Saturday, July 13, 2013

Trigeminal Neuralgia Diagnosis

Trigeminal neuralgia (TN) is defined by the International Headache Society (IHS) as “unilateral disorder characterized by brief electric shock-like pains, abrupt in onset and termination, and limited to the distribution of one or more divisions of the trigeminal nerve” [International Headache Society, 2004]. The IHS suggests a classification of TN as either classic (essential or idiopathic) TN (CTN) or symptomatic TN (STN; pain indistinguishable from that of CTN, but caused by a demonstrable structural lesion other than vascular compression). The diagnosis of CTN requires the absence of a clinically evident neurological deficit. CTN starts in the second or third divisions, affecting the cheek or the chin [International Headache Society, 2004]. The ophthalmic division alone is involved in less than 5% of cases [De Simone et al. 2005]. The single attack generally lasts from less than a second to a few seconds, but it may present in clusters of variable intensity with up to 2 minutes duration. In many cases it is followed by a brief refractory period during which a new stimulation is not able to evoke another attack. Between paroxysms the patient is usually pain free, but a dull background pain may persist in some cases [International Headache Society, 2004]. Growing neurosurgical data advocate the distinction of these two subtypes of TN into type 1 as defined as >50% episodic onset of TN pain and type 2 defined by >50% constant pain [Tatli et al. 2008; Limonadi et al. 2006]. The mechanisms associated with the development of this persistent pain are not well understood but concomitant background pain is associated with poor medical and surgical outcome [Obermann et al. 2008; Sandell and Eide, 2008; ]. Recent investigations focused on the suspected central component in the pathophysiology of TN, which could involve central allodynic mechanisms that may also engage the nociceptive neurons at thalamic and cortical level .

Microvascular Decompression

Microvascular decompression

Microvascular decompression is an operation to release the pressure of blood vessels pressing on the trigeminal nerve.

During microvascular decompression surgery, the surgeon will either remove or relocate the blood vessels, separating them from the trigeminal nerve.

For most people, this type of surgery is effective in easing the pain of trigeminal neuralgia and appears to provide the long lasting relief.

However, the operation can cause hearing loss which is estimated to occur in less than 3% of people. Also, it is possible for pain to return after surgery and for surgery to cause a loss of sensation in the face, but this is unusual and often temporary. Very rarely, this type of surgery can result in stroke, meningitis or even death.

Treating Trigeminal Neuralgia

Medication can provide temporary relief from the pain of trigeminal neuralgia. Surgery may be considered for people who experience severe pain despite medication, worsening pain or adverse effects from the medication.

Your Doctor will first prescribe a type of medicine called an anticonvulsant (usually used to treat seizures in epilepsy), which can help relieve pain in your face. These drugs work by slowing down electrical impulses in the nerve and reducing its ability to transmit pain. Normal painkillers such as paracetamol are not effective in treating trigeminal neuralgia.

The anticonvulsant medicine called carbamazepine (see below) is usually the first medication recommended. However, if carbamazepine is not effective, a different anticonvulsant called gabapentin may be used.


Although carbamazepine is usually used to treat epilepsy, it can sometimes be effective in treating trigeminal neuralgia because it lessens the uncontrollable pain signals.

You will usually need to take this medicine one to two times a day to begin with, although some people may need a higher dose.

Carbamazepine can cause side effects which may make it difficult for some people, such as the elderly, to use. Possible side effects are outlined below.

Very common side effects

These side effects have affected more than one in 10 people and include:

  • nausea (feeling sick) and vomiting
  • dizziness
  • tiredness
  • finding it difficult to control movements
  • a reduced number of infection-fighting white blood cells (leukopenia)
  • changes in liver enzyme levels (enzymes are proteins that speed up any reaction happening in the body)

Less common side effects

These side effects have affected up to one in 10 people and include:

  • increased risk of bruising or bleeding
  • fluid retention (being unable to pass urine)
  • weight gain
  • confusion
  • headache
  • blurred or double vision
  • dry mouth

Uncommon side effects

Uncommon side effects of carbamazepine can include:

  • uncontrollable (involuntary) movements such as tremors
  • abnormal eye movements
  • diarrhoea
  • constipation

Nice Guidelines for Neuropathic Pain