Match each clinical presentation of cognitive decline to its most likely underlying pathophysiologic mechanism.
- A 67-year-old man presents with a 3-month history of rapidly progressive memory loss, akinetic mutism, and sudden, brief muscle jerks elicited by loud noises.Conformational alteration of a normal cellular protein into a protease-resistant beta-pleated sheet isoform
- A 59-year-old woman exhibits a 2-year history of socially inappropriate comments, compulsive consumption of sweets, and profound apathy, with preserved visuospatial skills.Intracellular accumulation of hyperphosphorylated tau or ubiquitinated TDP-43 proteins
- A 74-year-old man develops progressive cognitive impairment, pronounced fluctuations in daytime alertness, vivid hallucinations of animals, and a new-onset resting tremor.Widespread cortical and brainstem neuronal cytoplasmic inclusions containing alpha-synuclein
- A 71-year-old woman with a long-standing history of medication-noncompliant hypertension experiences abrupt declines in executive function separated by periods of stability, along with a right-sided Babinski sign.Chronic ischemic injury to deep cerebral white matter and basal ganglia resulting from small vessel arteriolosclerosis
- A 76-year-old man presents with an insidious onset of a broad-based, magnetic gait, urinary urgency culminating in incontinence, and generalized cognitive slowing over 8 months.Impaired reabsorption of cerebrospinal fluid leading to ventricular expansion and stretching of the corona radiata
Answer
The correct pairings match Creutzfeldt-Jakob disease to prion misfolding, frontotemporal dementia to tau/TDP-43 accumulation, Lewy body dementia to alpha-synuclein inclusions, vascular dementia to ischemic white matter injury, and normal pressure hydrocephalus to impaired cerebrospinal fluid reabsorption.
Each clinical vignette provides classic hallmark features of a specific neurocognitive disorder, which directly corresponds to a unique pathophysiologic mechanism. Creutzfeldt-Jakob disease is caused by prion misfolding. Frontotemporal dementia is caused by tau or TDP-43 inclusions. Lewy body dementia is caused by alpha-synuclein aggregation. Vascular dementia is caused by ischemic white matter injury from small vessel disease. Normal pressure hydrocephalus is caused by impaired cerebrospinal fluid reabsorption leading to ventricular expansion.
Step-by-Step Solution
Key Concept
Distinct clinical presentations of neurocognitive disorders directly correlate with specific pathophysiologic mechanisms, such as abnormal protein aggregations or structural brain changes.