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Dementia

Basics

  • Progressive cognitive decline in domains such as attention, executive function, memory, language, and social cognition.
  • Interferes significantly with activities of daily living (ADLs).
  • Classified by DSM-5 under major and mild neurocognitive disorders with specific etiologies:
  • Alzheimer disease (AD)
  • Vascular dementia (VaD)
  • Lewy body dementia
  • Parkinson disease dementia
  • Frontotemporal dementia
  • Creutzfeldt-Jakob disease (CJD)
  • HIV dementia
  • Substance-/medication-induced neurocognitive disorder

Epidemiology

  • Incidence increases with age:
  • 0.4% (65–74 years), 3.2% (75–84 years), 7.6% (≥85 years) for AD.
  • Prevalence in ≥65 years:
  • AD 11.3%, VaD 1.6%, Other dementias 13%.
  • Estimated 5–6 million Americans currently affected; projected 14 million by 2050.

Etiology and Pathophysiology

  • AD: β-amyloid plaques, neurofibrillary tangles, synaptic dysfunction, and neuronal loss.
  • VaD: cerebral atherosclerosis and infarcts.
  • Genetic factors: APOE4 allele increases AD risk; familial AD accounts for <5%.
  • Other contributing factors: age, systemic diseases, smoking.

Risk Factors

  • Age (strongest)
  • Female sex > male
  • Genetic predisposition
  • Hypertension, hypercholesterolemia, diabetes, obesity, smoking (VaD)
  • Endocrine/metabolic: hypothyroidism, Cushing syndrome, vitamin deficiencies
  • Chronic alcoholism, lower educational status, head injury, sedentary lifestyle

General Prevention

  • Treat reversible causes: drug-induced, vitamin deficiencies, alcohol-induced.
  • Manage hypertension, diabetes, and hypercholesterolemia.
  • No strong evidence for statins in prevention.
  • Maintain physical activity and cognitive stimulation.

Commonly Associated Conditions

  • Anxiety and depression
  • Psychosis (delusions common)
  • Delirium
  • Behavioral disturbances (agitation, aggression)
  • Sleep disturbances

Diagnosis

History

  • Requires informant report of cognitive and behavioral changes.
  • Probable AD diagnosis: age 40–90, insidious and progressive cognitive decline, no consciousness disturbance, no other causes.
  • Rule out reversible causes: thyroid disease, vitamin B12 deficiency, depression.

Physical Exam

  • Neurologic exam: assess deficits, motor/gait abnormalities, tremors.
  • Cognitive screening: Mini-Cog, MMSE, Montreal Cognitive Assessment (MoCA), ADAS-Cog.
  • Neuropsychological testing for complex cases.

Differential Diagnosis

  • Major depression
  • Medication side effects
  • Chronic alcohol use
  • Delirium
  • Subdural hematoma
  • Normal pressure hydrocephalus
  • Brain tumor
  • Parkinson disease
  • Vitamin B12 deficiency
  • Exposure to toxins (solvents, heavy metals, drugs)

Diagnostic Tests

  • Labs to exclude secondary causes: CBC, CMP, TSH, vitamin B12, HIV, RPR, ESR, folate.
  • CSF biomarkers (research): decreased β-amyloid, increased tau proteins (AD-specific).
  • Neuroimaging (CT/MRI): hippocampal and cerebral atrophy (AD), infarcts (VaD).
  • PET scans (selective use to differentiate dementias).

Treatment

General Measures

  • Structured daily schedules and written instructions.
  • Nutritional support, hygiene, safety, and home modifications.
  • Socialization and sensory stimulation.
  • Occupational therapy and physical exercise.
  • Family support and advance care planning.

Medications

Cognitive Dysfunction

  • Mild dementia: cholinesterase inhibitors (donepezil, rivastigmine, galantamine).
  • Moderate to severe dementia: add or use memantine.
  • Monitor for adverse effects: GI upset, bradycardia, nightmares.

Behavioral Symptoms

  • Nonpharmacologic first-line (behavioral, music therapy).
  • Mood stabilizers (valproic acid, carbamazepine) – limited evidence.
  • Antipsychotics (risperidone, olanzapine, quetiapine, aripiprazole) for severe symptoms.
  • Pimavanserin for Parkinson disease psychosis.
  • Caution: antipsychotics carry black box warning for increased mortality in elderly dementia patients.
  • Avoid benzodiazepines due to increased fall risk.

Issues for Referral

  • Neuropsychiatric evaluation for early or mild cognitive impairment.
  • Psychiatric admission for safety or behavioral crises.

Additional Therapies

  • Behavioral modification
  • Adult daycare, socialization to prevent isolation
  • Sleep hygiene programs
  • Scheduled toileting to prevent incontinence

Inpatient/Nursing Considerations

  • Psychiatric admission for safety concerns or behavioral issues.

Ongoing Care

  • Monitor cognitive decline with standardized tools.
  • Monitor behavioral symptoms and adverse medication effects.
  • Evaluate caregiver stress.

Patient Education

  • Advance care planning, safety, legal issues.
  • Discuss guardianship and skilled facility placement early.
  • National Institute on Aging: https://www.nia.nih.gov/health/topics/dementia

Prognosis

  • AD: steady progression, average survival ~10 years.
  • VaD: progressive decline; improvement unlikely.
  • Secondary dementias may improve with treatment.
  • Late-stage dementia: palliative and hospice care beneficial.

Complications

  • Wandering
  • Sundowner syndrome
  • Falls and injuries
  • Neglect and abuse
  • Caregiver burnout

ICD10:
- F03 Unspecified dementia
- G30.9 Alzheimer’s disease, unspecified
- F01.50 Vascular dementia without behavioral disturbance

Clinical Pearls:

  • Medications show small improvements in cognition; clinical significance unclear.
  • Adult protective services play an important role in elder abuse cases (Hotline: 800-922-2275).
  • Alternatives to physical restraints and antipsychotics should be prioritized in nursing homes.