Case 11. two faces of the medallion

Rapid eye movement sleep behavior disorder (RBD) is one of the core clinical features of dementia with Lewy bodies (DLB). However, increasing evidence has shown that RBD could be also found in clinically diagnosed Alzheimer’s disease (AD). Patients with RBD in AD tend to have a longer duration of AD. When RBD develops acutely, it could be due to structural/inflammatory brain lesions, central nervous system (CNS) diseases, alcohol withdrawal, post-traumatic stress disorder or medications. Acetylcholinesterase inhibitors (AEIs) are the drugs of choice in the treatment of AD. Although they have been shown to reduce RBD symptoms, they were also reported to induce RBD in two patients with late stage AD. Herein, we report a 76-year-old man with probable AD who developed acute RBD due to AEI (rivastigmine). On account of his obstructive sleep apnea, melatonin was prescribed for RBD. During follow-up, there was partial resolution of RBD episodes.