Trigeminal neuralgia is a chronic pain condition that affects the face.
Trigeminal Neuralgia is a disorder of the trigeminal nerve (fifth cranial nerve) that carries sensation from your face to your brain.
Trigeminal Neuralgia Causes
It has three branches:
Ophthalmic (V1) – this supplies the forehead, eyelids and nose.
Maxillary (V2) – this supplies the cheeks and upper lip.
Mandibular (V3) – this supplies the side of the face, the jaw and the chin.
Trigeminal neuralgia is caused by a disruption of the normal function of the nerve.
The usual problem is contact between a blood vessel and the trigeminal nerve at the base of your brain. This contact puts pressure on the nerve and causes it to malfunction.
Trigeminal neuralgia can develop when the protective myelin sheath around the nerve is damaged. This can occur with multiple sclerosis ageing, as well as with the process of ageing. It can also happen when a tumour compresses the nerve. In some patients, a brain lesion, surgical injury, stroke or facial trauma may cause trigeminal neuralgia.
Trigeminal neuralgia affects women more often than men, and it's more likely to occur in people over 50.
Trigeminal Neuralgia Symptoms
Patients describe severe, sporadic, sudden burning or shock-like facial pain in the areas of the face that is supplied by the trigeminal nerve.
The pain usually affects one side of the face at a time, though may rarely affect both sides of the face.
The pain may be spontaneous or be triggered by things such as touching the face, chewing, speaking or brushing your teeth. The pain might last from a few seconds to several minutes.
These attacks can occur in quick succession or in volleys lasting as long as two hours.
Episodes of several attacks lasting days, weeks, months or longer — some people have periods when they experience no pain Attacks that become more frequent and intense over time
Some patients experience a constant aching, burning feeling that may occur before it evolves into the spasm-like pain of trigeminal neuralgia
You may initially experience short, mild attacks. But trigeminal neuralgia can progress and cause longer, more frequent bouts of searing pain.
The “atypical” form of the disorder (called TN2), is characterized by constant aching, burning, stabbing pain of somewhat lower intensity than TN1. Both forms of pain may occur in the same person, sometimes at the same time.
Trigeminal Neuralgia Diagnosis
An accurate diagnosis of trigeminal neuralgia is important, because facial pain may be caused by many different conditions.
The History: The diagnosis of trigeminal neuralgia based on the patient’s description of the pain:
This would include:
The type and timing of the pain. Pain related to trigeminal neuralgia is sudden, shock-like and brief.
The location.The parts of your face that are affected by pain.
The triggers of the pain. The pain usually is brought on by light stimulation of the cheeks, such as eating, talking or brushing your teeth. Even a light cool breeze can sometimes act as a trigger for the pain.
The physical examination:
Touching and examining the face will determine exactly where the pain is occurring and which branches of the trigeminal nerve may be affected.
Investigations and imaging:
An MRI scan of the head might determine if multiple sclerosis or a tumour is causing the trigeminal neuralgia. In some cases, a contrast dye may be injected into a blood vessel to view the arteries and veins and highlight blood flow (magnetic resonance angiogram).
Trigeminal Neuralgia Treatment
This initially involves medications, and some patients don't need any additional treatment. Some patients however experience unpleasant side effects to the medication or might stop responding to them with time. In such circumstances, injections or surgery would provide further options.
Anticonvulsant drugs:These are the most effective drugs for treating Trigeminal Neuralgia.
Carbamazepine is the most effective and is usually the first prescribed. Other anticonvulsant drugs that may be used include the following:
Side effects of the anticonvulsants include dizziness, confusion, drowsiness and nausea. Carbamazepine on occasions can cause bone marrow depression, so regular blood tests would be recommended.
Antispasmodic drugs: Muscle-relaxing agents such as baclofen may be used alone or in combination with carbamazepine. Side effects may include confusion, nausea and drowsiness.
2. Surgery and injections:
Microvascular decompression:This is a surgical operation that involves relocating or removing blood vessels that are pressing on the nerve. The surgery involves making an incision behind the ear and drilling through the skull bone. The compressing artery is then moved and a soft tissue cushion is placed between the nerve and the artery.
This operation can usually eliminate or reduce the pain, but it can recur in some patients. The risks of surgery include decreased hearing, facial weakness and numbness, and a stroke.
Brain stereotactic radiosurgery (Gamma knife): This procedure involves directing a focused dose of X-ray radiation to the root of your trigeminal nerve. This damages the trigeminal nerve and the subsequent pain reduction may take up to a month to occur.
This procedure is successful in most people and can be repeated. Facial numbness can be a side effect.
Rhizotomy of the Trigeminal Ganglion: This involves destroying the nerve fibres at the junction of the three nerves at an opening in the base of the skull. The ways in which the nerve fibres can be destroyed include the following:
Glycerol injection. A needle is inserted through the face under the cheekbone, and guided into an opening (the foramen ovale) in the base of your skull. Asmall quantity sterile glycerol is then injected around the nerve. This procedure often relieves pain, but patients may experience facial numbness or tingling afterwards, and the pain can recur.
Balloon compression: This procedure involves inserting a hollow needle through the face under the cheekbone, and guiding the needle through the same opening at the base of the skull. A thin, flexible tube (catheter) tube with a balloon at the end is then threaded through the needle. The balloon is then inflated and this destroys the nerve fibres by crushing them. This successfully controls pain in most patients for a period of time, and most patients experience transient facial numbness.
Radiofrequency thermal lesioning: This procedure again involves the insertion of a needle through the face under the cheekbone and through the foramen ovale. An electrode is then inserted and an electrical current is passed up to the tip of the electrode. The heat of the electric current destroys the nerve fibres (thermal lesioning). Patients often have temporary facial numbness after the procedure, and the pain may return after three to four years.