Guideline source: American Academy of Neurology
Literature search described? Yes
Evidence rating system used? Yes
Published source:Neurology, October 2008
Trigeminal neuralgia is defined as sudden, usually unilateral, severe, brief, stabbing, recurrent episodes of pain in one or more branches of the trigeminal nerve (i.e., the fifth cranial nerve). The annual incidence of trigeminal neuralgia is four to five cases per 100,000 persons.
The International Headache Society has classified trigeminal neuralgia into two categories: classic and symptomatic. Classic trigeminal neuralgia has no established etiology, although it may include potential vascular compression of the trigeminal nerve. The diagnosis of classic trigeminal neuralgia requires the absence of any clinically evident neurologic deficit, whereas the diagnosis of symptomatic trigeminal neuralgia requires the identification of a structural abnormality other than vascular compression. Possible abnormalities include multiple sclerosis (MS) plaques, tumors, and abnormalities of the skull base.
A panel of experts from the American Academy of Neurology (AAN) and the European Federation of Neurological Societies (EFNS) reviewed the literature on the diagnosis and treatment of trigeminal neuralgia. Evidence ratings were based on AAN's method for determining the strength of recommendations: Level A = established as effective, ineffective, or harmful for the given condition in the specified population (i.e., should be done, or should not be done); Level B = probably effective, ineffective, or harmful for the given condition in the specified population (i.e., should be considered, or should not be considered); Level C = possibly effective, ineffective, or harmful for the given condition in the specified population (i.e., may be considered, or may not be considered); or Level U = data inadequate or conflicting, or treatment is unproven (no recommendation).
How often does routine neuroimaging with computed tomography or magnetic resonance imaging (MRI) identify a structural cause of trigeminal neuralgia (excluding vascular compression of the trigeminal nerve)?
Routine neuroimaging in patients diagnosed with trigeminal neuralgia may identify a structural (nonvascular) cause in up to 15 percent of patients. (Level C recommendation)
Which clinical or laboratory features accurately identify patients with symptomatic trigeminal neuralgia?
To distinguish symptomatic from classic trigeminal neuralgia, clinical characteristics such as patient age at onset, the presence of sensory deficits, bilateral involvement of the trigeminal nerve, and unresponsiveness to treatment were examined. A younger age at onset and abnormal trigeminal nerve–evoked potentials are probably associated with an increased risk of symptomatic trigeminal neuralgia. However, there is too much overlap in patients with classic trigeminal neuralgia and symptomatic trigeminal neuralgia to consider these clinical characteristics diagnostic for the latter. (Level B recommendation)
The presence of trigeminal sensory deficits or bilateral involvement of the trigeminal nerves likely indicates symptomatic trigeminal neuralgia. However, because of poor specificity, the absence of these features does not rule out symptomatic trigeminal neuralgia. (Level B recommendation)
The involvement of the first division of the trigeminal nerve and an unresponsiveness to treatment are not considered useful features for identifying patients with an increased risk of symptomatic trigeminal neuralgia. (Level B recommendation)
Abnormal trigeminal reflexes should be considered useful in distinguishing symptomatic from classic trigeminal neuralgia because of the high specificity (94 percent) and sensitivity (87 percent). (Level B recommendation)
Does high-resolution MRI accurately identify neurovascular compression in patients with classic trigeminal neuralgia?
The literature is inconsistent about the accuracy of MRI in determining neurovascular compression in classic trigeminal neuralgia. Therefore, there is not sufficient evidence to support or refute the usefulness of MRI in identifying vascular contact of the trigeminal nerve in classic trigeminal neuralgia, or to indicate the most reliable MRI technique. (Level U recommendation)
Which medications effectively manage pain from classic trigeminal neuralgia?
Carbamazepine (Tegretol; 200 to 1,200 mg per day) is effective for controlling pain in patients with classic trigeminal neuralgia. (Level A recommendation)
Oxcarbazepine (Trileptal; 600 to 1,800 mg per day) is probably effective for treating pain in patients with classic trigeminal neuralgia. (Level B recommendation)
Baclofen, lamotrigine (Lamictal), and pimozide (Orap) are possibly effective for controlling pain in patients with classic trigeminal neuralgia. (Level C recommendation)
Use of topical ophthalmic anesthetics is probably ineffective for controlling pain in patients with classic trigeminal neuralgia. (Level B recommendation)
There is insufficient evidence to support or refute the effectiveness of clonazepam (Klonopin), gabap-entin (Neurontin), phenytoin (Dilantin), tizanidine (Zanaflex), topical capsaicin (Zostrix), and valproic acid (Depakene) for controlling pain in patients with classic trigeminal neuralgia. (Level U recommendation)
Which medications effectively manage pain from symptomatic trigeminal neuralgia?
Because there are no placebo-controlled trials in patients with symptomatic trigeminal neuralgia, there is insufficient evidence to determine the effectiveness of any medication over another for controlling pain in patients with symptomatic trigeminal neuralgia. (Level U recommendation)
Is there evidence of effectiveness of intravenous administration of medications in acute exacerbations of trigeminal neuralgia?
There are no randomized controlled trials or large population studies to determine the effectiveness of intravenous medications for controlling pain in patients with trigeminal neuralgia. (Level U recommendation)
When should surgery be considered for the treatment of trigeminal neuralgia?
Although there is limited evidence showing that patients with trigeminal neuralgia who underwent surgery would have preferred to have surgery earlier, there are insufficient data to recommend when surgery should be offered. (Level U recommendation)
Which surgical technique gives the longest pain-free period with the fewest complications and good quality of life in patients with trigeminal neuralgia?
Percutaneous procedures on the gasserian ganglion, gamma knife radiosurgery, and microvascular decompression are possibly effective in the treatment of trigeminal neuralgia. (Level C recommendation)
Evidence for the use of peripheral techniques is negative or insufficient. (Level U recommendation)
Patients undergoing microvascular decompression have a longer duration of pain control than patients undergoing other surgical interventions. However, a lack of direct comparisons prevents any formal conclusions about the effectiveness of surgery. (Level U recommendation)
Which surgical techniques should be used in patients with MS?
There is insufficient evidence regarding the effectiveness of surgical management of trigeminal neuralgia in patients with MS. (Level U recommendation)
Putting the Evidence into Context
The initial diagnostic evaluation of patients with trigeminal neuralgia focuses on clinical characteristics known to identify patients with the symptomatic variety (i.e., the presence of trigeminal sensory deficits and bilateral involvement). If the physician suspects symptomatic trigeminal neuralgia, more testing should be performed. Trigeminal reflex testing or MRI is a reasonable next step. However, given the relatively high diagnostic accuracy of abnormal trigeminal reflexes, MRI is probably unnecessary in the presence of normal trigeminal reflexes.
If first-line therapy (i.e., carbamazepine or oxcarbazepine) fails, physicians may consider add-on therapy with lamotrigine or a switch to baclofen. The effect of other medications commonly used in neuropathic pain is unknown. There are no studies directly comparing polytherapy with monotherapy.
When trigeminal neuralgia is refractory to medical therapy, referral for surgical consultation is appropriate.