Overview
Cluster Headache
Quick Reference
Critical Alerts
- Cluster headache is the most severe primary headache: "Suicide headache"
- High-flow oxygen (100%, 12-15 L/min) is first-line: Most effective acute treatment
- Sumatriptan SC is highly effective: 6 mg SC
- Attacks are short (15-180 min) but excruciating
- Rule out secondary causes: Especially with atypical features
- Patients are agitated, restless: Unlike migraine (quiet, dark room)
Classic Presentation
| Feature | Description |
|---|---|
| Location | Strictly unilateral, periorbital/temporal |
| Quality | Stabbing, boring, severe |
| Duration | 15-180 minutes |
| Frequency | 1-8 attacks/day (cluster period) |
| Autonomic features | Ipsilateral lacrimation, conjunctival injection, rhinorrhea, ptosis, miosis |
| Behavior | Restless, agitated, pacing |
Emergency Treatments
| Treatment | Dose | Notes |
|---|---|---|
| High-flow oxygen | 100% via non-rebreather, 12-15 L/min × 15-20 min | First-line |
| Sumatriptan SC | 6 mg | Most effective triptan route |
| Sumatriptan nasal | 20 mg | Alternative |
| Zolmitriptan nasal | 5 mg | Alternative |
Definition
Overview
Cluster headache is a primary headache disorder classified as a trigeminal autonomic cephalalgia (TAC). It is characterized by severe, strictly unilateral headaches with ipsilateral autonomic features (lacrimation, conjunctival injection, nasal congestion). Attacks are short (15-180 minutes) but intensely painful. High-flow oxygen and subcutaneous triptans are the most effective acute treatments.
Classification
By Periodicity:
| Type | Features |
|---|---|
| Episodic | Cluster periods lasting weeks-months, separated by remission periods ≥3 months |
| Chronic | No remission period, or remission <3 months |
Epidemiology
- Prevalence: 0.1% of population
- Male predominance: 3:1 (historically higher; narrowing)
- Onset age: 20-40 years
- Familial: 5-20% have affected first-degree relative
Etiology
Pathophysiology:
- Hypothalamic dysfunction (circadian pacemaker)
- Trigeminal nerve activation
- Parasympathetic (autonomic) outflow
Triggers (During Cluster Period):
| Trigger | Mechanism |
|---|---|
| Alcohol | Vasodilation; most reliable trigger |
| Histamine | Vasodilation |
| Nitroglycerin | Vasodilation |
| Sleep | Attacks often occur during REM sleep |
Pathophysiology
Mechanism
- Hypothalamic activation: Circadian regulation; explains periodicity
- Trigeminal-autonomic reflex: Trigeminal afferents activate parasympathetic efferents
- Autonomic features: Lacrimation, nasal congestion, conjunctival injection
- Pain: Severe periorbital pain via trigeminal nerve
Why Patients Are Agitated
- Pain is so severe that lying still exacerbates perception
- Restlessness is a hallmark; differentiates from migraine
Clinical Presentation
Symptoms
| Feature | Description |
|---|---|
| Headache location | Strictly unilateral; periorbital, temporal, supraorbital |
| Quality | Excruciating, stabbing, "hot poker in eye" |
| Intensity | Severe to very severe (10/10) |
| Duration | 15-180 minutes (usually 45-90 min) |
| Frequency | 1-8 attacks/day; often same time each day |
| Circadian pattern | Nocturnal attacks common (1-2 hours after falling asleep) |
Autonomic Features (Ipsilateral to pain):
| Feature | Notes |
|---|---|
| Lacrimation | Tearing of eye |
| Conjunctival injection | Red eye |
| Nasal congestion or rhinorrhea | Runny or stuffy nose |
| Eyelid edema | Swelling |
| Forehead/facial sweating | |
| Miosis and/or ptosis | Partial Horner syndrome |
Behavior During Attack:
History
Key Questions:
Physical Examination
During Attack:
| Finding | Significance |
|---|---|
| Conjunctival injection | Ipsilateral |
| Lacrimation | Ipsilateral |
| Rhinorrhea or nasal congestion | Ipsilateral |
| Ptosis, miosis | Partial Horner |
| Agitation | Hallmark behavior |
Between Attacks:
Restless, agitated, pacing
Common presentation.
Unable to lie still
Common presentation.
May bang head against wall
Common presentation.
Red Flags
Secondary Causes to Exclude
| Finding | Concern | Action |
|---|---|---|
| First attack ever | Must rule out secondary causes | Imaging |
| Atypical features | Longer duration, no autonomic features | MRI |
| Focal neurological deficits | Structural lesion | MRI |
| Fever, neck stiffness | Meningitis | LP |
| Sudden thunderclap onset | SAH | CT, LP |
| Progressive or daily headaches | Tumor, chronic daily headache | MRI |
Differential Diagnosis
Other Causes of Severe Unilateral Headache
| Diagnosis | Features |
|---|---|
| Migraine | Longer duration, nausea, photophobia, prefers dark quiet room |
| Paroxysmal hemicrania | Shorter attacks (2-30 min), more frequent, responds to indomethacin |
| SUNCT/SUNA | Very short attacks (seconds), very frequent |
| Trigeminal neuralgia | Electric shock-like, triggered by touch |
| Giant cell arteritis | Age >0, jaw claudication, vision changes |
| Acute angle-closure glaucoma | Eye pain, halos, mid-dilated pupil |
| Cavernous sinus lesion | Cranial nerve deficits |
Diagnostic Approach
Clinical Diagnosis
- Cluster headache is a clinical diagnosis
- Based on ICHD-3 criteria
ICHD-3 Criteria (Summary)
- At least 5 attacks of severe unilateral orbital/supraorbital/temporal pain lasting 15-180 min
- Either or both:
- At least one ipsilateral autonomic symptom (lacrimation, congestion, rhinorrhea, eyelid edema, sweating, miosis, ptosis)
- Restlessness or agitation
- Frequency: 1 every other day to 8 per day
- Not better explained by another diagnosis
Imaging
Not Required for Typical Cases if Prior Diagnosis
Indications for MRI:
| Indication | Notes |
|---|---|
| First presentation | Rule out secondary causes |
| Atypical features | Duration, frequency, lack of autonomic features |
| Focal neurological signs | Structural lesion |
| Treatment-refractory | Reconsider diagnosis |
Laboratory
- Generally not needed
- ESR if GCA suspected (age >50)
Treatment
Principles
- Acute (abortive) treatment: Oxygen, triptans
- Transitional therapy: Bridge during cluster period (steroids)
- Preventive therapy: Started early in cluster period (verapamil)
- Avoid triggers: Alcohol during cluster period
Acute Treatment
First-Line: High-Flow Oxygen:
| Parameter | Details |
|---|---|
| Flow rate | 12-15 L/min |
| Delivery | Non-rebreather mask |
| Duration | 15-20 minutes |
| Efficacy | ~80% response within 15 min |
First-Line: Triptans:
| Agent | Route | Dose | Notes |
|---|---|---|---|
| Sumatriptan | SC | 6 mg | Most effective; fastest onset |
| Sumatriptan | Nasal | 20 mg | Alternative |
| Zolmitriptan | Nasal | 5 mg | Effective |
Triptan Contraindications:
- CAD, prior MI/stroke
- Uncontrolled hypertension
- Basilar migraine
Transitional Therapy
Steroids (Bridge until preventive takes effect):
| Agent | Dose | Duration |
|---|---|---|
| Prednisone | 60-80 mg/day × 5 days, then taper over 2-3 weeks | Short-term |
Occipital Nerve Block:
- Consider for refractory cases
Preventive Therapy (Started in Cluster Period)
First-Line: Verapamil:
| Dose | Notes |
|---|---|
| 240-960 mg/day in divided doses | Monitor ECG for heart block |
Alternatives:
| Agent | Notes |
|---|---|
| Lithium | For chronic cluster |
| Topiramate | Alternative |
| Melatonin | Adjunct |
| Galcanezumab (CGRP mAb) | FDA-approved for episodic cluster |
Refractory Cases
- Greater occipital nerve block
- Sphenopalatine ganglion block/stimulation
- Neurology/Headache specialist referral
Disposition
Discharge Criteria
- Attack resolved
- Oxygen and triptan prescriptions provided
- Educated on use
- Follow-up with neurology or PCP
Admission Criteria
- Rarely needed for cluster headache
- Consider if:
- Status cluster (continuous attacks)
- Secondary cause suspected
- Suicidal ideation due to pain
Referral
| Indication | Referral |
|---|---|
| First presentation | Neurology for confirmation |
| Preventive therapy needed | Neurology/Headache specialist |
| Refractory cluster | Headache specialist |
Prescriptions at Discharge
| Item | Notes |
|---|---|
| Oxygen (prescription for home) | 12-15 L/min × 15-20 min |
| Sumatriptan 6 mg SC auto-injector | First-line abortive |
| Sumatriptan nasal or zolmitriptan nasal | Alternative |
| Neurology referral | For preventive therapy |
Patient Education
Condition Explanation
- "Cluster headache is one of the most painful headache disorders."
- "Attacks are short but severe, and happen in clusters over weeks to months."
- "Oxygen and an injection called sumatriptan are highly effective."
- "Preventive medications can reduce the number of attacks."
Home Care
- Have oxygen ready at home (prescription required)
- Use sumatriptan at first sign of attack
- Avoid alcohol during cluster period
- Maintain regular sleep schedule
- Keep a headache diary
Warning Signs to Return
- Headache different from usual cluster attacks
- Fever, neck stiffness
- Weakness, numbness, or vision changes
- Thoughts of self-harm
Special Populations
Elderly
- First presentation requires workup (rule out GCA, other secondary causes)
- Triptans: Use with caution if cardiovascular risk
Pregnant Women
- Oxygen is safe
- Avoid triptans in pregnancy (limited data; consult OB)
Chronic Cluster Headache
- No remission >1 year
- More difficult to treat
- Lithium may be considered
Quality Metrics
Performance Indicators
| Metric | Target | Rationale |
|---|---|---|
| High-flow O2 offered | 100% | First-line treatment |
| Sumatriptan SC offered | >0% | Most effective triptan |
| Neurology referral | >0% | Preventive therapy |
| Imaging for first presentation | 100% | Rule out secondary |
Documentation Requirements
- Attack duration and frequency
- Autonomic features
- Behavior during attack
- Treatment response
- Neurology referral
Key Clinical Pearls
Diagnostic Pearls
- "Suicide headache": Most severe primary headache
- Restlessness is hallmark: Unlike migraine (quiet, dark room)
- Autonomic features ipsilateral: Lacrimation, conjunctival injection
- Attacks are short (15-180 min): Longer = consider migraine
- Circadian pattern: Often same time each day; nocturnal
- First presentation = MRI: Rule out secondary causes
Treatment Pearls
- High-flow O2 is first-line: 12-15 L/min × 15-20 min
- Sumatriptan SC is fastest: 6 mg
- Oral triptans are too slow: SC or nasal preferred
- Steroids for transitional therapy: Prednisone taper
- Verapamil is first-line preventive: Monitor ECG
- Avoid alcohol during cluster period: Reliable trigger
Disposition Pearls
- Prescribe home oxygen: Requires prescription
- Prescribe sumatriptan SC auto-injector: For attacks
- Refer to neurology: For preventive management
- Rarely admit: Unless suicidal or secondary cause
References
- Headache Classification Committee of the International Headache Society. The International Classification of Headache Disorders, 3rd edition. Cephalalgia. 2018;38(1):1-211.
- May A, et al. Cluster headache. Nat Rev Dis Primers. 2018;4:18006.
- Robbins MS, et al. Treatment of Cluster Headache: The American Headache Society Evidence-Based Guidelines. Headache. 2016;56(7):1093-1106.
- Cohen AS, et al. High-flow oxygen for treatment of cluster headache: a randomized trial. JAMA. 2009;302(22):2451-2457.
- Law S, et al. Sumatriptan plus naproxen for the treatment of acute migraine attacks in adults. Cochrane Database Syst Rev. 2016;4(4):CD008541.
- Goadsby PJ, et al. Pathophysiology of Migraine: A Disorder of Sensory Processing. Physiol Rev. 2017;97(2):553-622.
- AAN Practice Parameter. Treatment of episodic cluster headache. 2010.
- UpToDate. Cluster headache: Treatment and prognosis. 2024.