A 75-year-old man is brought to the office for evaluation due to memory loss and increasing confusion for 6 months. The patient is unable to manage his finances and occasionally gets lost in his neighborhood, needing to ask for directions. On examination, he can recall only 1 of 3 objects after 5 minutes. The patient performs poorly on cognitive assessment testing. Cranial nerves and gait are normal. T2-weighted MRI reveals multiple white matter abnormalities (hyperintensities) within the left frontal, bilateral parietal, and occipital white matter. Also noted are subcortical gray matter hyperintensities in the bilateral thalamus. Which of the following is the most likely diagnosis?

Question

A 75-year-old man is brought to the office for evaluation due to memory loss and increasing confusion for 6 months.  The patient is unable to manage his finances and occasionally gets lost in his neighborhood, needing to ask for directions.  On examination, he can recall only 1 of 3 objects after 5 minutes.  The patient performs poorly on cognitive assessment testing.  Cranial nerves and gait are normal.  T2-weighted MRI reveals multiple white matter abnormalities (hyperintensities) within the left frontal, bilateral parietal, and occipital white matter.  Also noted are subcortical gray matter hyperintensities in the bilateral thalamus.  Which of the following is the most likely diagnosis?

Quizplus · Accepted Answer

11ec160b_39e6_efb6_9249_b57ef5ca5217_MD0001_00 This patient has had a relatively abrupt cognitive decline with prominent executive dysfunction (eg, managing finances, getting lost). Neuroimaging reveals scattered lesions in the white matter and subcortical gray matter, especially the thalamus. This is consistent with vascular dementia (VaD), which often occurs due to one of the following mechanisms: Atherosclerosis of large vessels (eg, basilar arteries, carotid arteries, circle of Willis): Plaque accumulation narrows the lumen; plaque rupture can lead to thrombosis and thromboembolism, often causing a clinical stroke, resulting in localized neurologic deficits. MRI would reveal a discrete cortical infarct. Small-vessel disease, which includes the development of microatheromas; small-vessel degeneration with eosinophilic, lipid-rich accumulations in the vessel wall; and arteriolosclerosis (ie, thickening and stiffening of arteriole walls): Small-vessel disease can lead to microaneurysm formation, obstruction, or breakage of the vessel walls. It more often impacts subcortical regions (eg, thalamus, basal ganglia) because there is less arteriole collateralization in these regions compared to the cerebral cortex. MRI often reveals signs of multiple small infarcts or microbleeds in these areas. Cerebral amyloid angiopathy: Beta-amyloid deposits in the walls of small to medium cerebral arteries and leads to increased fragility of the vessels. Although the most common manifestation is spontaneous, lobar intracranial hemorrhage, it can also cause multiple small infarcts and present as VaD. (Choice A) Although patients with Alzheimer dementia also have progressive memory loss with functional impairments, this disease often has a more insidious onset than VaD. MRI typically reveals parietotemporal cortical atrophy with no evidence of structural disease. (Choice B) Although brain metastases can result in a rapidly deteriorating mental status, they most often cause focal neurologic findings, which are not seen in this patient, and would be visible on MRI as mass lesions, usually located at the gray-white matter junction. (Choice C) MRI in a patient with multiple sclerosis can reveal hyperintensities corresponding to demyelinating plaques, typically located in the periventricular areas. However, MS typically presents in young women (age <50) with neurologic deficits (eg, blurry vision, diplopia, focal weakness/numbness, bowel/bladder dysfunction) disseminated in time and space. (Choice E) Although Wernicke encephalopathy (due to thiamine deficiency) can present with cognitive deficits, the classic triad consists of oculomotor dysfunction, ataxia, and encephalopathy. Chronic thiamine deficiency results in anterograde and retrograde amnesia, confabulation, and apathy. MRI reveals hyperintensities most commonly affecting the mammillary bodies and periaqueductal gray matter. Educational objective: Vascular dementia often presents with prominent executive dysfunction. MRI typically reveals signs of multiple small infarcts, microbleeds, and areas of hyperintensity in the white matter that represent demyelination or axon loss.

A 75-Year-Old Man Is Brought to the Office for Evaluation