Cluster Headache¶

DIAGNOSIS: Cluster Headache ICD-10: G44.009 (Cluster headache syndrome, unspecified) SCOPE: Acute cluster headache attack treatment, transitional therapy, and preventive therapy for episodic and chronic cluster headache. Excludes other trigeminal autonomic cephalalgias (paroxysmal hemicrania, SUNCT/SUNA - separate protocols).

STATUS: Draft - Pending Review

PRIORITY KEY: STAT = Immediate | URGENT = Within hours | ROUTINE = Standard | EXT = Extended/atypical cases | - = Not applicable to this setting

SECTION A: ACTION ITEMS¶

1. LABORATORY WORKUP¶

1A. Essential/Core Labs¶

Test	Rationale	Target Finding	ED	HOSP	OPD	ICU
CBC	Baseline before starting preventive therapy; rule out infection	Normal	STAT	ROUTINE	ROUTINE	-
BMP	Baseline renal function before lithium or other preventives	Normal	STAT	ROUTINE	ROUTINE	-
TSH	Thyroid dysfunction can mimic or exacerbate headache; baseline for lithium	Normal (0.4-4.0 mIU/L)	-	ROUTINE	ROUTINE	-
LFTs	Baseline hepatic function before verapamil, valproate	Normal	-	ROUTINE	ROUTINE	-

1B. Extended Workup (Second-line)¶

Test	Rationale	Target Finding	ED	HOSP	OPD	ICU
Pituitary function panel (FSH, LH, prolactin, IGF-1, cortisol)	Atypical features or pituitary lesion on imaging	Normal	-	ROUTINE	ROUTINE	-
Lithium level	Monitoring when on lithium therapy	0.6-1.0 mEq/L therapeutic range	-	ROUTINE	ROUTINE	-
Calcium, PTH	Lithium-induced hypercalcemia monitoring	Normal calcium; PTH not elevated	-	ROUTINE	ROUTINE	-
Free T4	Lithium-induced thyroid dysfunction monitoring	Normal	-	ROUTINE	ROUTINE	-
BUN, creatinine	Lithium nephrotoxicity monitoring	Normal	-	ROUTINE	ROUTINE	-

1C. Rare/Specialized (Refractory or Atypical)¶

Test	Rationale	Target Finding	ED	HOSP	OPD	ICU
ESR, CRP	Atypical features; rule out giant cell arteritis in older patients	Normal	URGENT	ROUTINE	ROUTINE	-
Growth hormone stimulation test	Suspected pituitary adenoma with GH deficiency	Normal response	-	-	EXT	-
Sleep study (polysomnography)	Suspected obstructive sleep apnea as trigger	AHI <5 (normal)	-	-	ROUTINE	-

2. DIAGNOSTIC IMAGING & STUDIES¶

2A. Essential/First-line¶

Study	Timing	Target Finding	Contraindications	ED	HOSP	OPD	ICU
MRI Brain with pituitary protocol	New diagnosis of cluster headache	Normal; exclude pituitary lesion, hypothalamic lesion, cavernous sinus pathology	MRI-incompatible devices, severe claustrophobia	URGENT	ROUTINE	ROUTINE	-
MRA Head	Suspected vascular etiology; atypical features	No aneurysm, dissection, vascular malformation	MRI contraindications	URGENT	ROUTINE	ROUTINE	-

2B. Extended¶

Study	Timing	Target Finding	Contraindications	ED	HOSP	OPD	ICU
MRI orbits with contrast	Orbital pain, suspected retro-orbital pathology	No orbital mass, Tolosa-Hunt syndrome	Gadolinium allergy, severe renal impairment	URGENT	ROUTINE	EXT	-
CT Head non-contrast	MRI unavailable; acute presentation	No acute pathology	Pregnancy (relative)	STAT	STAT	-	-
CTA Head/Neck	Urgent vascular imaging if MRI unavailable	No aneurysm, dissection	Contrast allergy, CKD	STAT	URGENT	-	-

2C. Rare/Specialized¶

Study	Timing	Target Finding	Contraindications	ED	HOSP	OPD	ICU
MRV Brain	Suspected cerebral venous thrombosis	Patent venous sinuses	MRI contraindications	URGENT	ROUTINE	EXT	-
CT sinuses	Suspected sinus pathology contributing	No sinusitis, mucocele	Pregnancy (relative)	-	ROUTINE	EXT	-
Carotid Doppler ultrasound	Suspected carotid dissection	No dissection	None	URGENT	ROUTINE	EXT	-

3. TREATMENT¶

3A. Acute/Emergent (Abortive Therapy for Active Attacks)¶

Treatment	Route	Indication	Dosing	Contraindications	Monitoring	ED	HOSP	OPD	ICU
High-flow oxygen	INH	First-line abortive; most effective acute treatment	100% at 12-15 L/min x 15-20 min :: INH :: :: 100% O2 via non-rebreather mask at 12-15 L/min for 15-20 min; patient seated, leaning forward; may repeat	Severe COPD with CO2 retention (relative)	SpO2; symptom resolution typically within 15 min	STAT	STAT	ROUTINE	-
Sumatriptan	SC	First-line abortive; rapid onset	6 mg SC :: SC :: :: 6 mg SC at onset; may repeat after 1 hr if needed; max 12 mg/24hr	Uncontrolled HTN; CAD; prior MI/stroke; hemiplegic migraine; MAOIs; within 24h of ergot	Triptan sensation; monitor BP if cardiac risk factors	STAT	STAT	ROUTINE	-
Sumatriptan	Intranasal	Alternative to SC when injection not preferred	20 mg intranasal :: Intranasal :: :: 20 mg intranasal at onset; may repeat after 2 hr; max 40 mg/24hr	Same as SC sumatriptan	Nasal irritation; triptan sensation	URGENT	URGENT	ROUTINE	-
Zolmitriptan	Intranasal	Alternative triptan; effective nasal delivery	5 mg intranasal :: Intranasal :: :: 5 mg intranasal at onset; may repeat after 2 hr; max 10 mg/24hr	Same as sumatriptan	Triptan sensation; nasal discomfort	URGENT	URGENT	ROUTINE	-
Zolmitriptan	PO	Oral option when SC/nasal unavailable	5 mg PO; 10 mg PO :: PO :: :: 5-10 mg PO at onset; may repeat after 2 hr; max 10 mg/24hr	Same as sumatriptan	Triptan sensation	URGENT	URGENT	ROUTINE	-
Octreotide	SC	Second-line; triptan contraindications or failure	100 mcg SC :: SC :: :: 100 mcg SC at onset; may repeat once after 1 hr	Gallbladder disease; diabetes (may alter glucose)	Blood glucose; GI symptoms	URGENT	URGENT	EXT	-
Lidocaine	Intranasal	Adjunctive therapy; sphenopalatine ganglion block	1 mL of 4-10% solution :: Intranasal :: :: Instill 1 mL of 4-10% lidocaine into nostril ipsilateral to pain; head tilted back 45 degrees toward affected side; may repeat x1	Local anesthetic allergy	Numbness; bitter taste	URGENT	URGENT	ROUTINE	-

3B. Transitional Therapy (Bridge Until Preventive Takes Effect)¶

Treatment	Route	Indication	Dosing	Contraindications	Monitoring	ED	HOSP	OPD	ICU
Prednisone	PO	Rapid cluster suppression; bridge to verapamil	60 mg daily x 5 days; 40 mg daily x 5 days; 20 mg daily x 5 days :: PO :: :: Start 60-80 mg daily x 5 days, taper by 10-20 mg q5d over 2-3 weeks; limit to 2-3 courses/year	Active infection; uncontrolled diabetes; GI bleeding; psychosis history	Glucose; BP; mood changes; sleep	-	ROUTINE	ROUTINE	-
Dexamethasone	IV/PO	Alternative steroid; hospitalized patients	8 mg IV/PO daily x 3-5 days :: IV/PO :: :: 4-8 mg IV or PO daily x 3-5 days, then taper or switch to prednisone	Same as prednisone	Glucose; BP	URGENT	URGENT	-	-
Greater occipital nerve block	SC	Transitional therapy; rapid reduction in attack frequency	2-3 mL 2% lidocaine + 40 mg triamcinolone :: SC :: :: Inject 2-3 mL of 2% lidocaine + 40 mg triamcinolone (or 6 mg betamethasone) at greater occipital nerve ipsilateral to pain; may do bilaterally	Local anesthetic allergy; infection at site; anticoagulation (relative)	Immediate relief; vasovagal reaction; alopecia at injection site	-	ROUTINE	ROUTINE	-
Dihydroergotamine (DHE)	IV	Status cluster; refractory attacks; inpatient protocol	0.5 mg IV q8h x 5 days; 1 mg IV q8h x 5 days :: IV :: :: 0.5-1 mg IV q8h (after test dose 0.25-0.5 mg) for 3-5 days; pretreat with antiemetic; requires telemetry	Pregnancy; CAD; uncontrolled HTN; peripheral vascular disease; use within 24h of triptan; hepatic/renal impairment; sepsis	BP; ECG monitoring; nausea; leg cramps; paresthesias	-	URGENT	-	-
Dihydroergotamine (DHE)	SC/IM	Home transitional therapy; bridge after inpatient protocol	1 mg SC/IM at onset :: SC/IM :: :: 1 mg SC or IM at onset of attack; max 3 mg/24hr; max 6 mg/week	Same as IV DHE	Same as IV DHE	-	ROUTINE	ROUTINE	-

3C. Second-line/Refractory (Acute Treatments)¶

Treatment	Route	Indication	Dosing	Contraindications	Monitoring	ED	HOSP	OPD	ICU
Sphenopalatine ganglion block	Intranasal	Refractory acute attacks; alternative to nerve block	0.3 mL 0.5% bupivacaine :: Intranasal :: :: Apply 0.3 mL of 0.5% bupivacaine via intranasal catheter (Tx360, SphenoCath) to sphenopalatine ganglion	Local anesthetic allergy; nasal pathology	Local numbness; epistaxis; vasovagal	-	EXT	ROUTINE	-
Ketamine	Intranasal	Refractory attacks; investigational	50-75 mg intranasal :: Intranasal :: :: 50-75 mg intranasal via atomizer; may repeat x1	Uncontrolled HTN; psychosis; increased ICP	Dissociation; BP; HR	-	EXT	-	-
Ergotamine tartrate	SL/PO	Alternative when DHE unavailable	2 mg SL at onset :: SL :: :: 2 mg sublingual at onset; may repeat 1-2 mg q30min; max 6 mg/attack, 10 mg/week	Same as DHE	Nausea; peripheral vasoconstriction	-	EXT	EXT	-

3D. Preventive Therapies¶

Treatment	Route	Indication	Dosing	Pre-Treatment Requirements	Contraindications	Monitoring	ED	HOSP	OPD	ICU
Verapamil	PO	First-line preventive; episodic and chronic CH	80 mg TID; 120 mg TID; 160 mg TID; 240 mg TID :: PO :: :: Start 80 mg TID; increase by 80 mg q10-14d as tolerated; target 240-480 mg TID (720-960 mg/day total); some patients require up to 960 mg/day	Baseline ECG; repeat ECG with each dose increase	Second/third-degree heart block; sick sinus syndrome; severe hypotension; decompensated HF; concurrent beta-blocker (relative)	ECG before each dose increase (monitor PR interval >0.24s or 40% increase); HR; BP; constipation; edema	-	ROUTINE	ROUTINE	-
Lithium carbonate	PO	Chronic cluster headache; verapamil failure/intolerance	300 mg BID; 300 mg TID; 450 mg BID; 600 mg BID :: PO :: :: Start 300 mg BID; titrate by 300 mg q3-7d to target level 0.6-1.0 mEq/L; typical dose 600-1200 mg/day	Baseline TSH, BMP, calcium, ECG	Renal impairment; sick sinus syndrome; pregnancy; Brugada syndrome; concurrent NSAIDs/ACE-I/thiazides	Lithium level q1wk during titration, then q1-3mo; TSH, creatinine, calcium q3-6mo; tremor; polyuria	-	ROUTINE	ROUTINE	-
Topiramate	PO	Preventive; especially with comorbid migraine	25 mg qHS; 50 mg BID; 75 mg BID; 100 mg BID :: PO :: :: Start 25 mg qHS; increase by 25 mg/wk; target 100-200 mg/day divided BID	None	Glaucoma; kidney stones; pregnancy; metabolic acidosis	Cognitive effects; paresthesias; weight; serum bicarbonate; kidney stones	-	ROUTINE	ROUTINE	-
Galcanezumab (Emgality)	SC	FDA-approved for episodic cluster headache; CGRP mAb	300 mg SC monthly :: SC :: :: 300 mg SC (3 consecutive 100 mg injections) at onset of cluster period; repeat monthly during cluster period	None	Hypersensitivity to galcanezumab	Injection site reactions; constipation	-	-	ROUTINE	-
Melatonin	PO	Adjunctive prevention; circadian dysregulation	10 mg qHS; 15 mg qHS; 20 mg qHS :: PO :: :: 10-20 mg PO 30 min before bedtime; may help regulate cluster periodicity	None	None significant	Sedation; morning grogginess	-	ROUTINE	ROUTINE	-
Valproate/Divalproex	PO	Alternative preventive; especially with comorbid epilepsy/mood disorder	250 mg BID; 500 mg BID; 500 mg ER daily; 1000 mg ER daily :: PO :: :: Start 250 mg BID or 500 mg ER daily; titrate to 500-1500 mg/day	LFTs, CBC	Hepatic disease; pregnancy (teratogen); urea cycle disorders; pancreatitis history	LFTs q6mo; CBC; ammonia if AMS; weight; hair loss; tremor	-	ROUTINE	ROUTINE	-
Baclofen	PO	Alternative preventive; trigeminal autonomic pathway modulation	5 mg TID; 10 mg TID; 20 mg TID :: PO :: :: Start 5 mg TID; titrate by 5 mg/dose q3d; target 30-60 mg/day divided TID	None	Withdrawal if abrupt discontinuation; renal impairment (reduce dose)	Sedation; weakness; withdrawal syndrome; do not stop abruptly	-	ROUTINE	ROUTINE	-
Gabapentin	PO	Alternative preventive; neuropathic pain component	300 mg qHS; 300 mg TID; 600 mg TID; 900 mg TID :: PO :: :: Start 300 mg qHS; titrate by 300 mg q1-3d; target 1800-3600 mg/day divided TID	None	Reduce dose in renal impairment	Sedation; dizziness; edema; weight gain	-	ROUTINE	ROUTINE	-

3E. Refractory/Interventional Therapies¶

Treatment	Route	Indication	Dosing	Pre-Treatment Requirements	Contraindications	Monitoring	ED	HOSP	OPD	ICU
Occipital nerve stimulation	Implant	Chronic refractory cluster headache; failed multiple preventives	N/A - surgical implant :: Implant :: :: Percutaneous or surgical implantation of occipital nerve stimulator; specialist referral required	Neurosurgical evaluation; psychological screening; failed at least 3 preventive medications	Active infection; coagulopathy; psychiatric instability	Post-implant follow-up; battery life; lead migration	-	-	EXT	-
Deep brain stimulation	Implant	Severe refractory chronic CH; last resort	N/A - surgical implant :: Implant :: :: Targeting posterior hypothalamus; investigational; specialist center only	Extensive workup; ethics committee review; failed all other options	Same as ONS; structural brain abnormality	Long-term neurological monitoring	-	-	EXT	-
Sphenopalatine ganglion stimulation	Implant	Refractory CH; acute and preventive effects	N/A - surgical implant :: Implant :: :: Pulsante SPG microstimulator; patient-controlled acute therapy	Neurosurgical evaluation; imaging confirmation	Facial/jaw abnormalities; active infection	Lead integrity; battery; efficacy	-	-	EXT	-
Radiofrequency ablation trigeminal ganglion	Procedure	Refractory chronic CH; trigeminal nerve modulation	N/A - procedure :: Procedure :: :: Percutaneous RF ablation; provides 6-18 months relief; may need repeat	Facial imaging; failed medical therapy	Anticoagulation; infection; facial numbness intolerance	Facial sensation; corneal reflex; recurrence	-	-	EXT	-

4. OTHER RECOMMENDATIONS¶

4A. Referrals & Consults¶

Recommendation	ED	HOSP	OPD	ICU
Headache specialist/Neurology referral for diagnosis confirmation and preventive therapy optimization	URGENT	ROUTINE	ROUTINE	-
Pain management referral for interventional procedures (nerve blocks, neuromodulation evaluation) in refractory cases	-	ROUTINE	ROUTINE	-
Sleep medicine evaluation for polysomnography if obstructive sleep apnea suspected as cluster trigger	-	-	ROUTINE	-
Endocrinology referral if pituitary abnormality identified on imaging or atypical hormone levels	-	ROUTINE	ROUTINE	-
Neurosurgery consultation for neuromodulation or ablative procedures in medically refractory cases	-	-	EXT	-
Cardiology clearance before initiating high-dose verapamil in patients with cardiac history	-	ROUTINE	ROUTINE	-
Psychiatry referral for suicidal ideation screening given high depression/suicide risk in cluster headache patients	URGENT	ROUTINE	ROUTINE	-

4B. Patient Instructions¶

Recommendation	ED	HOSP	OPD
Return immediately for sudden severe headache different from typical cluster attacks which may indicate new pathology	STAT	-	ROUTINE
Keep high-flow oxygen available at home during cluster period for acute attack treatment	-	ROUTINE	ROUTINE
Use sumatriptan injection at first sign of attack for fastest relief; do not wait for pain to worsen	URGENT	ROUTINE	ROUTINE
Maintain detailed headache diary including attack timing, duration, severity, and treatment response	-	ROUTINE	ROUTINE
Avoid known triggers during cluster period especially alcohol (even small amounts), strong odors, and napping	-	ROUTINE	ROUTINE
Do not abruptly stop preventive medications especially lithium and baclofen which require gradual taper	-	ROUTINE	ROUTINE
Carry injectable sumatriptan at all times during active cluster period for emergency use	-	ROUTINE	ROUTINE
Alert healthcare providers to cluster headache diagnosis as this affects anesthesia and medication choices	-	ROUTINE	ROUTINE

4C. Lifestyle & Prevention¶

Recommendation	ED	HOSP	OPD
Strict alcohol avoidance during entire cluster period as even small amounts trigger attacks	-	ROUTINE	ROUTINE
Maintain regular sleep schedule with consistent bedtime and wake time to regulate circadian rhythm	-	ROUTINE	ROUTINE
Avoid daytime napping during cluster period as sleep transitions can trigger attacks	-	ROUTINE	ROUTINE
Smoking cessation to reduce vascular risk and potential cluster exacerbation	-	ROUTINE	ROUTINE
Avoid high altitude exposure during cluster period if altitude is a known trigger	-	ROUTINE	ROUTINE
Avoid vasodilators (nitroglycerin, sildenafil) during cluster period as these trigger attacks	-	ROUTINE	ROUTINE
Screen for and treat obstructive sleep apnea as treatment may reduce cluster frequency	-	ROUTINE	ROUTINE
Stress management techniques as emotional stress may influence cluster cycle onset	-	ROUTINE	ROUTINE
Avoid strong chemical odors (solvents, perfumes, gasoline) which can trigger attacks in some patients	-	ROUTINE	ROUTINE

SECTION B: REFERENCE¶

5. DIFFERENTIAL DIAGNOSIS¶

Alternative Diagnosis	Key Distinguishing Features	Tests to Differentiate
Migraine	Longer duration (4-72 hrs); bilateral or alternating sides; nausea/vomiting prominent; photophobia/phonophobia; no autonomic features	Clinical criteria (ICHD-3); MRI if new onset
Paroxysmal hemicrania	Shorter attacks (2-30 min); more frequent (>5/day); absolute response to indomethacin	Indomethacin trial (150-225 mg/day); complete response diagnostic
SUNCT/SUNA	Very brief attacks (seconds to minutes); very frequent (up to 200/day); triggered by cutaneous stimuli	Clinical criteria; may have refractory period; no response to indomethacin
Trigeminal neuralgia	Electric shock-like pain; seconds duration; triggered by touch, chewing, talking; refractory period	MRI for vascular compression; response to carbamazepine
Hemicrania continua	Continuous baseline pain with superimposed exacerbations; unilateral; autonomic features	Absolute response to indomethacin diagnostic
Primary stabbing headache	Ultra-short jabs (seconds); unpredictable location; no autonomic features	Clinical diagnosis; exclusion of secondary causes
Secondary cluster headache	Atypical features; pituitary or hypothalamic lesion; carotid dissection	MRI with pituitary protocol; MRA head/neck
Tolosa-Hunt syndrome	Painful ophthalmoplegia; orbital pain; CN III, IV, VI involvement	MRI orbits with contrast; CSF if needed; steroid response
Giant cell arteritis	Age >50; scalp tenderness; jaw claudication; visual symptoms; elevated ESR/CRP	ESR, CRP; temporal artery biopsy
Carotid dissection	Neck pain; Horner syndrome; stroke symptoms	CTA or MRA neck; carotid ultrasound

6. MONITORING PARAMETERS¶

Parameter	Frequency	Target/Threshold	Action if Abnormal	ED	HOSP	OPD	ICU
Attack frequency diary	Daily during cluster	50% reduction with preventive	Escalate preventive therapy; consider transitional bridge	-	ROUTINE	ROUTINE	-
ECG (if on verapamil)	Baseline and with each dose increase	PR interval <0.28s and <40% increase from baseline	Hold dose increase; may need cardiology clearance	-	ROUTINE	ROUTINE	-
Heart rate (if on verapamil)	Each visit	HR >50 bpm	Reduce dose; consider alternative	-	ROUTINE	ROUTINE	-
Lithium level	Weekly during titration, then q1-3 months	0.6-1.0 mEq/L	Adjust dose; assess renal function if unexpected level	-	ROUTINE	ROUTINE	-
TSH (if on lithium)	Baseline, 3 months, then q6 months	Normal (0.4-4.0 mIU/L)	Endocrine referral; may need thyroid replacement	-	ROUTINE	ROUTINE	-
BUN/Creatinine (if on lithium)	Baseline, q1-3 months	Normal; no progressive rise	Dose reduction; nephrology referral if progressive	-	ROUTINE	ROUTINE	-
Calcium (if on lithium)	Baseline, q6 months	Normal	Evaluate for hyperparathyroidism	-	ROUTINE	ROUTINE	-
Serum bicarbonate (if on topiramate)	Baseline, 3 months	>18 mEq/L	Reduce dose or discontinue	-	ROUTINE	ROUTINE	-
Depression/Suicidal ideation screening	Each visit	PHQ-9 <10; no suicidal ideation	Urgent psychiatric referral; crisis intervention	URGENT	ROUTINE	ROUTINE	-
Oxygen saturation (during O2 therapy)	During treatment	>94%	Adjust flow rate	STAT	STAT	ROUTINE	-

7. DISPOSITION CRITERIA¶

Disposition	Criteria
Discharge home	Acute attack aborted with oxygen/triptan; stable; access to home oxygen and rescue medications; follow-up arranged
Admit to floor	Status cluster (continuous attacks); requires IV DHE protocol; suicidal ideation requiring monitoring; oral intake compromised
Admit to ICU	Rare; only if hemodynamic instability, cardiac arrhythmia from verapamil, or severe psychiatric crisis
Outpatient follow-up	Within 1-2 weeks if in active cluster period; 2-4 weeks after initiating new preventive; q3 months during remission
Transfer to headache center	Refractory to multiple preventives; candidate for neuromodulation; requires specialized interventional procedures

8. EVIDENCE & REFERENCES¶

Recommendation	Evidence Level	Source
High-flow oxygen (100% at 12-15 L/min) first-line abortive	Class I, Level A	Cohen et al. JAMA 2009
Subcutaneous sumatriptan 6 mg effective for acute attacks	Class I, Level A	The Sumatriptan Cluster Headache Study Group. NEJM 1991
Intranasal zolmitriptan 5-10 mg effective for acute attacks	Class I, Level A	Cittadini et al. Neurology 2006
Verapamil first-line preventive for episodic and chronic CH	Class I, Level C (expert consensus)	May et al. Cephalalgia 2006
Galcanezumab FDA-approved for episodic cluster headache	Class I, Level A	Goadsby et al. NEJM 2019
Greater occipital nerve block effective as transitional therapy	Class II, Level B	Ambrosini et al. Pain 2005
Lithium effective for chronic cluster headache prevention	Class II, Level B	Steiner et al. Headache 1997
Prednisone taper effective transitional therapy	Class II, Level C	Obermann et al. Curr Pain Headache Rep 2011
Octreotide effective when triptans contraindicated	Class II, Level B	Matharu et al. Ann Neurol 2004
Melatonin 10 mg may reduce attack frequency	Class II, Level C	Leone et al. Cephalalgia 1996
Occipital nerve stimulation for refractory chronic CH	Class III, Level C	Burns et al. Lancet 2007
European Headache Federation cluster headache guidelines	Guideline	Mitsikostas et al. J Headache Pain 2023

CHANGE LOG¶

v1.0 (January 27, 2026) - Initial template creation - Comprehensive acute abortive, transitional, and preventive therapy coverage - Includes FDA-approved galcanezumab for episodic cluster headache - Structured dosing format for order sentence generation - Emphasis on high-flow oxygen as first-line treatment - Verapamil with ECG monitoring protocol - Differential diagnosis including other trigeminal autonomic cephalalgias