neurologic disorders
Trigeminal Neuralgia
Etiology of Trigeminal Neuralgia
Trigeminal neuralgia is usually caused by Compression of the trigeminal nerve at its root by an aberrant loop of an intracranial artery (eg, anterior inferior cerebellar artery, ectatic basilar artery) Less often, a venous loop that compresses the 5th cranial (trigeminal) nerve at its root entry zone into the brain stem Otherless common causesinclude compression by a tumor, an arteriovenous malformation, an aneurysm, and occasionally a multiple sclerosis plaque at the root entry zone (usually in younger patients), but these causes are usually distinguished by accompanying sensory loss and other deficits. Other disorders that cause similar symptoms (eg, Multiple Sclerosis (MS) ) are sometimes considered to be trigeminal neuralgia and sometimes not. Recognizing the cause is what is important. The mechanism is unclear. One theory suggests that nerve compression causes local demyelination, which may result in ectopic impulse generation (ephaptic transmission) and/or disinhibition of central pain pathways involving the spinal trigeminal nucleus. 