Repetitive transcranial magnetic stimulation for treatment‐resistant depression in an elderly patient with an unruptured intracranial aneurysm: a case report

Abstract

Rupture of an intracranial aneurysm is a main cause of subarachnoid haemorrhage (SAH), which leads to sudden death. The prevalence of unruptured intracranial aneurysm (UIA) was estimated as 3.2%. A previous systematic review reported an increasing prevalence of UIA and a higher incidence of subarachnoid haemorrhage among the elderly population. Major depressive disorder (MDD) in elderly adults is a global public health problem. Many elderly patients with MDD have problems with limited effectiveness of antidepressants and high rates of adverse drug events. Although electroconvulsive therapy is a treatment option for severe MDD in elderly patients who do not respond to antidepressants, it causes definite cognitive impairment. Therefore, newer forms of nonpharmacological treatments have emerged. Repetitive transcranial magnetic stimulation (rTMS) is a non-invasive brain stimulation technique that has been used globally for treatment-resistant MDD over the past decade. rTMS has few serious adverse effects, and no effects on cognitive function have been described. Therefore, rTMS appears to be safe and efficacious in the treatment of elderly patients with treatment-resistant depression. However, few studies have clarified the safety of rTMS in patients with UIAs. In this study, we report the first case of rTMS for treatment-resistant depression in an elderly man with a UIA. We obtained signed informed consent from the patient. A 76-year-old Japanese man with a 1-year history of MDD was treated in an outpatient clinic. He had poor outcomes with several antidepressants (amoxapine, nortriptyline, mirtazapine and sertraline). At 60 years of age, he had been diagnosed with a UIA (4 mm in the left middle cerebral artery branch). The lesion was assessed annually with magnetic resonance angiography. The patient had no history of epilepsy or the injection of ferromagnetic material into the body or close to the head. The rTMS protocol consisted of energy intensity at 120% of the motor threshold (MT), 75 trains of 10 Hz (each train was 4 s in duration), a 41-s intertrain interval, and 3000 total pulses per session over the left prefrontal cortex using a NeuroStar TMS system (Neuronetics, Inc., Malvern, PA, USA). He completed 27 sessions over 6 weeks. The stimulation site was located 5.5 cm anterior to the MT location. His MT was higher than normal at 1.62 standard MT units, which extended the interval time. Blood pressure was taken every 10 min during each rTMS session. Moreover, we assessed pain by the visual analogue scale after each rTMS session. During the first rTMS session, the patient did not tolerate an intensity of 120% MT because of application site pain, and therefore, stimulation was performed at 100% MT. He was able to tolerate a 5% titration increase per day. During the rTMS sessions, both systolic (SBP) and diastolic blood pressure (DBP) were variable. In particular, SBP displayed greater variability than DBP (maximum change from baseline: SBP, 34 mmHg; DBP, 25 mmHg). In addition, there was a wide variation in the difference between maximum and minimum blood pressure (change range: SBP, 13–34 mmHg; DBP, 7–25 mmHg). The daily variance in blood pressure was not associated with the intensity of stimulation or the visual analogue scale score. There were no adverse events other than application site pain and no change in the UIA according to magnetic resonance angiography after the rTMS sessions. The patient achieved remission (17-item Hamilton Depression Rating Scale ≤7) after 27 treatment sessions. The stimulation depth and spatial resolution of the iron-core coil are 2 and 1 cm, respectively. The prefrontal cortex of the rTMS target site and middle cerebral artery branch were anatomically distant from