OVERVIEW

What is Trigeminal Autonomic Cephalalgia?

Trigeminal Autonomic Cephalalgias (TACs) are a relatively rare group of syndromes.

They include five types: cluster headache, paroxysmal hemicrania, SUNCT syndrome (Short-lasting Unilateral Neuralgiform headache attacks with Conjunctival injection and Tearing), SUNA syndrome (Short-lasting Unilateral Neuralgiform headache attacks with cranial Autonomic symptoms), and hemicrania continua.

These disorders all manifest as brief unilateral headaches, primarily occurring in the first branch (ophthalmic branch) of the trigeminal nerve region, accompanied by ipsilateral cranial autonomic symptoms such as tearing, conjunctival injection, eyelid edema, nasal congestion, miosis, and ptosis.

There is currently no cure, but medications can help control attacks.

Are Trigeminal Autonomic Cephalalgias common?

They are relatively uncommon.

• The prevalence of cluster headache is <1%, with more male patients.
• Paroxysmal hemicrania, SUNCT syndrome, SUNA syndrome, and hemicrania continua are very rare, and their prevalence remains uncertain.
• The incidence of paroxysmal hemicrania is estimated to be only 1%-3% that of cluster headache, with more female patients.
• Only a few hundred cases of hemicrania continua have been reported so far.

SYMPTOMS

What are the symptoms and manifestations of trigeminal autonomic cephalalgias?

They are all transient unilateral headaches, mainly concentrated in the orbital, supraorbital, and temporal regions. The pain may be stabbing, burning, or pressing. However, the frequency and duration of headache episodes vary among different conditions.

• Cluster headaches last the longest, ranging from minutes to hours, with a relatively low frequency of up to 8 episodes per day.
• Paroxysmal hemicrania has a moderate duration, lasting around minutes, with an intermediate frequency of up to 40 episodes per day.
• SUNCT syndrome and SUNA syndrome have the shortest duration, lasting seconds to minutes, with the highest frequency of up to over 200 episodes per day.
• Hemicrania continua involves continuous, daily headaches that may persist for months or even years.

Most trigeminal autonomic cephalalgia episodes occur without a cause, but there are exceptions.

For example, cluster headaches may be triggered by alcohol, paroxysmal hemicrania by exercise, and SUNCT syndrome or SUNA syndrome by skin touch, bathing, coughing, or light stimulation.

In addition to headaches, patients may experience autonomic symptoms such as tearing, conjunctival injection, eyelid edema, nasal congestion, miosis, and ptosis. These symptoms occur only during the pain episode and on the same side as the headache.

CAUSES

Why does trigeminal autonomic cephalalgia occur?

The exact cause is currently unknown, and the pathogenesis is relatively complex.

Some believe it is caused by the trigeminovascular complex, others associate it with hypothalamic neural dysfunction, and some suggest it results from abnormal trigeminal autonomic reflexes.

Whether the various headaches included under trigeminal autonomic cephalalgia share the same pathological mechanism remains unclear, and many questions remain to be answered.

Is trigeminal autonomic cephalalgia hereditary?

It is uncertain.

Previously, these conditions were thought not to be hereditary, but recent findings show many patients have a family history, suggesting possible genetic factors. However, no definitive evidence supports this, and many questions remain unresolved.

Is trigeminal autonomic cephalalgia contagious?

No.

DIAGNOSIS

How is Trigeminal Autonomic Cephalalgia Diagnosed?

Diagnosis is primarily based on clinical presentation and past medical history. According to the International Classification of Headache Disorders, 3rd Edition (ICHD-3), the diagnostic criteria are as follows:

1. Cluster Headache

• At least 5 previous episodes;
• Severe or very severe unilateral orbital, supraorbital, and/or temporal pain lasting 15–180 minutes if untreated;
• At least one of the following on the same side as the headache: conjunctival injection and/or lacrimation; nasal congestion and/or rhinorrhea; eyelid edema; forehead and facial sweating; forehead and facial flushing; sensation of fullness in the ear; miosis and/or ptosis;
• Restlessness or agitation;
• Attack frequency ranging from once every other day to 8 times per day;
• Not attributable to another disorder.

2. Paroxysmal Hemicrania

• At least 20 previous episodes;
• Severe unilateral orbital, supraorbital, or temporal pain lasting 2–30 minutes;
• At least one of the following cranial autonomic symptoms or signs ipsilateral to the headache: conjunctival injection and/or lacrimation; nasal congestion and/or rhinorrhea; eyelid edema; forehead and facial sweating; forehead and facial flushing; sensation of fullness in the ear; miosis and/or ptosis;
• Attack frequency exceeding 5 per day;
• Complete prevention by indomethacin;
• Not attributable to another disorder.

3. SUNCT Syndrome and SUNA Syndrome

• At least 20 previous episodes;
• Moderate or severe unilateral orbital, supraorbital, temporal, and/or other trigeminal-distribution pain lasting 1–600 seconds, presenting as single stabs, series of stabs, or sawtooth-pattern stabs;
• At least one of the following cranial autonomic symptoms or signs ipsilateral to the headache: conjunctival injection and/or lacrimation; nasal congestion and/or rhinorrhea; eyelid edema; forehead and facial sweating; forehead and facial flushing; sensation of fullness in the ear; miosis and/or ptosis;
• Attack frequency of at least once daily;
• Not attributable to another disorder;
• If conjunctival injection and lacrimation are present, it is SUNCT syndrome; otherwise, it is SUNA syndrome.

4. Hemicrania Continua

• Unilateral headache;
• Continuous for >3 months, with moderate to severe pain that may worsen;
• At least one of the following: cranial autonomic symptoms or signs ipsilateral to the headache (conjunctival injection and/or lacrimation; nasal congestion and/or rhinorrhea; eyelid edema; forehead and facial sweating; forehead and facial flushing; sensation of fullness in the ear; miosis and/or ptosis); restlessness or agitation, or worsening with physical activity;
• Response to indomethacin;
• Not attributable to another disorder.

What Tests Are Needed for Trigeminal Autonomic Cephalalgia?

• Imaging studies: Such as cranial CT or MRI, mainly to rule out structural brain lesions.
• Diagnostic indomethacin test: A trial of oral indomethacin over 9 days, with incremental dosing (starting at 75–100 mg/day, increasing to 150 mg/day after 3 days, and then to 200–225 mg/day after another 3 days) to observe headache relief.

Which Conditions Can Be Confused with Trigeminal Autonomic Cephalalgia? How to Differentiate?

Mainly involves distinguishing between the subtypes of trigeminal autonomic cephalalgias based on attack duration, frequency, and response to indomethacin.

Additionally, differentiation from trigeminal neuralgia is necessary. Trigeminal neuralgia lacks autonomic symptoms, has "trigger points," and typically presents with sudden, brief attacks.

TREATMENT

Which department should I see for trigeminal autonomic cephalalgia?

Neurology.

Is it necessary to go to the hospital for trigeminal autonomic cephalalgia?

Yes.

How is trigeminal autonomic cephalalgia treated?

For acute cluster headache attacks, 100% pure oxygen inhalation or subcutaneous sumatriptan injections can be tried. If medication tolerance occurs, intranasal triptans may be used. Alternatives include intranasal lidocaine, oral ergotamine, or intravenous dihydroergotamine.

Paroxysmal hemicrania and hemicrania continua are primarily treated with indomethacin, while SUNCT syndrome and SUNA syndrome can only be managed with lidocaine.

Does trigeminal autonomic cephalalgia require hospitalization?

No.

Can trigeminal autonomic cephalalgia be cured?

No.

Medications can only control symptom flare-ups, but since the cause is unknown, headaches may persist indefinitely.

DIET & LIFESTYLE

What should be noted in daily life for trigeminal autonomic cephalalgia?

Keep a headache diary, recording the duration of each episode and daily frequency to help doctors understand the condition during consultations.

Does trigeminal autonomic cephalalgia require follow-up visits?

Yes. Prompt follow-up is needed if medication tolerance develops or headache patterns change.

Does trigeminal autonomic cephalalgia affect fertility?

No.

Can patients with trigeminal autonomic cephalalgia fly, engage in intense exercise, or travel to high-altitude areas?

Yes.

Are there dietary precautions for trigeminal autonomic cephalalgia?

Alcohol may trigger cluster headaches and should be avoided. Identify and avoid other dietary triggers if present. Otherwise, maintain a healthy, balanced diet with no specific restrictions.

PREVENTION

Can Trigeminal Autonomic Cephalalgias Be Prevented? How to Prevent It?

The cause of trigeminal autonomic cephalalgias is unknown, and there is no effective way to prevent the onset of these disorders. For those already suffering from these conditions, certain medications can help prevent headache attacks, including:

• Verapamil is the first-choice oral medication for preventing cluster headaches, while corticosteroids and topiramate may also be tried.
• Paroxysmal hemicrania and hemicrania continua can also be prevented by taking indomethacin.
• SUNCT syndrome and SUNA syndrome can be managed with lamotrigine, topiramate, and gabapentin to prevent attacks.