Memory impairment

• Alzheimer’s Disease:

  • Gradual, progressive short-term memory loss first, then other cognitive decline.
  • Patho: Amyloid plaques, tau tangles, hippocampal atrophy.
  • Genetics: APOE4 (late), APP/PSEN1/2 (early).

• Vascular Dementia:

  • Stepwise decline or sudden onset after stroke; focal neuro deficits common.
  • Hx: Stroke, TIA, cardiovascular risk factors.
  • Imaging: Shows infarcts/white matter lesions.

• Lewy Body Dementia:

  • Fluctuating cognition, visual hallucinations (detailed), Parkinsonism (often after cognitive sx).
  • REM sleep behavior disorder. Sensitive to antipsychotics.
  • Patho: Alpha-synuclein (Lewy bodies) in cortex.

• Frontotemporal Dementia (FTD):

  • Early personality/behavior changes (disinhibition, apathy) OR aphasia. Memory relatively spared early.
  • Younger onset typical.
  • Patho: Frontal/temporal lobe atrophy; Pick bodies (tau) in some.

• Delirium:

  • Acute onset, fluctuating course, impaired attention & consciousness.
  • Caused by underlying illness, drugs, withdrawal. Reversible.

• Depression (Pseudodementia):

  • Patient complains prominently of memory loss; “don’t know” answers.
  • Associated mood symptoms (sadness, anhedonia, sleep/appetite changes).
  • Improves with depression treatment.

• Normal Pressure Hydrocephalus (NPH):

  • Triad: Dementia, gait disturbance (magnetic), urinary incontinence. “Wet, Wobbly, Wacky.”
  • Ventricular enlargement on imaging. Potentially reversible with shunting.

• Wernicke-Korsakoff Syndrome:

  • Thiamine (B1) deficiency (often alcoholism).
  • Wernicke (acute): Confusion, Ataxia, Ophthalmoplegia (nystagmus, CN VI palsy).
  • Korsakoff (chronic): Anterograde amnesia, confabulation, mamillary body atrophy.

• Vitamin B12 Deficiency:

  • Memory loss PLUS neuropathy (paresthesias, ataxia), macrocytic anemia.
  • Subacute combined degeneration (dorsal columns, lateral corticospinal).

• Hypothyroidism:

  • Cognitive slowing, memory issues, fatigue, other systemic signs of low thyroid.

General Approach:

1. Onset/Progression: Acute (delirium) vs. Gradual (dementias) vs. Stepwise (vascular).
2. Key Symptoms: What stands out? (Hallucinations? Personality change? Gait issues?).
3. Associated Signs: Focal deficits? Parkinsonism? Neuropathy?
4. Reversibility: Always consider and rule out reversible causes (Delirium, Depression, NPH, B12/Thyroid, Meds).