Circuit 4, station 13

Trigeminal neuralgia (TN), also known as tic douloureux, is a debilitating condition characterised by intense facial pain. Dental practitioners hold a crucial role as the initial point of contact for patients, necessitating accurate diagnosis and effective management of TN. The review encompasses various aspects of TN, ranging from its presentation and classification to diagnosis and available treatment options.

TN is a neurological disorder distinguished by sudden, excruciating, and transient shock-like facial pain localised to the distribution of the trigeminal nerve. Classical TN (CTN) commonly exhibits pain triggers such as mastication, touch, tooth brushing, eating, talking, and exposure to cold wind, while hair combing typically does not elicit pain. Pain predominantly occurs along the Trigeminal V2 and V3 branches, and trigger zones manifest in over 90% of patients. Although pain may manifest on either side of the face, the right side is more frequently affected.

Classification: The classification of trigeminal neuralgia has undergone significant revisions in recent years. According to the third edition of the International Classification of Headache Disorders (ICHD-3), TN is now categorised into three distinct types: classical, secondary, and idiopathic.

1. Classical trigeminal neuralgia (CTN): This form is the most prevalent type encountered by GPs. CTN is characterised by recurrent, unilateral facial pain along the trigeminal nerve’s distribution, with pain-free intervals between episodes.
2. Secondary trigeminal neuralgia (STN): Patients with STN experience similar symptoms to CTN, but with underlying pathology contributing to the condition. Potential etiologies include multiple sclerosis, space-occupying lesions, and neuropathy.
3. Idiopathic trigeminal neuralgia: This subtype exhibits classical TN symptoms without significant abnormalities detected through electrophysiological tests or radiological investigations.

Healthcare providers must differentiate between these TN types due to potential variations in management approaches.

1. The defining characteristics of trigeminal neuralgia (TN) are distinctive pain presentation, triggers, distribution, and prevalence across facial sides.
2. There are three distinct types of TN: classical, secondary, and idiopathic, and provide examples of conditions associated with secondary trigeminal neuralgia.
3. Know the importance of differentiating between TN types for healthcare providers, particularly focusing on classical TN, which is the most encountered subtype by general practitioners.

Carbamazepine (CBZ) is the drug of choice. Additionally, alternative therapeutic interventions, such as local anaesthetic injections and botulinum toxin A injections can be utilised. Surgical options, including percutaneous procedures and microvascular decompression, are potential alternatives for patients unresponsive to or intolerant of medication.

Other disorders that can mimic TN symptoms, include painful trigeminal neuropathy, Herpes Zoster infestation, chronic paroxysmal hemicrania, Tolosa-Hunt syndrome, migraine, cluster headache, and glossopharyngeal neuralgia.

Diagnostic approaches for TN, include the patient’s history, thorough physical and neurological examination, and utilisation of neurophysiological tests and imaging techniques such as MRI/MRA.

Carbamazepine (CBZ), as the drug of choice for TN, alternative medications, such as oxcarbazepine (OXC), pregabalin, gabapentin, topiramate, levetiracetam, and valproic acid, for patients unresponsive to or intolerant of CBZ. 

Non-pharmacological interventions, includes local anaesthetic injections (alcohol, glycerol, phenol, tetracaine, or bupivacaine) and botulinum toxin A injections, as potential options for pain relief.

Surgical procedures, include percutaneous trigeminal ganglion balloon compression rhizotomy, percutaneous radiofrequency gangliolysis, trigeminal ganglion compression, retrogasserian glycerol rhizolysis, microvascular decompression (MVD), stereotactic radiosurgery, and peripheral neurectomy, as alternative approaches for patients who do not respond to conservative management.