Causes

Experts do not completely understand how trigeminal neuralgia (TN) pain occurs. However, they do know that TN is often caused by one or more blood vessels “compressing” or pressing against the trigeminal nerve. The nerve is most commonly compressed by an artery (or arteries). Sometime, but less commonly, it can be compressed by a vein.  The compression usually occurs where the trigeminal nerve enters the brainstem, or the trigeminal root entry zone.



Normally, the trigeminal nerve consists of several different types of nerve fibers that carry sensations such as pain, touch, and heat to the brain. These nerve fibers are covered by a protective layer called myelin. Myelin keeps nerve signals for pain, touch, and temperature separate from each other. Many experts believe that repeated pressure or pulsing of blood vessels against the trigeminal nerve can wear away the myelin and irritate the nerve. If the myelin is damaged, the different nerve signals mix together instead of remaining separate. For example, mixed nerve signals may cause a woman with TN to feel pain when she lightly touches her face.

TN caused by nerve compression has been called idiopathic, although this is not a good term since the cause is actually known.

What can trigger TN pain?

TN pain can happen without any warning or reason. It can be triggered when certain areas of your face are touched. Things that trigger pain may include: