Disorders of olfactory nerve

This code signifies a primary dysfunction or pathology affecting the first cranial nerve, responsible for the sense of smell. It encompasses conditions where the olfactory nerve itself is damaged, diseased, or otherwise impaired, leading to a diminished or absent sense of smell.

Use this code for diagnoses such as anosmia or hyposmia when the underlying cause is identified as a disorder of the olfactory nerve, rather than a conductive issue in the nasal passages or a central nervous system disorder. Documentation should clearly link the olfactory deficit to a specific nerve pathology, such as trauma, tumor compression, or inflammatory conditions directly affecting the nerve.

• Differentiate from R43.0 (Anosmia) or R43.1 (Parosmia) when the cause is not specifically identified as an olfactory nerve disorder.
• Consider sequencing this code as a primary diagnosis when the olfactory nerve disorder is the reason for the encounter.
• Look for documentation of neurological examination findings, imaging results (e.g., MRI showing nerve compression), or specific etiologies affecting the olfactory nerve.