Editing Vagus nerve (section)

===Vagus nerve pathology===
The sympathetic and parasympathetic components of the autonomic nervous system (ANS) control and regulate the function of various organs, glands, and involuntary muscles throughout the body (e.g., vocalization, swallowing, heart rate, respiration, gastric secretion, and intestinal motility).  Hence, most of the signs and symptoms of vagus nerve dysfunction, apart from vocalisation, are vague and non specific. Laryngeal nerve palsy results in paralysis of an ipsilateral vocal cord and is used as a pointer to diseases affecting the vagus nerve from its origin down to termination of its branch of the laryngeal nerve.

* '''Sensory neuropathy'''

The hypersensitivity of vagal afferent nerves causes refractory or idiopathic cough.

[[Auricular branch of vagus nerve|Arnold's nerve]] ear-cough reflex, though uncommon, is a manifestation of a vagal sensory neuropathy and this is the cause of a refractory chronic cough that can be treated with [[gabapentin]]. The cough is triggered by mechanical stimulation of the external auditory meatus and accompanied by other neuropathic features such as throat irritation (laryngeal paresthesia) and cough triggered by exposure to nontussive triggers such as cold air and eating (termed allotussia). These features suggest a neuropathic origin to the cough.<ref>{{cite journal|vauthors=Ryan NM, Gibson PG, Birring SS|title=Arnold's nerve cough reflex: evidence for chronic cough as a sensory vagal neuropathy|journal=Journal of Thoracic Disease|volume=6|issue=Suppl 7|pages=S748–S752|date=October 2014|pmid=25383210|pmc=4222929|doi=10.3978/j.issn.2072-1439.2014.04.22}}</ref>

* '''Motor neuropathy'''

Pathology of the vagus nerve proximal to the laryngeal nerve typically presents with symptom hoarse voice and physical sign of paralysed vocal cords.  Although a large proportion of these are the result of idiopathic vocal cord palsy but tumours especially lung cancers are next common cause.  Tumours at the apex of right lung and at the hilum of the left lung are the most common oncological causes of vocal cord palsy.  Less common tumours causing vocal cord palsy includes thyroid and proximal oesophageal malignancy.