What I Treat
Trigeminal Neuralgia
Electric-shock facial pain
Trigeminal neuralgia is a disorder characterised by recurrent attacks of severe, unilateral facial pain affecting one or more divisions of the trigeminal nerve. Patients describe the pain as electric-shock-like, stabbing, sudden, and extremely intense, lasting seconds to two minutes and triggered by harmless stimuli such as touching the face, speaking, eating, shaving, washing or brushing the teeth.
Classification
Three types, three causes
The type of trigeminal neuralgia you have determines which treatment is most likely to help.
Classical TN
A blood vessel — most often the superior cerebellar artery — compresses the nerve at its root entry zone, producing morphological changes such as distortion or atrophy. This is the most common type and the one most reliably treated by microvascular decompression.
Secondary TN
Caused by another identifiable disorder. Multiple sclerosis is the most frequent neurological cause. Other causes include tumours, epidermoid cysts, AVMs, and inflammatory disease. Treating the underlying disorder is the priority.
Idiopathic TN
A convincing TN clinical picture, but investigations show no neurovascular compression or structural cause. These patients are managed similarly to those with classical TN.
Each type can be subdivided into purely paroxysmal TN (brief electrical attacks only) or TN with concomitant continuous facial pain (a background aching or burning between attacks). The electrical component generally responds more predictably to treatment than the constant background discomfort.
The mechanism
Why does the pain occur?
The most widely accepted explanation is focal demyelination — damage to the insulating myelin sheath of the trigeminal nerve, usually near the root entry zone. This allows abnormal electrical transmission between adjacent nerve fibres, a phenomenon called ephaptic transmission, making the nerve hyperexcitable.
A normally harmless stimulus — a light touch, a breeze, chewing, or speaking — can trigger a barrage of electrical signals that the brain interprets as searing pain.
Clinical picture
Symptoms
Cardinal features
- Recurrent unilateral facial-pain paroxysms
- Pain confined to the trigeminal distribution (V1, V2, V3)
- Severe, electric, stabbing, shooting or sharp in quality
- Attacks lasting seconds, occasionally up to two minutes
- Triggered by innocuous facial or oral stimulation (touch, speaking, eating, shaving, brushing teeth)
- Stereotyped attacks similar each time, with a brief refractory period after
Findings that should cause concern
Most patients with classical or idiopathic TN have a normal neurological examination. The following findings increase the likelihood of a secondary lesion or a different facial-pain syndrome:
- •Objective facial sensory loss
- •Absent or asymmetrical corneal reflex
- •Facial weakness
- •Hearing loss or cranial neuropathy
- •Bilateral symptoms
- •Continuous numbness or burning
- •Symptoms beginning at a young age
- •Pain outside the trigeminal distribution
- •Constitutional or malignant features
Important differential diagnoses: dental disease, temporomandibular disorder, persistent idiopathic facial pain, painful trigeminal neuropathy, post-herpetic neuralgia, glossopharyngeal neuralgia, cluster headache, and SUNCT/SUNA. Many patients undergo unnecessary dental treatment before TN is recognised.
Work-up
How it is diagnosed
Clinical diagnosis
Trigeminal neuralgia is primarily a clinical diagnosis. The history is more important than any single scan. A focused neurological examination should include light touch and pinprick sensation in V1, V2 and V3; corneal reflexes; facial motor function; muscles of mastication; and hearing and cerebellar examination.
MRI protocol
High-resolution 3D heavily T2-weighted imaging (CISS or FIESTA), time-of-flight MR angiography, and contrast-enhanced T1-weighted imaging. These sequences assess the trigeminal pathway, exclude tumours or demyelination, and evaluate neurovascular compression. A normal MRI does not disprove TN, and vascular contact alone does not prove it.
For patients with ancestry from populations in which HLA-B*15:02 is prevalent, including several Asian populations, pharmacogenetic testing should be considered before starting carbamazepine — this allele is strongly associated with carbamazepine-induced Stevens-Johnson syndrome.
Management
Treatment options
Treatment is individualised according to pain severity, age, general health, medication tolerance, MRI findings and patient preference.
First-line medical therapy
Carbamazepine and oxcarbazepine remain the principal first-line medications. Treatment is started at a low dose and titrated according to response and adverse effects. These drugs are taken regularly, not only during attacks. Monitoring includes full blood count, liver function, renal function, and serum sodium. Additional agents may include lamotrigine, baclofen, gabapentin, pregabalin, and botulinum toxin type A in selected patients.
A neurosurgical opinion is appropriate when medication no longer controls the pain, effective doses cause unacceptable adverse effects, attacks significantly impair quality of life, or there is compelling neurovascular compression on MRI.
Surgical procedures
Microvascular decompression
MVD
Through a small retrosigmoid craniotomy, the offending artery or vein is separated from the nerve. MVD offers the highest probability of durable pain relief, preserves facial sensation, and avoids deliberately lesioning the nerve. Risks include CSF leak, hearing impairment, facial numbness, and vascular injury.
Percutaneous procedures
RF / Balloon / Glycerol
These reach the trigeminal ganglion through the foramen ovale and intentionally injure selected pain fibres. They offer rapid pain relief with a relatively short procedure and are useful in elderly or medically frail patients. Facial numbness is expected to varying degrees, and recurrence is more common than after successful MVD.
Stereotactic radiosurgery
Gamma Knife
Delivers focused radiation to the trigeminal nerve. No incision is required, it is usually performed as a day procedure, and it is useful in patients who are not ideal candidates for open surgery. Pain relief is usually delayed rather than immediate, and recurrence may occur.
Outcomes
What to expect
The therapeutic goal is not only pain relief — successful treatment should restore eating, speaking, sleep, personal care, confidence, and the ability to touch the face without fear.
Medical disclaimer: The information on this page is for general educational purposes only. It is not a substitute for individual medical advice, diagnosis, or treatment. Always consult your own doctor or specialist with any questions you may have regarding a medical condition.
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