1st February 2024

Lewy Body Dementia

It is the third commonest type of dementia. It is a progressive neurodegenerative cognitive decline, which constitutes approximately around 10% of all cases of dementia. It is generally characterised by difficulties in attention, focusing on tasks and executive function. There is a fluctuating cognitive problem noted rather than learning. They also present with visual hallucinations and mobility problems.

Background

Epidemiology

• Unlike Alzheimer’s dementia, this is higher in males.
• It is a disease of middle-aged and older people.
• It constitutes 10% of dementias.

Pathophysiology

Lewy Body dementia is a broad term that includes two subtypes:

1. Dementia with Lewy bodies- the individual develops fluctuating cognition-related problems that affect the way they think and behave. They would also experience changes in their visual perception, resulting in visual hallucinations. These symptoms occur first or together with movement and mobility problems.
2. Parkinson’s disease dementia- In this type of dementia, Parkinsonian symptoms are seen earlier than cognitive difficulties. The cognitive difficulties may be seen many years later in general.

In both these types of dementia, the common factor is the presence of Lewy bodies. The site of location of the Lewy bodies determines these two subtypes. They are small round neuronal inclusions comprised of altered neurofilament proteins (Tau proteins and tangles). 

In dementia with Lewy Body, the Lewy bodies are mainly concentrated in the cerebral cortex. In Parkinson’s disease, it is more in the substantia nigra, whilst in Parkinson’s disease dementia; the Lewy bodies are seen in both the cerebral cortex and substantia nigra.

Risk factors

• No specific risk factors. It is generally multifactorial.

Clinical features

1. General symptoms, as seen in Alzheimer’s, might be noted due to cognitive difficulties. However, the cognitive symptoms are generally fluctuating with varying levels of alertness and attention. Intellectual functioning is better preserved than in Alzheimer’s dementia.
2. Visual hallucinations- vivid
3. Executive functions and visuospatial deficits are more prominent here than in Alzheimer’s dementia.
4. Parkinsonian symptoms:
   • Masked facies
   • Shuffling gait
   • Rigid limbs
   • Bradykinesia
   • Stooped posture
   • Tremors
5. Supportive symptoms:
   • Repeated falls, balance problems
   • Syncope
   • Transient loss of consciousness
   • Neuroleptic sensitivity
   • Rapid eye movement sleep disorder
   • Systematised Delusions
   • Restless Leg Syndrome
   • Autonomic dysfunction- constipation, orthostatic hypotension, urinary incontinence
   • Speech and swallowing problems
6. Behavioural problems:
   • Anger, agitation
   • Depression, anxiety
   • Apathy
   • Excess daytime sleeping
   • Problems following instructions, handling money

Differential Diagnosis

• Other types of dementias
• Parkinson’s Disease dementia
• Depression
• HIV-associated neurocognitive disorder
• Huntington’s disease dementia

Evaluation

• Very similar to Alzheimer’s dementia. Basic screening for memory problems
• Specific tests, investigations
  1. Physical health assessment
  2. Special tests- serology (VDRL, HIV) in specific situations
• Neuroimaging- CT, MRI, PET, SPECT, DAT SCAN

Management

General principles 

• There are no specific treatments as such. These treatment options can provide symptomatic treatment. 
• It is pertinent to get the diagnosis accurately so the right symptomatic treatment and support can be offered. Hence, the importance of detailed collateral history and investigations.
• Medications used for visual hallucinations can worsen Parkinson’s, and treatment offered for Parkinson’s symptoms can worsen psychosis. Moreover, neuroleptic sensitivity can add to the difficulty of offering limited medications.
• Non-pharmacological treatment should be used in the first instance.

Bio

• Acetylcholinesterase inhibitors are used as the first choice for hallucinations and behavioural problems like agitation. They also can help with cognitive problems. The aim is to lead a better quality of life and manage activities of daily living.
• Should a need arise to offer antipsychotics, atypical neuroleptics/ antipsychotics are preferred (Quetiapine, Aripiprazole, Clozapine), especially if there is a poor response to cholinesterase inhibitors.
• For motor symptoms, anti-Parkinson medications such as levodopa and carbidopa are helpful in a few individuals.
• For the REM sleep disorder, Clonazepam and Melatonin (especially at lower doses) have been helpful.
• Consider antipsychotics, prn Benzodiazepine for behavioural and psychological symptoms of dementia, weighing the pros and cons of antipsychotics and the physical health.

Psycho

• Apart from the ones mentioned in Alzheimer’s dementia, CBT is used for anxiety and depression.
• Cognitive stimulation therapy

Social

• Apart from the ones mentioned in Alzheimer’s dementia, education regarding a healthy lifestyle (smoking cessation, reducing alcohol excess, exercise and a healthy diet)
• Physiotherapy and Occupational therapy input- adaptations at home for independent living
• Speech and Language therapy
• Carer support, Respite care
• Reminiscence therapy- sharing life experiences and memories
• Positive interactions and activities that interest and distract them
• Basic sleep hygiene

Prognosis

Dementia with Lewy body is a progressive illness, and it progresses faster than Alzheimer’s dementia. Mortality is associated with complications such as swallowing problems and poor nutrition. Dysphagia and mobility issues can worsen aspiration and pneumonia. Mobility problems can lead to frequent falls and injuries.

People with a diagnosis live approximately 5 years or so following the diagnosis. This could be due to multiple physical health risk factors.

References

1. Rongve, A. and Aarsland, D. (2020). The Lewy body dementias: Dementia with Lewy bodies and Parkinson’s disease dementia. academic.oup.com. [online] doi:https://doi.org/10.1093/med/9780198807292.003.0032.
2. McKeith, I.G. (2002). Dementia with Lewy bodies. The British Journal of Psychiatry, [online] 180(2), pp.144–147. doi:https://doi.org/10.1192/bjp.180.2.144.
3. Chin, K.S., Teodorczuk, A. and Watson, R. (2019). Dementia with Lewy bodies: Challenges in the diagnosis and management. Australian & New Zealand Journal of Psychiatry, 53(4), pp.291–303. doi:https://doi.org/10.1177/0004867419835029.
4. Vik-Mo, A.O., Giil, L.M., Borda, M.G., Ballard, C. and Aarsland, D. (2019). The individual course of neuropsychiatric symptoms in people with Alzheimer’s and Lewy body dementia: 12-year longitudinal cohort study. The British Journal of Psychiatry, 216(1), pp.43–48. doi:https://doi.org/10.1192/bjp.2019.195.
5. bestpractice.bmj.com. (n.d.). Dementia with Lewy bodies – Symptoms, diagnosis and treatment | BMJ Best Practice. [online] Available at: https://bestpractice.bmj.com/topics/en-gb/320?q=Lewy%20body%20dementia&c=suggested [Accessed 21 Feb. 2023].