Trigeminal neuralgia commonly known as tic douloureux is a condition in which severe sharp pain which is like electric current is felt on the face, lips, gums cheeks or even in eye: in the distribution of trigeminal nerve. It is one of the most painful conditions, that is why it is also called suicide disease.
According to an estimate 1 in 15000 people suffer from this condition. Trigeminal neuralgia symptoms are more common in females as compared to males. Incidence of trigeminal neuralgia symptoms is highest after the age of 50 years, but people younger than this age are also found to have trigeminal neuralgia
Symptoms of trigeminal neuralgia
Most characteristic symptom of tic douloureux is severe facial pain which is sharp and electric current like and comes in episodes. Each episode of pain usually last for a few seconds to several minutes, rarely pain may last for hours. Episodes come in paroxysms often several times a day.
Patients may describe an area over the face, which on touching can trigger episode of intense. Other triggering factors for pain are, chewing, eating, talking, brushing the teeth , shaving, noise, and blowing of wind. Some times pain starts without any stimulant factor. Attacks of pain are described by the patient as stabbing electric shocks, pressing over the face, severe burning sensation, crushing, or shooting pain that is unbearable. Trigeminal neuralgia worsens the quality of life of the sufferer.
Usually pain attacks occur on one side of the face but 10-12% of the sufferers feel pain on both side of the face. Tic douloureux symptoms usually come in cycles; pain episodes continue for months then stop just to recur after a pain free interval which may last from several months to years. In some patient pain worsens as the time passes. Some patient has initially pain in one branch of trigeminal nerve, and then gradually other branches of trigeminal nerves are also involved. Pain in index finger is also an accompanying feature in small proportion of the patients suffering from tic douloureux.
Signs of trigeminal neuralgia
In most of the patients there are no apparent signs of trigeminal nerve dysfunction. Sensation in the distribution of trigeminal nerve are usually intact except in cases of multiple sclerosis and some other systemic diseases in which sensation are lost over face along with weakness of muscles supplied by trigeminal nerve.
In males sometime, they leave an area over face while shaving that indicates the triggering zone for tic douloureux symptoms and shaving may trigger pain.
Causes of trigeminal neuralgia
There are many theories about the pain of trigeminal neuralgia; according to old theory nerve is compressed while exiting from the skull. The newer theory stated that enlarged blood vessel( superior cerebellar artery) throbs against the microvasculature of trigeminal nerve at its connection with pons. This can injure the myelin sheath of trigeminal nerve which causes hyper functioning of the nerve. This can lead to episodic pain attack on ordinary stimulation of the area supplied by trigeminal nerve.
Other causes of trigeminal neuralgia include:
- Multiple sclerosis
- Stroke
- Tumor of posterior cranial fossa
- Arachnoid cyst in Cerebellopontine angle
- Aneurysm (dilatation) of blood vessel
- Tongue piercing
If no cause is identified it is called idiopathic trigeminal neuralgia.
Diagnosis of trigeminal neuralgia
Diagnosis of tic douloureux is usually clinical however neuro-imaging like magnetic resonance imaging and magnetic resonance angiogram is performed when suspicion of multiple sclerosis, stroke or aneurysm of blood vessel is there. It also helps to localize the aberrant blood vessel compressing trigeminal nerve at its exit from pons.
Treatment of trigeminal neuralgia
Trigeminal neuralgia has medical and surgical treatment.
Medical treatment
Medical treatment for tic douloureux include following medication
1. Anticonvulsants
Anticonvulsants are main stay of medical treatment for trigeminal neuralgia. The first line drug among anticonvulsant is carbamazipine, it is started in low dose and dose is increased every 2-3 days till the symptoms are controlled, it is continued for months then if symptoms are controlled for long time, is slowly tapered.
Second line drugs used are phenytoin, beclofin, gabapentin and valproic acid. Other effective drugs which are proved beneficial in clinical trials are clonazipam and lidocaine.
2. Anti depressants
Among this class of medications amitriptylin at low doses is proved efficacious in neuropathic pain, but these medications are usually reserved for depression associated with chronic pain. Duloxetine which is again an antidepressant can be used if patient has neuropathic pain of trigeminal neuralgia and depression together.
3. Botox
Botox which is botulinum toxin is also a choice for treatment of trigeminal neuralgia. It is injected into the trigeminal nerve ganglion by the physician.
4. Neurostimulator
is another option, implanted to the patient who has its role in nerve stimulation and reducing pain of tic douloureux.
5. Opoid analgesic
like morphine and oxycodone, if found helpful in relieving pain may be used.
If one drug is found ineffective, other drug of the same group or other group should be tried. Often combination of drugs is needed to suppress the symptoms of trigeminal neuralgia. Topical preparation of gabapentin can be used in patients who don’t tolerate long term oral medications.
Surgical treatment of trigeminal neuralgia
Surgical procedure for treating trigeminal neuralgia is based on either relieving pressure on trigeminal nerve or destroying this nerve partially. Surgical options available include
1. Microvascular decompression.
In this procedure neurosurgeon enters the skull, if blood vessel is compressing the nerve, the vessel and nerve are separated in order to relieve pressure on the nerve. This procedure has got very good results.
2. Glycerol injections
This involves injecting cavern near trigeminal nerve, nerve is damaged due to its corrosive effect.
Other decompressive procedures involve advancing needle or catheter through mouth into the area where trigeminal nerve is divided into three divisions. Selective destruction of the division which causes pain can be done.
3. Gamma knife surgery
Non invasive surgery in which trigeminal nerve is destroyed through stereotactic technique. This technique is used for patients who are unfit for anesthesia.
4. Radio-frequency rhizotomy
Another approach in destroying the nerve by application of heat.