Reversible cerebral vasoconstriction syndrome (RCVS): symptoms, treatment and recovery

The Walton Centre, a specialist neurology and neurosurgery NHS trust in Liverpool, describes RCVS as a neurological disorder characterised by a sudden onset of severe headache associated with narrowing of the intracranial blood vessels that supply the brain. On brain imaging the narrowing can look similar to a string of beads.

In addition to headaches, RCVS can present as a medical emergency with strokes (either a blocked vessel or a bleed), seizure or brain swelling. Usually the narrowing resolves spontaneously within three months, which is why it is called reversible.

The most common symptom is a sudden, intense headache described as a thunderclap. The Walton Centre says the headaches are either widespread or located at the back or top of the head, are often associated with nausea and sensitivity to light, can come and go, and it is not unusual for them to recur over a few days to weeks. The majority of patients recover following the headache.

RCVS can also be associated with seizures and stroke. The stroke-related symptoms listed are changes in vision, difficulty speaking or understanding others, loss of balance, and sudden weakness or loss of sensation on one side of the body. If you develop these after leaving hospital, call 999 or go to A&E immediately.

The NHS says a sudden headache that is extremely painful and does not go away is a reason to call 999, because the same symptom can be a subarachnoid haemorrhage, a life-threatening bleed on the brain. For that reason a first thunderclap headache is always treated as an emergency until the cause is known.

The Walton Centre says there is currently no proven treatment for RCVS, although some treatments help. Calcium channel blockers, most commonly nimodipine, can help reduce headache intensity. Most people remain on nimodipine for two to three weeks, depending on presentation, and the length is decided by your consultant neurologist. Side effects include low blood pressure, flushing, changes in heart rate, headache and feeling sick. Do not drink alcohol or grapefruit juice while taking it, and have your blood pressure checked by your GP after the course.

Supportive treatment includes early identification and withdrawal of any triggering substance, whether a medicine or an illegal drug. You are advised to rest, take regular pain relief and avoid becoming dehydrated. Simple painkillers such as paracetamol and opioids are recommended for headache, while triptans should be avoided because they can exacerbate or cause RCVS.

The Walton Centre also advises avoiding medicines that constrict blood vessels, such as serotonin reuptake inhibitor antidepressants, over-the-counter nasal decongestants and illicit drugs, because of the risk of recurrence.

The Walton Centre says RCVS usually affects young and middle-aged adults between 20 and 50, in both men and women but more commonly women. In younger women it can sometimes be associated with the changes that happen after giving birth, pregnancy, or starting or changing contraceptive pills.

Risk factors listed are certain prescription drugs (antidepressants, migraine medicines, immune-suppressant medicines, drugs to prevent bleeding after childbirth and some anti-Parkinson's medicines), over-the-counter nasal decongestants and nicotine patches, energy drinks containing caffeine and ginseng, illegal drugs such as cannabis, cocaine, ecstasy, amphetamines and LSD, alcohol, head trauma, high blood calcium, certain tumours, blood transfusions, immunoglobulin treatment, autoimmune diseases and blood disorders.

Triggers you may notice include orgasm, exercise, stressful or emotional situations, straining, coughing or sneezing, bathing and swimming. It is believed these may change the tone of the blood vessels in the brain.

The Walton Centre says most people diagnosed with RCVS there are initially admitted for investigation of a bleed in the brain, such as a haemorrhagic stroke or subarachnoid haemorrhage. A CT angiogram, a scan to view the vessels of the brain, is usually the first investigation. If it does not find a cause, a formal cerebral angiogram, or an MRI with MR angiogram, may be used to see whether the arteries are narrowed in a way that suggests RCVS. A consultant neurologist then makes the diagnosis after taking a detailed history, reviewing the imaging and examining you.

Blood tests and a lumbar puncture may be needed to rule out other causes of similar narrowing. Many people with thunderclap headache have no abnormality on the first scans. The initial scans can be normal in 25% or more of cases, and the chance is higher if the scan is taken in A&E, so the diagnosis may only be made at outpatient follow-up.

A follow-up CT or MR angiogram, usually between four and 12 weeks, confirms the diagnosis because the narrowing should have resolved completely.

The Walton Centre says thunderclap headaches typically resolve over days to weeks, and visual and neurological symptoms start to resolve at about the same time. The constriction in the arteries varies between people but usually lasts between four and six weeks, and by three months most people's scans are back to normal.

You are expected to recover well and be independent in daily activities. A small number of people need help with things such as managing finances, and those who have had a stroke need follow-up with a neurologist, physiotherapist and rehabilitation. Some people go on to have chronic migraine-like headaches or low mood, in which case you should tell your GP, neurologist or neurovascular nurse so that support such as counselling can be arranged.

If you have had one or more seizures, the Walton Centre says you must inform the DVLA and cannot drive until you have been given permission. Visual problems such as blurring, blind spots or double vision may also occur and should be reported.

A thunderclap headache has several possible causes, and only tests can tell them apart. The table shows how the Walton Centre and the NHS describe two conditions that are investigated at the same time.

A sudden severe headache is assessed as an emergency in A&E, usually with a CT scan and angiography. People with RCVS are generally admitted under neurology, neurosurgery or stroke teams, and a neurovascular nurse team may call you about two weeks after going home. Follow-up with a neurologist as an outpatient includes repeat scans.

Private neurology can help with follow-up and second opinions, but the acute assessment of a thunderclap headache is an emergency hospital matter and should not wait for a private appointment.