Definition and Overview
Paroxysmal hemicrania is a type of trigeminal autonomic cephalalgia. It is a headache with short and frequently repeated attacks of severe pain in one orbital region, above the eye, and in the temporal region. Attacks last 2-30 minutes and are repeated five or more times a day.
It has clinical features similar to cluster headaches, but is distinguished by its shorter and more frequent attacks and its absolute response to indomethacin. In one prospective study, the proportion of female patients was reported to be more than half, showing a difference from cluster headache, which is common in men.
symptoms
headache attack
- Attack duration: 2 to 30 minutes.
- Attack frequency: 5 or more times a day, occurring more than half of the days
- Pain location: One side of the orbit, above the eye, temporal area
- Pain pattern: Sharp, stabbing or throbbing pain.
Autonomic symptoms (ipsilateral)
During the attack, ipsilateral conjunctival injection, tearing, stuffy or runny nose, ptosis, miosis, and eyelid edema are present.
Classification
Paroxysmal hemicrania is classified according to the attack pattern as follows:
- Episodic paroxysmal hemicrania: repeated attacks and relief periods
- Chronic paroxysmal hemicrania: attacks that last for more than a year without relief
Differentiation from cluster headache
Paroxysmal hemicrania has a shorter attack time (2 to 30 minutes) than cluster headache (15 minutes to 3 hours), and has more attacks per day. The critical difference is the response to indomethacin: paroxysmal hemicrania fully responds to indomethacin, whereas cluster headache does not. Drug reactivity serves as a diagnostic clue to distinguish between the two diseases.
diagnosis
The diagnosis is a clinical diagnosis according to the International Classification of Headache Disorders, Third Edition (ICHD-3) criteria. Diagnostic criteria include unilateral attacks lasting 2 to 30 minutes, ipsilateral autonomic symptoms, a attack frequency of five or more per day, and complete response to therapeutic doses of indomethacin.
Brain MRI is recommended to rule out secondary causes, such as pituitary lesions.
treatment
indomethacin
Indomethacin is the first-line treatment and serves both diagnosis and treatment. Maintain the lowest dose that completely controls attacks.
Side Effect Management
Indomethacin is a non-steroidal anti-inflammatory drug with a risk of gastrointestinal bleeding, gastric ulcer, and decreased renal function. When taking it for a long time, use a gastroprotective agent such as a proton pump inhibitor and check renal function periodically.
Clinical implications
If short, frequent unilateral attacks are accompanied by ipsilateral autonomic symptoms, paroxysmal hemicrania should be suspected and a trial of indomethacin should be considered. Indomethacin responsiveness is a key clue in differentiating it from cluster headache, so it is important to test with sufficient dose and duration.