Editing Polio (section)

==== Bulbar polio ====
[[File:Brain bulbar region.svg|thumb|right|The location and anatomy of the bulbar region (in orange)]]
Making up about two percent of cases of paralytic polio, bulbar polio occurs when poliovirus invades and destroys nerves within the [[bulbar]] region of the [[brain stem]].<ref name = PinkBook2021 /> The bulbar region is a [[white matter]] pathway that connects the [[cerebral cortex]] to the brain stem. The destruction of these nerves weakens the muscles supplied by the [[cranial nerve]]s, producing symptoms of [[encephalitis]], and causes [[Dyspnea|difficulty breathing]], speaking and swallowing.<ref name=Late /> Critical nerves affected are the [[glossopharyngeal nerve]] (which partially controls swallowing and functions in the throat, tongue movement, and taste), the [[vagus nerve]] (which sends signals to the heart, intestines, and lungs), and the [[accessory nerve]] (which controls upper neck movement). Due to the effect on swallowing, secretions of [[mucus]] may build up in the airway, causing suffocation.<ref name = Silverstein /> Other signs and symptoms include [[facial weakness]] (caused by destruction of the [[trigeminal nerve]] and [[facial nerve]], which innervate the cheeks, [[tear duct]]s, gums, and muscles of the face, among other structures), [[diplopia|double vision]], difficulty in chewing, and abnormal [[respiratory rate]], depth, and rhythm (which may lead to [[respiratory arrest]]). [[Pulmonary edema]] and [[shock (circulatory)|shock]] are also possible and may be fatal.<ref name=Guide/>