Neurosurgery notes/Functional/Craniofacial pain/Trigeminal autonomic cephalalgias (TACs)/Hemicrania Continua (HC)

Hemicrania Continua (HC)

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Trigeminal autonomic cephalalgias (TACs)

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General

  • Part of trigeminal autonomic cephalalgias
  • Hemicrania continua (HC) is a primary headache disorder with a pathognomonic treatment response to indomethacin.

Diagnostic criteria

  • Unilateral headache fulfilling criteria 2-4
  • Present for greater than 3 months, with exacerbations of moderate or greater intensity
  • Either or both of the following:
    • At least one of the following symptoms or signs, ipsilateral to the headache:
      • Conjunctival injection and/or lacrimation
      • Nasal congestion and/or rhinorrhoea
      • Eyelid edema
      • Forehead and facial sweating
      • Miosis and/or ptosis
    • A sense of restlessness or agitation, or aggravation of the pain by movement
  • Responds absolutely to therapeutic doses of indomethacin
  • Not better accounted for by another ICHD-3 diagnosis.

Number

  • Rare headache disorder
    • 1% of all headaches
  • Prevalent in 30s
  • F>M

Aetiology

  • Without a secondary organic cause.
  • Theories
    • Cavernous sinus inflammation,
    • Intracranial arterial vasodilation,
    • Upregulation of vasopeptides, eg
      • Calcitonin gene-related peptide (CGRP)
      • Vasoactive intestinal peptide (VIP),
    • Trigeminal nerve autonomic dysregulation resulting in the increased cranial parasympathetic outflow.
  • Interestingly, transection of the trigeminal nerve does not relieve symptoms in all the patients

Clinical feature

  • Pain
    • Unremitting pain
      • A baseline continuous unilateral headache for months that intermittently exacerbates
      • 20% may experience pain-free periods lasting from one day to several weeks
    • Periods of exacerbation
      • Associated autonomic features
        • Autonomic symptoms are generally less prominent than other TACs,
        • Forehead sweating, lacrimation, conjunctival injection and swelling, ptosis, miosis, a feeling of foreign body sensation in the eye, nasal congestion, rhinorrhea, and/or aural fullness.
      • Last for a few minutes to days
      • Fq: 20 attacks daily to one attack in 4 months
        • 50% 1 attack daily
      • Restless, agitated, and have difficulty staying still.
      • Migrainous features of photophobia, phonophobia, nausea, and/or vomiting may occur during exacerbations
      • Aura is uncommon.
      • Triggered by
        • Stress,
        • Alcohol,
        • Irregular sleep patterns,
        • Menstruation
    • Dull in character
    • Described as
      • Worst headache of their lives and may also experience suicidal thoughts during these exacerbations.
    • Often does not affect physical activity.
    • Location
      • Always occurs on the same side
        • Slight preference for the right side
      • V1
      • But other extra-trigeminal areas may also be involved.

Management

  • Indomethacin
    • NSAID
    • Indomethacin is more effective than other NSAIDs, probably due to
      • Highest central nervous system penetration
      • Central serotonergic effects,
      • Inhibition of nitrous oxide-dependent vasodilation.
    • Low dose of 25 mg three times a day with meals and titrated slowly depending upon the response
  • Other drugs (not as effective as Indomethacin
    • Melatonin
    • Topiramate
    • COX-2 inhibitors (rofecoxib and celecoxib),
    • Gabapentin,
    • Corticosteroids,
    • Lamotrigine,
    • Lithium,
    • Amitriptyline,
    • Valproate,
    • Naproxen.
  • Vagus nerve stimulation (VNS)
    • Is a non-invasive neuromodulation
    • No much data to back its use
  • Botulinum toxin-A
    • Used when medication fails
  • Occipital nerve stimulation (ONS),
    • Used when medication fails
  • Sphenopalatine ganglion (SPG)
    • To cut trigeminal autonomic response in HC
  • DBS
    • Target: posterior hypothalamus

Prognosis

  • Not a life-threatening condition.