A 71-year-old man is brought to the office by his daughter due to a change in behavior over the past year. He began having memory problems several years ago and frequently forgot his grandchildren's names. Also, the patient often had difficulty finding words. Several times recently, he was found roaming his apartment building because he was lost. The patient insists that there is nothing wrong with him and jokingly makes excuses for the symptoms his daughter is reporting. He has never used alcohol or illicit drugs. Blood pressure is 155/85 mm Hg, pulse is 90/min, and respirations are 15/min. Plantar reflexes are downgoing bilaterally. The remainder of the neurologic examination is within normal limits. Montreal Cognitive Assessment score is 15 on a scale of 30 (normal: ≥26). Laboratory results are as follows: Which of the following abnormalities is most likely to be seen on this patient's MRI?

Question

A 71-year-old man is brought to the office by his daughter due to a change in behavior over the past year.  He began having memory problems several years ago and frequently forgot his grandchildren's names.  Also, the patient often had difficulty finding words.  Several times recently, he was found roaming his apartment building because he was lost.  The patient insists that there is nothing wrong with him and jokingly makes excuses for the symptoms his daughter is reporting.  He has never used alcohol or illicit drugs.  Blood pressure is 155/85 mm Hg, pulse is 90/min, and respirations are 15/min.  Plantar reflexes are downgoing bilaterally.  The remainder of the neurologic examination is within normal limits.  Montreal Cognitive Assessment score is 15 on a scale of 30 (normal: ≥26).  Laboratory results are as follows:  Which of the following abnormalities is most likely to be seen on this patient's MRI?

Quizplus · Accepted Answer

This patient's cognitive impairment (Montreal Cognitive Assessment score of <26) with diminished daily functioning is most consistent with Alzheimer disease (AD). AD occurs almost exclusively in individuals age >60, and the risk increases with age. AD typically presents with early and prominent memory loss that progresses over time. Other common findings include word-finding difficulty and loss of visuospatial skills and executive function (eg, getting lost in familiar surroundings). Neuroimaging is typically performed to exclude alternate diagnoses such as a lesion (eg, tumor, subdural hematoma, infarction) or normal-pressure hydrocephalus (NPH). In patients with early AD, MRI may be normal. However, temporal lobe atrophy, which is most prominent in the hippocampi and surrounding medial temporal lobes, is typically seen in later stages. (Choice A) Vascular dementia is associated with focal neurologic signs and evolves in a stepwise fashion. Multiple hypointense cortical and subcortical lesions corresponding to old infarcts may be seen on T1-weighted MRI sequences. (Choice B) NPH is characterized by the triad of cognitive impairment, gait disturbance, and bladder incontinence. In some dementing syndromes, the ventricles may appear enlarged on neuroimaging due to general cortical atrophy (ie, hydrocephalus ex vacuo); however, ventriculomegaly in the absence of cortical atrophy is more suggestive of NPH. (Choice C) Atrophy of the frontal lobes on neuroimaging is consistent with frontotemporal dementia, which has an earlier age of onset than AD (usually age 50-60) and typically presents with personality changes and loss of social inhibition. Unlike in AD, memory impairment is usually mild in the initial stages of frontotemporal dementia. (Choice D) Atrophy of the parietal lobes may be seen in primary progressive aphasia, a dementing syndrome that primarily affects language early in the disease. Educational objective: Alzheimer disease initially presents with memory impairment. Neuroimaging generally demonstrates temporal lobe atrophy, which is most prominent in the hippocampi and surrounding medial temporal lobes. References: Clinical validity of medial temporal atrophy as a biomarker for Alzheimer's disease in the context of a structured 5-phase development framework. (http://www.ncbi.nlm.nih.gov/pubmed/28317647)

A 71-Year-Old Man Is Brought to the Office by His