Cluster Headache

Introduction

• Definition: Recurrent episodes of acute severe right para-orbital pain.
• Accompanied by: Autonomic manifestations like ipsilateral meiosis and lacrimation.
• Vision Changes: No vision changes associated.

Pathophysiology

• Complex Pathogenesis: Not completely understood.
• Theories:
  • Hypothalamic activation with secondary activation of the trigeminal autonomic reflex (trigeminal-hypothalamic pathway).
  • Neurogenic inflammation: Obliterates venous outflow, injuring sympathetic fibers of the intracranial internal carotid artery.

Clinical Features

• Pain Location: Severe orbital, superorbital, or temporal pain.
• Accompanied by: Autonomic phenomena, restlessness, or agitation.
• Attack Frequency: Up to eight times a day.
• Symptom Consistency: Unilateral symptoms, possibly switching sides in different attacks (15% cases).

Autonomic Symptoms

• Symptoms Include: Ptosis, meiosis, lacrimation, conjunctival injection, rhinorrhea, nasal conjunction.
• Sympathetic Impairment: Symptoms are ipsilateral to the pain and may include sweating and cutaneous blood flow increase.

Circadian Periodicity

• Timing: Painful attacks of 15 to 180 minutes.
• Episodic Form: Most common, affecting 80-90% of patients.
• Chronic Form: Lacks remissions, diagnosed after a year without remission or with remissions lasting less than three months.

Diagnostic Criteria

• Requirements: At least five attacks with severe unilateral orbital, superorbital, or temporal pain.
• Autonomic Symptoms: At least one ipsilateral symptom like conjunctival injection, nasal conjunction, etc.
• Attack Frequency: 1 every other day to 8 per day.

Episodic vs. Chronic

• Episodic Cluster Headache: Attacks occur in bouts of 7 days to 1 year, separated by remission periods of 3 months or more.
• Chronic Cluster Headache: Attacks occur without remission or with remissions lasting less than three months for at least one year.

Treatment

Acute Treatments

• Initial Treatment: Oxygen or tryptans (e.g., subcutaneous sumatriptan).
• Alternatives: Intranasal sumatriptan/zomatriptan, intranasal lidocaine, oral ergotamine.

Preventive Treatments

• Early Initiation: Start once a cluster episode begins.
• Frequent Attacks:
  • First-line: Verapamil.
  • Dosage: Start at 240 mg daily, may require titration up to 960 mg daily.
• Less Frequent Attacks:
  • First-line: Glucocorticoids (prednisone).
  • Alternatives: Galcanezumab, lithium, topiramate.

Conclusion

• Key to effective management is early diagnosis and initiation of treatment to suppress attacks.
• Alternative treatments are available for patients not responding to standard therapy.