A 69-year-old man is brought to the emergency department after he was found by police trying to break into the back office of a grocery store, claiming that he worked there and that he had left his keys in the office. The owner of the grocery denied that the patient was employed there but thought that she recognized him as a regular patron. The patient's medical problems include hypertension, hyperlipidemia, major depressive disorder, alcohol use disorder, and type 2 diabetes mellitus. Family history is significant for Alzheimer disease on both sides of the family. Temperature is 37 C (98.6 F), blood pressure is 135/86 mm Hg, pulse is 82/min, and respirations are 12/min. The patient answers questions without difficulty but provides conflicting information to different examiners. He is unable to account for how he ended up in the grocery store; however, he does provide detailed accounts of his previous job as an English professor, even reciting Shakespeare's Macbeth at length. He does not appear troubled by his inability to recall events accurately. The remainder of the examination is within normal limits. Which of the following is the most likely explanation for this patient's symptoms?

Question

A 69-year-old man is brought to the emergency department after he was found by police trying to break into the back office of a grocery store, claiming that he worked there and that he had left his keys in the office.  The owner of the grocery denied that the patient was employed there but thought that she recognized him as a regular patron.  The patient's medical problems include hypertension, hyperlipidemia, major depressive disorder, alcohol use disorder, and type 2 diabetes mellitus.  Family history is significant for Alzheimer disease on both sides of the family.  Temperature is 37 C (98.6 F), blood pressure is 135/86 mm Hg, pulse is 82/min, and respirations are 12/min.  The patient answers questions without difficulty but provides conflicting information to different examiners.  He is unable to account for how he ended up in the grocery store; however, he does provide detailed accounts of his previous job as an English professor, even reciting Shakespeare's Macbeth at length.  He does not appear troubled by his inability to recall events accurately.  The remainder of the examination is within normal limits.  Which of the following is the most likely explanation for this patient's symptoms?

Quizplus · Accepted Answer

This patient's retrograde and antegrade amnesia with intact long-term memory, confabulation, apathy, lack of insight, and history of alcohol use disorder are most consistent with a diagnosis of Korsakoff syndrome (KS). KS is a potential complication of Wernicke encephalopathy (WE), an acute disorder of thiamine deficiency characterized by the classic triad of encephalopathy, ataxia, and oculomotor dysfunction. Although WE may be seen in conditions other than alcohol use disorder (eg, anorexia, hyperemesis gravidarum), the risk of WE progressing to KS is much higher in alcohol use disorder than in other WE-associated conditions. However, in some patients who abuse alcohol, KS may develop without a recognized acute episode of WE, as seen in this patient. Although patients may experience a significant recovery of function in WE with thiamine supplementation, recovery is rare in KS. KS is associated with lesions in the anterior and medial thalami as well as the corpus callosum; the neuropathologic findings in WE include mamillary body atrophy and dorsomedial thalamic neuron loss. (Choices A and F) Although the dementing syndromes of Alzheimer disease and vascular dementia might account for this patient's confusion, his confabulation, strikingly intact long-term memory, and profound disruption of short-term memory in the context of a history of alcohol use disorder are better explained by KS. (Choice B) Dissociative amnesia develops in the context of psychologic trauma, affects traumatic autobiographical memory, and is frequently reversible. There is no evidence of trauma in this patient, whose memory deficits involve widespread memory systems. (Choice D) Marchiafava-Bignami disease presents with dementia, motor dysfunction, and dysarthria. It is associated with severe damage to the corpus callosum and surrounding white matter in the context of chronic alcohol use disorder and attendant malnutrition. (Choice E) Transient global amnesia is a disorder of anterograde amnesia and disorientation that typically lasts <1 day, is reversible, and is not associated with significant morbidity. Confabulation and apathy make KS more likely in this patient. (Choice G) This patient's intact sensorium, marked deficits in anterograde and retrograde memory, confabulation, and preservation of long-term memory are characteristic of KS. He lacks the encephalopathy, oculomotor dysfunction, and ataxia seen in WE. Educational objective: Korsakoff syndrome is a potential complication of Wernicke encephalopathy that is characterized by retrograde and anterograde amnesia with preserved long-term memory, confabulation, lack of insight, and apathy. Korsakoff syndrome is caused by thiamine deficiency and develops more frequently in alcohol use disorder than in other malnourished states. References: Neural correlate of anterograde amnesia in Wernicke-Korsakoff syndrome. (http://www.ncbi.nlm.nih.gov/pubmed/25148770) Alcohol-related dementia: an update of the evidence. (http://www.ncbi.nlm.nih.gov/pubmed/23347747)

A 69-Year-Old Man Is Brought to the Emergency Department After