ARTICLE IN BRIEF:
A team of experts has established a new set of criteria and a scoring system for diagnosing reversible cerebral vasoconstriction syndrome, a group of conditions involving rapidly changing, reversible narrowing and dilatation of the segmental cerebral artery.
A set of five straightforward diagnostic criteria, summed up in an easy-to-remember mnemonic, has strong sensitivity and specificity in differentiating reversible cerebral vasoconstriction syndrome (RCVS) from other large/medium-vessel intracranial arteriopathies with which it is easily confused. The criteria are described in a new study from a team of experts at Massachusetts General Hospital, Federal University of Sao Paulo, Brazil, and Hacettepe University in Ankara, Turkey, appearing in the January 11 edition of Neurology.
A group of conditions involving rapidly changing, reversible narrowing and dilatation of the segmental cerebral artery, RCVS is often characterized by the sudden onset of recurrent, severe, and often disabling headaches known as “thunderclap” headaches (TCH). While more than 90 percent of patients ultimately have a benign clinical outcome, RCVS is associated with both hemorrhagic and ischemic strokes.
The syndrome can appear clinically and angiographically similar to other arteriopathies, including Moyamoya disease, premature atherosclerosis, and primary angiitis of the central nervous system (PACNS), the authors of the study noted. Differentiating RCVS from these other conditions is important because of key differences in treatment. The most similar appearing mimic, PACNS, is a rare and complex form of vascular inflammatory disease typically treated with a combined course of immunotherapy that includes oral corticosteroids. But in patients with RCVS, glucocorticoid treatment has been found to be an independent predictor of clinical deterioration, according to a 2017 study published in Neurology.
“With RCVS, it's important to make proper a diagnosis up front. Traditionally people have often waited for disease evolution to confirm the diagnosis based on reversibility of angiographic abnormalities over two to three months,” said study author Aneesh Singhal, MD, FAAN, vice chair of the department of neurology at Massachusetts General Hospital. “But this approach allows us to make the diagnosis at the bedside with very high confidence, allowing us to avoid inappropriate treatment as well as unnecessary invasive tests such as intra-arterial catheter angiogram, cerebrospinal fluid studies, or even open brain biopsy.”
The mnemonic, RCVS2, stands for Recurrent or single TCH; Carotid (intracranial) artery involvement; Vasoconstrictive trigger; Sex; and Subarachnoid hemorrhage, with points for each that can total a score ranging from –2 to +10.
Study Methodology, Findings
In the new study investigators retrospectively compared the data from 110 consecutive patients from their institutional databases with newly diagnosed RCVS (30) or non-RCVS (80) arteriopathies. They found that a score of ≥5 had 99 percent specificity and 90 percent sensitivity for diagnosing RCVS, while a score of ≤2 had 100 percent specificity and 85 percent sensitivity for excluding RCVS. Scores 3-4 had 86 percent specificity and 10 percent sensitivity for diagnosing RCVS.
“The 86 percent specificity of the intermediate 3-4 scores is not bad by itself,” Dr. Singhal said. “But when we combined those scores with a clinical approach based on recurrent thunderclap headaches, trigger and normal brain scans, or convexity subarachnoid hemorrhage, we were able to correctly diagnose 25 of 37 patients with a 3-4 score.”
The new set of criteria won't surprise anyone with expertise in the field, said David W. Dodick, MD, FAAN, professor of neurology at the Mayo Clinic in Phoenix, AZ, who is the chairman of the American Migraine Foundation and the president of the International Headache Society. “This is intuitive; it has face validity for me because it's exactly the sort of informal system and clinical attributes that I've used in clinical practice to distinguish these syndromes for quite some time now,” he explained. “This tool, with its high sensitivity and specificity, is going to help a lot of clinicians who aren't experts — internists, emergency physicians, interventionalists — reduce the number of false positives and false negatives that currently happen frequently in general clinical practice.”
Dr. Dodick also praised the easy to recall mnemonic design that matches the name of the condition itself, an idea Dr. Singhal credits to co-author Eva Rocha, MD, of the University of Sao Paulo.
Steven R. Messe, MD, FAAN, FAHA, associate professor of neurology at the University of Pennsylvania and director of its vascular neurology fellowship program, praised the tool as “very worthwhile,” noting Dr. Singhal's leadership in understanding the diagnosis of RCVS and differentiating it from other arteriopathies.
“The only caveat I would raise is that the confirmatory cohort of 110, including only 30 patients with RCVS, is fairly small,” he said. “But prior publications also came to the same conclusions about which variables are important. Putting those variables together into this rule, with a score that you can easily calculate and come up with a likelihood of RCVS versus another arteriopathy, will be very helpful in clinical practice.”
One diagnostic challenge posed by RCVS, Dr. Dodick noted, is that about 20-25 percent of patients who present with what turns out to be RCVS will have no initial abnormalities on angiography, especially noninvasive imaging such as CT and MR angiography, which is typically used upon first presentation.
“If a patient presents with recurrent thunderclap headaches, initial CT and magnetic resonance angiography findings could be negative even if they have RCVS, because the cerebral artery involvement doesn't always manifest initially,” he said. “Unless you do the appropriate investigation or have an index of suspicion that this could be RCVS, you may discharge this patient. Many of the complications that these patients experience, such as brain edema, brain hemorrhage, and ischemic stroke, typically occur within the first two weeks as vasoconstriction progresses. If someone shows up in the emergency department with a thunderclap headache but they look fine on a CT scan, which almost inevitably they will, the doctor is likely to let them go, and they may show up a week or so later with an intracranial hemorrhage or ischemic stroke based on this missed diagnosis. This diagnostic tool can help avoid that.”
And it doesn't require any costly imaging tests or complicated training. “In medicine we can overdo the use of highly advanced technology,” said Dr. Singhal. “It's even been suggested that patients with suspected RCVS should be subjected to catheter angiography with injection of vasodilators to see if the arteries open up in order to establish the diagnosis. But all that can be easily avoided based on this simple bedside scoring system.”
Dr. Singhal has received an honoraria from UptoDate, Inc. and Medlink, and he has received consultant fees as a medicolegal expert witness. Dr. Messe has consulted with Clare Medical, Inc. on an embolic protection device used in transcatheter aortic valve replacement.