What Is Reversible Cerebral Vasoconstriction Syndrome?

Reversible cerebral vasoconstriction syndrome (RCVS) is a rare condition but a true emergency. In RCVS, blood vessels in the brain suddenly narrow, or constrict. These vessels carry oxygen and nutrients to the brain. A stroke may occur as a result, but the "reversible" in RCVS means that symptoms often go away.

The main feature of RCVS is a "thunderclap" headache. This is a sudden, severe, and disabling form of headache. It primarily affects women at middle age, and is often associated with childbirth. In recent years, scientists have found other reasons for why someone may have RCVS episodes.

This article looks at exactly what RCVS is, and its common symptoms and risk factors. It explains why RCVS may be different from other kinds of strokes, and discusses how RCVS is diagnosed and treated.

It's important to know what RCVS is, and what it is not. An RCVS may or may not lead to a stroke. In many cases, stroke symptoms occur but are completely reversed later. However, some people may be left with permanent effects. An RCVS event also may cause seizures and death.

Strokes caused by damage to blood vessels in the brain fall into two categories. Ischemic strokes happen when blood flow is blocked, usually by a blood clot. Hemorrhagic strokes happen when the blood vessel itself is damaged. RCVS can cause either type, but it's usually linked to a subarachnoid hemorrhage. This refers to bleeding between the brain itself and the membrane that surrounds it.

Symptoms 

The severe "thunderclap" headache is the hallmark sign of RCVS and it may be the only symptom. The definition of this type of headache includes:

• an abrupt onset without warning
• the headache intensity peaks in less than 60 seconds
• the headache lasts at least five minutes

Some people report a surge of high blood pressure when the headache comes on. A person having an RCVS event also may have a seizure at the time.

Causes

The cause of RCVS is not known, but it may be linked to a temporary change in an arterial wall. This leads to the blood vessel narrowing. There may be several reasons for why this occurs, apart from the link between RCVS and childbirth. RCVS also may happen more than once, though this is rare.

In some cases, doctors have seen RCVS episodes in people with pheochromocytoma. This rare condition is associated with high blood pressure. They have also encountered cases that appear linked to exertion, including sexual activity, or to physical activities as simple as bathing or coughing.

Several medications and street drugs also are linked with RCVS. They include:

• Selective serotonin reuptake inhibitors (SSRIs)
• Nasal decongestants containing pseudoephedrine or ephedrine
• Ergotamine
• Tacrolimus
• Nicotine patches
• Cocaine
• Cannabis
  

Diagnosis

Constricted blood vessels can be diagnosed using a range of imaging techniques. For RCVS, an imaging technique called cerebral catheter digital subtraction angiography (DSA) is considered the gold standard.

However, there are many tests that may be other options. They include computed tomography (CT), which may be the first image available when someone with RCVS arrives in the emergency room. Other imaging tests include:

• CT angiography
• magnetic resonance angiography (MRA)
• transcranial Doppler

A final diagnosis will include the individual signs and symptoms of the person with a possible RCVS episode, as well as any trigger for RCVS that's been identified. Doctors also may use an RCVS score that includes a person's history of "thunderclap" headaches. The score also looks at whether there is a brain bleed, if the carotid intracranial artery is involved, and any information about trigger events.

Treatment

In many cases, RCVS will resolve by itself. But there are some cases that may be linked to an underlying medical condition. Treatment will depend on what your doctor has learned about the potential causes.

If RCVS does lead to a stroke, seizure, or other medical issue, health workers will treat that problem.

Summary

RCVS is relatively rare, but an episode is a serious event that requires medical attention. There are no lasting impacts in many cases, which is why it is thought "reversible." But it can lead to a stroke or result in permanent stroke-like deficits.

Why RCVS happens is not entirely known. It occurs more often in middle-aged women, usually under the age of 50, and is linked to childbirth. But researchers looking for other causes have found links to cannabis and other drugs. There also appear to be links to physical stress, as well as cases linked to head trauma. Ask your doctor about RCVS if you have concerns about your own risks.

A Word From Verywell

Doctors aren't always sure what causes RCVS but the research generally agrees on one thing: RCVS is underdiagnosed and gets missed in a lot of cases. So if you or a loved one have symptoms, or an episode that seems consistent with RCVS, don't dismiss it as a passing thing. Be sure to take it seriously and call your doctor to get checked out.