Olfactory Dysfunction Associated With Neuro-Behçet Disease

Neurologic involvement associated with Behçet disease (BD) is defined as a different entity: Neuro-Behçet disease (NBD). Behçet disease presents with olfactory dysfunction. It is not known whether this is the consequence of mucosal involvement or neurologic involvement.

The aim of this study was to investigate whether olfactory dysfunction was further aggravated as the result of neurologic involvement.

Sixteen patients diagnosed with NBD and 16 healthy control patients with similar demographic characteristics were recruited as the healthy control group. Expanded Disability Status Scale (EDSS) scoring was used for quantification of neurological disability. All diagnoses were confirmed and categorized with magnetic resonance imaging studies in all patients individually: parenchymal or nonparenchymal. A well-established test of orthonasal olfaction developed at the CCCRC was used. Correlation analysis was carried out.

The mean CCCRC score of NBD patients was 4.60 out of 7, and this group was diagnosed to be moderately hyposmic, whereas the average score of the control group was 6.5; the difference was significant (P < 0.0001). CCCRC scores of NBD patients were significantly lower compared both healthy control patients and those of BD patients reported in the literature. Mean EDSS score of NBD patients was 1.75 ± 1.0 out of 10 (0-no neurologic disability and 10-worst neurologic disability). Magnetic resonance imaging of NBD patients revealed 4 nonparenchymal and 12 parenchymal patients. Neuro-Behçet disease patients with parenchymal involvement presented with (worse) EDSS scores. Mean olfactory CCCRC score of this group was 4.38 whereas the average olfactory score of the vascular group was 5.25 out 7. Average EDSS score of vascular group was 0.75, much better compared to higher average neurologic disability score of 2.08 for the parenchymal group. Significant correlation existed between the duration of NBD and both olfactory and neurologic dysfunction scores.

Neuro-Behçet disease present with aggravated olfactory dysfunction compared to BD. Neurologic involvement-especially parenchymal involvement-seems to deteriorate the olfactory dysfunction. Duration of disease is correlated with this severity of dysfunction.