In simple words: A cranial nerve injury is damage to one of the 12 pairs of nerves that come directly from the brain. These nerves control things like your senses of smell, taste, sight, and hearing, as well as facial expressions, balance, and swallowing.An injury can cause problems with these functions. Doctors diagnose these injuries by looking at how the injury happened, your symptoms, special nerve tests, and scans like MRIs and CT scans.

Injury to the cranial nerve refers to some form of trauma to one or more cranial nerves, which are 12 nerve pairs that carry signals from the brain through openings in the skull to control primarily sensory, but also some motor, functions. Injury to a cranial nerve may result in alteration in the sense of smell, taste, vision, altered sensation in the face, changes in facial expression, difficulty in hearing, speech, balance, and/or swallowing.Providers diagnose the condition based on the patient’s history, signs and symptoms, cranial nerve tests; and imaging techniques such as magnetic resonance imaging (MRI), or computed tomography (CT).

Example 1: A patient presents to the ER after a motor vehicle accident with facial numbness and difficulty speaking. Imaging reveals damage to the trigeminal and facial nerves, leading to a diagnosis of cranial nerve injury (S04).A secondary code would be assigned for the external cause of the injury (e.g., a code from the V00-Y99 range)., A patient experiences loss of smell and taste after a fall, and is diagnosed with injury to the olfactory and glossopharyngeal nerves (S04). The physician documents the details of the fall for accurate coding of the external cause., During a surgical procedure, a patient's accessory nerve is accidentally damaged, resulting in weakness in the neck and shoulder muscles. The surgeon documents the iatrogenic injury to the cranial nerve, which is coded as S04. An additional code would be assigned for the intraoperative complication.

Documentation should include the following: the specific cranial nerve(s) affected, the nature of the injury (e.g., compression, laceration, transection), associated symptoms, diagnostic methods used (e.g., physical exam findings, imaging results), and treatment plan.Documentation of the external cause of the injury is also required for accurate coding.

** Excludes1: birth trauma (P10-P15), obstetric trauma (O70-O71). Excludes2: burns and corrosions (T20-T32), effects of foreign body in ear (T16), effects of foreign body in larynx (T17.3), effects of foreign body in mouth NOS (T18.0), effects of foreign body in nose (T17.0-T17.1), effects of foreign body in pharynx (T17.2), effects of foreign body on external eye (T15.-), frostbite (T33-T34), insect bite or sting, venomous (T63.4)