Cases: Charles Bonnet syndrome: visual loss and hallucinations.

69-year-old man presented to his doctor with complaints of visual hallucinations that first occurred 6 months before presentation. He reported having hallucinations most evenings. He saw the faces of people, odd shapes, animals and a spider, which he had tried to kill. He also reported seeing people that he knew sitting in the armchair next to his night table. The patient had no history of mood disorders or psychiatric or neurologic diseases. He had type 2 diabetes, hyperten-sion, arthritis and coronary artery disease. His current medications included amlodipine, acetylsalicylic acid, clopidogrel bisulfate, glimepiride, hydrochlorothiazide, furosemide, lisinopril, metoprolol succinate, simvastatin and tramadol. He was also taking tamsulosin and dutasteride for benign prosta-tic hypertrophy and allopurinol for gout. None of his medications had been changed before the onset of the hallucinations. The patient reported having an abrupt change in vision about 16 months before presentation, at which time he noted distortion in his vision. He received a diagnosis of exudative age-related macular degeneration and had 12 intraocular ranibizumab injections after diagnosis. On examination, he has clear cognition. His visual acuity was 20/70 in the right eye and 20/50 in the left eye. Discussion Diagnosis A hallucination is " a sensory perception that has the compelling sense of reality of a true perception but that occurs without external stimulation of the relevant sensory organ. " 1 Visual hallucinations can include both formed images, such as people, and unformed images, such as flashes of light. In elderly patients, visual hallucinations may be caused by dementia, delirium, drug-induced states or primary psychiatric disorders. Based on 3 characteristics (visual loss, clearly formed recurrent visual hallucinations, and insight into the unreal nature of the hallucinations), our patient received a diagnosis of Charles Bonnet syndrome. Loss of vision The reported prevalence of Charles Bonnet syndrome in people with visual impairment is 10%–38%. This wide range is attributed to differences in definition, history-taking and patients' willingness to disclose the symptom because of concern that it implies mental incompetence. 2 Historically, not all authors cited loss of vision as a component of the diagnosis. 3 However, the association with visual loss is now widely thought to be a required part of the diagnosis. Hallucinations as part of this syndrome can occur in patients of any age with any type or degree of visual loss. Hallucinations The hallucinations associated with Charles Bonnet syndrome can vary widely from simple, repeated coloured patterns …