Trigeminal neuralgia revisited
Trigeminal neuralgia (TN) is characterised by touch-evoked unilateral brief shock-like paroxysmal pain in one or more divisions of the trigeminal nerve. In addition to the paroxysmal pain, some patients also have continuous pain. A neurovascular conflict which involves morphological changes of the trigeminal nerve is highly associated with classical TN and is present in about half of TN patients. TN can be divided into classical TN and secondary TN. Secondary TN is caused by either multiple sclerosis or a space-occupying lesion affecting the trigeminal nerve reports Maarbjerg et al., 2017.
Clinical implication: The diagnosis is based on patient history.
1. Pain onset is important:
1a. If the pain was preceeded by or coincided with a herpes zoster in the ipsilateral trigeminal distribution, painful trigeminal neuropathy attributed to acute herpes zoster should be considered.
1b. If the pain was preceeded by a relevant trauma to the ipsilateral side of the face, e.g. such as invasive dental procedures or fractures, painful post-traumatic trigeminal neuropathy is more likely.
2. Pain location is important:
2a. In bilateral constant pain located in the temporomandibular area, tension-type headache, TMD and persistent idiopathic facial pain should be considered.
2b. If short-lasting intense stabbing pain is isolated to the scalp or occipital area, diagnoses such as occipital neuralgia, primary stabbing headache and paroxysmal hemicranias should be considered.
Practical application: An early work-up should include and MRI of the brain and brainstem, ECG and laboratory testing. Generally, first line treatment is prophylactic medication with sodium channel blockers. In medically refractory patients, surgical treatment is the next step.
Reference: Maarbjerg, S., Di Stefano, G., Bendtsen, L. and Cruccu, G., 2017. Trigeminal neuralgia–diagnosis and treatment. Cephalalgia, 37(7), pp.648-657.