Occurrence in the United States
CPH is a rare syndrome, but the number of diagnosed cases is increasing. The prevalence of CPH is not known, but the relative frequency compared with CH is reported to be approximately 1-3%.
Many cases of CPH have been described throughout the world, in different races and in different countries, including Australia, the Czech Republic, Slovakia, Denmark, Italy, France, Mexico, Canada, Sweden, Germany, Poland, India, Spain, Brazil, South Africa, Norway, New Zealand, the United Kingdom, and the United States.
Sex- and age-related demographics
In the past, because of a female preponderance, CPH was considered a disease of women. However, CPH has been reported in increasing numbers of men. A study conducted in 1979 reported a female-to-male ratio of 7:1, but a review of 84 patients in 1989 reported a female-to-male ratio of 2.3:1. A more recent prospective study of 31 patients found a female-to-male ratio of 1:1.
CPH can occur at any age, with the mean age of onset being 34 years. Patients as young as age 6 years have been described in the literature, while the oldest known patient with CPH was age 81 years. In one report, CPH beginning at age 3 years was described; however, the condition may have been related to ipsilateral occipital hemorrhagic infarction in this patient.
Patients in the nonremitting stage of CPH may need lifelong therapy, possibly with smaller doses of indomethacin.
Long-lasting remission periods usually reflect a nonchronic stage, but they may occur in patients with established chronic disease. In chronic cases, in fact, recurrence of attacks after a drug-free period of 1.5 years has been reported.
The mortality rate and morbidities associated with CPH have not been reported, although the therapy of choice for this condition, indomethacin, is known to be associated with the risk of bleeding.
Factors that may or may not affect the course of CPH include the following:
- Pregnancy – CPH attacks have been reported to improve during pregnancy; however, they recur after delivery
- Menstruation – Menstruation may have either a positive or negative effect on attacks
- Birth control – Birth control pills do not seem to influence attack frequency
- Menopause – Reliable data do not exist regarding the effects of menopause on CPH
The pain in chronic paroxysmal hemicrania (CPH) is characteristically unilateral. However, pain may switch sides between attacks and can rarely be bilateral.
Patients usually report pain that is severe in intensity and has an abrupt onset and cessation. During severe attacks, excruciating pain that is throbbing, boring, pulsating, or clawlike in character has been described. The location of pain is primarily in the distribution of the ophthalmic division of the trigeminal nerve and C2, followed by the maxillary-mandibular and C3 distributions. Accompanying photophobia and phonophobia has been reported, usually lateralizing to the side of the pain. Occasionally, patients may experience nausea, though vomiting is rare. In 50%–80% of patients, agitation or restlessness may be noted.
Headache can develop at any time in patients with CPH, in contrast to CH, in which the headache usually occurs at night.
The attack frequency usually is 10–20 attacks daily, but it may range from 2 to 40 attacks daily. Attacks usually last 2–25 minutes, but they may last as long as 60 minutes. In a prospective study, mean attack duration was 13 minutes (range 3–46 min). In a retrospective study, the mean duration of attacks was 21 minutes (range 2–120 min).
CPH has been reported to be triggered by various stimuli, including neck movement, external pressure to the neck, or other factors.
CPH attacks are accompanied by autonomic symptoms, mostly on the same side as the pain, such as red eyes, tearing, nasal congestion, and, sometimes, rhinorrhea. Occasionally, photophobia may be present. Gastrointestinal symptoms are very rare.
Recognizing the various stages and different patterns of CPH is important. For example, during severe, frequent attacks, patients may describe a constant headache or persisting tenderness on the symptomatic side.
The pain is severe in patients with CPH, and attacks are associated with autonomic features, such as the following:
- Lacrimation – 62%
- Conjunctival injection – 36%
- Ipsilateral nasal congestion – 42%
- Rhinorrhea – 36%
- Eyelid edema – 33%
Lacrimation may occur bilaterally but is always more marked on the symptomatic side. Occasionally, mild ipsilateral miosis may be observed during attacks.
Patients with CPH who have had dissociation in pain and autonomic features also have been described. Other points to consider in the physical examination include the following:
- No definite evidence points to a Hornerlike syndrome, such as that described in cluster headache (CH), but mild miosis and eyelid edema that may mimic ptosis may be observed
- Forehead sweating may increase on the ipsilateral side, and patients with generalized sweating have been reported
- The coexistence of CPH and trigeminal neuralgia is called CPH-tic syndrome; many cases of this syndrome have been reported
- Simultaneous occurrence of ipsilateral CH and migraine headache in patients with CPH has been reported
- PH has been reported to co-occur with primary cough and stabbing headache, which are also indomethacin-sensitive
- Perform a careful physical examination to evaluate pathologic secondary headache
More in next chapter …