St. Paul, Minn. – Newly revised criteria for diagnosing headaches reflects a better understanding of some disorders and the identification of new ones, according to a special article published in the “Views & Reviews” section of the August 10 issue of Neurology, the scientific journal of the American Academy of Neurology. Some of the new additions are chronic migraine, hypnic headache and hemicrania continua.
The criteria of the International Headache Society (IHS) have been an accepted diagnostic standard since the first edition appeared in 1988. In “Views & Reviews” an international group of headache specialists recapped the second edition of The International Classification of Headache Disorders that was released earlier this year.
“We believe that having well-specified consensus criteria will provide a firm foundation for improving diagnosis and treatment,” said article author Richard B. Lipton, MD, a neurologist at Albert Einstein College of Medicine in Bronx, N.Y. “A number of clinically important, treatable and previously undefined disorders were added.”
Primary headaches – whose diagnoses require the exclusion of any other disorder that might be the cause of the headache – are divided into four categories: migraine, tension-type headache, cluster headache and other primary headaches. Each category is further broken into subtypes. In the second edition, migraine added a subtype for “chronic migraine,” defined as a migraine lasting 15 or more days per month for three or more months, without medication overuse.
Tension-type headache – the most common primary headache – was revised into three subtypes: infrequent episodic, frequent episodic and chronic. Unlike migraine, tension-type headache is characterized as non-pulsating, mild-to-moderate intensity and no aggravation by routine activity.
Trigeminal autonomic cephalalgias (headaches involving the trigeminal nerve) were added to cluster headache in the second edition. Cluster headache is characterized by sharp, drilling or stabbing pain. Also added was episodic paroxysmal hemicrania, which consists of at least 20 severe yet brief attacks in the span of a few days, followed by an attack-free interval of one month or more.
The miscellaneous category for other primary headaches introduced hypnic headache (short-lived attacks of nocturnal head pain), primary thunderclap headache (severe, abrupt pain similar to a brain aneurysm) and new daily-persistent headache (daily, constant headache present for more than three months).
“Chronic daily headache” is excluded from the revised edition. To classify chronic daily headache, one option is the Silberstein and Lipton criteria which divide the syndrome into transformed migraine (similar to chronic migraine in the IHS second edition), chronic tension-type headache, new daily-persistent headache and hemicrania continua (continuous pain in one side of the head).
The authors also outline a diagnostic “algorithm,” or step-by-step procedure, based on frequency and duration of headaches. The first step is to determine whether a secondary headache is present (due to another underlying disorder).
“If there is no secondary headache, the physician can proceed to diagnosing a primary headache disorder,” said Lipton, who chaired the migraine subcommittee of the revised edition. “Is the headache frequency low to moderate or high, meaning 15 days or more per month? Does the headache last less than four hours or more? Is there a trigger such as coughing or physical exertion?”
In addition, a system for recognizing the importance of genetics was incorporated so that a disorder like familial hemiplegic migraine can now be defined in terms of specific genetic mutations, Lipton noted.
The classification committee of The International Classification of Headache Disorders was chaired by Jes Olesen, MD, PhD, of Glostrup Hospital in Copenhagen, Denmark. The second edition is available on the IHS Website at www.i-h-s.org.
The American Academy of Neurology, an association of more than 19,000 neurologists and neuroscience professionals, is dedicated to improving patient care through education and research. A neurologist is a doctor with specialized training in diagnosing, treating and managing disorders of the brain and nervous system such as stroke, Alzheimer's disease, epilepsy, Parkinson's disease, autism and multiple sclerosis.
For more information about the American Academy of Neurology, visit www.aan.com.
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