Paroxysmal Hemicrania: The Essentials

When it comes to primary headache disorders, there are three categories:

1. Migraine
2. Tension-Type Headache
3. Trigeminal Autonomic Cephalagias (TAC)

Although not as common as Migraine, the TACs are characterized by severe pain and autonomic symptoms such as nasal congestion, runny nose, involuntary tears, eyelid drooping, and more. One such TAC, paroxysmal hemicrania, is often overlooked. Its symptoms are similar to the more common cluster headache, with a few exceptions. The primary difference is that paroxysmal hemicrania attacks are shorter and more frequent than cluster headache.

A closer look at paroxysmal hemicrania

• Attacks are relatively brief (<30 minutes each) and can occur up to 40 times in a single day.
• Some reports state that attacks can last up to 45 minutes, but that has not been reflected in the current diagnostic criteria.
• Otherwise, the attack symptoms are identical to cluster headache.
• Unlike cluster headache, paroxysmal hemicrania is more common in women.
• Like many other headache disorders, paroxysmal hemicrania can be either episodic or chronic.
• The episodic variety will have active periods of 7 days up to 1 year with pain-free periods of more than 1 month.
• Chronic paroxysmal hemicrania is continuous for a year or more with less than 1 month pain-free.
• To the untrained eye, it can be difficult to distinguish paroxysmal hemicrania from cluster headache.
• Attack frequency, duration, and treatment responsiveness are what set the two apart.

ICHD-3 Diagnostic Criteria:

Description:

Attacks of severe, strictly unilateral pain which is orbital, supraorbital, temporal or in any combination of these sites, lasting 2–30 minutes and occurring several or many times a day. The attacks are associated with ipsilateral conjunctival injection, lacrimation, nasal congestion, rhinorrhoea, forehead and facial sweating, miosis, ptosis and/or eyelid oedema. They respond absolutely to indomethacin.

Diagnostic criteria:

1. At least 20 attacks fulfilling criteria B-E
2. Severe unilateral orbital, supraorbital and/or temporal pain lasting 2–30 minutes
3. Either or both of the following:
   1. at least one of the following symptoms or signs, ipsilateral to the pain:
      • conjunctival injection and/or lacrimation
      • nasal congestion and/or rhinorrhoea
      • eyelid oedema
      • forehead and facial sweating
      • miosis and/or ptosis
   2. a sense of restlessness or agitation
4. Occurring with a frequency of >5 per day
5. Prevented absolutely by therapeutic doses of indomethacin
6. Not better accounted for by another ICHD-3 diagnosis.

Note:

In an adult, oral indomethacin should be used initially in a dose of at least 150 mg daily and increased if necessary up to 225 mg daily. The dose by injection is 100–200 mg. Smaller maintenance doses are often employed.

Comment:

In contrast to cluster headache, there is no male predominance. Onset is usually in adulthood, although childhood cases are reported.

Treatment

• Acute attacks will often respond to both high-flow oxygen and sumatriptan injections.
• Due to the high frequency of attacks, frequent use of triptans is discouraged and preventive treatment is required.
• Paroxysmal hemicrania responds to treatment with indomethacin, where cluster headache is rarely responsive.
• Not everyone can tolerate the side effects of indomethacin, so second-line preventives include Celebrex, verapamil, and corticosteroids.

Comorbidities Cloud the Picture

Patients with paroxysmal hemicrania may also meet criteria for trigeminal neuralgia with both attacks triggering one another. What can be even more confusing is that either of these headache disorders can occur in people with migraine. It is possible to experience attacks of paroxysmal hemicrania or cluster headache in the middle of a migraine attack, making an accurate diagnosis even more difficult.

Sources

1. International Headache Society (IHS) (2018). 3.2 Paroxysmal hemicrania. (n.d.). Retrieved April 16, 2018, from https://www.ichd-3.org/3-trigeminal-autonomic-cephalalgias/3-2-paroxysmal-hemicrania/
2. OUCH (UK). Paroxysmal Hemicrania. OUCH (UK). Retrieved online 23 Sept. 2016 at https://ouchuk.org/paroxysmal-hemicrania