Trigeminal neuralgia is a neurological condition which is accompanied by acute excruciating pain affecting the unilateral side of the face, along the path of distribution of the trigeminal nerve and its branches.
The trigeminal nerve is the fifth cranial nerve which is responsible for sensations near the face as well as few motor functions such as biting and chewing. Neuralgia refers to a sharp, shocking type of pain that follows the path of a nerve. This is usually caused due to some kind of irritation or damage to the nerve.
This condition is of sudden onset and of short duration. It may last from a few seconds to a minute or two. The pain usually is described as a severe, sharp, shooting, stabbing pain that feels like an electric shock.
Trigeminal neuralgia is also called ‘Tic douloureux’ or ’Fothergill’s disease’. There are trigger zones in the face which when touched triggers the sharpshooting unbearable pain.
And because of this, the person with this particular problem avoids any touch, especially shaving or washing. This is due to the fear of electric shock-like pain.
Tic douloureux is the most common neurological condition causing facial pain. It affects females more than males, mostly in the age group of 40 and above.
It most commonly involves one side of the face, usually the right side of the face. In rare cases, both sides of the face may be involved.
What Are the Causes of Trigeminal Neuralgia?
Although the actual reason is unknown, there are certain factors which are likely to trigger the neuralgia of the trigeminal nerve.
There could be triggering factors in the brain which could lead to the condition due to compression of the trigeminal nerve root, like the following.
- Multiple sclerosis
- Petrous ridge compression
- Intracranial tumors
- Intravascular abnormalities like aneurysms or vascular compression
There could also be extracranial triggering factors which may cause this condition, like the following.
- Dental infections
- Post-traumatic neuralgia caused either due to trauma or some dental procedure.
- Infection involving the nerve.
- Viral infections
Types of Trigeminal Neuralgia and Their Features
There are mainly two types of Trigeminal Neuralgia.
- Classic idiopathic /atypical neuralgia
- Symptomatic neuralgia
Some of the important clinical features of Trigeminal Neuralgia may be listed as follows based on the type of pain experienced by the individual.
- The symptom occurs as a sudden, paroxysmal, unilateral, sharp and excruciating pain which is triggered by a slight touch of the trigger points in the face.
- The pain lasts up to a few minutes but may recur.
- The pain shoots like an electric shock.
- The pain usually does not cross the midline.
- The pain does not occur during sleep.
Paroxysmal pain or paroxysmal attacks refer to the sudden recurrence or intensification of symptoms. The paroxysms of pain occur in cycles ranging from weeks to months with pain becoming intense and unbearable with time. Some cases with severe pain, the face becomes motionless or mask-like.
The trigger zones of the face for this kind of pain, are the cheek region, alar region, upper lip, upper gums, lower lip, teeth or gums, around the eye.
The individual usually refrains himself from touching the face, washing, shaving or even brushing the teeth as the slightest touch might trigger the pain. In this condition, the sensory function of the affected side is intact.
Following procedures may be followed when trying to diagnose Trigeminal Neuralgia.
- A detailed history with a good clinical examination may help the doctor to confirm the diagnosis.
- A diagnostic nerve block with a local anesthetic may be administered which is not only helpful in alleviating the pain symptoms but also aids in the diagnosis of the condition.
- MRI and EEG may also be done.
The pain and discomfort caused in case of Trigeminal Neuralgia do not respond to painkillers. So anticonvulsants are used as the first line of treatment. Medications such as Carbamazepine are the first line of drugs administered for relieving the pain associated with Trigeminal Neuralgia.
Muscle relaxing agents or antispasmodic drugs are also sometimes used for the treatment of Tic douloureux (TN). These may be used as stand-alone drugs or in combination with Carbamazepine.
The dosage of the drugs used for treating this condition may depend on the blood profiling report of the individual. Also, utmost care may be required in monitoring the side effects of the drug on the individual.
There are other drugs like Phenytoin, Gabapentin, Baclofen, Lamotrigine, Clonazepam, etc which may also be used in the treatment of Neuralgia of Trigeminal nerve.
These drugs may be used alone or in combination, as done in multiple drug therapy. Multiple drug therapies have shown better responses.
Local Anaesthetic Injections
Peripheral nerve injections like long-acting local anesthetics may be used in case of an emergency where the individual is suffering from severe pain.
Intraoral injections of 95%alcohol may be injected into the nerve branches which acts as an anesthetic and controls the pain. But this method is not preferred for long term use due to the side effects, such as local tissue toxicity, inflammation, fibrosis, and also neuritis.
In cases of alcohol injections, extraoral injections at the level of the base of the skull into the branches of the nerve may be given.
This procedure is also called nerve avulsion. This is one of the oldest and effective surgical treatment which involves interruption of the flow of afferent impulses to central trigeminal apparatus.
This procedure is done in patients where extensive cranial procedures are contraindicated. It is usually done under general anesthesia. The procedure is commonly done on branches of the trigeminal nerve such as infraorbital, inferior alveolar or mental nerve.
Cryotherapy for Trigeminal Neuralgia
Cryotherapy for peripheral nerves may be considered a treatment option which involves the application of probes in temperatures less than -65 degrees Celsius.
Cryotherapy is a type of pain treatment which uses the localized freezing temperatures to destroy the affected parts of the nerve without completely destroying it.
Doing this causes the degeneration of parts of the nerve without destroying the complete nerve, thereby relieving the symptoms.
Gasserian Ganglion Procedures
Gasserian Ganglion is the sensory ganglion of the trigeminal nerve. A Ganglion refers to the cluster of nerve cells. There are certain procedures carried out in this area to treat Trigeminal Neuralgia.
The three procedures on Gasserian ganglion are glycerol injection, thermocoagulation, and balloon compression.
There are many other treatment procedures being carried out recently with moderate success. Some of them are
- Radiofrequency thermal lesioning of the trigeminal ganglion.
- Microvascular decompression of the trigeminal root.
- Gamma knife radiation to the trigeminal root entry zone.