Neurological Disorders: Trigeminal Neuralgia

Trigeminal neuralgia is a neurological disorder involving the trigeminal-nerve (the 5th cranial nerve). This nerve supplies face and related structures. Symptoms are generally in the form of severe recurrent brief episodes of pain on the face.

There are totally 12 cranial nerves that supply head, face and related structures. The 5th cranial nerve (trigeminal nerve) exits from the brainstem part of brain and travels towards the front aspect of the skull and supply the face area. Some of its intra-brain structures called as nucleus extends even up to the upper cervical spinal cord. The cranial nerves exist as a pair, the individual nerve supplying one half of the head and face.

It can sometimes idiopathic (primary) means no obvious or identifiable cause is found at all. The commonest known cause is considered to be an abnormal blood vessel compressing (pinching) the nerve along its path. This causes irritation and sensitization of the nerve resulting in facial pain. Structural abnormalities like a MS (multiple sclerosis) plaque, tumors, stroke etc occurring in the brainstem in the region of 5th cranial nerve nucleus can produce this. Similarly any growth pressing the nerve along its path also can irritate the nerve.

Pain on one side of the face is the typical manifestation. The following features of the pain are generally characteristic for this condition;

• Most often unilateral
• Stabbing, shooting, electric shocking like feeling
• Recurrent; a patient may experience sometimes even 100s of attack/day
• Short lasting; typically last only for few seconds up to couple of minutes
• Trigger factors like touching the face, shaving, chewing food, cold exposure etc can precipitate these attacks
• Facial paralysis is generally not seen

On majority of the occasions the diagnosis has to be made clinically since investigations do not throw much light in to the cause of this condition. A CT or a brain MRI scan is frequently ordered and it may show a brainstem pathology like MS (multiple sclerosis) plaque, stroke, tumor, AVM (arteriovenous malformation), venous angioma etc. If investigations are negative then it is called as idiopathic or primary trigeminal- neuralgia.

If any MRI lesions are found in the brain it will be treated accordingly.

Either way patient will require symptomatic treatments for the facial pain and following medications are frequently used;

• Carbamazepine
• Oxcarbazepine
• Gabapentin
• Pregabalin
• Duloxetine
• Clonazepam
• Baclofen etc

If drug therapy is not successful then there are varieties of surgical options for trigeminal neuralgia.

The following are some Surgical Options with their own plus and minus;

• Gamma knife radiosurgery
• Percutaneous procedures:

- Glycerol injection
- Radiofrequency trigeminal rhizotomy
- Balloon compression
- Alcohol injection

• Microvascular decompressive surgery

A neurologist is frequently involved in the care of these patients.