Chronic Paroxysmal Hemicrania (CPH)
CPH may be a variation on chronic cluster headache, but this remains unclear.
CPH has a female-to-male ratio of 3:1, with a typical onset from age 25 to
35. The pain is usually about the ophthalmic division of the trigeminal nerve,
concentrated around the eye, temple, and forehead. However, pain may occur
in the occiput or periaural areas. While almost exclusively unilateral, there
have been rare instances of bilateral pain. The attacks last from 2 to 45
minutes, with a frequency of 5 to 20 or more per day. The usual attack lasts
from 10 to 15 minutes. Occasionally, head movement or mechanical stimulation
may precipitate the pain. The pain is associated with at least one of the
following: conjunctival injection, lacrimation, nasal congestion, rhinorrhea,
ptosis, or eyelid edema. Except for the ptosis, these are mediated by
parasympathetic nerves. The pain tends to be very severe, and is usually
stabbing or severely aching. However, at the beginning of the headache, it
may be throbbing. There is no clear increase at one particular time of day,
and CPH may awaken patients from sleep. In the unusual situation where there
is a break of at least a few months (or possibly years), we would term it
episodic paroxysmal hemicrania.
Since CPH is rare, a workup to exclude secondary causes may be appropriate.
These would include tumors, collagen vascular disease, cerebrovascular disease,
and an aneurysm. MRI and MRA, along with routine lab tests including the
sedimentation rate, would be prudent. If extremely high doses of medication
are required, we think about secondary causes of CPH. With bilateral CPH,
intracranial hypertension may need to be excluded by a lumbar puncture (LP).
In very rare circumstances, a chest x-ray may be necessary to discover a
Pancoast tumor as the cause of the CPH. Arteriovenous malformations (AVMs)
have been reported to be a secondary cause of CPH.
Medication Treatment of CPH
CPH is almost always relieved by indomethacin (Indocin). If indomethacin
does not help, the diagnosis of CPH is in doubt (although it still could
be CPH). The dose of indomethacin varies greatly with some patients requiring
as little as 25mg per day and others needing 250mg or more. Although the
Indocin SR 75mg renders dosing more convenient, the 25 or 50mg capsules,
taken throughout the day, may be more effective. Patients may titrate their
own dose, for at times the attacks may decrease in severity. Usually, when
Indocin is tapered or stopped, the attacks resume, but long term remissions
may occur. Indomethacin should be taken with food, as GI upset is very common.
Although headache may occur as a side effect of indomethacin, it is not common
in patients with preexisting headaches. Cognitive side effects, such as fatigue,
lightheadedness, and mood swings, may be a problem with indomethacin. Retinal
or corneal problems have been reported with long term us of indomethacin.
As with all of the anti-inflammatories, renal and hepatic functions need
to be monitored through blood tests. Tachyphylaxis does not usually occur
with indomethacin.
Corticosteroids, naproxen, and calcium blockers (verapamil) may provide some
benefit, but these have limited usefulness in CPH. Acetazolamide may be of
benefit in some patients. The triptans do not appear to be particularly effective
for CPH.
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