Cluster Headache

Definition | Aetiology | Pathophysiology | Risk Factors | Signs and Symptoms | Investigations | Management

Definition

Cluster headache is a primary headache disorder characterised by recurrent attacks of severe, unilateral periorbital pain, occurring in clusters over weeks to months, often with associated autonomic symptoms.

Aetiology

The exact cause is unknown, but cluster headaches are thought to be related to hypothalamic dysfunction and trigeminal autonomic activation.

Pathophysiology

  • Involves the hypothalamus, which regulates the circadian rhythm (explaining the cyclical nature of attacks).
  • Activation of the trigeminal-autonomic reflex leads to severe pain and autonomic symptoms.
  • Histamine and serotonin dysregulation may contribute to attack triggers.

Risk factors

  • Male sex (4:1 male-to-female ratio).
  • Smoking and alcohol use.
  • Family history of cluster headaches.
  • Disrupted sleep patterns (e.g., shift work).

Signs and symptoms

Cluster headaches present as episodic, severe, unilateral pain with associated autonomic dysfunction.

Key Features:

  • Severe unilateral headache: periorbital or temporal pain, often described as stabbing or burning.
  • Duration: typically lasts 15 minutes to 3 hours.
  • Frequency: occurs in clusters (1–8 attacks per day for weeks to months, followed by remission).

Associated Autonomic Symptoms (Ipsilateral):

  • Redness of the eye (conjunctival injection).
  • Lacrimation (excessive tearing).
  • Rhinorrhoea (runny nose) or nasal congestion.
  • Ptosis (drooping eyelid) and miosis (constricted pupil).
  • Forehead sweating.

Behavioural Features:

  • Patients are often restless or agitated during an attack (unlike migraine sufferers, who prefer to lie still).

Investigations

  • Clinical diagnosis: based on characteristic features.
  • MRI brain: performed if atypical features or secondary causes are suspected.
  • CT head: may be done to exclude secondary pathology in acute settings.

Management

1. Acute Treatment (Abortive Therapy):

  • High-flow oxygen (100% via non-rebreather mask for 15 minutes): first line treatment.
  • Subcutaneous sumatriptan (6 mg): rapid relief within 15 minutes.
  • Nasal zolmitriptan (5 mg): alternative option if subcutaneous administration is not available.

2. Preventative Treatment (To Reduce Attack Frequency):

  • Verapamil (first line): 240–960 mg daily (requires ECG monitoring for heart block).
  • Prednisolone (short term course): 60 mg tapered over 2–3 weeks for rapid cluster suppression.
  • Topiramate or lithium (specialist): Considered in refractory cases.

3. Lifestyle and Patient Education:

  • Avoid alcohol during cluster periods (common trigger).
  • Maintain a regular sleep schedule to prevent attacks.

4. Specialist Referral:

  • Neurology referral if diagnosis is uncertain or if symptoms are refractory to first line treatments.
NeurologymypanotesCluster Headache