Atypical trigeminal neuralgia (ATN), otherwise known as type 2 trigeminal neuralgia, is a rare form of trigeminal neuralgia. Around 4-5 people per 100,000 have trigeminal neuralgia and a small subset of those have ATN.
It is a disorder of the fifth cranial nerve (trigeminal nerve), where the nerve becomes inflamed and/or demyelinates.
What are the Symptoms of ATN?
ATN is less painful than its more common counterpart, trigeminal neuralgia, but the pain is more constant. Patients may experience a persistent headache that lasts for days at a time and keeps re-occurring. This may be mistaken for a migraine. They will have pain in the trigeminal nerve, sometimes in all of the nerve branches and may have pain around their ears, jaws, nose, eyes and scalp. Pain can be felt as a mild ache, a crushing pressure sensation or a sharp stabbing sensation.
Unlike ordinary trigeminal neuralgia, the atypical type affects people of all ages. Trigeminal neuralgia is more common in those over 40.
What Causes ATN?
ATN can be caused by vascular compression and this is the most common cause of the disease. If the pain is constant, rather than coming and going, it may be a sign of a tumor compressing the nerve, in which case further investigations need to be carried out. If the pain is intermittent, this is not the case.
It can also be caused by trauma, either by an accident or more commonly, a surgical procedure. It can occur after dental surgery. Sometimes it occurs as part of the aging process.
If an infection or long-term inflammatory condition has been present, this can, over time, damage the trigeminal nerve and result in ATN.
Medical Treatments for ATN
ATN is difficult to treat. The conventional medical treatments are either:
1. Use of high dose anti-inflammatory painkillers during a bout.
2. Use of anti-depressants or the anti-convulsant, Gabapentin, to shut down abnormal nerve function. It is thought after a long period of use that the nerve may regenerate normally. There is limited evidence that this type of treatment actually works, particularly for non-epileptic drugs.