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Mild Cognitive Impairment

BASICS

Description

  • Defined as significant cognitive impairment without dementia
  • Criteria:
  • Concern regarding change in cognition
  • Independence in ADLs is preserved
  • Impairment in ≥1 cognitive domains (attention, executive function, memory, learning, visuospatial, language)
  • Other terms: CIND, mild cognitive disorder, mNCD (DSM-5)
  • MCI may precede Alzheimer’s disease
  • Older adults with MCI are 3× more likely to develop dementia within 2–5 years

EPIDEMIOLOGY

  • Incidence:
  • Male > Female
  • Increases with age and lower education

  • 12–15/1,000 PY (≥65 y), 50–75/1,000 PY (≥75 y)

  • Prevalence:

  • More common than dementia in the U.S.
  • 12–18% (≥60 y), ~25% (80–84 y)

ETIOLOGY AND PATHOPHYSIOLOGY

  • Subtypes:
  • Single- or multiple-domain, amnestic or nonamnestic
  • Amnestic subtypes have higher risk of Alzheimer’s progression
  • Causes: vascular, neurodegenerative, metabolic, psychiatric, genetic
  • APO E4 genotype linked to Alzheimer’s pathology

RISK FACTORS

  • Vascular risk factors: diabetes, HTN, hyperlipidemia
  • Smoking, sleep apnea
  • Low education, depression, sedentary lifestyle
  • APO E4 gene

PREVENTION

  • Manage vascular risks
  • Maintain active, healthy lifestyle

COMMONLY ASSOCIATED CONDITIONS

  • Depression
  • Sleep apnea
  • Cardiovascular disease

DIAGNOSIS

History

  • Evaluate new-onset cognitive changes
  • Review meds (especially anticholinergics)
  • Rule out depression
  • Assess function (ADLs), interpersonal impact
  • Consider olfactory dysfunction (linked to amnestic MCI)

Physical Exam

  • General and neurologic exam
  • Screen for vascular signs
  • Cognitive tests: MoCA, SLUMS

Differential Diagnosis

  • Normal aging, dementia, delirium, depression
  • Reversible causes: meds, B12 deficiency, hypothyroidism, sleep disorders

Diagnostic Tests

  • Labs: CBC, CMP, TSH, B12, HIV, syphilis
  • Imaging: CT/MRI if atypical or focal signs
  • Neuropsych testing: every 1–2 years
  • Consider CSF biomarkers, amyloid scans for Alzheimer’s confirmation

Test Interpretation

  • Pathology: intermediate amyloid and tangles (esp. hippocampus)
  • Amnestic MCI → white matter hyperintensity
  • Nonamnestic MCI → infarcts

TREATMENT

General Measures

  • Treat atherosclerosis and vascular risks

Medication

  • Cholinesterase inhibitors (ChEIs) are not recommended
  • Antiamyloid therapies require confirmatory Alzheimer’s diagnosis

Referral

  • To memory specialists (geriatric, neurology, neuropsych)

Other Therapies

  • Cognitive training, exercise
  • No benefit from vitamin E, Ginkgo biloba

Inpatient/Nursing Considerations

  • Avoid anticholinergics, sedatives
  • Optimize environment:
  • Moderate stimulation
  • Orient to time/place
  • Ensure glasses/hearing aids
  • Family presence helpful

ONGOING CARE

Follow-Up

  • Every 6–12 months
  • Monitor:
  • Cognition, ADL changes, depression
  • Try to wean cognitive-impairing meds

Diet

  • Heart-healthy diet

Patient Education

  • Discuss:
  • Advanced directives
  • Driving, firearm, financial safety
  • Encourage:
  • Exercise (30 mins/day)
  • Mental stimulation: puzzles, books, computer activities
  • Cognitive rehabilitation
  • Manage comorbidities
  • CPAP for sleep apnea
  • Dental hygiene
  • Avoid excess alcohol

PROGNOSIS

  • 3× higher risk of dementia in 2–5 years
  • Amnestic MCI → higher conversion to Alzheimer’s
  • Women, olfactory dysfunction, psychiatric symptoms → higher risk

ICD-10

  • G31.84 — Mild cognitive impairment, so stated

Clinical Pearls

  • Amnestic MCI = memory dominant, high progression risk
  • Screen for reversible causes: meds, depression, sleep disorders
  • Do not routinely use ChEIs
  • Neuropsych testing every 1–2 years
  • If used, do ECG before starting ChEIs (risk of bradycardia, syncope)