Dementia and Cognitive Impairment

Definitions & Overview - Mind Fades

• Dementia: Chronic, progressive, global cognitive decline; consciousness clear; ADLs impaired.
• Delirium: Acute, fluctuating attention deficit; altered consciousness; ADLs often impaired. 📌 I WATCH DEATH (Infection, Withdrawal, Acute metabolic, Trauma, CNS pathology, Hypoxia, Deficiencies, Endocrinopathies, Acute vascular, Toxins/drugs, Heavy metals).
• Mild Cognitive Impairment (MCI): Cognitive decline greater than normal for age/education; ADLs intact; not dementia.
• Key Differentiating Features:

Key Dementia Syndromes - The Rogue's Gallery

Clinical Approach & Workup - The Cognitive Quest

• History: Collateral history is crucial. Obtain from family/caregivers.
• Neurological Exam: Key elements: focal deficits, gait changes, primitive reflexes.
• Cognitive Screening Tools:
  • MMSE: Score < 24/30 suggests impairment.
  • MoCA: Score < 26/30; more sensitive for Mild Cognitive Impairment (MCI).
  • Clock Drawing Test (CDT): Assesses visuospatial and executive functions.
• Laboratory Workup (for reversible causes): Thyroid function (TSH), Vitamin B12, CBC, CMP.
  • 📌 Mnemonic for reversible causes: DEMENTIAS (Drugs, Emotional disorders, Metabolic, Endocrine, Nutritional, Trauma, Infection, Alcohol/Arteriosclerosis, Subdural hematoma).
• Neuroimaging:
  • CT/MRI: Indications: acute onset, age <60, focal neurological signs, suspected NPH. Typical AD: hippocampal atrophy.
  • PET: Role in differentiating dementias (FDG-PET for metabolic patterns); amyloid/tau PET for specific proteinopathies.

⭐ CSF analysis for ↓ amyloid beta 42 (A$\beta$42) and ↑ tau protein (total & phosphorylated) can support Alzheimer's Disease (AD) diagnosis, particularly in atypical presentations.

Management Strategies - Navigating the Maze

• Non-Pharmacological Interventions (First-line):

  • Cognitive stimulation, regular physical activity.
  • Environmental modifications (e.g., safety, orientation aids).
  • Caregiver education and strong support.

• Pharmacological Treatment:

  Drug Class	Examples	Primary Indication	Common Doses	Key Side Effects
  Cholinesterase Inhibitors	Donepezil, Rivastigmine, Galantamine	Mild-Moderate AD, LBD	Donepezil: 5-10 mg/day; Rivastigmine: 3-12 mg/day; Galantamine: 8-24 mg/day	GI upset (nausea, diarrhea), bradycardia, insomnia
  NMDA Receptor Antagonist	Memantine	Moderate-Severe AD (adjunct or mono)	Start 5 mg/day, target 20 mg/day (10 mg BID)	Dizziness, headache, confusion, agitation, constipation

• Behavioral & Psychological Symptoms of Dementia (BPSD):

  • Non-pharmacological strategies first.
  • Judicious psychotropics for severe/refractory symptoms.

⭐ Cholinesterase inhibitors often show better efficacy in Lewy Body Dementia (LBD) for cognitive and neuropsychiatric symptoms than in Frontotemporal Dementia (FTD).

High‑Yield Points - ⚡ Biggest Takeaways

• Alzheimer's Disease (AD): Most common; amyloid plaques, tau tangles, progressive memory loss.
• Vascular Dementia: Stepwise decline in cognition; associated with CVD risk factors and stroke history.
• Lewy Body Dementia (LBD): Visual hallucinations, parkinsonism, fluctuating cognition; REM sleep behavior disorder is a key early sign.
• Frontotemporal Dementia (FTD): Early personality changes, disinhibition, or progressive aphasia.
• Always rule out reversible causes: B12 deficiency, hypothyroidism, Normal Pressure Hydrocephalus.
• MMSE < 24 suggests impairment; cholinesterase inhibitors (e.g., Donepezil) are used for AD treatment.