What are the diagnostic criteria and treatment options for trigeminal autonomic cephalgias (TACs), including cluster headache, paroxysmal hemicrania, and short-lasting unilateral neuralgiform headache attacks with conjunctival injection and tearing (SUNCT/SUNA)?

Trigeminal Autonomic Cephalgias: Diagnostic Criteria and Treatment

Overview and Classification

Trigeminal autonomic cephalgias (TACs) are a distinct group of primary headache disorders characterized by strictly unilateral head pain in the trigeminal distribution accompanied by ipsilateral cranial autonomic features such as lacrimation, conjunctival injection, rhinorrhea, nasal blockage, facial redness, and ear fullness. 1, 2, 3

The TACs include four main subtypes that are distinguished primarily by attack duration and frequency 3, 4:

• Cluster headache (CH): Attacks lasting 15-180 minutes, occurring 1-8 times daily 3
• Paroxysmal hemicrania (PH): Attacks lasting 2-30 minutes, occurring more frequently (5-40 times daily) 3
• SUNCT/SUNA: Attacks lasting seconds to several minutes, occurring up to 200 times daily with no refractory period between attacks 1, 2
• Hemicrania continua (HC): Continuous unilateral pain with exacerbations 3

Critical Diagnostic Features

Key Distinguishing Characteristics

The presence of prominent autonomic features with no refractory period between attacks and very high attack frequency (up to 200 daily) distinguishes SUNCT/SUNA from trigeminal neuralgia, which has mandatory refractory periods between paroxysmal attacks. 1, 2

Attack patterns that differentiate TACs 1, 2, 3:

• SUNCT/SUNA: Rapid attacks lasting seconds to several minutes, mainly in first and second trigeminal divisions, with tearing, red eye, rhinorrhea, facial redness, and ear fullness visible during attacks 1, 2
• Cluster headache: Exquisitely painful attacks around the eye and temple region lasting 15-180 minutes 3
• Paroxysmal hemicrania: Shorter duration (2-30 minutes) but higher frequency than cluster headache 3

Essential Diagnostic Workup

MRI including pituitary fossa views is mandatory for all suspected TAC cases to exclude secondary causes such as tumors, multiple sclerosis, or structural lesions. 1, 2

In patients over 50 presenting with temporal region pain and autonomic features, giant cell arteritis must be urgently ruled out with ESR, CRP, and temporal artery biopsy, as this requires immediate high-dose corticosteroids (minimum 40 mg daily) to prevent vision loss. 1, 5

Treatment Algorithms

Cluster Headache

Acute treatment 5, 6, 7:

• First-line: 100% oxygen inhalation (12-15 L/min for 15 minutes) or subcutaneous sumatriptan 6 mg 6, 7
• Second-line: Sumatriptan nasal spray 20 mg or zolmitriptan nasal spray 5 mg 6

Preventive treatment 5, 6, 7:

• First-line: Verapamil at least 240 mg/day (often requires higher doses) 6, 7
• Transitional therapy: Oral prednisone 60-100 mg/day or IV methylprednisolone 250-500 mg/day for 5 days with taper to control bouts while waiting for verapamil to take effect 6
• Alternative preventives: Lithium carbonate 800-1600 mg/day, methylergonovine 0.4-1.2 mg/day, or topiramate 100-200 mg/day 6

Paroxysmal Hemicrania and Hemicrania Continua

Indomethacin 75-150 mg/day is the definitive treatment and diagnostic criterion—complete response to indomethacin is mandatory for diagnosis. 5, 6, 7

The robust response to indomethacin distinguishes these conditions from cluster headache and serves as both diagnostic test and treatment 8, 3

SUNCT/SUNA

First-line preventive treatment 1, 5, 6:

• Lamotrigine 100-300 mg/day is the preventive drug of choice 1, 5, 6

Alternative preventives 6, 7:

• Gabapentin 800-2700 mg/day 6
• Topiramate 50-300 mg/day 6
• Carbamazepine 200-1600 mg/day 6

Acute exacerbations 6:

• IV lidocaine 1-4 mg/kg/hour can reduce attack flow during severe exacerbations 6

Critical Diagnostic Pitfalls

Misdiagnosis of TACs as trigeminal neuralgia leads to inappropriate treatment with anticonvulsants when indomethacin or oxygen/triptans are needed—always assess for autonomic features. 5, 8

The continuous pain component in hemicrania continua can be mistaken for chronic migraine, but the absolute response to indomethacin and presence of autonomic features during exacerbations distinguish it. 3

Patients with cluster headache typically first consult dentists or ophthalmologists due to the periorbital and upper jaw location of pain—early neurologist evaluation prevents unnecessary dental procedures and delays in effective treatment. 8

The ability to trigger attacks repeatedly without pain-free intervals should prompt consideration of SUNCT/SUNA rather than trigeminal neuralgia, which has mandatory refractory periods. 2