Clinical aspects and pharmacological treatment of trigeminal neuralgia

Resumo

Trigeminal neuralgia (TN) is defined as sudden, usually
unilateral, severe and brief pain episodes within the distribution of
one or more branches of the trigeminal nerve. In some patients a
constant background pain may persist, additionally to pain attacks,
which can make difficult to differentiate the trigeminal neuralgia from
other orofacial pain types. Objective: To review the classification,
physiopathological aspects, epidemiologic data and pharmacological
options to control pain related to trigeminal neuralgia. Literature
review: One of the proposed etiologies for this condition is a localcircumscribed demyelination of the trigeminal nerve resulting in
neuronal hyperexcitability and generation of ephaptic coupling,
which would be responsible for the pain paroxysms. Initially, the
treatment of patients with these pain characteristics is based on the
use of anticonvulsants, in order to attenuate the ectopic-generated
pain impulses. Carbamazepine is the first-line drug, but other
anticonvulsants may be employed and have shown variable efficacy
in the treatment of trigeminal neuralgia. Conclusion: According to
the new classification of the International Headache Society, classic
trigeminal neuralgia is divided in purely paroxysmal and with
concomitant persistent facial pain. The pathophysiology is unclear,
but trigeminal neuralgia seems to be the consequence of vascular compression of the trigeminal nerve near the brain stem. Although
TN presents a low prevalence in general population (i.e. 5-30 new
patients per 100,000), trigeminal neuralgia is an important clinical
concern both by pain severity and difficulty of its satisfactory control.
Anticonvulsants are the medication of choice in the treatment of
trigeminal neuralgia; however, their use is associated with several
adverse effects and possibility of treatment refractoriness.