Charles Bonnet Syndrome with Atypical Features: Case Report

Introduction

A 78-year-old African American male presented at the emergency department (ED) accompanied by his family. The primary concern was the sudden exacerbation of his chronic VHs, which now featured more intricate, vivid, and inappropriate content [1]. Alongside this, there was a noticeable progression in troubling behavioral disturbances and episodes of agitation. The patient’s family was deeply worried about his deteriorating mental state and behavioral issues, to the extent that they were considering admitting him for inpatient care at a geriatric acute psychiatry hospital [2]. Their concern centered on what they perceived as a progressive psychosis and disruptive behavior. Interestingly, the family mentioned the possibility of these changes being connected to some form of spiritual possession by “evil spirits”.

Discussion

The diagnosis and management of CBS remain intricate, hindered by its limited recognition within the medical field despite the increasing prevalence of ocular issues among the elderly. Research has yielded varying prevalence estimates for CBS among those with visual impairment, spanning from 0.4% to 12% [4, 5]. Remarkably, epidemiological investigations indicate that as many as 63% of older adults with substantial visual deficits might be susceptible to CBS [6]. The underlying pathophysiology of CBS originates from visual impairments affecting any portion of the visual pathway, extending from ocular structures to the cerebral visual cortex. These impairments result in sensory deafferentation, prompting uncontrolled firing of visual cortical regions through a disinhibitory mechanism and this process gives rise to an array of hallucinations and visual distortions. In the elderly demographic, a predisposition towards cognitive impairment can exacerbate CBS, coinciding with the high prevalence of concurrent visual deficits [7].

Unlike hallucinations seen in psychotic conditions, where individuals firmly believe in the authenticity of their perceptual experiences, CBS patients are aware of the illusory nature of their hallucinations and acknowledge that others do not share their perceptions. In contrast to individuals with delirium or dementia, those with CBS maintain their cognitive abilities and functional capacities. However, despite their awareness, these patients can experience emotional distress due to the recurring and vivid nature of their hallucinations, occasionally leading to behavioral disturbances.

This particular case of CBS stands out due to its atypical characteristics, notably the presence of reduced cognitive faculties. The patient’s memory assessment showed intact registration and immediate recall, but delayed recall was impaired, with the ability to recollect only one out of three tested items. Intriguingly, his digit span and concentration remained unaffected, and no signs of paranoia or self- harm tendencies were evident. This distinctive cognitive profile introduces intriguing possibilities in the context of CBS. Although CBS is primarily linked with primary visual deficiency, the concurrent presence of neurocognitive impairment adds a unique dimension to this case. This coexistence could potentially differentiate this case from others, highlighting the interplay between sensory deficits and cognitive functioning in CBS.

In the pursuit of accurate diagnosis and heightened healthcare provider awareness, adopting established diagnostic criteria, comprehensive patient interviews, collateral insights, and thorough analysis of contributing factors is crucial. A defining characteristic of CBS, a disorder marked by hallucinations, is its occurrence in elderly patients grappling with age-related visual changes such as macular degeneration, glaucoma, and cataracts.

While a definitive remedy for CBS remains elusive, various interventions can alleviate symptoms, including pharmaceutical agents, behavioral strategies, patient education, ophthalmic interventions, and reassurance. The chosen approach hinges on symptom severity. Alongside assuring patients about the benign nature of their hallucinations, both non-pharmacological and pharmacological interventions have proven effective in managing CBS. In cases of distressing and unrelenting hallucinations, especially those that resist treatment, considering the off-label use of psychotropic medications may be prudent. However, such a decision requires meticulous evaluation of potential risks, benefits, and alternatives, particularly in the elderly population with comorbidities. Notably, atypical CBS presentations may occasionally align with underlying neurocognitive disorders, a common occurrence in the elderly. Moreover, atypical CBS tends to affect elderly patients who are experiencing age-related cognitive decline, which can erroneously lead to diagnoses such as Lewy Body dementia or a primary psychotic disorder. It is important to be aware of the presentation of hallucinations in CBS, which occurs solely without delusions or paranoia, versus a psychosis presentation in early dementia, which may present with command auditory hallucinations, delusions, or paranoia [8].

Conclusion

This case serves as a valuable illustration of the diagnostic approach and management strategies applied to CBS, a condition often linked with age-related macular degeneration, glaucoma, and cataracts. The patient’s clinical presentation and the timeline of symptom development align consistently with CBS, underscoring the complexity involved in diagnosing this syndrome. Indeed, arriving at a CBS diagnosis can be intricate due to the overlap of symptoms with several potential differential diagnoses. In this specific case, the list of differentials encompassed psychotic disorders, dementia, and hallucinations induced by substances. Nonetheless, through a meticulous assessment, distinctive features emerged that pointed toward CBS as the most plausible explanation for the patient’s visual hallucinations. Notably, his reality testing remained intact, he exhibited an awareness of the hallucinatory nature of his experiences, and his visual impairment was apparent. These critical insights guided the diagnosis. The patient’s presentation was aligned with the hallmark symptomatology of CBS, characterized by a history of visual impairment and reported visual hallucinations that abated in response to increased illumination or a change in surroundings.

While the initial presentation exhibited atypical behavioral disturbance and agitation at home, the absence of psychotic features and the normalization of his behavior during his stay on the inpatient medical floor suggested that these issues were precipitated by the VHs experienced in his home environment. A distinct facet of this case was the potential presence of an underlying neurocognitive disorder, as indicated by the patient’s impaired recall during the initial neurological assessment. It is plausible that this unique CBS presentation was influenced by sensory deprivation, stemming from his history of cataracts and compromised visual acuity when not using glasses, particularly in dimly lit settings. His challenges in appropriately administering his glaucoma eye drops further emphasized the impact of his visual impairment. This case not only showcases the nuances of diagnosing CBS but also highlights the importance of considering both classic symptomatology and atypical features, such as concurrent neurocognitive disorders, when evaluating patients with visual hallucinations associated with visual impairment.

Conflicting Interests: The author(s) declare no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Funding: None