Sixth [abducent] nerve palsy, bilateral

This code signifies a bilateral impairment of the sixth cranial nerve, which controls the lateral rectus muscle responsible for outward eye movement. Patients typically present with esotropia (inward turning of one or both eyes) that worsens when looking to the side of the affected muscle. This condition results in horizontal diplopia (double vision).

Apply this code when documentation clearly indicates a diagnosis of abducens nerve palsy affecting both eyes. This diagnosis is often supported by neurological examination findings such as limited abduction of both eyes, esotropia, and horizontal diplopia. It is crucial to confirm the bilateral nature of the palsy.

• Ensure documentation explicitly states "bilateral" to support the use of this specific code.
• Distinguish from unilateral sixth nerve palsy (H49.21 or H49.22) based on laterality.
• Code any underlying cause of the palsy (e.g., tumor, stroke, trauma) as a primary diagnosis if applicable, with the sixth nerve palsy as a secondary diagnosis.