The Primary Afferents of Trigeminal Autonomic Reflex May not be Nociceptive: A Case Report

Autonomic symptoms have been long noticed coming along with pain in the head, e.g. Trigeminal Neuralgia, trigeminal autonomic cephalalgias. The symptoms show up during pain attacks, so they are assumed to be activated by the nociceptive afferents of the trigeminal nerve. Here, we present a case with hypersalivation as the complication after percutaneous balloon compression for trigeminal neuralgia, although the patient was pain-free after the treatment. A 71-year-old female with excessive salivation on the affected side after percutaneous balloon compression is described. The patient underwent microvascular decompression several years ago, and both the microvascular decompression and the preoperative imaging examination confirmed that there was no offending vessel at the root entry zone of the trigeminal nerve. After the percutaneous balloon compression, the patient was free of pain, but the autonomic symptoms (hypersalivation) still showed up. The autonomic symptoms which usually came along with pain presented solely as post-percutaneous balloon compression complication in the case. Contrary to popular belief, for the patient who was pain-free after percutaneous balloon compression, the transiently overactivated nerve fibers that led to hypersalivation were not nociceptive afferents of the trigeminal nerve.