WBR0205

Author	[[PageAuthor::William J Gibson (Reviewed by Yazan Daaboul, M.D.)]]
Exam Type	ExamType::USMLE Step 1
Main Category	MainCategory::Microbiology, MainCategory::Pathology
Sub Category	SubCategory::Neurology, SubCategory::Infectious Disease
Prompt	[[Prompt::A 62-year-old woman is brought to the emergency department (ED) by her husband. He reports that one month ago, the patient had complaints of sleep disorder and decrease in appetite. A few days later, she started to become forgetful. At first, the patient was forgetting minor details like the car keys or appointments. The husband is now more concerned that she has lately been forgetting the names of her children, has developed slurred speech, and has experienced progressive difficulty in walking. Physical exam in the ED is remarkable for confusion, muscular hypokinesis, and atrophy. The physician also notes the presence of involuntary intermittent myoclonic jerks of the lower extremities. Cerebrospinal fluid analysis demonstrates 14-3-3 tau proteins. Brain biopsy of this patient would most likely demonstrate which of the following findings?]]
Answer A	AnswerA::Lymphocytic infiltrate
Answer A Explanation	AnswerAExp::Lymphocytic infiltrates may be observed in brain biopsies of patients with encephalitis. Encephalitis is characterized by more systemic symptoms such as fever and focal neurologic deficits.
Answer B	AnswerB::Alpha-synuclein deposits
Answer B Explanation	AnswerBExp::Alpha-synuclein deposits are observed in brain biopsies of patients with Lewy body dementia. Lewy body dementia is characterized by the presence of dementia, early parkinsonism, and visual hallucinations.
Answer C	AnswerC::Beta-pleated sheets
Answer C Explanation	AnswerCExp::Beta-pleated sheets are observed among patients with Creutzfeldt-Jakob disease.
Answer D	AnswerD::Abnormally phosphorylated tau protein
Answer D Explanation	[[AnswerDExp::Neurofibrillary tangles are pathological changes associated with Alzheimer disease. Manifestations of Alzheimer disease include slowly progressive dementia and late disability. The patient's symptoms are progressing relatively rapidly, which is not consistent with Alzheimer disease.]]
Answer E	AnswerE::Beta-amyloid deposits
Answer E Explanation	[[AnswerEExp::Beta-amyloid deposits correspond to the composition of senile plaques, which are pathological changes characteristic of Alzheimer disease. Manifestations of Alzheimer disease include slowly progressive dementia and late disability. The patient's symptoms are progressing relatively rapidly, which is not consistent with Alzheimer disease.]]
Right Answer	RightAnswer::C
Explanation	[[Explanation::The patient in this vignette is suffering from Creutzfeldt-Jakob disease, an infectious disease caused by the abnormal aggregation of prions. Prions are an abnormally folded protein composed of beta pleated sheets which act as a scaffold to induce the conversion of other proteins into an abnormally folded prion state as well. Creutzfeldt-Jakob disease is characterized by the rapid onset of dementia in otherwise well people. It is universally fatal and there is no treatment. Educational Objective: Creutzfeldt-Jakob disease is characterized by rapidly progressive dementia, and is caused by prions which are proteins folded as beta pleated sheets. References: First Aid 2014 page 483]]
Approved	Approved::Yes
Keyword	WBRKeyword::Neurology, WBRKeyword::Pathology, WBRKeyword::Neuropathology, WBRKeyword::Prion, WBRKeyword::Creutzfeldt-Jakob disease, WBRKeyword::Dementia, WBRKeyword::Mental status change
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