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Paroxysmal hemicrania (PH) is a primary headache disorder characterized by multiple attacks of unilateral pain that occur in association with cranial autonomic symptoms. The hallmarks of this syndrome are the relative shortness of the attacks and the complete response to indomethacin therapy.
- Synonym(s): -
- Prevalence: 1-9 / 100 000
- Inheritance: -
- Age of onset: Adult
- ICD-10: G44.0
- OMIM: -
- UMLS: C1399352
- MeSH: D051302
- GARD: 10794
- MedDRA: 10019461
The prevalence is estimated to be 1:50,000, with a mean age of onset of 40 years (range 5-68 years) and a slight female predominance (in initial reports) or male-to-female ratio of 1:1.
Most patients (>60%) describe the pain as severe to very severe, rating it at 10 on a verbal rating scale of 0-10. The pain has a temporal, orbital or supraorbital localization. In rare cases, the pain may involve other areas of the face, head or neck. Accompanying ipsilateral autonomic features include lacrimation, conjunctival injection, rhinorrhea, nasal congestion, ptosis and facial flushing. Unilateral phono- and photophobia are frequent. Osmophobia, nausea or vomiting during the attacks has been reported. The attacks are triggered by stress or relaxation after stress, agitation, exercise, alcohol, neck movement, environmental temperature changes, and dietary products (cheese, chocolate, and coffee). The duration of attacks ranges from 2-30 minutes. Attacks usually have a frequency of above five per day (with a mean of 20 attacks per day). In 80% of patients, the disease is described as chronic (when patients have daily attacks without remission for at least one month). As a rule, patients with PH have normal neurological tests. PH has been reported in association with migraine, cluster headache, trigeminal neuralgia and cough headaches.
Etiopathology remains unclear. Trauma, arteriovenous malformations and pituitary adenomas may play a causative role.
Diagnosis is clinical.
Cluster headache and hemicrania continua (see these terms) are the main differential diagnoses. It is very important to differentiate PH from other trigeminal autonomic cephalgias, as each of these syndromes has a highly selective response to treatment.
Familial cases of PH have been reported.
Management and treatment
A complete response to indomethacin confirms the diagnosis of PH. Treatment with indomethacin with a median dose of 150 mg/day (ranging from 30-300/day) results in dramatic relief of the disabling symptoms caused by PH.