Charles Bonnet syndrome: an important differential diagnosis in new onset hallucinations

Abstract

The onset of new visual hallucinations in a patient with a longstanding history of bipolar disorder is extremely rare and when seen is often attributed to the pre-existing condition. A case of 73 year old male is presented here who developed new onset visual hallucinations on a background of stable mental health and was treated with multiple inpatient admissions and extensive antipsychotic therapy. He was later diagnosed to have Charles Bonnet Syndrome. Had visual loss been considered and treated earlier in the diagnostic process, the patient could have avoided the distress of these admissions, side effects of medication, radiation exposure from imaging and above all would have received appropriate treatment sooner. Furthermore, the Mental Health Services would have saved the cost of inpatient stay. It is therefore better to consider Charles Bonnet Syndrome as a differential diagnosis even in patients with well-established mental illness if they develop new onset visual hallucinations. This case report examines why the diagnosis of Charles Bonnet Syndrome can be missed, and its impact on geriatric patients.