Trigeminal neuralgia is a condition affecting the 5th cranial nerve, is characterized by unilateral paroxysms of shooting an intense shooting pain in the area innervated by any of the three branches, but mostly involves 2Nd and 3rd branches of the trigeminal nerve. The pain ends as abruptly as it starts and is described as a unilateral shooting and stabbing sensation and the unilateral nature of the pain is an important feature. Involuntary contraction of the facial muscles can cause a sudden closing of the eye or twitching of the mouth. Although the cause is not certain, vascular compression and pressure are possible causes. As the brain changes with age, a loop of cerebral artery or vein may compress the nerve root entry point which can be identified on MRI scan. The trigeminal nerve emerges from the pons. The nerve has 3 divisions via ophthalmic, maxillary and mandibular.
- The ophthalmic branch: it controls your eye, upper eyelid, and forehead.
- The maxillary branch: this effects your lower eyelid, cheek, nostril, upper lip and upper gum.
- The mandibular branch: it runs your jaw, lower lip, lower gum, and some muscles used for chewing.
Trigeminal neuralgia occurs most often before 35 years of age and is more common in women than men, at a rate of 3:2 respectively. Pain-free intervals may be measured in terms of minutes, hours, days, or longer. With advancing years, the painful episodes tend to aggravate, agonize and are frequent. The person lives in constant fear of attacks.
Paroxysms can occur with any stimulation of the affected nerve branches, such as washing face, eating, drinking, shaving, brushing the teeth or direct pressure against the nerve trunk can also cause pain. Some areas are called trigger points because the slightest touch immediately a starts a paroxysm or episode. To avoid such stimulation to these areas, a person with trigeminal neuralgia should try not to touch or wash their faces, shave, chew or do anything that causes the pain or attack.
Signs and symptoms of Trigeminal Neuralgia
- Pain usually abrupt in onset, unilateral, lasts from few seconds to few minutes.
- Pain described as excruciating sharp, piercing, shooting and burning extends to the midline of the face.
- The trigger zone is usually a small area on the cheek, lip, gum or forehead. These trigger zones are sensitive to the simplest stimuli such as cold, touch, pressure or a blast of air.
- Many patients experience bouts of pain for weeks or months with spontaneous cessation of symptoms and remission.
- The pain limits the activities of the patient and he/she may not maintain daily performance such as talk, eat and avoid personal hygiene.
Causes of Trigeminal Neuralgia
- The cause is still unknown
- Trauma and infection of the teeth or jaw
- preceding flu-like illness
- Pressure on the 5th cranial nerve by the neoplasm.
- Certain diseases like multiple sclerosis can injure the myelin sheath.
Diagnostic methods and investigation
Diagnosis is based on characteristic behavior. Medical history and Neurological examination. MRI or CT is done to identify the compressed nerve root and possible trauma to the associated nerve.
Treatment of Trigeminal Neuralgia
Anti-seizure agents, such as carbamazepine (Tegretol), reduce transmission of impulses at certain nerve terminals and relieve pain in most patients. Carbamazepine is given with food. The patient is observed for side effects, including nausea, dizziness, drowsiness, and aplastic anaemia. The patient is monitored for bone marrow depression during long-term therapy. Serum level must be monitored to avoid toxicity in the patients who require high doses to control the pain. Gabapentin and baclofen are also used to treat pain. If pain control is still not achieved, phenytoin (Dilantin) may be used as adjunctive therapy.
If pharmacologic management fails to relieve pain, a number of surgical options are available. Although these procedures may relieve facial pain for a few years, recurrence and complication rates are high. The choice of procedure depends on the patient’s preference and health status. In microvascular decompression of the trigeminal nerve, and intracranial approach (craniotomy) to decompress the trigeminal nerve is used. Percutaneous radio-frequency produce a thermal lesion on the trigeminal nerve. Although immediate pain relief is experienced, dysesthesia of the face and loss of the corneal reflex may occur. Use of stereotactic magnetic resonance imaging (MRI) for the identification of trigeminal nerve followed by Gama knife radiosurgery is being used at some medical centres. Percutaneous balloon micro-compression disrupts large myelinated fibers in all three branches of the terminal nerve.
Home-based care after the surgery
- After surgery, the affected side of the face is insensitive to pain permanently.
- The patient must be cautioned against rubbing the eye because the protective mechanism of pain is lost
- The eye should also be inspected for redness and conjunctival erythema. Insert artificial tears, if prescribed, to prevent dryness to the affected eye.
- Instruct patient to rinse mouth after eating when tooth brushing causes pain and to perform personal hygiene during pain-free intervals.
- Advise patient to take food and fluids at room temperature, to chew on the unaffected side, and to ingest soft foods.
- Recognize that anxiety, depression, and insomnia often accompany chronic painful conditions and use appropriate interventions and referrals.
- A routine visit to the dentist should be scheduled to detect caries.
- Follow up