Syncope Associated with Subthalamic Nucleus Deep Brain Stimulation in a Patient with Parkinson’s Disease

In advanced Parkinson's disease (PD), deep brain stimulation (DBS) may be an alternative option for the treatment of motor symptoms. Side effects associated with subthalamic nucleus (STN) DBS in patients with PD are emerging as the most frequent sensory and motor symptoms. DBS-related syncope is reported as extremely rare. We wanted to discuss the mechanisms of syncope associated with STN DBS in a patient with Parkinson's disease. Case report. Sixty-three-year-old female patient is followed up with diagnosis of idiopathic Parkinson's disease for 6 years in our clinic. The patient has undergone STN DBS due to painful dystonia and drug resistant tremor. During the operation, when the left STN was stimulated at 5 milliampere (mAmp), the patient developed presyncopal symptoms. However, when the stimulation was stopped symptoms improved. During the early period after the operation, when the right STN was stimulated at 1.3 millivolts (mV), she developed the pre-yncopal symptoms and then syncope. Our case shows that STN DBS may lead to directly autonomic symptoms resulting in syncope during stimulation-on (stim-on). 1. Introduction Parkinson’s disease (PD) is a chronic neurodegenerative disorder primarily characterized by progressive motor impairments due to dopamine insufficiency. As the disease progresses, levodopa-related motor complications develop. At this stage, it is difficult to treat motor symptoms of PD. In advanced PD, deep brain stimulation (DBS) may be an alternative option for the treatment of motor symptoms. Side effects associated with subthalamic nucleus (STN) DBS in patients with PD are not rare. These side effects are emerging as the most frequent sensory and motor symptoms [1]. Also STN DBS is associated with neuropsychiatric side effects and weight gain in some individuals. DBS related syncope is reported as extremely rare. The pathomechanisms of these side effects are completely unknown. However, it has been suggested that these side effects are associated with the spread of electrical activity to the structures surrounding the STN [1]. We wanted to discuss the mechanisms of syncope associated with STN DBS in a patient with Parkinson’s disease. 2. Case Report Sixty-three-year-old female patient is followed with diagnosis of idiopathic PD since 6 years in our clinic. The patient has undergone STN DBS due to painful dystonia and drug resistant tremor. The patient’s clinical motor symptoms were assessed by UPDRS III in both off and on medication states. Thus, levodopa response (LR) rate of the patient was determined. During the operation,