Headache, Cluster



  • Excruciatingly painful primary headache disorder:
    • Infrequent cause of ED visits and affects only 0.1% of the population
  • Often has abated by time of presentation:
    • Attacks last between 15–180 min (75% last <60 min)
  • More common in men (∼3:1)
  • Onset usually between 30–50 yr of age
  • Headaches occur in clusters lasting weeks to months followed by remission >1 mo
  • Commonly occur 1–3 times per day during cluster period
  • Often occur during the same time of day
  • Often occur during the same time of the year:
    • Highest incidence in spring and fall
  • Chronic cluster headache:
    • Remission <1 mo
    • Do not experience remission
    • 10% of patients
    • Often evolves from episodic cluster headaches
  • May have many clinical and pathophysiologic similarities with migraine and variants
  • Often follows a trigeminal nerve dermatome


  • A well-described physiologic reflex arc:
    • The trigeminovascular reflex potentiates the trigeminal pain and cranial autonomic features of cluster headache by positive feedback mechanisms and subsequent hypothalamic dysfunction
    • Release of CGRP from trigeminal perivascular afferents causes vasodilation/modulation of nociceptive activity of trigeminal neurons leading to severe pain

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