Prevalence of Olfactory Impairment in Granulomatosis with Polyangiitis

Granulomatosis with Polyangiitis (GPA) is a rare disease of unknown origin. It may damage all organs and systems, even olfactory and taste sense. The aim of the study was to determine the sense of smell in patients with GPA and to identify factors related to disease course, activity, and duration, which may be associated with olfactory dysfunction. The comparison of olfactory function screening scores with Sniffin' Sticks standardized norms showed that 74% of the investigated patients had olfactory dysfunction. The olfactory performance was diminished in all parts of Sniffin' Sticks test: threshold scores 4.4 vs. 7.1 (p = 0.007); odor discrimination 9.0 vs. 11.9 (p = 0.008); and olfactory identification 9.8 vs. 12.2 (p = 0.011) in the GPA patients vs. control subjects, respectively. Scores acquired during all three parts of the test were combined to assess the TDI-score. The median TDI-score in the GPA group (27.5) was significantly lower than that in the control group (32.0) (p = 0.002). Active nasal and paranasal sinus inflammation in GPA leads to olfactory dysfunction, the patients are often unaware of. The dysfunction is permanent and does not abates along with decreasing intensity of the inflammatory process. GPA therapy should include recommendations on nutrition, personal hygiene, and food poisoning prevention.