PARIS — A severe headache with near-instantaneous onset—a “thunderclap” headache—is likely to represent a reversible cerebral vasoconstrictive process rather than central nervous system vasculitis, Dr. Leonard H. Calabrese said at the annual European Congress of Rheumatology.
The reversible cerebral vasoconstriction syndrome (RCVS) has been associated with a variety of conditions, including pregnancy, head trauma, and exposure to drugs such as nasal decongestants, selective serotonin reuptake inhibitors, and cannabis.
“RCVS can be readily diagnosed if you understand the clinical picture, but despite remarkable progress in understanding this condition in the past 5 years, it is still misdiagnosed and mismanaged as CNS vasculitis,” said Dr. Calabrese, who holds the R.J. Fasenmeyer Chair of Clinical Immunology at the Cleveland Clinic.
CNS vasculitis requires a brain biopsy for diagnosis, and treatment involves extended immunosuppression. Neither is typically necessary in RCVS.
The rapid-onset headache of RCVS, developing over 1-2 minutes, is the hallmark of the condition and can occur with or without other neurologic signs and symptoms. It is more common in women and often develops in the wake of sexual activity, exercise, coughing, or the Valsalva maneuver and is “the worst headache of the patient's life,” he said.
Headache associated with CNS vasculitis, in contrast, is indolent and progressive and typically is associated with episodes of neurologic dysfunction.
Angiographic findings in the two conditions can be indistinguishable, with multiple areas of stenosis and beading, but the abnormalities are reversible, usually within 3 months, in RCVS.
In contrast, although few follow-up angiographic studies have been done in patients with CNS vasculitis, the data that exist suggest that resolution does not occur.
Analysis of spinal fluid is essential for the patient with thunderclap headache to rule out not only CNS vasculitis but also subarachnoid hemorrhage. The fluid should be within normal limits, with only a few cells and a little protein, Dr. Calabrese said.
“However, we do not advocate biopsy with the classic presentation of RCVS—female patients, pristine spinal fluid, and thunderclap headache,” he said.
But if the pretest probability for RCVS is low and vasculitis seems more likely, with a more insidious onset of headache, abnormal spinal fluid, or other abnormalities such as elevated acute phase reactants, biopsy may be warranted.
The headache associated with RCVS can abate but may recur within a week or two, and unfortunately may be accompanied by stroke, seizures, or other sequelae, he said.
In one recent prospective series of 67 patients, complications included cortical subarachnoid hemorrhage in 22%, intracerebral hemorrhage in 6%, and reversible posterior leukoencephalopathy in 9% (Brain 2007;130:3091-4101). Treatment thus far has been guided by observational data and experience, because no trials of any therapy have been conducted. “Some patients have recovered with no treatment whatsoever, but we often use calcium channel blockers, in conjunction with glucocorticoids if stroke is present,” he said.
The reason for using glucocorticoids in RCVS—which is not an inflammatory condition, but rather is thought to be an endothelial disease with increased expression of adhesion molecules—is that in experimental models of induced vasoconstriction, their use represents the most potent pharmacologic intervention, he explained.