Trigeminal Neuralgia

Trigeminal neuralgia (TN), also known as tic douloureux or Fothergill's disease, is a chronic pain disorder that affects the trigeminal nerve, responsible for sensation in the face and motor functions such as biting and chewing. It is one of the most painful conditions known to medicine, often leading to significant impacts on quality of life.

The trigeminal nerve and its three major divisions (shown in yellow): the ophthalmic nerve (V1), the maxillary nerve (V2), and the mandibular nerve (V3)

Signs and Symptoms

TN is characterized by episodes of severe, sudden, shock-like pain on one side of the face, typically lasting from a few seconds to several minutes. These episodes can recur in quick succession over hours. The pain is often described as stabbing, burning, or electric shock-like. TN can be classified into two types:

• Typical TN: Characterized by sudden, severe, shock-like pain.
• Atypical TN: Involves a constant, less severe burning pain.

Triggers for TN episodes can include everyday activities such as eating, talking, shaving, or even exposure to wind. The condition significantly impacts daily living and can lead to depression and anxiety due to the unpredictability and severity of the pain.

Trigeminal neuralgia

Causes

The exact cause of TN is often unknown. However, it is believed to involve the compression of the trigeminal nerve, leading to the loss of its protective myelin sheath. Potential causes include:

• Compression by blood vessels (most commonly the superior cerebellar artery).
• Multiple sclerosis, stroke, or trauma.
• Less commonly, a tumour or arteriovenous malformation.

Diagnosis

Diagnosis of TN is primarily based on the characteristic symptoms and the exclusion of other possible causes, such as postherpetic neuralgia. Magnetic resonance imaging (MRI) may be used to detect vascular compression of the trigeminal nerve.

Treatment

Medical Management

Initial treatment typically involves medications:

• Carbamazepine and oxcarbazepine are the first-line treatments, effective in about 90% of cases.
• Other medications include lamotrigine, baclofen, gabapentin, amitriptyline, and pimozide.
• Opioids are generally ineffective for TN.

Surgical Management

When medications are ineffective, surgical options may be considered:

• Microvascular decompression: Relieves pressure on the trigeminal nerve by placing a sponge between the nerve and the compressing blood vessel.
• Percutaneous procedures: Include balloon compression, glycerol injection, and radiofrequency thermocoagulation, all of which intentionally damage the nerve to reduce pain.
• Stereotactic radiosurgery: Uses focused radiation to damage the nerve.

Complications

The severity of pain and its impact on daily activities can lead to significant psychological distress, including depression and anxiety. The fear of unpredictable and severe pain episodes can severely limit social interactions and quality of life.

History and Notable Cases

TN has been known since the 18th century and was first described in detail by John Fothergill. Historically referred to as "suicide disease" due to its severe pain and psychological impact, TN has affected several notable individuals, including four-time British Prime Minister William Gladstone and Indian film star Salman Khan.

The Scream, a painting by Edvard Munch, is often used as a symbol of intense facial pain, including trigeminal neuralgia

TN continues to be a significant medical condition requiring comprehensive management involving both medical and surgical treatments to alleviate pain and improve patient quality of life.

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Self-assessment MCQs (single best answer)

Which of the following medications is NOT commonly used in the treatment of Trigeminal Neuralgia?

What is the most common initial treatment for Trigeminal Neuralgia?

Which branch of the trigeminal nerve is most commonly affected in Trigeminal Neuralgia?

What type of pain is typically experienced in Trigeminal Neuralgia?

Which surgical procedure involves placing a sponge between the nerve and the compressing blood vessel in Trigeminal Neuralgia?

What is a common side effect of percutaneous procedures for Trigeminal Neuralgia?

Which of the following conditions can cause symptoms similar to Trigeminal Neuralgia?

In Trigeminal Neuralgia, what is believed to cause the loss of myelin in the trigeminal nerve?

What is the typical age of onset for Trigeminal Neuralgia?

Which of the following symptoms is most characteristic of atypical Trigeminal Neuralgia?