Reversible Cerebral Vasoconstriction Syndrome

The Reversible Cerebral Vasoconstriction Syndrome (RCVS) is one of the important causes of thunderclap headache. RCVS can cause repeated episodes of sudden severe headache, sometimes provoked by exercise.

It has also been known as migrainous angiitis, Call-Fleming Syndrome, or benign cerebral angiopathy.

In most series, women outnumber men 2:1.

Most cases are "Idiopathic" (idiopathic means no obvious cause) but there are recognised triggers for the condition.

Apologies for such a long list, but this is is supposed a comprehensive listing, and if I hear of more I will add these in due course:

  1. Idiopathic RCVS, some times called Call-Fleming Syndrome
  2. Pregnancy
  3. Eclampsia / delayed post-partum eclampsia
  4. Acute Severe Hypertension (Hypertensive crisis)
  5. Drugs
    • Pseudoephedrine
    • Ergotamine
    • Bromocriptine
    • SSRI anti-depressants
    • Sumatriptan
    • Cocaine
    • Ecstasy
    • Amphetamines
    • Marijuana / LSD
    • Tacrolimus
    • Cyclophosphamide
    • Erythropoietin (EPO)
  6. Blood product associated
    • Intravenous Immunoglobulin
    • Red Cell Transfusion
  7. Hypercalcaemia
  8. Porphyria
  9. Phaeochromocytoma
  10. Bronchial Carcinoid Tumor
  11. Head trauma
  12. Spinal Subdural Haematoma
  13. Carotid Endarterectomy Following Neurosurgical Procedures
  14. Exercise Induced Headache
  15. Sexual Activity

IS RCVS a Dangerous Headache Syndrome?

In a small number of cases, stroke can happen, due to persistent or severe vasoconstriction.

Vasoconstriction means a narrowing of blood vessels, so that blood flow and oxygen supply to parts of the brain are reduced.

If the vasoconstriction is bad enough, then a stroke could occur. If that stroke is in the cerebellum, it could cause a secondary rise in intracranial pressure, which could become life-threatening if unrecognised and untreated.

There are a few cases reported where cerebral vasoconstriction did lead to strokes, which caused brain swelling which led to patient death.

I have yet to see such a serious outcome in my own practice of the last 10 years.

Diagnosis

The diagnosis is made on a cerebral angiogram (up to date MR angiogram can be good enough).

A catheter angiogram is the gold standard for demonstrating vasoconstriction.

Before undergoing an angiogram, the patient will have had initial investigations for thunderclap headache (CT Brain and Lumbar Puncture), which will have ruled out other causes of the headache.

Treatment

A single episode of thunderclap headache due to Reversible Cerebral Vasoconstriction Syndrome (RCVS) does not need treatment, especially if the headache has resolved.

If repeated, Nimodipine is sometimes recommended, but my own success with this has not been that impressive.

Verapamil (which is a drug closely related to Nimodipine) is also used by some, and corticosteroids like Prednisolone, or intravenous magnesium are also used.

None of these drugs have been tested in proper randomised trials, so the actual benefit of using them is uncertain.

Patients who have signs of reduced blood flow, like numbness or weakness, may need to be treated.

It is a difficult balancing act, as many people will come through unscathed without treatment, but with the risk of a stroke (presumably it is s small risk) in the background, it is hard not to do something!

Outcomes

The vast majority of patients make a good recovery - hence the term Reversible Cerebral Vasoconstriction Syndrome.

A few people will have a stroke. One series reported a stroke rate of 54%, but cases are much more likely to be reported if they have an adverse outcome, than good outcome - (the medical literature is same as other media - bad stories sell).

I am not aware of large numbers of cases who have took strokes the context of thunderclap headache, and I usually follow these people up, so the 54% estimate is in my view an extreme over-estimate of stroke risk.

What matters is that the history of thunderclap headache is taken seriously and that appropriate investigations occur.

If headache and other symptoms persist, the diagnosis should be reviewed, and consideration given to treatment with nimodipine.

Could anything alse be confused with RCVS?

The main mimics of Reversible Cerebral Vasoconstriction Syndrome are other conditions where there is thunderclap headache, and the Cerebrospinal Fluid is relatively normal but abnormal appearing arteries are seen on at angiography.

These conditions include:

  1. Primary Angiitis of the Central Nervous System
    2. Usually the CSF has a higher protein count, and headache is more dull and less sudden in PACNS.

  2. Carotid Dissection
    3. This could cause thunderclap headache in a minority of cases and lead to focal neurological symptoms like weakness or numbness, but usually the angiography is characteristic for dissection.

    Dissection will usually involve the carotid within the neck and at the skull base, rather than at its junction with the middle cerebral artery.

  3. Subarachnoid Haemorrhage
    4. This diagnosis could be missed if the cerebrospinal fluid analysis does not include spectrophotometry for xanthochromia i.e. bilirubin.

References

Calabrese LH, Dodick DW, Schwedt TJ, and AB Singhal.Reversible Cerebral Vasoconstriction Syndrome. Annals of Internal Medicine 2007;146:34-44. (Free Full Text)

Call GK, Fleming MC, Sealfon S, Levine H, Kistler JP, Fisher CM. Reversible cerebral segmental vasoconstriction. Stroke. 1988;19:1159-70. (Free Full Text)

Dodick DW, Brown RD Jr, Britton JW, Huston J 3rd. Nonaneurysmalthunderclap headache with diffuse, multifocal, segmental, and reversible vasospasm. Cephalalgia. 1999;19:118-23. (Free Abstract only)

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