Trigeminal neuralgia (TN or TGN) is a long-term pain disorder that affects the trigeminal nerve,[1] the nerve responsible for sensation in the face and motor functions such as biting and chewing. It is a form of neuropathic pain.[7] There are two main types: typical and atypical trigeminal neuralgia.[1] The typical form results in episodes of severe, sudden, shock-like pain in one side of the face that lasts for seconds to a few minutes.[1] Groups of these episodes can occur over a few hours.[1] The atypical form results in a constant burning pain that is less severe.[1] Episodes may be triggered by any touch to the face.[1] Both forms may occur in the same person.[1] It is regarded to be one of the most painful disorders known to medicine, and often results in depression.[5]
The exact cause is unknown, but believed to involve loss of the myelin of the trigeminal nerve.[1][6] This might occur due to compression from a blood vessel as the nerve exits the brain stem, multiple sclerosis, stroke, or trauma.[1] Less common causes include a tumor or arteriovenous malformation.[1] It is a type of nerve pain.[1] Diagnosis is typically based on the symptoms, after ruling out other possible causes such as postherpetic neuralgia.[7][1]
Treatment includes medication or surgery.[1] The anticonvulsant carbamazepine or oxcarbazepine is usually the initial treatment, and is effective in about 90% of people.[7] Side effects are frequently experienced that necessitate drug withdrawal in as many as 23% of patients.[7] Other options include lamotrigine, baclofen, gabapentin, amitriptyline and pimozide.[6][1] Opioids are not usually effective in the typical form.[1] In those who do not improve or become resistant to other measures, a number of types of surgery may be tried.[6]
It is estimated that 1 in 8,000 people per year develop trigeminal neuralgia.[1] It usually begins in people over 50 years old, but can occur at any age.[1] Women are more commonly affected than men.