This summary is based on the article published in Dental Clinics of North America
Neurologic Disorders of the Maxillofacial Region
Trigeminal neuralgia, also called tic douloureux, is characterized by sudden onset of recurrent unilateral electric shock–like, stabbing, or shooting pain lasting between a fraction of a second and 2 minutes.1
It occurs along the distribution of the trigeminal nerve and has a trigger zone/point, typically in the maxillary (V2) and maxillary (V3) nerve distributions.
Pain is triggered by innocuous stimuli such as facial touch, brushing teeth, talking, or cold air. However, patients have intermittently pain-free periods, with pain occurring sporadically and terminating abruptly. Symptoms occur in the absence of neurologic deficits.
- Maarbjerg S, Di Stefano G, Bendtsen L, et al. Trigeminal neuralgia – diagnosis and treatment. Cephalalgia 2017;37:648–57.
Most cases of trigeminal neuralgia occur in women more than 40 years of age, peaking between 50 and 60 years.3 An incidence of 4.3 to 32.1 per 100,000 person years and prevalence of 0.07% to 0.3%1,2 has been reported.
- Maarbjerg S, Di Stefano G, Bendtsen L, et al. Trigeminal neuralgia – diagnosis and treatment. Cephalalgia 2017;37:648–57.
- Cruccu G. Trigeminal neuralgia. Continuum 2017;23:396–420.
- Matwychuk M. Diagnostic challenges of neuropathic tooth pain. J Can Dent Assoc 2004;70:542–6.
Classic trigeminal neuralgia1
a. Idiopathic form: no disorder is evident.
b. Classic form: hypothesized to be related to vascular compression on the trigeminal nerve near the skull base or vasospasm.
Secondary (symptomatic) trigeminal neuralgia
Occurs from presence of brain tumors, infections, multiple sclerosis, trauma, and so forth. Most commonly, prior dental procedures or anesthetic injections can cause such iatrogenic injuries.
- Cruccu G. Trigeminal neuralgia. Continuum 2017;23:396–420.
Clinical presentation
Unilateral sharp, shooting, electric shock–like, paroxysmal or episodic pain symptoms are commonly encountered. Pain is severe enough for the patient to stop any ongoing activity, including cessation of talking mid sentence.
In addition to patients with paroxysmal pain, there is another group of patients with trigeminal neuralgia that present with constant burning pain, usually affecting 1 side of the face. It is important to consider this subtype and recognize such atypical presentations, in order not to miss a diagnosis of trigeminal neuralgia.
Diagnosis is based on thorough history and clinical examination.
Management
Pharmacologic Sodium channel blockers are the first-line drugs in the management of patients with trigeminal neuralgia. Both carbamazepine and oxcarbazepine are highly effective, with mechanism of action being the blockade of voltage-gated sodium channels.
Patients on carbamazepine require periodic CBC assessment, because this drug is known to cause aplastic anemia in 1% to 2% of users.1 Oxcarbazepine is better tolerated than carbamazepine and with fewer side effects.
For patients with allergies or drug interactions with carbamazepine, or who have low sodium levels, baclofen or lamotrigine are other beneficial alternatives.
Neuromodulation therapy
This technique is explored for the treatment of chronic neuropathic pain. Although certain types of peripheral nerve stimulation procedures are US Food and Drug Administration (FDA) approved for pain in the extremities and back, using this technique for facial pain is still considered an off-label use.
Surgical
1. Microvascular decompression is a common surgical procedure if the condition is non-responsive to medication
2. Glycerol blockade
3. Radiofrequency thermocoagulation
4. Stereotactic (Gamma Knife) radiosurgery
- Daughton JM, Padala PR, Gabel TL. Careful monitoring for agranulocytosis during carbamazepine treatment. Prim Care Companion J Clin Psychiatry 2006;8: 310–1.
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CDA Oasis Team