CC March 2016 Charles Bonnet Hallucinations

echoecho's version from 2016-06-30 08:30


Question Answer
List the 5 medical conditions that compromises visual acuity and can cause visual hallucinations?1) glaucoma 2) macular degeneration 3) cataracts 4) diabetic retinopathy 5) stroke
Define visual hallucinations?perception of an external stimullus when none exists
When was CBH first described?in 1760
CBH occurs mostly (although not exclusively) in what age group? Are accompanied by what 2 sensations?1) elderly 2) olfactory or auditory
List the 2 classifications?1) complex 2) simple
Define the complex form of CBH?consist of geometric patterns which may move and be colored
Define the simple form of CBH?faces, animals or other complete or incomplete pictures
How long do the CBH last?a minute or two (but may last longer)
CBH may occur at varying intervals, daily or weekly and often gradually become what?less frequent
CBH may disappear completely in ___ to ___ years after onset even if visual acuity worsens?1; 2
Does the patient know that the hallucinations are the real?yes (they are not scary or familiar as faces to not represent known individuals)
Do patients identify a pattern of timing and frequency of their hallucinations?yes
List the differential diagnoses of CBH?1) drug or alcohol abuse 2) migraine 3) Parkinson's disease 4) epilepsy 5) narcolepsy 5) cerebral infarct 6) other problems affecting the visual pathway
Are people who are born blind afflicted with CBH?no
What is the incidence of CBH?27%
Most patients will not reveal their experience, why? What are the consequences?1) for the fear of being diagnosed with a psychiatric disorder 2) CBH is underreported and often undiagnosed
Is there evidence that these hallucinations are prognostic of mental illness or cognitive deterioration? Why can these conditions coexist?1) no 2) because they mainly occur in the elderly
What is the cause of the hallucinations?not known
Some compare CBH to what syndrome?phantom limb syndrome
What is the phantom limb syndrome?it is a release phenomena whereby the abnormal signals are combined with normal signals in the visual associative cortex resulting in the hallucination
What is the deprivation theory?where a lack of sensory input results in spontaneous visual images that result in the hallucination
In support of the deprivation theory is the finding that risk of CBH is higher in those with what impairments and social issues, cognitive function?1) b/l vision loss and / or hearing impairment 2) socially isolated 3) lower cognitive function 4) who live in environment with poor lighting
What is a major risk fx?advancing age (most diagnosed in the 8th decade of life)
How is the dx made?by thorough hx
Only if coexisting problems are found is further testing and imaging indicated, true or false?true
What is the treatment of CBH?no treatment although various drugs (atypical antipsychotics and TCA, cholinesterase inhibitors have been tried, but good evidence for efficacy is lacking
*** In most situations, what is all that patient requires?reassurance and explanation
List some things the patient can do to control visions temporarily?1) closing eyes 2) increasing intensity of light in the environment 3) looking from side to side
Increasing what stimulation is also of benefit?1) social 2) visual 3) auditory
*** SUMMARY = These hallucinations are seen in older patients with decreased what?visual acuity
*** SUMMARY = Are hallucinations scary to the patient? What often falls into a pattern for the affected patient?no; timing and frequency
*** SUMMARY = What is the only intervention as no medications are well studied for CBH?reassurance