Mr. B’s symptoms are atypical for CBS, but they fit the diagnosis when considering the entire clinical picture. While hallucinations in CBS are more often simple shapes, complex hallucinations including people and scenes have been noted in several instances.6
Similar to Mr. B’s case, patients with CBS can have recurring figures in their hallucinations, and the images may even move across the visual field.1 Patients with CBS also frequently recognize that their hallucinations are not real, and may or may not be distressed by them.4 Patients with CBS often have hallucinations multiple times daily, lasting from a few seconds to many minutes,7 consistent with Mr. B’s temporary symptoms.
Although auditory and tactile hallucinations are typically not included in CBS, they can also be explained by Mr. B’s significant sensory impairment. Severe hearing impairment in geriatric adults has been associated with auditory hallucinations8; in 1 survey, half of these hallucinations consisted of voices.9 In contrast, tactile hallucinations are not described in sensory deprivation literature. However, in the context of Mr. B’s severe comorbid hearing and vision loss, we propose that these hallucinations reflect his interpretation of sensory events around him, and their integration into his extensive hallucination framework. In other words, Harry poking him and causing him to drop things may be Mr. B’s way of rationalizing events that he has trouble perceiving entirely, or his mild forgetfulness. Mr. B’s social isolation is another factor that may worsen his sensory deprivation and contribute to his extensive hallucinations.10 Additionally, his mild cognitive deficits on testing with chronic microvascular changes on the MRI may suggest a mild vascular-related dementia process, which could also exacerbate his hallucinations. While classic CBS occurs without cognitive impairment, dementia can often co-occur with CBS.11
TREATMENT No significant improvement with medications
During his inpatient stay, Mr. B is treated with risperidone, 1 mg nightly, and is also started on donepezil, 5 mg/d, to treat a possible comorbid dementia. However, he continues to hallucinate without significant improvement.
The authors’ observations
There is no definitive treatment for CBS, and while the hallucinations may spontaneously resolve, per case reports, this typically occurs only as visual loss progresses to total blindness.12 However, many patients can have the hallucinations remit after the underlying ocular etiology is corrected, such as through ocular surgery.13 Other optical interventions, such as special glasses or contact lenses, may help maximize remaining vision.8 In patients without this option, such as Mr. B, there are limited data on beneficial medications for CBS.
Continue to: Evidence for treatment of CBS...