Differential Diagnosis for Decreased Sense of Smell
- Single most likely diagnosis
- Post-traumatic olfactory dysfunction: The patient has a history of a consistent canal removal, which may have damaged the olfactory nerves, leading to a decrease in the sense of smell.
- Other Likely diagnoses
- Chronic rhinosinusitis: Although the imaging study does not show any mucosal thickening or sinus disease, chronic rhinosinusitis can cause a decrease in the sense of smell, and the patient may have had a previous episode that has since resolved.
- Nasal polyposis: The patient may have nasal polyps that are not visible on the imaging study, which can cause a decrease in the sense of smell.
- Age-related olfactory decline: As people age, their sense of smell can decline, and this may be a contributing factor to the patient's symptoms.
- Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
- Meningioma: A tumor in the anterior cranial fossa could compress the olfactory nerves and cause a decrease in the sense of smell. Although the imaging study does not show any evidence of a tumor, it is essential to consider this possibility.
- Cranial nerve injury: Injury to the olfactory nerves or other cranial nerves can cause a decrease in the sense of smell, and it is crucial to investigate this possibility.
- Rare diagnoses
- Kallmann syndrome: A rare genetic disorder that affects the development of the olfactory system and can cause a decrease in the sense of smell.
- Neurodegenerative diseases (e.g., Parkinson's disease, Alzheimer's disease): Certain neurodegenerative diseases can cause a decrease in the sense of smell, although this is typically a late symptom.
- Infections (e.g., meningitis, encephalitis): Infections in the central nervous system can cause a decrease in the sense of smell, although this is typically accompanied by other symptoms such as fever, headache, and confusion.