What is the difference in diagnosis and treatment between hemicrania continua and cluster headaches?

Differences Between Hemicrania Continua and Cluster Headache: Diagnosis and Treatment

Hemicrania continua and cluster headache are distinct primary headache disorders with different diagnostic criteria and treatment approaches, with indomethacin being the definitive treatment for hemicrania continua while cluster headaches respond best to oxygen therapy and triptans.

Diagnostic Differences

Hemicrania Continua

• Characterized by continuous, unilateral headache that is present for at least 3 months without pain-free periods 1
• Pain is typically moderate in intensity but with fluctuations including severe exacerbations 1
• May have associated autonomic features similar to cluster headache (lacrimation, nasal congestion) 2
• Definitive diagnostic feature is complete response to indomethacin 3, 1
• Often misdiagnosed due to overlapping features with other headache disorders 1

Cluster Headache

• Features strictly unilateral, severe pain lasting 15-180 minutes (not continuous) 4, 1
• Presents with prominent ipsilateral autonomic symptoms including lacrimation, nasal congestion, and ptosis 4, 5
• Occurs in cluster periods with multiple attacks per day, followed by remission periods in episodic form 5
• Chronic cluster headache defined as remission periods lasting less than 3 months 1
• Associated with restlessness during attacks (67.9% of patients) 5
• May include nausea/vomiting (27.8%) and photophobia/phonophobia (61.2%) 5

Treatment Differences

Hemicrania Continua Treatment

• Indomethacin is the gold standard treatment and diagnostic test - complete response is required for diagnosis 3, 1
• Typical effective doses range from 75-225 mg/day 2
• Alternative treatments for patients who cannot tolerate indomethacin may include valproic acid 6

Cluster Headache Treatment

• Acute treatment:

  • Normobaric oxygen therapy (100% oxygen at flow rates of at least 12 L/min for 15 minutes) 7, 8
  • Subcutaneous sumatriptan (6 mg) or intranasal zolmitriptan (10 mg) 7, 8
  • These acute treatments show high effectiveness (81.2% for subcutaneous sumatriptan) 5

• Prophylactic treatment:

  • Galcanezumab is recommended as first-line prophylactic treatment for episodic cluster headache 8
  • Verapamil (70.3% usage rate) and glucocorticoids (57.7% usage rate) are commonly used with high effectiveness 5
  • Noninvasive vagus nerve stimulation is suggested for short-term treatment of episodic cluster headache 7

Clinical Pitfalls and Special Considerations

• Cluster headache is sometimes responsive to indomethacin, which can lead to misdiagnosis as hemicrania continua or paroxysmal hemicrania 3
• Some patients may have both conditions concurrently or evolving from one to the other, complicating diagnosis 6, 2
• Cluster headache is often triggered by alcohol (particularly red wine in 70% of patients) and strong smells 8, 5
• Misdiagnosis and mismanagement are common in cluster headache patients - 67.9% report using first-line treatments 5
• Secondary headache causes should always be ruled out before confirming either diagnosis 4

Treatment Algorithm

1. For suspected hemicrania continua:

   • Trial of indomethacin (starting at 25mg TID, increasing to 75mg TID if needed) 2
   • Complete response confirms diagnosis 1
   • For indomethacin intolerance, consider valproic acid as alternative 6

2. For suspected cluster headache:

   • Acute treatment: Oxygen therapy and/or injectable sumatriptan 7, 8
   • Prophylactic treatment: Galcanezumab for episodic cluster headache 8
   • Alternative prophylaxis: Verapamil or short-course glucocorticoids 5