Dementia with Lewy Bodies (DLB)
Summary
Dementia with Lewy Bodies (DLB) is the second most common type of degenerative dementia (after Alzheimer's Disease). It is characterised by alpha-synuclein protein deposits (Lewy bodies) in the cortex and brainstem. The clinical triad includes fluctuating cognition, recurrent visual hallucinations, and spontaneous parkinsonism. REM Sleep Behaviour Disorder (RBD) – acting out dreams – is a key supportive feature and may precede dementia by years. A critical management consideration is severe sensitivity to antipsychotics, which can cause neuroleptic malignant-like syndrome (Severe rigidity, Obtundation, Death) – avoid typical antipsychotics (e.g., Haloperidol) absolutely. Treatment includes Cholinesterase inhibitors (Donepezil, Rivastigmine – Effective for cognition and hallucinations). Parkinsonism responds poorly to Levodopa. DLB overlaps significantly with Parkinson's Disease Dementia (PDD) – differentiated by timing ("1-Year Rule": Dementia before/within 1 year of parkinsonism = DLB; Dementia >1 year after parkinsonism = PDD).
Key Facts
- Epidemiology: ~10-15% of dementia cases.
- Core Features: Fluctuating cognition, Visual hallucinations (vivid, detailed), Parkinsonism (spontaneous).
- Supportive Features: REM Sleep Behaviour Disorder, Severe antipsychotic sensitivity.
- Pathology: Lewy Bodies (Alpha-synuclein aggregates) in cortex.
- Treatment: Cholinesterase inhibitors (Donepezil, Rivastigmine). AVOID typical antipsychotics.
- 1-Year Rule: Dementia within 1 year of parkinsonism = DLB. Dementia >1 year after parkinsonism = PDD.
Clinical Pearls
"Fluctuating Cognition": Alertness and cognitive abilities vary dramatically, sometimes hour-to-hour. Patients may be lucid one moment, profoundly confused the next.
"Vivid Visual Hallucinations Before Memory Loss": Hallucinations (often people, animals, children) are typically early and prominent.
"Antipsychotics Can Kill": Neuroleptic sensitivity is severe and potentially fatal. AVOID Haloperidol, Risperidone. If absolutely necessary, use Quetiapine or Clozapine with extreme caution.
"REM Sleep Behaviour Disorder Precedes Dementia": Acting out dreams (Punching, Kicking in sleep) can appear 10+ years before cognitive decline.
Why This Matters Clinically
DLB is often misdiagnosed as Alzheimer's or Parkinson's. Recognising it avoids the catastrophic harm from antipsychotics and guides appropriate treatment.
Incidence
- Prevalence: ~10-15% of dementia cases (Second most common after Alzheimer's).
- Age: Typically >65 years.
- Sex: Slight male predominance.
Spectrum
DLB is part of the Lewy Body Spectrum along with Parkinson's Disease and Parkinson's Disease Dementia (PDD). All share alpha-synuclein pathology.
Lewy Bodies
| Feature | Description |
|---|---|
| Composition | Aggregates of Alpha-Synuclein protein. |
| Location | Cortical (Especially Temporal, Parietal, Cingulate) and Brainstem (Substantia Nigra). |
| Appearance | Eosinophilic, Spherical, Intracytoplasmic inclusions with a dense core and halo. |
Comparison with Other Synucleinopathies
| Condition | Primary Lewy Body Location |
|---|---|
| Parkinson's Disease | Brainstem (Substantia Nigra). |
| DLB | Cortex (Widespread) + Brainstem. |
| PDD | Cortex (Developing later). |
| MSA | Glial cells (Oligodendrocytes). |
Cholinergic Deficit
- Marked loss of Cholinergic neurons (Nucleus Basalis of Meynert).
- Basis for Cholinesterase inhibitor efficacy.
Core Clinical Features (McKeith Criteria)
| Feature | Description |
|---|---|
| Fluctuating Cognition | Variable alertness and attention. "Good days and bad days". Can fluctuate hour-to-hour. |
| Recurrent Visual Hallucinations | Well-formed, Detailed, Vivid. Often people (children, strangers), animals. Patient often has insight early on. |
| Spontaneous Parkinsonism | Rigidity, Bradykinesia, Resting Tremor (Less common than PD). NOT drug-induced. |
Probable DLB = Dementia + 2+ Core Features (Or 1 Core + 1+ Indicative Biomarker).
Possible DLB = Dementia + 1 Core Feature (Or 1+ Indicative Biomarker).
Supportive Clinical Features
| Feature | Description |
|---|---|
| REM Sleep Behaviour Disorder (RBD) | Acting out dreams. Kicking, Punching, Shouting during sleep. Often injures bed partner. May precede dementia by years. |
| Severe Neuroleptic (Antipsychotic) Sensitivity | Typical antipsychotics (Haloperidol) cause severe extrapyramidal rigidity, Altered consciousness, Autonomic instability (NMS-like). Can be fatal. |
| Repeated Falls / Syncope | Autonomic dysfunction. Orthostatic hypotension. |
| Transient Loss of Consciousness | Unexplained episodes. |
| Depression / Apathy | Early feature. |
| Delusions | Often paranoid or misidentification syndromes (Capgras). |
| Other Hallucinations | Auditory, Tactile. |
Cognitive Profile
| Domain | Notes |
|---|---|
| Attention / Executive Function | Disproportionately impaired (Differs from Alzheimer's). |
| Visuospatial Function | Impaired. Drawing, Perception. |
| Memory | Relatively spared early (Unlike Alzheimer's). |
McKeith Consensus Criteria (4th Consensus, 2017)
Essential Feature
- Dementia (Progressive cognitive decline interfering with function).
Core Clinical Features
- Fluctuating Cognition.
- Recurrent Visual Hallucinations.
- REM Sleep Behaviour Disorder.
- Parkinsonism (One or more: Bradykinesia, Rest Tremor, Rigidity).
Indicative Biomarkers
| Biomarker | Findings |
|---|---|
| FP-CIT SPECT (DaTSCAN) | Reduced dopamine transporter uptake in basal ganglia. |
| MIBG Myocardial Scintigraphy | Reduced cardiac sympathetic innervation. |
| Polysomnography | REM without atonia (Confirms RBD). |
Supportive Biomarkers
| Biomarker | Findings |
|---|---|
| MRI | Relative preservation of Medial Temporal Lobe (vs. atrophy in Alzheimer's). |
| FDG-PET / SPECT Perfusion | Decreased occipital activity. Cingulate Island Sign. |
| EEG | Posterior slow-wave activity with periodic fluctuations. |
Probable DLB
- Dementia + 2+ Core Features, OR
- Dementia + 1 Core Feature + 1+ Indicative Biomarker.
Possible DLB
- Dementia + 1 Core Feature (No Indicative Biomarkers), OR
- Dementia + 1+ Indicative Biomarkers (No Core Features).
| Investigation | Purpose |
|---|---|
| Cognitive Testing (MoCA, ACE-III) | Document deficits. Profile (Attention, Visuospatial). |
| FP-CIT SPECT (DaTSCAN) | Reduced dopaminergic uptake supports diagnosis. |
| Polysomnography | Confirm RBD (REM without atonia). |
| MRI Brain | Exclude other pathology. Assess medial temporal lobe (Preserved in DLB). |
| Routine Bloods | Exclude reversible causes (B12, Folate, TSH, Glucose, Calcium). |
| CSF (If Diagnostic Uncertainty) | May show low Aβ42 (Like AD). Normal tau vs. elevated tau in AD. |
Principles
- Multidisciplinary Team: Neurology, Geriatrics, Psychiatry, OT, Physio.
- Cholinesterase Inhibitors for Cognition and Hallucinations.
- AVOID Typical Antipsychotics.
- Manage Parkinsonism Cautiously.
- Treat RBD.
- Safety Modifications.
- Carer Support.
Pharmacological Management
Cognition & Hallucinations: Cholinesterase Inhibitors
| Drug | Dose | Notes |
|---|---|---|
| Donepezil | 5-10mg OD | First-line. Well-tolerated. |
| Rivastigmine | 1.5-6mg BD (Or Patch) | Strong evidence in DLB. Can help hallucinations. |
Cholinesterase inhibitors are more effective in DLB than Alzheimer's (Greater cholinergic deficit).
Hallucinations / Psychosis (If Severe and Distressing)
| Drug | Notes |
|---|---|
| AVOID Haloperidol, Risperidone | Severe sensitivity. Potentially fatal. |
| Quetiapine (Low Dose, e.g., 12.5-50mg) | If absolutely needed. Use with extreme caution. |
| Clozapine (Low Dose) | Alternative. Requires blood monitoring. |
Parkinsonism
| Drug | Notes |
|---|---|
| Levodopa (Low Dose) | May help motor symptoms. Often poor/limited response. May worsen hallucinations. |
| Avoid Dopamine Agonists | High risk of exacerbating psychosis. |
REM Sleep Behaviour Disorder
| Drug | Dose | Notes |
|---|---|---|
| Clonazepam | 0.25-1mg ON | First-line for RBD. |
| Melatonin | 3-12mg ON | Alternative. Safer. |
Other
- Depression: SSRIs (Sertraline).
- Orthostatic Hypotension: Fludrocortisone, Midodrine. Non-pharmacological measures.
Non-Pharmacological
| Intervention | Notes |
|---|---|
| Simplify Environment | Reduce visual stimuli. Good lighting. |
| Routine / Structure | |
| Safety Modifications | Falls prevention. Bed rails (Caution – RBD). |
| Carer Education & Support | Lewy Body Society. Carer respite. |
| Occupational Therapy | |
| Physiotherapy | Balance, Mobility. |
| Complication | Notes |
|---|---|
| Falls / Fractures | Parkinsonism. Orthostatic hypotension. |
| Neuroleptic Sensitivity Syndrome | From antipsychotics. Severe rigidity, Hyperthermia, Obtundation. Can be fatal. |
| Aspiration Pneumonia | Swallowing difficulties. |
| Rapid Cognitive Decline | |
| Caregiver Burnout | Hallucinations/Fluctuating cognition are distressing. |
| Measure | Notes |
|---|---|
| Disease Duration | Average ~6-8 years from diagnosis to death. |
| Cause of Death | Aspiration pneumonia. Falls. Sepsis. |
| Compared to AD | Faster decline. Higher morbidity. Greater caregiver burden. |
| Condition | Distinguishing Features |
|---|---|
| Alzheimer's Disease | Memory impairment prominent early. No parkinsonism/hallucinations initially. |
| Parkinson's Disease Dementia (PDD) | Parkinsonism > year before dementia (1-Year Rule). |
| Vascular Dementia | Stepwise decline. Vascular risk factors. MRI infarcts. |
| Delirium | Acute. Identifiable trigger. Reversible. (But DLB fluctuations mimic delirium). |
| Late-Onset Psychosis | Hallucinations without dementia initially. |
Key Guidelines
| Guideline | Organisation | Notes |
|---|---|---|
| NICE NG97 | NICE | Dementia Assessment and Management. |
| McKeith Criteria (2017) | Consortium | Diagnostic Criteria. |
| Lewy Body Society | Charity | Resources for patients/carers. |
Scenario 1:
- Stem: A 72-year-old man presents with 18 months of progressive confusion. His wife reports he has "good days and bad days". He describes seeing "children in the house" who aren't there. He walks slowly and has a resting tremor. What is the most likely diagnosis?
- Answer: Dementia with Lewy Bodies (DLB). (Fluctuating cognition + Visual hallucinations + Parkinsonism).
Scenario 2:
- Stem: What class of drugs is absolutely contraindicated in DLB?
- Answer: Typical Antipsychotics (e.g., Haloperidol). Risk of severe neuroleptic sensitivity syndrome.
Scenario 3:
- Stem: What is the "1-Year Rule" in Lewy Body spectrum disorders?
- Answer: If dementia develops within 1 year of parkinsonism = DLB. If dementia develops >1 year after parkinsonism = PDD (Parkinson's Disease Dementia).
| Scenario | Urgency | Action |
|---|---|---|
| Suspected DLB (Hallucinations + Parkinsonism + Cognitive Decline) | Urgent | Neurology / Memory Clinic. |
| Antipsychotic Adverse Reaction | Emergency | Stop drug. Admit. Supportive care. |
| Falls / Syncope | Urgent | Falls Clinic. Cardiology (Autonomic testing). |
| Caregiver Crisis | Urgent | Social Services. Carer support. Respite. |
What is Dementia with Lewy Bodies?
Dementia with Lewy Bodies is a type of dementia caused by tiny deposits of protein (Lewy bodies) in the brain. It affects memory, thinking, movement, and can cause vivid hallucinations.
What are the main symptoms?
- Confusion that varies a lot – Good days and bad days.
- Seeing things that aren't there – Often people, animals, or children.
- Movement problems – Stiffness, slowness, tremor (Like Parkinson's).
- Disturbed sleep – Acting out dreams.
What should you avoid?
- Certain medications (Antipsychotics like Haloperidol) can be very dangerous. Always tell doctors about this diagnosis.
How is it treated?
- Medications (Donepezil, Rivastigmine) can help with thinking and hallucinations.
- Physiotherapy helps with movement.
- Safety measures at home.
Key Counselling Points
- Carry a Medical Alert Card: "Some medications are dangerous for this condition – always inform doctors."
- Fluctuations Are Expected: "Good and bad days are part of the condition."
- Support is Available: "Organisations like the Lewy Body Society can provide advice and support."
| Standard | Target |
|---|---|
| Antipsychotic use minimised / avoided | >5% |
| Cholinesterase inhibitor offered | >0% |
| Falls risk assessment completed | 100% |
| Carer support offered | 100% |
- Friederich Lewy (1912): First described Lewy bodies in Parkinson's Disease.
- Kosaka (1976-1984): Described "Diffuse Lewy Body Disease" with dementia.
- McKeith Criteria: First published 1996, Revised 2005, 2017 (4th Consortium).
- NICE NG97. Dementia: assessment, management and support. nice.org.uk
- McKeith IG, et al. Diagnosis and management of dementia with Lewy bodies (Fourth Consensus Report). Neurology. 2017. PMID: 28592453
Last Reviewed: 2025-12-24 | MedVellum Editorial Team
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