A 55-year-old man is brought to his physician's office with a 3-month history of progressive mental deterioration in the form of memory loss, mood changes, and errors in judgment. His gait is unsteady, and he requires assistance to prevent falling. He has no history of seizures, head trauma, or incontinence. Computed tomography (CT) scan and lumbar puncture are unremarkable. Physical examination reveals hypeonicity of all extremities, bilateral equivocal plantar response, ataxic gait, and myoclonic jerks in the lower extremities. What is the mechanism by which this infectious agent causes its pathology?
This is the classic presentation of Creutzfeldt-Jacob disease (CJD). Although the pathogenesis is incompletely understood, these patients develop extracellular deposition of abnormal fibrillar proteins in the brain, ie, amyloid. Autoimmune destruction is not indicated because there is no immunologic response to the deposition of these extracellular proteins; thus there is no chronic inflammation. Although embolization and infarction could complicate the presentation in the age group typically afflicted with CJD, these processes are not believed to have any direct role in this pathology.
Amyloid deposition
Autoimmune destruction
Chronic inflammation
Embolization and infarction