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Alzheimer Disease

      The diseased brain is from a patient who had had cognitive decline for 5 years and died of aspiration pneumonia.
      What is the most likely diagnosis and neuropathologic finding?
      • a.
        Pick disease; tau protein deposits in neurons
      • b.
        Lewy body dementia; α-synuclein deposits in neurons
      • c.
        Hepatic encephalopathy; Alzheimer type II gliosis
      • d.
        Alzheimer disease; neurofibrillary tangles and neuritic plaques
      Answer: d. Alzheimer disease; neurofibrillary tangles and neuritic plaques
      Alzheimer disease is the most common neurodegenerative disease, and unlike the other diseases listed, classically exhibits global cerebral atrophy.
      • Knopman D.S.
      • Petersen R.C.
      Mild cognitive impairment and mild dementia: a clinical perspective.
      The atrophy is typically greatest in the medial temporal lobe/hippocampus. Alzheimer disease is characterized by tau and amyloid protein deposition. Tau protein forms neurofibrillary tangles within affected neurons and also forms neuritic plaques in conjunction with β-amyloid protein.
      • Josephs K.A.
      • Dickson D.W.
      • Murray M.E.
      • et al.
      Quantitative neurofibrillary tangle density and brain volumetric MRI analyses in Alzheimer's disease presenting as logopenic progressive aphasia.
      β-Amyloid protein may also deposit as diffuse plaques within the cortex or as amyloid angiopathy within leptomeningeal and cortical vessels.

      References

        • Knopman D.S.
        • Petersen R.C.
        Mild cognitive impairment and mild dementia: a clinical perspective.
        Mayo Clin Proc. 2014; 89: 1452-1459
        • Josephs K.A.
        • Dickson D.W.
        • Murray M.E.
        • et al.
        Quantitative neurofibrillary tangle density and brain volumetric MRI analyses in Alzheimer's disease presenting as logopenic progressive aphasia.
        Brain Lang. 2013; 127: 127-134