A Note on Trigeminal Neuralgia with no Apparent Organic Cause

Trigeminal Neuralgia with no Apparent Organic Cause

Such conditions have many names: idiopathic trigeminal neuralgia, trigeminal neuralgia, benign paroxysmal trigeminal neuralgia, tic doloureux.

Trigeminal neuralgia is the most common neurological cause of orofacial pain. It is, however, rare and seen mainly in middle-aged or older patients.

Aetiology

The cause is unclear, but trigeminal neuralgia may be due to an atherosclerotic blood vessel pressing on the roots of the trigeminal nerve.

Clinical Features

Trigeminal neuralgia has the following main characteristics.

Pain which is:

severe;
of abrupt onset and termination;
electric shock-like, brief, stabbing (lancinating);
unilateral;
restricted to the trigeminal nerve distribution.

The pain usually involves the mandibular and, rarely, the other divisions of the trigeminal nerve. In some patients the pain is triggered. The trigger site may bear no relation to the painful area, but is always ipsilateral to the pain. Patients do not necessarily recognize the trigger for what it is, and may find that pain is brought on by chewing, talking, swallowing, smiling or temperature changeóusually exposure to cold air.

Pain-free Intervals Between Attacks

This is often an intermittent disease, with apparent remissions for months or years. However, recurrence is common. Very often the pain spreads to involve a wider area over time and the intervals between episodes tend to shorten.

Lack of Neurological Abnormality

There is no sensory loss in the trigeminal region; nor are other neurological abnormalities present. Neurological assessment is needed because similar pain is secondary to multiple sclerosis, tumours, neurosyphilis, HIV infection and other lesions.

Diagnosis and Management

Patients with trigeminal neuralgia are ideally seen at an early stage by a specialist in order to confirm the diagnosis and initiate treatment

Roles of the dental clinical team in the management of a patient with trigeminal neuralgia
Dental surgeon	*Ancillary, Hygienist, Nurse*
Refer to specialist. Understand disease and management in order to extend education of, and reassure, patient Alert specialist to any possible adverse effects of treatment Oral healthcare; in particular to avoid causes of pain Oral health education of patient Avoid any trigger zones Avoid drug interactions with carbamazepine or other agents	Understand disease and management in order to extend education of, and reassure, patient Oral health education of patient Avoid any trigger zones Alert dental surgeon to any changes, or possible adverse effects of treatment

Patient information sheet: trigeminal neuralgia

This is an uncommon disorder

The cause is unknown but involves spontaneous activity of pain nerves

It is not inherited

It is not known to be infectious

Similar symptoms may be seen in some neurological conditions (which we will exclude)

There are usually no long-term consequences

X-rays and blood tests may be required

Symptoms may be controlled but not cured by drugs with an anticonvulsant action

Uncontrolled pain may be treated by freezing the nerve, or by surgery

Medical treatment, typically using anticonvulsants, is successful for most patients. Carbamazepine (Tegretol) is still the main agent used. It must be given continuously prophylactically for long periods. However, it is not an analgesic and, if given when an attack starts, will not relieve the pain.

Carbamazepine must be used carefully and under strict medical surveillance because it can have a range of adverse effects, particularly affecting balance, blood cells, blood pressure and liver function. Typically, the dose is increased to try to control the pain while at the same time trying to avoid ataxia and other adverse effects. If carbamazepine fails, phenytoin or baclofen or other drugs are occasionally useful.

If medical treatment fails or the adverse drug effects are too pronounced, surgery may be required. Injections of local analgesic will temporarily block the pain. Local cryosurgery to the trigeminal nerve branches involved (cryoanalgesia) can produce analgesia without permanent anaesthesia, but the benefit can usually be measured only in months rather than years.

For intractable cases neurosurgery, such as destruction of the trigeminal ganglion (radiofrequency ganglionolysis) or decompression of the trigeminal nerve, may be required. Unfortunately, pain is exchanged for anaesthesia and risk of damage to the cornea and, occasionally, continuous anaesthesia but with pain (anaesthesia dolorosa).

Trigeminal Neuralgia ppt 1