Dementia

• Dementia is irreversible, progressive decline and impairment of more than one aspect of higher brain function (concentration, memory, language, personality, emotion). This occurs without impairment of consciousness.
• Alzheimer's dementia:

  • Most common cause of dementia in UK
  • Slightly more common in females
  • Tends to progress steadily over time
  • Amyloid plaques (clumps of beta-amyloid) and neurofibrillary tangles (tau protein) - leads to reduction in information transmission and brain cell death
  • Usually over 60 years old
  • Most common presenting symptom is memory loss
• Vascular dementia:

  • Second most common type
  • More common in males - due to increased risk of vascular disease
  • Increased prevalence in those who have had a stroke
  • Progresses in a stepwise fashion
  • Several subtypes - most common is multiple cerebrovascular infarcts
  • Most affected areas of the brain is the white matter
  • Hypertension is a major risk factor for diffuse vascular dementia
  • Mood disturbances and disorders are common - psychosis, delusions, hallucinations and paranoia can be seen
• Lewy body dementia:

  • Affects people over 50
  • More men than women
  • Rapidly progressive - death most commonly within 7 years
  • Spherical Lewy body proteins (alpha-synuclein) are deposited (widespread)
  • Often involves visual hallucinations and Parkinson like symptoms
  • Sleep disorders and fluctuations in cognitive ability
• Cognitive assessment tools:

  • 10-point cognitive screener (10-CS)
  • 6-item cognitive impairment test (6CIT)
  • Memory impairment screen (MIS)
  • Mini-Cog
  • Test Your Memory (TYM)
• Drugs to be used with caution in dementia due to anticholinergic burden:

  • TCAs e.g. amitriptyline
  • Antiemetics e.g. metoclopramide
  • Analgesics
  • Sedatives
  • Antihistamines
• People with dementia must inform the DVLA
• Pharmacological therapy:

  • Acetylcholinesterase inhibitors e.g. rivastigmine - mild to moderate AD
  • N-methyl-D-aspartic acid receptor antagonists e.g. memantine - moderate to severe AD
  • Mainly indicated in patients with Alzheimer's dementia
  • Antipsychotics or benzodiazepines for acute agitation
  • Cardiovascular drugs for patients with significant cerebrovascular disease
• Vascular dementia disease specific features:

  • Step wise decline in function
  • Gait abnormalities
  • Attention and personality changes
  • May have focal neurological signs due to previous cerebrovascular event
• Vascular dementia medication:

  • Acetylcholinesterase inhibitors such as donepezil may be used if there is evidence of mixed dementia
• Core features of dementia with lewy body:

  • Fluctuating cognition with pronounced variations in attention and alertness
  • Recurrent visual hallucinations that are typically well formed and detailed
  • REM sleep behaviour disorder, which may precede cognitive decline
  • One or more spontaneous cardinal features of parkinsonism (e.g. bradykinesia, rest tremor, rigidity)
• DLB pharmacological intervention:

  • Acetylcholinesterase inhibitors - generally first line
  • Anti-psychotics e.g. Quetiapine - only if severe behavioural symptoms due to their anti-dopaminergic effects that may worsen symptoms
  • Melatonin - may be used for REM sleep disorders
  • Levodopa - for severe, disabling parkinsonism features