Charles Bonnet Syndrome: A Case Series from a Psychogeriatric Clinic in a Tertiary Hospital in Nigeria

Charles Bonnet Syndrome (CBS), also known as visual release hallucinations is the experience of complex visual hallucinations in an individual with partial or severe blindness. It is an uncommon disorder with a worldwide prevalence ranging between 0.5%40%. However, the prevalence in Africa is largely unknown due to unavailability of reliable statistics. Furthermore, there has generally been an under-reporting of visual hallucinations by patients due to fear of being labeled psychologically unstable. As the population of old people increases in our society, there is also the likelihood of an increase in visual impairment among them and consequently an increase in those affected by CBS. We therefore report the two cases of this uncommon disorder that presented in our psychogeriatric clinic in order to raise awareness among clinicians with the aim of encouraging early detection and prompt treatment in a resource constrained setting like Nigeria. Case Report Charles Bonnet Syndrome: A Case Series from a Psychogeriatric Clinic in a Tertiary Hospital in Nigeria Osundina AF1*, Fela-Thomas AL1, Akanni OO1, Olotu SO1, Agbonile IO1 and Akpalaba RU2 1Federal Neuropsychiatric Hospital, Benin-City, Nigeria 2Department of Optometry, University of Benin, Nigeria Dates: Received: 04 April, 2017; Accepted: 04 July, 2017; Published: 05 July, 2017 *Corresponding author: Osundina AF, Federal Neuropsychiatric Hospital, Benin-City, Nigeria, Tel: +2348037273739; E-mail:


Introduction
Charles Bonnet Syndrome (CBS) is a rare disorder characterized by the presence of vivid, complex and recurrent visual hallucinations not occurring as a result of delirium [1]. The disorder usually occurs in elderly individuals who are visually impaired as a result of age-related macular degeneration [2].
However other causes such as retinitis pigmentosa, severe myopia, glaucoma, cataract, diabetic retinopathy and optic neuritis have been reported [3].
CBS usually occurs following abrupt and unexpected loss of vision and has not been found to occur with lifetime blindness [4]. The experience of hallucinations in the disorder are considered to occur as a result of a 'release phenomenon' secondary to the de-afferentation of the cerebral cortex [5].
With normal vision, the information received from the eyes stops the brain from releasing its own pictures. However in blindness, the information reaching the brain is grossly reduced and the brain now fi ll in these gaps by releasing fantasy pictures, patterns or old pictures it had stored thereby resulting in hallucination [6].
The content of the hallucination varies and may include images of people, animals, plants and inanimate objects.
These images may be familiar or strange to the individual and may appear in different colours. Individuals may experience different hallucinations in each episode and they are usually unable to infl uence the hallucinations [7], some patients have reported images lasting for varying length of time from seconds to hours. These hallucinations may be triggered by factors such as changes in the degree of illumination, stress and fatigue [8].
There is an under-reporting of CBS in our environment because many cases presenting in the psychiatric clinics are misdiagnosed as either Schizophrenia or Organic mental disorder due to the prominence of visual hallucinations. We report these two cases of CBS in order to improve the level of awareness amongst medical professionals about this relatively uncommon disorder.

Case 1
A 60 year old married clergyman presented at the During his subsequent visit, he reported that the frequency of having the visual hallucinations had reduced. He however gave information that he was yet to be further reviewed by the ophthalmologist due to fi nancial constraints. After about eight months, he defaulted from the psycho-geriatric clinic.

Case 2
A 73 year old man presented at the psychogeriatric clinic on account of repeatedly seeing images not seen by others. He usually sees these images frequently in clear consciousness and described these images as vivid in nature. He reported always seeing a woman and a man having sex although no other person around him has ever seen these images.
He described this scene as frightening. On several occasions, he sees white people but no other person around him sees them. He agreed to the fact that these images were not real.

Discussion
In elderly patients, visual hallucinations occur as a result of some medical disorders such as dementia, delirium or drug-induced states [9]. However, in CBS, there is usually a triad of visual impairment, clearly formed vivid and recurrent hallucinations and preserved cognitive status [10], as is the case in both elderly men.
In the past, there were controversies regarding visual impairment as an important component of the disorder [4].
However, in recent times, it has been widely accepted that visual loss is required as part of the symptoms for diagnosis [9]. In the second case of this report; it was found that the failing eye sight worsened the visual hallucination. This fi nding is consistent with previous reports on cases of Charles Bonnet Syndrome.
The prevalence of CBS is understandably higher among the geriatric population. Some of them report improvement or resolution of symptoms after several years though this is not the fi nding with the second case who has been on follow up for some years. The fi rst case reported has not been suffi ciently followed up to comment on long term outcome of the syndrome before he defaulted. Pharmacological agents such as antipsychotics, Selective Serotonin Reuptake Inhibitors (SSRIs) and anticonvulsants have been tried but the evidence for treatment remains limited [11].

Conclusion
We have highlighted cases of two elderly men who presented at the psychogeriatric clinic of our hospital with features of Charles Bonnet Syndrome. This is aimed at improving knowledge and early detection among clinicians with the overall aim of reducing suffering among patients.