Cluster headache

A 35 year old male presents to the neurology clinic with severe episodic unilateral periorbital pain that began 48 hours ago. The pain is excruciating, stabbing, and rapidly reaches peak intensity, lasting 30 to 90 minutes per episode. He reports associated ipsilateral eye redness, lacrimation, nasal congestion or rhinorrhea, ptosis, and miosis during attacks. The episodes occur multiple times daily, often at the same time each day, especially at night, waking him from sleep. During attacks, he is restless and agitated, pacing around the room. He has experienced similar headaches in the past occurring in cycles lasting weeks to months, followed by months to years of remission. MRI of the brain is normal. Diagnosis?

Diagnosis is Cluster headache.

1. Definition

Cluster headache is a primary headache disorder within the trigeminal autonomic cephalalgias, characterized by severe unilateral orbital or periorbital pain with ipsilateral autonomic symptoms, occurring in cyclical cluster patterns.

2. Etiology

1. Exact cause is unknown
2. Involves:
• Trigeminal-autonomic reflex activation
• Hypothalamic dysfunction
• Trigeminovascular system activation
3. Risk factors:
• Male sex
• Smoking
• Alcohol use
4. Possible genetic predisposition

3. Pathophysiology

1. Activation of the trigeminovascular system → release of CGRP and other neuropeptides → vasodilation and pain
2. Activation of parasympathetic pathways via the sphenopalatine ganglion → ipsilateral autonomic symptoms
3. Hypothalamic dysfunction leads to:
• Circadian periodicity
• Nocturnal attacks
• Cluster pattern

4. Clinical Features

1. Severe unilateral periorbital, supraorbital, or temporal pain
2. Duration: 15 to 180 minutes
3. Frequency: 1 every other day up to 8 per day
4. Occurs in clusters lasting weeks to months, followed by remission

4.2 Associated Features

1. Ipsilateral autonomic symptoms:
• Lacrimation and conjunctival injection
• Nasal congestion or rhinorrhea
• Eyelid edema
• Ptosis and miosis
2. Behavioral feature:
• Restlessness and agitation
3. Distinguishing feature:
• Patients are restless, unlike migraine patients who prefer to lie still
4. Other features:
• Nocturnal attacks
• Circadian pattern
• Alcohol triggers attacks during active cluster periods

5. Diagnosis

1. Based on ICHD-3 clinical criteria
2. Requires:
• At least 5 attacks
• Typical pain characteristics
• Ipsilateral autonomic symptoms or restlessness
• Frequency 1 every other day to 8 per day
3. Neuroimaging:
• MRI is recommended to exclude secondary causes, especially in atypical presentations

6. Management

6.1 Acute Treatment

1. High-flow oxygen via non-rebreather mask
2. Subcutaneous sumatriptan
3. Intranasal triptans as alternatives

6.2 Preventive Treatment

1. Verapamil is first-line
• Requires ECG monitoring
2. Transitional therapy:
• Corticosteroids
• Greater occipital nerve block
3. Other options:
• Lithium
• Topiramate
• Melatonin

7. Key Clinical Insight

Severe unilateral orbital pain with ipsilateral autonomic symptoms, circadian pattern, nocturnal attacks, and restlessness strongly indicates cluster headache

8. Exam Level Pearls

1. Cluster headache causes the most severe primary headache pain
2. Patients are restless, unlike migraine
3. Occurs in circadian and cluster patterns
4. Alcohol triggers attacks during cluster periods
5. First-line acute therapy is high-flow oxygen and subcutaneous sumatriptan