Summary

Trigeminal neuralgia (TN) is characterised by recurrent, severe, unilateral, shock-like facial pain in the distribution of one or more branches of the trigeminal nerve (CN V). It is considered one of the most severe pain conditions known to medicine, often described as "the suicide disease." Classical TN is caused by vascular compression of the trigeminal nerve root (usually the superior cerebellar artery), while secondary TN occurs due to underlying pathology such as multiple sclerosis or tumours. First-line treatment is carbamazepine; surgical options include microvascular decompression for refractory cases. [1,2]

Key Facts

• Incidence: 4-13 per 100,000 per year; increases with age. [3]
• Peak Age: 50-70 years.
• Sex: Female greater than Male (1.5:1).
• Distribution: V2/V3 most common (95%); V1 alone rare (less than 5%).
• Cause: Vascular compression (80-90%), MS (2-4%), tumour (less than 1%).
• First-Line Treatment: Carbamazepine (or oxcarbazepine).
• Surgical Cure: Microvascular decompression (MVD) - 80-90% success rate.

Clinical Pearls

"Suicide Disease": Trigeminal neuralgia is one of the most painful conditions known. The severity of pain can lead to depression and, historically, suicide - hence the name.

Trigger Zones: Light touch triggers the pain (eating, talking, washing face, wind); paradoxically, firm pressure often does NOT trigger pain.

Refractory Period: After an attack, there is typically a refractory period of seconds to minutes where another attack cannot be triggered.

Red Flags for Secondary TN: Age less than 40, bilateral symptoms, sensory loss, V1 involvement, or progressive course should prompt MRI to exclude MS or tumour.

General Observation

• Patient may guard face or avoid touching affected side.
• May grimace or wince during attack (tic douloureux = painful tic).
• May have poor oral hygiene (avoiding brushing).

Neurological Examination

Cranial Nerves (Focus on V and Neighbours)

Key Points

• Classical TN: Examination should be NORMAL.
• Any sensory or motor deficit suggests secondary cause.
• Test all three divisions of trigeminal nerve.

Trigger Zone Identification

• Lightly stimulate face with cotton wool.
• Affected patients often refuse examination of trigger zone.
• Location helps confirm diagnosis but rarely needed.

Natural History

• Spontaneous remissions occur (months to years) early in disease.
• Over time, remissions become shorter and attacks more frequent.
• Untreated, condition is progressive.

Treatment Outcomes

Prognostic Factors

Favourable

• Classical TN with clear neurovascular conflict.
• Good response to carbamazepine.
• Younger, fit patients (for MVD).
• Short duration of symptoms.

Unfavourable

• Secondary TN (MS, tumour).
• Long disease duration before surgery.
• Multiple previous procedures.
• Continuous background pain (TN type 2).

Key Guidelines

Landmark Studies

1. Carbamazepine Efficacy (Cochrane 2019) [4]

• Question: Is carbamazepine effective for TN?
• Result: Carbamazepine is effective; NNT approximately 1.7-1.8.
• Impact: Confirmed as first-line treatment.
• PMID: 31034599.

2. Barker et al. MVD Outcomes (1996)

• Question: Long-term outcomes of MVD for TN?
• N: 1,185 patients with 10-year follow-up.
• Result: 70% pain-free at 10 years.
• Impact: Established MVD as durable surgical option.
• PMID: 8637212.

3. Gamma Knife vs MVD (Comparison Studies)

• MVD provides more durable pain relief.
• Gamma Knife preferred for elderly/unfit.
• Both superior to percutaneous procedures for long-term control.

What is Trigeminal Neuralgia?

Trigeminal neuralgia (TN) is a condition that causes sudden, severe, shock-like pain in the face. The pain follows the course of the trigeminal nerve, which carries sensation from your face to your brain. It usually affects one side of the face and can be triggered by everyday activities.

What Causes It?

The most common cause is a blood vessel pressing on the trigeminal nerve near the brain. This causes the nerve to misfire, sending pain signals when there should be none. Other causes include multiple sclerosis (MS) or, rarely, a tumour.

What Does the Pain Feel Like?

• Extremely severe, electric shock-like pain.
• Lasts a few seconds to a minute or two.
• Usually on one side of the face (cheek, jaw, or lips).
• Comes in attacks, sometimes many times a day.
• Can have pain-free periods lasting weeks or months.

What Triggers the Pain?

• Touching your face.
• Eating, chewing, or drinking.
• Talking or smiling.
• Brushing teeth.
• Cold wind on your face.
• Washing your face.

How is it Diagnosed?

• Your doctor will ask about your symptoms.
• Neurological examination should be normal.
• An MRI scan is usually done to check for other causes.

How is it Treated?

Medication (First-Line)

• Carbamazepine (Tegretol) is the main treatment.
• It reduces the nerve's tendency to fire.
• Needs regular blood tests to monitor.
• Other medications include oxcarbazepine, gabapentin, or pregabalin.

Surgery (If Medication Doesn't Work)

• Microvascular Decompression (MVD): Brain surgery to separate the blood vessel from the nerve. High success rate.
• Gamma Knife: Focused radiation treatment. Non-invasive.
• Needle Procedures: Ablation or compression of the nerve.

What is the Outlook?

• Most people get good pain relief with medication or surgery.
• Some people have remissions without treatment.
• A small number have difficult-to-control pain.

When to Seek Help

• If you have sudden, severe facial pain.
• If treatments are not working.
• If you develop numbness or weakness in your face.
• If you are under 40 (may need extra tests).