Clinical Syndrome

Hemicrania continua is a primary headache disorder that is classified as a trigeminal autonomic cephalgia that shares characteristics of both cluster headache and migraine headache ( Table 4.1 ). Similar to cluster headache, hemicrania continua is a severe, unilateral headache with associated signs of autonomic dysfunction, including lacrimation, scleral injection, eyelid ptosis, and nasal stuffiness syndrome ( Fig. 4.1 ). In contrast to cluster headache, which occurs 10 times more commonly in men, hemicrania continua occurs more commonly in women, a characteristic it shares with migraine. Like migraine headache, hemicrania continua is associated with nausea and vomiting, as well as sonophobia and phonophobia. Unlike the pain of cluster and migraine headache, the pain of hemicrania continua is continuous with intermittent severe exacerbations of pain. This pain is unilateral and is side locked (i.e., it does not change sides like migraine headache occasionally does). Hemicrania continua is an indomethacin responsive headache, with complete resolution of headache and associated symptoms with therapeutic doses of indomethacin. The cause of hemicrania continua is unknown, but like other trigeminal autonomic cephalgias, functional magnetic resonance scanning and positron emission tomography reveal activation in the posterior hypothalamus during exacerbation of headaches.

Hemicrania continua is a unilateral side-locked headache with associated signs of autonomic dysfunction. In contrast to cluster headache, which occurs primarily in men, hemicrania continua occurs primarily in women.

Signs and Symptoms

During attacks of hemicrania continua, patients exhibit the following physical findings suggestive of Horner syndrome on the ipsilateral side of the pain:

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  Conjunctival and scleral injection

  
  
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  Lacrimation

  
  
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  Nasal congestion

  
  
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  Rhinorrhea

  
  
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  Ptosis of the eyelid

As in cluster headache, the patient may become agitated during attacks, rather than seeking dark and quiet as does the patient with migraine. In contrast to cluster headache, alcohol consumption does not seem to trigger attacks of hemicrania continua. Between attacks, the neurological examination of a patient with hemicrania continua should be normal.