5-Minute Clinical Consult

Headache, Cluster

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  • Primary headache disorder
  • Multiple attacks of unilateral, excruciating, sharp, searing, or piercing pain. Typically localized in the periorbital area and temple accompanied by signs of ipsilateral autonomic features.
  • Autonomic symptoms: Parasympathetic hyperactivity signs (ipsilateral lacrimation, eye redness, nasal congestion) and sympathetic hypoactivity (ipsilateral ptosis and miosis)
  • Patients often pace, rub their head to try to alleviate the pain
  • Symptoms usually remain on the same side during a single cluster attack.
  • Individual attacks last 15–180 minutes if untreated and occur from once every other day to 8 times per day.
  • Attacks usually occur in series (cluster periods) lasting for weeks or months separated by remission periods usually lasting months or years. However, about 10–15% of patients have chronic symptoms without remissions.


1-year incidence: 53/100,000

  • Lifetime prevalence 124/100,000 (∼0.1%)
  • Predominant sex: Male > Female (4.3:1)
  • Mean age of onset: Between 29.6 and 35.7 years
  • Episodic/Chronic ratio 6:1

Etiology and Pathophysiology

  • Complex and incompletely understood
  • Proposed mechanisms include:
    • Activation of posterior hypothalamus may trigger an attack, causing activation of the trigeminal nerve, leading to intense pain symptoms
    • Autonomic symptoms: Activation of craniofacial parasympathetic nerve fibers secondary to pathologic activation of trigemino-autonomic brainstem reflex

  • Usually sporadic: Autosomal dominant in ∼5% of cases, autosomal recessive or multifactorial in other families
  • Evidence varies: 1st-degree relatives carry 5–8-fold; 2nd-degree 1–3-fold increased relative risk of disease

Risk Factors

  • Male gender
  • Age (70% onset before age 30)
  • Cigarette smoking
  • Family history of cluster headache (CH)
  • Head trauma
  • Alcohol induces attacks during a cluster, but not during remission.
  • Small amounts of vasodilators (e.g., alcohol, nitroglycerine, sildenafil)
  • Strong odors

Commonly Associated Conditions

  • Depression (24%)
  • Increased risk of suicide secondary to the extreme nature of the pain
  • Medication overuse headache
  • Asthma (9%)
  • History of migraine, frequently in female patients
  • Sleep apnea (14%)
  • Increased prevalence of cardiac right-to-left shunt and patent foramen ovale (relationship unclear)

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