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Trigeminal Neuralgia

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Trigeminal neuralgia\: a form of neuropathic pain characterised by sharp, shooting sensations in the face; intense and often
impacts quality of life; typically a
Anatomy\: trigeminal nerve (CN V) has three divisions - ophthalmic (V1) for the cornea, scalp, and forehead; maxillary (V2) for
the cheek, upper jaw, and upper lip; mandibular (V3) for the lower jaw, teeth, and gums.
Pathophysiology\: caused by disruption and demyelination of the nerve, often due to compression. Types include\:
Classic\: vascular compression (most commonly by the superior cerebellar artery).
Secondary\: related to tumours or underlying diseases (e.g., multiple sclerosis).
Idiopathic\: unknown cause.
Risk factors\: female sex, age over 50, and multiple sclerosis (increased risk by a factor of 20).
Clinical features\: episodes of unilateral, sharp facial pain; triggers include talking, washing face, shaving, brushing teeth,
exposure to cold air; less commonly, ophthalmic symptoms (lacrimation, conjunctival redness, photophobia).
Examination\: classic/idiopathic trigeminal neuralgia usually shows a normal physical examination, while secondary causes
may show signs of underlying disease.
Di
symptoms may warrant further investigation for multiple sclerosis.
Investigations\: primarily a clinical diagnosis; blood tests (WCC, CRP) to exclude other causes; MRI to identify tumours,
vascular abnormalities, or demyelination (suggestive of multiple sclerosis).
Management\:
First-line\: carbamazepine (side e
Other options\: oxcarbazepine, lamotrigine, topiramate, gabapentin, pregabalin; eye care and anaesthetic eyedrops for
ophthalmic symptoms.
Surgical options\: nerve decompression or ablation if medical management fails; risks include corneal anaesthesia if V1 is
damaged.
Complications\: severe pain can impair daily activities and increase the risk of depression.
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Introduction

Trigeminal neuralgia is a form of neuropathic pain characterised by a sharp, shooting sensation a
is intense and often signi
The condition typically a
1,2

Aetiology

Anatomy

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The trigeminal nerve (CN V) conveys sensory input from the face in a mask-like distribution and provides motor supply to
the muscles of mastication via three divisions\:
The ophthalmic branch (upper, V1) supplies sensation to most of the cornea, scalp and forehead
The maxillary branch (middle, V2) supplies sensation to the cheek, upper jaw, upper lip, teeth and gums, and the lateral
aspect of the nose
The mandibular branch (lower, V3) supplies sensation to the lower jaw, teeth and gums, and lower lip
Trigeminal nerve dermatomes

Pathophysiology and classi

Trigeminal neuralgia is caused by disruption to the nerve function. The underlying pathophysiology is demyelination of the
nerve, which is believed to be caused by compression.
Trigeminal neuralgia can be divided into 3 types\:
3
Classic trigeminal neuralgia\: vascular compression by a nearby artery or vein (most commonly the superior cerebellar
artery)
Secondary trigeminal neuralgia\: relating to a tumour or due to underlying disease (e.g. multiple sclerosis, damage
following facial injury/surgery, cyst or tumour)
Idiopathic trigeminal neuralgia\: if the cause is unknown

Risk factors

Risk factors for trigeminal neuralgia include\:
2,4
Female sex
Age (more common >50)
Multiple sclerosis (increases the risk by a factor of 20 in comparison to the general population)

Clinical features

History

The classical presentation of trigeminal neuralgia is episodes of unilateral, sharp facial pain (which may be described as
"burning").
5,6
Episodes may be associated with triggers, including\:
5,6
Talking
Washing the face
Shaving
Brushing teeth
Exposure to cold air
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Episodes may be triggered with only minor stimuli, and patients may be reluctant to have their face examined or touched
due to fear of triggering the pain.
Less commonly, patients can experience ophthalmic symptoms, including lacrimation, conjunctival redness and
photophobia.
7

Clinical examination

In classic/idiopathic trigeminal neuralgia, physical examination including neurological examination, is usually normal. In
secondary trigeminal neuralgia, there may be signs of the underlying disease process causing trigeminal neuralgia.

Di

Unilateral face pain can be a common presenting complaint for multiple other conditions such as migraines, cluster
headaches, atypical facial pain, dental neuralgia and TMJ dysfunction\:
8
Cluster headache\: the patient is usually between 30-40 years old, six to nine times more common in females.
Symptoms are always unilateral, lasting up to 1.5 hours and can be accompanied by other symptoms conjunctival
injection and epiphora. These headaches occur in clusters, with weeks to months intervals
Migraine\: age of onset is usually around 20 years of age, can be unilateral or bilateral, has other associated symptoms
such as photophobia. The attack can last 4-72 hours, it cycles in days to weeks intervals, with many di
provoking the attacks.
Atypical facial pain\: a
described as throbbing pain that is mild/moderate in severity. Can be provoked by stress and cold and associated with
sensory abnormalities
If symptoms are bilateral, this can warrant further investigations, such as MRI, to rule out multiple sclerosis. Multiple
sclerosis can have similar symptoms as TN, hence in younger patients, you would look for other symptoms (e.g. focal
weakness, ataxia, optic neuritis/vision changes).

Investigations

Trigeminal neuralgia is usually a clinical diagnosis. However, investigations, such as blood tests and imaging, can be used
to exclude other diagnoses or secondary causes of trigeminal neuralgia.
In
cerebellopontine angle tumours, vascular abnormalities or areas of demyelination suggestive of multiple sclerosis.

Management

Medical management

Current NICE guidelines suggest carbamazepine, an anti-convulsant, for
6
Side ehyponatraemia. If side e
carbamazepine doesn't relieve symptoms, the patient should be referred to a specialist.
Other treatment options include oxcarbazepine, lamotrigine, topiramate, gabapentin and pregabalin. Management of
ophthalmic symptoms includes eye care and anaesthetic eyedrops.

Surgical management

If symptoms persist despite medical management, there are surgical options available to decompress the nerve or to
ablate the nerve to prevent pain transmission through the nerve. However, these procedures have risks, especially if the V1
nerve is damaged, which can cause corneal anaesthesia.
7

Complications

Pain caused by trigeminal neuralgia can be so severe that patients’ activities of daily living become impaired, and they are
at risk of depression.
6
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References

National Institute of Neurological Disorders and Stroke. T r i g e m i n a l n e u r a l g i a . Published November 2023. Available from\:
[LINK]
Maarbjerg, S., Gozalov, A., Olesen, J., & Bendtsen, L. (2014). Trigeminal neuralgia–a prospective systematic study of clinical
characteristics in 158 patients. H e a d a c h e \: T h e J o u r n a l o f H e a d a n d F a c e P a i n , 5 4 (10), 1574-1582.
Olesen, J. (2018). Headache classi
classi
Cruccu, G., Di Stefano, G., & Truini, A. (2020). Trigeminal neuralgia. New England Journal of Medicine, 383(8), 754-762.
Cruccu, G., Finnerup, N. B., Jensen, T. S., Scholz, J., Sindou, M., Svensson, P., ... & Nurmikko, T. (2016). Trigeminal neuralgia\:
new classi
NICE CKS. Trigeminal neuralgia. Available from\: [LINK]
Bhatti, M. T., & Patel, R. (2005). Neuro-ophthalmic considerations in trigeminal neuralgia and its surgical treatment. Current
Opinion in Ophthalmology, 16(6), 334-340.
Singh MK, Egan RA. Trigeminal Neuralgia DiLINK]

Reviewer

Dr Hameed Shalash
Consultant Neurologist
Dr Russel Tilney
Honorary Clinical Research Fellow
UCL

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Contents

Introduction
Aetiology
Risk factors
Clinical features
Di
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Investigations
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