Migraine Comorbidity or Alternative Diagnosis — Hemicrania Continua

Think you have chronic Migraine? You might not…

There are times when diagnosing Migraine can be difficult. There are more than 300 different possible headache diagnoses. That’s a lot to consider for every patient walking into an office.

Our physicians always try to consider alternative diagnoses when patients come to their office with symptoms of Migraine Disease, and when unilateral chronic or intractable Migraine, chronic daily headache (CDH), new daily persistent headache (NDPH) or a trigeminal autonomic cephalalgia seems a possible culprit, it’s the wise physician who also considers and rules out a primary headache disorder called hemicrania continua.

If you have a current diagnosis of chronic or intractable Migraine, has your doctor talked to you about hemicrania continua? When hearing hoofbeats, sometimes it is not a horse but a zebra. Sometimes, it is even a unicorn.

What is Hemicrania Continua?

Hemicrania continua (HC) is a single-sided headache that does not go away and that rarely if ever changes sides, most often presenting with autonomic symptoms such as tearing or a runny nose that coincide with flares of increased pain activity. Unlike Migraine, patients often are agitated and active during their severe pain exacerbations, often even becoming verbally abusive. HC is said to be a cross-over between cluster headache (aka “suicide headaches”) and Migraine.

HC is uncommon, but cases of confusing headache diagnoses were presented and physicians were reminded at the 2011 Scottsdale Headache Symposium that HC is probably not nearly as rare as once thought, but actually very under-diagnosed.

In fact, in a recent study of 25 HC patients, not one had been appropriately diagnosed before going to the headache center, even though 85% of them had seen a physician within 6 months of the onset of their symptoms. Unfortunately, it takes the average HC patient years and several physicians to get an appropriate diagnosis.

Appropriate diagnosis is critical because hemicrania continua is very successfully treated with one particular medication — a prescription NSAID – which can be life changing for the patient who has most often endured years of nearly constant pain and disability.

The (IHS) International Headache Society’s ICHD-II (International Classification of Headache Disorders most recent version) uses the following criteria for hemicrania continua diagnosis:


Persistent strictly unilateral headache responsive to indomethacin.

Diagnostic criteria:

  1. Headache for >3 months fulfilling criteria B-D
  2. All of the following characteristics:
    1. unilateral pain without side-shift
    2. daily and continuous, without pain-free periods
    3. moderate intensity, but with exacerbations of severe pain
  3. At least one of the following autonomic features occurs during exacerbations and ipsilateral to the side of pain:
    1. conjunctival injection and/or lacrimation
    2. nasal congestion and/or rhinorrhoea
    3. ptosis and/or miosis
  4. Complete response to therapeutic doses of indomethacin
  5. Not attributed to another disorder

It is noted in ICHD-II that HC may rarely remit, but is usually continual.

There is also question whether the condition may be further subdivided. ICHD-III is due out in the next couple of years and it looks like change is in the air. It will be interesting to see if (how) the IHS changes the way we currently diagnose HC. Here is more information on changes that are being discussed.

Treating HC

HC is considered completely (100%) responsive to therapeutic doses of a drug called indomethacin. Indomethacin is a potent NSAID with powerful anti-inflammatory and other properties. Its chemical makeup is close to that of the brain chemical melatonin. In fact, some patients who may not tolerate the significant side effect profile of indomethacin may in fact be responsive to melatonin either in conjunction with decreased doses of, or in place of indomethacin.

It’s interesting to note that there can be a lag time after beginning treatment and before the indomethacin is effective, and physicians are encouraged not to be shy about using a higher than *normal* dosage to be sure the trial is sufficient before ruling HC out.

Because of HC’s responsiveness to indomethacin, many headache specialists choose a clinical trial of a therapeutic dose (often suggested to be 75 mgs) of the drug in patients they suspect may have HC or a similar presenting condition such as chronic Migraine or chronic daily headache.

Indomethacin is known to cause significant gastric and other side effects.

Additionally, for patients with gastric stasis symptoms, absorption may be a problem. Headache specialists will often suggest patients bypass the oral route normally used for indomethacin, prescribing compounded suppositories to use in place of oral tablets. Injections are also available, but much less frequently utilized often due to cost, availability and patient compliance. Bypassing the oral route unfortunately does not eliminate gastric side effects, but they can often be proactively treated with prescription and/or OTC medications when indomethacin treatment is started.

Start a conversation with your doctor

Migraine (and chronic Migraine) is a diagnosis of exclusion, and because of its disabling nature, excluding an indomethacin responsive headache disorder like HC is something that should be done to be sure patients are receiving appropriate treatment. Most headache specialists are aware of this and are prepared to help their patients try the drug, however non headache specialists are often too quick to diagnose other chronic conditions or psychological disorder in the absence of such a test, to the detriment of their often disabled patients.

Proactive patients with chronic, intractable (does not respond to treatment) unilateral (one side only, with no side shift) headache, especially with autonomic features such as tearing or runny nose, will want to be sure to educate themselves about HC and use this information to begin a conversation with their physician.

This article represents the opinions, thoughts, and experiences of the author; none of this content has been paid for by any advertiser. The Migraine.com team does not recommend or endorse any products or treatments discussed herein. Learn more about how we maintain editorial integrity here.
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