The incidence of Trigeminal Neuralgia is
approximately 70 cases per 100,000 population.
commonly occurs in people
50 years old and is rarely seen prior
to the age of
If TN occurs in a younger patient,
it almost always is associated with
Multiple Sclerosis (MS).
It occurs in females twice as often
as in males.
of the cases, and if it is bilateral
it occurs in the same division
of the nerve.
The second or third division of the nerve
is affected in the majority of patients,
with the first division affected
5% of the time. The right side
of the face is
affected 57% of the time.
The pain is characterized by paroxysms
shock-like pain lasting
from several seconds to 2 mins.
Many daily activities such as brushing
the teeth, eating, shaving, or washing the
may provoke attacks and cause spasms
of the facial muscles. This is
why it is
tic douloureux. It is important
to reassure patients that the
almost always be controlled.
TN occurs in many patients because
tortuous aberrant blood vessels compress
Trigeminal Root. Acoustic Neuromas,
and bony abnormalities may
also lead to the compression of nerve roots.
2-3% of patients with TN also have MS.
Therefore, coexistent MS should be
considered in any patient under 50 y/o
presents with TN. The diagnosis
is made by taking a careful history
exam. Tumors of the head
and neck and MS must be ruled out.
Idiopathic TN has four major characteristics:
a history of shooting, stabbing, jabbing,
electric-shock pain in the
of the Trigeminal Nerve, which occurs
Pain triggered by talking,
chewing, kissing, drinking, brushing the teeth;
A normal neurological exam
Relatively pain-free periods between attacks
The mainstay of treatment is pharmacotherapy,
and the first-line drug is
Carbamazepine (Tegretol) (CARB).
The usual rapid response to this drug
essentially confirms a clinical diagnosis
of TN. Baseline screening labs
blood count, urinalysis, and SMA-12)
should be obtained before starting the
Start with a 100-200 mg dose of CARB
at bedtime for two nights and caution
patient regarding side effects,
including dizziness, sedation, confusion, and rash.
The drug is in equally divided doses over
two days, as side effects allow, until
pain relief is obtained or a total
dose of 1200 mg daily is reached.
Careful monitoring of lab parameters
is mandatory to avoid the rare possibility
of life-threatening blood dyscrasia.
At the first sign of blood count abnormality
or rash, CARB should be discontinued.
Failure to monitor patients started on
can be disastrous, as Aplastic Anemia
can occur. When pain relief is
obtained, the patient should be kept
at that dosage at least six months
Routine hematologic monitoring after
stable dosage is reached is unnecessary.
CARB blood levels should be obtained
when non-compliance is suspected,
side effects occur at doses
under 1200 mg, and when a 1200 mg/day
reached, to establish
a baseline to allow safe titration of
the dosage upward.