Do Not Ignore a Headache
A thunderclap headache. Post-partum cerebral angiopathy. Sub-arachnoid hemorrhagic headache. Posterior reversible encephalopathy. Primary and benign angiopathies of the central nervous system. Call-Fleming syndrome. I am not throwing the dictionary at you. These are all sudden onset headaches resulting from changes in the flow of blood in cerebral arteries. Recent opinion tends to aggregate all these kinds of headaches under a common term, Reversible Cerebral Vasoconstriction Syndrome (RCVS).
What is RCVS?
RCVS results from sudden narrowing of cerebral arteries which results in reduced flow of blood to parts of the brain. In some cases, hemorrhage under the arachnoid membrane may also be seen. RCVS is usually diagnosed using Magnetic Resonance Imaging (MRI) and Magnetic Resonance Angiography (MRA) and by eliminating other known causes of headaches. A peculiar feature of this malady is the persistence of constrictions on brain vessels for up to three months after the headache has occurred. At times, a series of constrictions – termed as a ‘beads-on-a-string’ appearance – have been noted. However, there is very little knowledge to date about the actual physiological mechanisms of this pathology.
Women are more susceptible to RCVS than men. In a study conducted by Ducros and colleagues, 90% of the patients with a confirmed diagnosis of RCVS were women, with a mean age of 46 years.
How is RCVS different from other brain vascular diseases?
A significant difference between RCVS and strokes and transient ischemic attacks is that, unlike strokes, RCVS is not caused by atherosclerosis. However, recurrent episodes of RCVS may render patients susceptible to a stroke.
Migraine headaches are a well-known pathological condition associated with the cerebral blood vessel network. The jury is still out on whether migraines are caused by sudden expansion of blood vessels or by constrictions in blood vessels resulting in reduced cranial circulation. Cerebral arteries are joined in a loop known as the Circle of Willis. There is some evidence to show that people with an incomplete Circle of Willis are more likely to suffer from migraine headaches than those with a complete loop. An association between RCVS and the Circle of Willis has not yet been shown. A significant difference between RCVS and migraines is the absence of ‘aura’ or accessory sensorimotor symptoms during an RCVS headache episode.
How is RCVS diagnosed?
Diagnosis of RCVS is complicated owing to the fact that it is known to be associated with specific physiological states such as post-partum status. Another factor that complicates diagnosis of RCVS is the fact that symptoms presented by patients are highly variable. A sudden headache, possibly accompanied by subdural or subarachnoid hemorrhage as well as constriction of blood vessels, are the usual symptoms of RCVS. However, in one case, a patient suffered from a thunderclap headache and yet the initial cranial angiography images showed normal circulation. The patient’s health deteriorated in the subsequent period despite normal blood flow to the brain and eventually the patient suffered an ischemic stroke and went into a coma. Although the patient eventually recovered, the presentation and progression of symptoms has been quite different from those seen in other cases of RCVS.
A pediatric case of RCVS has also been documented. Administration of Eletriptan to a 12-year-old boy resulted in a sudden headache and paralysis of limbs. Magnetic resonance imaging and magnetic resonance angiography showed constricted blood vessels in a pattern consistent with RCVS.
How is RCVS treated?
Since the exact pathophysiology of RCVS has not been deciphered completely, treatment options are limited. Drugs like nimodipene and verapamil have been used to treat RCVS. Recovery from RCVS is achieved in approximately 90% of the cases. Some people may suffer permanent neurological damage from RCVS episodes and mortality has been noted in a tiny fraction of cases.
As things stand, a sudden headache may turn out to be quite a serious health emergency.
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