Trigeminal Neuralgia, also called 'tic douloureux' is a chronic condition which causes sharp, excruciating and sporadic pain, normally affecting one side of the face.
It can be triggered by simple things such as brushing your teeth, speaking and in some extreme situations, even a gentle breeze. The attacks often worsen over time, with fewer and shorter pain-free periods before they occur again.
Trigeminal neuralgia takes time to be appropriately diagnosed, therefore treatment maybe delayed, causing distress to sufferers who have even been known to have considered suicide as a 'way-out' from the pain. When the trigger sites are inside the mouth, patients become hesitant about eating and drinking. This may lead to weight loss and dehydration, prompting patients to think that there is something seriously affecting their health.
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| It’s painful but it can be treated |
| Although described as one of the most painful conditions experienced, it is reassuring to know that treatment for trigeminal neuralgia is available. Correct and timely diagnosis is essential. The Pain Clinic at the National Hospital handles such cases and is a blessing for individuals suffering from this debilitating and disabling condition, which affects their quality of life significantly. |
The first clinical description of this severe facial pain condition was made more than 300 years ago. Aretaeus of Cappadocia described a headache in which 'spasms and distortions of the countenance took place'. John Fothergill was the first to give a full and accurate description of trigeminal neuralgia in a paper titled 'On a Painful Affliction of the Face,' presented to the Medical Society of London in 1773.
The condition normally begins after the age of 50 years in 90% of patients, and is slightly more frequent in women. The incidence is approximately 4-5 per 100,000 persons, but this is likely to be an underestimate. It is more prominent in those suffering from a condition called multiple sclerosis. In these patients the pain is normally bilateral.
What causes the pain?
The Trigeminal nerve is a large nerve arising from the brain stem. It has two main functions - provision of sensation to the whole face by carrying the sensation of pain, temperature and touch and secondly, allowing us to chew our food properly. One theory for trigeminal neuralgia is that the nerve is constantly irritated by the pulsations of a vessel carrying blood. These pulsations are thought to cause a wearing down of the nerve thereby increasing the damage with time, and increasing the frequency of the attacks. But this is still controversial.
Tumours in the region of the nerve can also cause symptoms such as trigeminal neuralgia and therefore, appropriate investigations are vital in diagnosis.
How is the condition
diagnosed?
There are many causes of facial pain. Hence trigeminal neuralgia is a challenging condition to diagnose. Obtaining the patient's history and thorough examination by a medical practitioner are vital in determining that the right diagnosis is made early. Normally the pain is described as if being stabbed in the face. Patients normally describe trigger points on the face and this is always on one side of the face. The episodes maybe repetitive, recurring and remitting. The pain-free interval initially might last for years, but generally the intervals grow shorter as the disease progresses.
Medical examination findings are normal in patients with trigeminal neuralgia. Patients may refuse to have their face examined in the fear of triggering an attack. Male patients may not shave around the area which triggers the pain, and look unkempt. If there are other findings such as numbness or weakness, this should alert the doctor to look for other conditions that maybe the cause, such as a growth compressing the nerve or multiple sclerosis.
What tests are done?
The main aim of the investigations is to rule out other conditions. A special MRI scan of the brain called an MRA, or magnetic resonance arteriogram maybe carried out. This looks at the blood vessels closely to identify any abnormal loops that could be pressing on the nerve. In most cases these are not identified, but the patients still respond to the treatment. This again suggests the controversy surrounding the cause of the pain.
Treatment-
Medical Treatment
The treatment of choice and first line treatment choice for trigeminal neuralgia is Carbamazipine. With adjustment of the dose, the pain can be controlled initially in about 75 percent of patients. Phenytoin is less effective but can be used in patients who cannot tolerate the first line treatment. If both in combination or alone are ineffective, a drug called Baclofen maybe added. The adjustment of the drugs should be done in a controlled manner by a specialist who understands the condition.
Ideally the condition should be treated in a 'pain clinic'. With increasing availability of new drugs such as gabapentin and lamotrigine, medical treatment and fine tuning is bound to improve with time. It is also important to remember that eventually 50 percent of patients with trigeminal neuralgia will go on to have a surgical procedure
Surgical treatment
There are two types in general: The percutaneous technique and microvascular decompression.
Percutaneous technique ( through the skin), involves a needle being passed through the skin into a cavity (Mekel's cave)in the skull which contains the junction (gassarian ganglion) before the nerve splits into three to supply the top, middle and bottom of the face. A chemical such as glycerol maybe injected under a local anaesthetic under x-ray guidance.
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| The Trigeminal nerve |
Radiofrequency thermocoagulation is another method in which a needle is again directed through the skin to the ganglion and a current is passed which causes damage to part of the ganglion (the junction point) thereby stopping the pain.
Percutanous balloon compression is another method where a small balloon is passed through an inflation near the ganglion to cause damage.
All the percutaneous techniques can be done as outpatient procedures, generally under local anaeasthesia and on occasion, sedation. The main aim is to cause some damage to the ganglion thereby stopping the painful stimuli from being carried and therefore not felt.
The rate of recurrence is lowest in the radiofrequency ablation technique compared to the other percutaneous techniques.
Microvascular decompression
This is proper surgery, with the patient under general anaesthesia, where the nerve at the point it enters the brainstem is tackled. If a loop of blood vessel is identified, a small piece of sponge is placed between the nerve and the vessel. There is some belief that the technique works due to the massaging of the nerve rather than displacing the vessel. But the condition may recur.
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