What further evaluation is needed for a patient with a 2-year history of anosmia (loss of smell) without any changes or concerning symptoms and a normal physical exam?

From the Guidelines

For a patient with a 2-year history of isolated anosmia with a normal physical exam, further evaluation should include imaging studies and specialty consultation to rule out underlying causes. Given the patient's stable and long-standing symptoms without other neurological findings, the evaluation should focus on identifying potential causes of anosmia, such as structural abnormalities, chronic sinusitis, or nasal polyps.

• An MRI of the brain with special attention to the olfactory bulbs and tracts is recommended to rule out structural causes such as tumors, especially those affecting the anterior cranial fossa 1.
• CT imaging of the paranasal sinuses should also be considered to evaluate for chronic sinusitis or nasal polyps that might not be evident on physical examination 1.
• Referral to an otolaryngologist (ENT specialist) is appropriate for nasal endoscopy to directly visualize the olfactory cleft and assess for obstructive pathology.
• Additionally, formal smell testing using standardized tests like the University of Pennsylvania Smell Identification Test (UPSIT) or Sniffin' Sticks can quantify the degree of olfactory dysfunction.
• Laboratory testing should include thyroid function tests, vitamin B12, and zinc levels, as deficiencies can contribute to smell disorders. While the long-standing and stable nature of the symptoms without other neurological findings makes certain diagnoses like neurodegenerative diseases less likely, the evaluation remains important as anosmia can be an early sign of conditions like Parkinson's disease or can result from prior viral infections including COVID-19 1.

From the Research

Evaluation of Anosmia

The patient presents with a 2-year history of anosmia (loss of smell) without any changes or concerning symptoms, and a normal physical exam. To determine if additional evaluation is needed, consider the following:

• The patient's symptoms have been stable for 2 years, which may indicate a chronic condition.
• A normal physical exam does not rule out underlying conditions that may be contributing to the anosmia.

Diagnostic Considerations

When evaluating anosmia, consider the following diagnostic tools:

• Orthonasal smell tests, such as the Sniffin' Sticks and the UPSIT, along with validated abridged smell tests 2.
• Imaging modalities, such as MRI and CT, may be used to rule out underlying conditions, but are not typically used to primarily diagnose smell loss 2.

Treatment Options

While there is no clear indication of an underlying condition that can be treated, consider the following:

• Intranasal steroids, such as fluticasone, have been shown to improve symptoms of chronic rhinosinusitis, including anosmia 3, 4, 5.
• The exhalation delivery system (EDS-FLU) has been shown to be effective in delivering fluticasone to the deeper areas of the nasal cavities, including the posterior nasal cavity and middle and superior meatuses 3, 4, 5.

Further Evaluation

Based on the patient's stable symptoms and normal physical exam, further evaluation may include:

• A thorough history to rule out any underlying conditions that may be contributing to the anosmia.
• Validated orthonasal smell tests to assess the patient's sense of smell.
• Consideration of intranasal steroids, such as fluticasone, to improve symptoms of anosmia, if an underlying condition is suspected 3, 4, 5.