Hemicrania continua is a persistent unilateral headache

Headache

A headache or cephalalgia is pain anywhere in the region of the head or neck. It can be a symptom of a number of different conditions of the head and neck. The brain tissue itself is not sensitive to pain because it lacks pain receptors. Rather, the pain is caused by disturbance of the...

 that responds to indomethacin. It is usually unremitting, but rare cases of remission have been documented. Hemicrania continua is considered a primary headache disorder, meaning that it is not caused by another condition.

Classification

International Headache Society's International Classification of Headache Disorders classifies hemicrania continua as a primary headache disorder.

Diagnostic criteria

The following diagnostic criteria are given for hemicrania continua:

1. Headache for more than 3 months fulfilling other 3 criteria:
2. All of the following characteristics:
   • Unilateral pain without side-shift
   • Daily and continuous, without pain-free periods
   • 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:
   • Conjunctival injection and/or lacrimation
   • Nasal congestion and/or rhinorrhea
     Rhinorrhea
     Rhinorrhea or rhinorrhoea is a condition where the nasal cavity is filled with a significant amount of mucous fluid. The condition, commonly known as "runny nose", occurs relatively frequently and is not usually considered dangerous. Rhinorrhea is a common symptom of allergies or certain diseases,...
     
     
   • Ptosis
     Ptosis (eyelid)
     Ptosis is a drooping of the upper or lower eyelid. The drooping may be worse after being awake longer, when the individual's muscles are tired. This condition is sometimes called "lazy eye", but that term normally refers to amblyopia...
     
      and/or miosis
     Miosis
     Miosis is the constriction of the pupil of the eye to two millimeters or less...
     
     
4. Complete response to therapeutic doses of indomethacin

A variant on hemicrania continua has also been described, in which the attacks may shift sides, although meeting the above criteria in all other respects.

Epidemiology

Hemicrania continua was first described in 1981, at that time around 130 cases were described in the literature. However, rising awareness of the condition has led to increasingly frequent diagnosis in headache clinics, and it seems that it is not as rare as these figures would imply. The condition occurs more often in women than men and tends to first present in adulthood, although it has also been reported in children as young as 5 years old.

Cause and diagnosis

The cause of hemicrania continua is unknown. There is no definitive diagnostic test for hemicrania continua. Diagnostic tests such as imaging studies may be ordered to rule out other causes for the headache. When the symptoms of hemicrania continua are present, it's considered "diagnostic" if they respond completely to indomethacin.

The factor that allows hemicrania continua and its exacerbations to be differentiated from migraine

Migraine

Migraine is a chronic neurological disorder characterized by moderate to severe headaches, and nausea...

 and cluster headache

Cluster headache

Cluster headache, nicknamed "suicide headache", is a neurological disease that involves, as its most prominent feature, an immense degree of pain in the head. Cluster headaches occur periodically: spontaneous remissions interrupt active periods of pain. The cause of the disease is currently unknown...

 is that hemicrania continua is completely responsive to indomethacin. Triptans and other abortive medications do not affect hemicrania continua.

Symptoms

In addition to persistent daily headache of HC, which is usually mild to moderate, HC can present other symptoms. These additional symptoms of HC can be divided into three main categories:

1. Autonomic symptoms:
   • conjunctival injection
   • tearing
   • rhinorrhea
   • nasal stuffiness
   • eyelid edema
   • forehead sweating
2. Stabbing headaches:
   • Short, "jabbing" headaches superimposed over the persistent daily headache.
   • Usually lasting less than one minute.
3. Migrainous features:
   • throbbing pain
   • nausea and/or vomiting
   • phonophobia
   • photophobia
     Photophobia
     Photophobia is a symptom of abnormal intolerance to visual perception of light. As a medical symptom photophobia is not a morbid fear or phobia, but an experience of discomfort or pain to the eyes due to light exposure or by presence of actual physical photosensitivity of the eyes, though the term...
     
     

Treatment

Hemicrania continua generally responds only to indomethacin 25-300 mg daily, which must be continued long term. Unfortunately, gastrointestinal side effects are a common problem with indomethacin, which may require additional acid-suppression therapy to control.

In patients who are unable to tolerate indomethacin, the use of celecoxib

Celecoxib

Celecoxib INN is a sulfa non-steroidal anti-inflammatory drug and selective COX-2 inhibitor used in the treatment of osteoarthritis, rheumatoid arthritis, acute pain, painful menstruation and menstrual symptoms, and to reduce numbers of colon and rectum polyps in patients with familial...

 400-800 mg per day (Celebrex) and rofecoxib

Rofecoxib

Rofecoxib is a nonsteroidal anti-inflammatory drug that has now been withdrawn over safety concerns. It was marketed by Merck & Co. to treat osteoarthritis, acute pain conditions, and dysmenorrhoea...

 50 mg per day (Vioxx - no longer available) have both been shown to be effective and are likely to be associated with fewer GI side effects. There have also been reports of two patients who were successfully managed with topiramate

Topiramate

Topiramate is an anticonvulsant drug. It was originally produced by Ortho-McNeil Neurologics and Noramco, Inc., both divisions of the Johnson & Johnson Corporation. This medication was discovered in 1979 by Bruce E. Maryanoff and Joseph F. Gardocki during their research work at McNeil...

100-200 mg per day (Topamax) although side effects with this treatment can also prove problematic.