Injury of trochlear nerve, right side, initial encounter

This code signifies damage to the right trochlear nerve (cranial nerve IV), which is responsible for innervating the superior oblique muscle of the eye. Injury to this nerve typically results in impaired downward and outward gaze, often leading to vertical diplopia (double vision). This specific code indicates the initial treatment or encounter for such an injury.

Apply this code for a patient presenting with a newly diagnosed or acutely managed injury to the right trochlear nerve. Documentation should clearly state the laterality (right side) and the nature of the injury, such as trauma, compression, or other acute insult affecting the nerve. This code is appropriate for the first time the patient is seen for this specific injury.

• Ensure documentation specifies "right side" for laterality; otherwise, an unspecified laterality code may be more appropriate.
• Confirm this is the "initial encounter" for the injury; subsequent care would use a different seventh character.
• Code any underlying cause of the trochlear nerve injury (e.g., skull fracture, intracranial hemorrhage) as a primary diagnosis if applicable.