Makindo Medical Notes

Related Subjects: |Dementia |Alzheimer disease |Vascular Dementia |Dementia with Lewy bodies |Frontotemporal dementia |Corticobasal degeneration |Creutzfeldt Jakob disease | Huntington's Disease/Chorea |Anti Dementia Drugs |AIDS Dementia Complex |Normal Pressure Hydrocephalus |Acetylcholinesterase inhibitors |Mental Capacity Act 2005 |Behavioural and Psychological Symptoms of Dementia |Abbreviated Mental Test Score (AMTS)

There are reports of a Lewy Neuritis in the CA2 region of the hippocampus which may be unique to DLB.

About

• Dementia with Lewy bodies (DLB) is characterized by progressive cognitive decline and parkinsonian symptoms.
• Parkinsonism is often present, but the response to L-Dopa is limited.
• Individuals with DLB are highly sensitive to neuroleptic (antipsychotic) drugs, which can exacerbate symptoms.

Aetiology

• Lewy bodies, abnormal protein aggregates, are found in the cortex and subcortex but are not specific to DLB alone.
• They are composed of proteins like ubiquitin, parkin, and alpha-synuclein.
• Lewy body pathology often coexists with Alzheimer's disease pathology, such as senile plaques.

Clinical Features

• Fluctuating Cognition: DLB is characterized by pronounced fluctuations in attention and cognitive function, which can be mistaken for delirium.
• Visual Hallucinations: Vivid, detailed visual hallucinations are common and can cause distress, though not always.
• Parkinsonian Symptoms: Symmetrical parkinsonism with bradykinesia, rigidity, and shuffling gait is common, but tremor is less frequent.
• REM Sleep Behavior Disorder (RBD): Loss of normal muscle paralysis during REM sleep can lead to physically acting out dreams.
• Delusions and Behavioral Changes: Complex and bizarre delusions may occur, along with episodes of confusion or delirium.
• Sensitivity to Neuroleptics: Use of antipsychotic medications can precipitate severe reactions, including worsening parkinsonism.

Investigations

• Blood Tests: FBC, U&E, ESR, CRP, LFT, TFT, B12, folate levels to exclude other causes of cognitive impairment.
• Neuroimaging: MRI or CT scan may show generalized brain atrophy but is not specific to DLB.
• REM Sleep Study: A sleep study can confirm REM sleep behavior disorder (RBD).

Differential Diagnosis

• Idiopathic Parkinson's Disease (PD): PD can present with hallucinations and delirium, particularly due to medications like anticholinergics.
• Alzheimer's Disease: Often presents with memory impairment as the primary symptom, without early parkinsonism or hallucinations.
• Vascular Dementia: Stepwise cognitive decline with a history of stroke or vascular risk factors.

Management

• Parkinsonism: L-Dopa or dopamine agonists may be used cautiously, but the response is often limited, and these drugs can exacerbate hallucinations. Discontinue if no improvement.
• Cholinesterase Inhibitors: Medications like rivastigmine or donepezil may help with cognitive symptoms and may reduce visual hallucinations.
• Antipsychotics: Use with caution. Quetiapine may be considered for managing severe psychosis, but only at the lowest effective dose due to risk of worsening parkinsonism.
• REM Sleep Disorder: Clonazepam at bedtime may be beneficial for managing REM sleep behavior disorder.
• Depression: Selective serotonin reuptake inhibitors (SSRIs) such as sertraline or citalopram can be used to treat comorbid depression.
• Caregiver Support: Education and support for caregivers are essential, given the fluctuating and challenging nature of DLB symptoms.