IV Ig
18. Certain tumors that secrete vasoactive hormones: Pheochromocytoma, bronchial carcinoid, and glomus tumors.
19. IV contrast
20. Oral contraception, probably estrogen containing
21. Venous brain infarcts
22. Miscellaneous: High-altitude, cold-water exposure, severe grief, porphyria, nifedipine withdrawal, caffeine withdrawal, head trauma, TMS treatment

 

What is the treatment for PRES and RCVS?

No specific treatment is available. In fact, usually no specific treatment is needed. These are self-limiting conditions, and the main issue is to make the correct diagnosis as soon as possible, avoid treatment measures based upon incorrect diagnosis, and control all factors that can contribute to further problems for the patient.  These conditions are described under strokes but are not treated like them. For example, they are not treated by a blood thinner. On the other hand, like strokes, blood pressure management might be needed. It is also important to take detailed history and gather information and evidence to find the right or the possible trigger for these conditions, so that the patient can be advised to avoid any such or similar triggers.

Following specific measures can be helpful:

1. Severe hypertension: Admit to ICU and treat BP carefully (not to bring it too low too quickly) with calcium channel blockers and additional measures if needed.
2. Eclampsia: Deliver the child, admit patient to ICU and treat with magnesium.
3. Brain edema: Don’t use steroids, it may make the situation worse.
4. Confusion: Do an EEG and use anti-epileptic only if seizure disorder is confirmed.
5. Seizure(s): If clinical seizure has happened, may use a seizure med for a few weeks. Long-term medicine for seizure is usually not needed.
6. Avoid: Steroids, any vasoconstrictor drug (like triptans for headaches), prophylactic seizure medicine (without evidence of seizure), and interventions like brain biopsy.

 

What conditions may look like PRES and RCVS?

Following conditions may present with similar features:

1. Subarachnoid hemorrhage from cerebral aneurysm
2. Brain infection
3. Brain inflammatory conditions, like auto-immune cerebritis
4. Cerebral venous thrombosis
5. Cervical artery dissection
6. Strokes
7. Meningitis
8. Pituitary apoplexy

 

What investigations may be required to differentiate between PRES/RCVS and other similar conditions?

Other than brain imaging described above, blood tests and a lumbar puncture may also be helpful to differentiate between these conditions.

 

What is the prognosis for PRES and RCVS?

Most cases recover with resolution of symptoms. This can happen in days to weeks. MRI findings may take a little longer to resolve. About ¼ to 1/3^rd of patients may develop stroke(s) and permanent stoke associated symptoms.

 

Where can I get more information about PRES and RCVS?

American Academy of Neurology

American Stroke Association