The vagus nerve is one of 12 cranial nerves, meaning nerves that exit the spinal cord though the skull rather than through the vertebral column. The vagus nerve is known as the tenth cranial nerve. Its functions include supplying motor nerve impulses to the muscles of the voice box and tongue, receiving sensory impulses from the throat, ear and the organs of the chest and abdomen, and supplying visceral nerve impulses to the glands of the throat, and the chest and abdominal organs.
Diabetes
Diabetes can cause neuropathy, or nerve damage, to a number of different areas of the body. A prolonged increase in blood sugar associated with diabetes can alter nerve chemistry, and damage the blood vessels that support the nerves.
In cases where diabetes has damaged the vagus nerve, it can cause gastroparesis, a condition wherein the muscles of the stomach and intestine are not able to efficiently move food through the gastrointestinal system. Gastroparesis manifests in symptoms such as nausea, vomiting, heartburn, constipation, abdominal bloat, stomach spasms and decreased appetite.
Alcoholism
Chronic alcohol abuse is known to cause damage to nerves, a condition referred to as alcoholic neuropathy. Researcher J. Villalta of the Department of Internal Medicine at the University of Barcelona in Catalonia, Spain, found that alcohol abuse has a dose-related toxic effect on the autonomic nervous system, of which the vagus nerve is a part. Abstaining from alcohol, Villalta adds, can reverse the damage to the vagus nerve.
Viral Infection
Patients at the Center for Voice and Swallowing Disorders at Wake Forest University were identified as having incurred vagus nerve damage following upper respiratory viral infections. These infections initially involved symptoms such as cough, nasal congestion and runny noses.
Symptoms that persisted in patients identified as having post viral vagal neuropathy, or PVVN, included cough, throat clearing, difficulty speaking and vocal fatigue.
Surgical Complications
Mayoclinic.com states that the vagus nerve can sometimes be damaged during surgery to the stomach or small intestine.
A procedure called laparoscopic hemifundoplication, which is used to treat gastric reflux, has been associated with vagus nerve damage, according to Dr. Maud Y.A. Lindeboom of the Departments of Gastroenterology-Hepatology, Surgery, and Nuclear Medicine at the Leiden University Medical Center in the Netherlands. Patients saw a remission of their reflux symptoms after surgery, but 10 percent of patients who'd undergone the procedure showed signs of postoperative vagus nerve damage.
