Chronic Paroxysmal Hemicrania

Updated: Jun 12, 2019
  • Author: Monica Saini, MD, MBBS, MRCP(UK); more...
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Chronic paroxysmal hemicrania (CPH), also known as Sjaastad syndrome, was first described in 1974, by Sjaastad and Dale. [1] In 1976, the term CPH was proposed by Sjaastad on the basis of the first 2 patients, who had daily (ie, chronic), solitary, limited attacks (ie, paroxysmal) of unilateral headache that did not shift sides (ie, hemicrania). [2]

CPH falls under the Trigeminal Autonomic Cephalalgias (TACs); it accounts for about 3%–8% of TACs and is much less common than cluster headache (CH). [3] (See Presentation.)

The short-lasting primary headache syndromes may be divided into (1) headaches with autonomic activation and (2) headaches without autonomic activation. Headaches with autonomic activation include chronic and episodic paroxysmal hemicrania, CH, and short-lasting unilateral neuralgiform headache with conjunctival injection and tearing (SUNCT syndrome). (See Etiology and DDx.)

Diagnostic criteria

In the current International Classification of Headache Disorders (ICHD-3), TACs include cluster headache (CH), paroxysmal hemicrania (PH), and the short-lasting unilateral neuralgiform headache attacks (SUNHAs). [4]

ICHD-3 diagnostic criteria for PH include the following:

A. At least 20 attacks of headache fulfilling criteria B–E

B. Severe unilateral orbital, supraorbital and/or temporal pain lasting 2–30 minutes

C. Either or both of the following:

  1. at least one of the following symptoms or signs, ipsilateral to the headache: a) conjunctival injection and/or lacrimation, b) nasal congestion and/or rhinorrhoea, c) eyelid oedema, d) forehead and facial sweating, e) miosis and/or ptosis
  2. a sense of restlessness or agitation

D. Occurring with a frequency of >5 per day

E. Prevented absolutely by therapeutic doses of indomethacin

F. Not better accounted for by another ICHD-3 diagnosis

Chronic versus nonchronic

PH may be present in nonchronic or chronic form, although the chronic type is 4 times more common. Approximately 65%–85% of patients with PH have the chronic form. [5]

Nonchronic attacks are similar to chronic ones but tend to be less severe and less frequent. (See Prognosis.)

Before the development of chronic symptoms, many patients (42%) pass through a nonchronic stage, with attacks separated by intervals of complete remission.

The term pre-CPH stage or prechronic was preferred initially on the basis of the assumption that all patients would develop chronic symptoms. However, approximately 20% of patients appear to remain in the nonchronic stage for long periods.

ICHD-3 diagnostic criteria for CPH are as follows: [4]

A. Attacks fulfilling criteria for Paroxysmal hemicrania, and criterion B below

B. Occurring without a remission period, or with remissions lasting < 3 months, for at least 1 year



The mechanisms responsible for pain in CPH remain unknown. The past medical history in patients with CPH is usually unremarkable. A history of head or neck trauma is reported in about 20% of cases, but these findings are similar to those for CH or migraine.

Occasionally, attacks may be provoked mechanically by bending or rotating the head and by applying external pressure against the transverse processes of C4-C5, C2 root, or the greater occipital nerve.

No familial disposition is known for CPH; families of affected individuals do not have higher incidences of CH or migraine than does the general population.

Discussion of important features, such as intense, unilateral headache; autonomic abnormalities; and effectiveness of indomethacin, may help in understanding the pathogenesis. [6]

Trigeminal, sympathetic, and parasympathetic involvement

The release of trigeminal and parasympathetic neuropeptides during headache has been described. [7] Activation of the ipsilateral trigeminovascular system may explain sudden, unilateral headache and may lead to miosis, increased intraocular pressure (IOP), and other autonomic abnormalities.

Increased sweating and decreased salivation during attacks and the ability of an alpha-blocking agent or a stellate ganglion blockade to inhibit an increase in IOP suggest sympathetic involvement.

Increased tearing, nasal secretion, and miosis may be due to parasympathetic stimulation. Trigeminoparasympathetic activation during CPH attacks has been suggested; increases in the vasoactive intestinal peptide (ie, parasympathetic peptide) level have been reported. levels of calcitonin gene-related peptide also are reported to be high during CPH attacks.

Pain and pressure threshold, nociceptive flexion reflex, and blink and corneal reflexes have been studied in patients with CPH. The corneal reflex thresholds have been found to be decreased bilaterally during CPH attacks. Increases in corneal temperature on the symptomatic side also have been reported; this finding may be due to increased ocular blood flow.

The effectiveness of indomethacin in CPH may be due partly to reduction of intracranial blood flow (via a nonprostaglandin mechanism) and partly to the drug’s anti-inflammatory effects.

These findings may indicate a primary central mechanism and a secondary involvement of peripheral factors, affecting the sympathetic and parasympathetic systems.

Hypothalamic involvement

Studies have suggested a crucial role by the hypothalamus in CPH. Functional neuroimaging studies have demonstrated activation of the hypothalamus in cases of trigeminal autonomic cephalgias. [8, 9]



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%.

International occurrence

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. [10]

CPH can occur at any age, with the mean age of onset being 34 years. [11] Patients as young as age 6 years have been described in the literature, while the oldest known patient with CPH was age 81 years. [12, 13] 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. [14, 15]



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