Recovery from 3 Years of Daily Olfactory Distortions after Short-Term Treatment with GABA-Analogue

Abstract

This case report describes a healthy 47-year-old man with a 3 years history of daily unpleasant olfactory distortions with severe negative effects on the quality of life. The distorted smoke-like smell occurred every day and was most prominent in the evenings resulting in severe discomfort as the patient felt suffocated by the smoke when falling asleep. The distorted smell had no odour triggers and was classified as phantosmia. Patient history, nasal endoscopy, neurological and otolaryngological examination, depression screening, cognitive testing, and CT scan revealed no obvious aetiology, resulting in the diagnosis of idiopathic phantosmia. Quantitate olfactory function was normal. Based on anecdotal evidence in the literature, the patient was treated with a GABA-analogue (pregabalin 50 mg × 3) for 4 weeks. During this treatment, the olfactory distortions completely disappeared for the first time in 3 years and had not reoccurred after 7 months of follow-up. GABA-analogues may be a potential treatment for some of the patients suffering from olfactory distortions. While this constitutes a single case report without controls and phantosmia can disappear spontaneously, there is no proof of causality. However, given the long duration of symptoms, temporal relationship with treatment on the sudden disappearance of phantosmia, and long follow-up without recurrence, this highlights the need for further studies on GABA-analogues as a potential treatment of idiopathic phantosmia. Consequently, larger studies and systematic evaluation of potential effects in different patient groups are warranted before routine treatment with GABA-analogues is advised.