Trigeminal neuralgia (including post-herpetic neuralgia)

Trigeminal neuralgia is a relatively rare condition that comprises intractable neuropathic pain relating to the trigeminal nerve, the nerve which relays sensory impulses from the face. Patient will commonly describe severe shooting, “electric shock”-type pain in one or more distributions of the trigeminal nerve, not responding to over-the-counter (OTC) medications and unpredictable in nature. Indeed, the unpredictability of the pain and sporadic nature can be one of the most anxiety-inducing aspects of this condition for patients, severely impacting quality of life.

What causes trigeminal neuralgia?

Trigeminal neuralgia may be caused by underlying conditions (e.g. multiple sclerosis, shingles – the latter known as post-herpetic neuralgia) but is often idiopathic (no identified cause). I will commonly ask for cross-sectional imaging, usually magnetic resonance imaging (MRI), to see whether there is any neurovascular conflict with the trigeminal nerve (pressure from an adjacent blood vessel causing the nerve to “short circuit” due to loss of the protective covering). This may enable patients to be candidates for nerve decompression surgery, but often treatment is medical with anticonvulsant drugs (e.g carbamazepine) which can be titrated up slowly to response.

In addition, MRI can exclude a wide range of other features including:

• sinusitis;
• extracranial masses;
• malignancy and enhancement of the trigeminal nerve;
• cavernous sinus masses;
• demyelination plaques that may indicate multiple sclerosis (MS);
• intrinsic brain lesions;
• cerebellopontine angle (CPA) masses.

It is essential to exclude these potentially sinister and (in some instances) eminently treatable causes of trigeminal neuralgia where present.

What are the options for treatment?

In a minority of cases where mono therapy is not successful, combinations of drugs may be required, with close monitoring. Other alternatives exist including percutaneous and open surgical ablative procedures of the nerve (e.g. radiofrequency lesioning, glycerol rhizolysis or balloon compression) and stereotactic radiosurgery. These are complex options and I will often request additional opinions from colleagues in Neurology and/or Pain Medicine to optimise your pain control strategies and balance risks and benefits of each treatment modality to get you the best improvements in quality of life with the lowest side effect profile.