What is the management of Charles Bonnet Syndrome?

Management of Charles Bonnet Syndrome

The primary management of Charles Bonnet Syndrome (CBS) consists of patient education and reassurance that the hallucinations are a common phenomenon in visually impaired people and not a sign of mental illness. 1

Understanding Charles Bonnet Syndrome

Charles Bonnet Syndrome is characterized by four key findings:

• Recurrent, vivid visual hallucinations
• Insight that what is seen is not real
• No other neurological or medical diagnosis to explain the hallucinations
• Some degree of vision loss 1

CBS occurs in patients with visual impairment, with prevalence ranging from 15% to 60% depending on the definition and population studied. The hallucinations are attributed to a "cortical-release phenomena" resulting from a lack of afferent visual information to the brain.

Management Approach

First-Line Management

1. Education and Reassurance

   • Explain to patients and their families/caregivers that these phantom visions are common in visually impaired people
   • Reassure that CBS is not a psychiatric disorder or sign of cognitive decline
   • Discussion about the nature of CBS often leads to significant relief and decreased anxiety 1

2. Self-Management Techniques

   • Eye movements
   • Changing lighting conditions
   • Distraction techniques
   • These methods have shown to reduce hallucinations in some patients based on limited evidence from case series 1

Second-Line Management

If hallucinations are distressing and persistent despite education and self-management:

1. Vision Rehabilitation

   • Optimize remaining vision through vision rehabilitation services
   • Improve lighting and contrast in the environment
   • Use magnification devices when appropriate 1

2. Psychological Support

   • Psychological therapies such as support groups should be recommended for patients with vision loss
   • These have shown moderate effect on depression and low-certainty evidence of benefit on vision-related quality of life 1

3. Consider Transcranial Direct-Current Stimulation (tDCS)

   • A recent trial of 16 subjects with CBS reported reduced frequency of hallucinations with inhibitory tDCS 1

Pharmacological Treatment

There is currently no significant evidence of efficacy for pharmacological treatments of CBS. 1 However, in cases where hallucinations cause severe distress or when CBS coexists with other conditions:

• Selective serotonin reuptake inhibitors (SSRIs) have shown some promise in case reports 2
• Donepezil may be considered in patients who also have cognitive impairment 3
• Antipsychotics should be used with extreme caution and only in severe cases with psychiatric complications 4

Special Considerations

Monitoring for Atypical Features

Be vigilant for atypical features that should raise suspicion of diagnoses other than CBS:

• Lack of insight into the unreal nature of the images despite explanation
• Images that interact with the patient or environment
• Hallucinations in other sensory modalities
• Progressive cognitive decline 1

CBS in Patients with Cognitive Impairment

• Patients with both CBS and cognitive impairment may lose insight into the nature of their hallucinations
• This can complicate management and may require different approaches 3
• Regular cognitive assessment is important in elderly patients with CBS

Prognosis

• CBS can be chronic but is not typically progressive unless underlying vision continues to deteriorate
• Approximately 60% of patients experience improvement or resolution of hallucinations within 18 months
• Some patients may experience hallucinations for years, but with proper education and support, most learn to cope with them effectively

Key Pitfalls to Avoid

1. Misdiagnosing CBS as a psychiatric disorder, leading to inappropriate treatment with antipsychotics
2. Failing to address the underlying vision loss that contributes to CBS
3. Not providing adequate education and reassurance, which are the most effective interventions
4. Overlooking the psychological impact of both vision loss and hallucinations on quality of life
5. Missing atypical features that may indicate other diagnoses requiring different management

Remember that while CBS itself is not harmful, the anxiety and distress it causes can significantly impact quality of life if not properly addressed through education and support.