Abstract
The patient was a 71-year-old woman who had been diagnosed with type 2 diabetes at 34 years of age. Intensive insulin therapy was started at 65 years of age; however, this therapy frequently resulted in hypoglycemic attacks despite adjustments to the dose of insulin. Therefore, the insulin was changed to liraglutide, a GLP-1 receptor agonist. However, the patient then suffered from a gradual loss of appetite and consequent reduction in dietary intake. These changes were associated with the onset of a taste disorder that manifested in terms of the inability to detect sweetness and umami. The patient also experienced an uncomfortable feeling in her eyes, which was subsequently diagnosed as a bilateral diffuse corneal disorder of the epithelium. Due to possible side effects, the administration of liraglutide was discontinued. An immediate improvement was noted in the patient's taste and corneal epithelial disorders. Given that she presented with manifestations of a dissociated taste disorder affecting only the sensations of sweetness and umami, a disorder of salivation or nerve fiber dysfunction was judged to be unlikely. As such, liraglutide-induced dysfunction of the GLP-1 receptor is the most plausible explanation for the symptoms observed in this case. Additionally, a drug-induced illness was strongly suspected based on the occurrence of the bilateral diffuse corneal disorder.
