What is hemicrania continua (HC)
Hemicrania continua (HC) is a rare disorder that may have a prevalence of up to 1% of the population. HC is more common in females than males, 1.6:1. The onset is often during the third decade of life with a range from the first to seventh decades.
The pain is strictly unilateral most commonly in the orbital, frontal, and temporal areas but can be occipital or other areas of the head or neck. The pain can be mild to severe throbbing or sharp.
The pain is typically constant, but 20% have pain-free periods for 1 day to several months. Exacerbations occur in 75% of patients and typically last 20 minutes to several days.
The pain can be associated with nausea, vomiting, light and noise sensitivity, and rarely a visual aura.
Cranial autonomic symptoms, most commonly tearing and conjunctival injection, occur in 75% of patients.
HC is a mimic of chronic migraine.
5 Interesting Facts of Hemicrania Continua
- Headache is unilateral, continuous, moderately intense, and occurs daily; also includes episodes of occasional short, piercing head pain
- Lasts 3 months or longer without shifting sides or pain-free periods 2
- Involves at least 1 of the following:
- Eye redness and/or lacrimation
- Nasal congestion and/or rhinorrhea
- Ptosis and/or miosis
- Completely responsive to treatment with indomethacin
- Differentiated based on history and physical examination
How is Hemicrania continua treated?
HC is defined by the fact that is resolves completely with indomethacin.
One regimen is the following: 25 mg three times a day for 3 days, subsequently increasing, if ineffective, to 50 mg three times a day for a further 3 days and then, if ineffective, to 75 mg three times per day for 3 days.
The lowest effective dose is continued. Because of the risk of gastroduodenal mucosal injury, indomethacin is typically taken with a proton pump inhibitor.
For those who cannot tolerate indomethacin, other treatments, although much less effective, include topiramate, melatonin 6 to 12 mg at bedtime, verapamil, and gabapentin.