A 72-year-old woman comes to the office for a routine follow-up visit accompanied by her son. The patient has experienced progressive memory loss over the last 2 years. She now needs help with her daily activities, such as shopping and housekeeping. The patient's son says, "She used to be such an independent person, but now she needs help with most things. She even forgot my name the other day!" Medical history includes hypertension, hyperlipidemia, and type 2 diabetes mellitus. Family history includes major depressive disorder in her father. MRI reveals diffuse cortical and hippocampal atrophy. Which of the following biochemical changes is most likely contributing to this patient's condition?

Question

A 72-year-old woman comes to the office for a routine follow-up visit accompanied by her son.  The patient has experienced progressive memory loss over the last 2 years.  She now needs help with her daily activities, such as shopping and housekeeping.  The patient's son says, "She used to be such an independent person, but now she needs help with most things.  She even forgot my name the other day!"  Medical history includes hypertension, hyperlipidemia, and type 2 diabetes mellitus.  Family history includes major depressive disorder in her father.  MRI reveals diffuse cortical and hippocampal atrophy.  Which of the following biochemical changes is most likely contributing to this patient's condition?

Quizplus · Accepted Answer

11ec160b_39a8_d5e5_9249_b36ca037d4ef_MD0001_00 Alzheimer disease (AD) is the most common cause of dementia. It has the following characteristic features: The most important biochemical abnormality noted in AD is a decrease in the acetylcholine level. This occurs due to a deficiency of choline acetyltransferase. The decline in acetylcholine is most notable in the nucleus basalis of Meynert, which participates in memory and cognition. This nucleus is located at the base of the forebrain and widely projects to the neocortex. Another involved structure is the hippocampus: The major function of the hippocampus is the formation of new memories. Symptomatic management of AD includes cholinesterase inhibitors, which target the acetylcholine deficit by inhibiting the degradation of acetylcholine at the synaptic cleft. (Choice B) Loss of dopaminergic neurons in the substantia nigra is seen in Parkinson disease and dementia with Lewy bodies. (Choice C) The raphe nuclei form the medial part of the brain stem's reticular formation (medulla, pons, and midbrain). Many neurons in the nuclei are serotonergic. Serotonin is implicated in the pathogenesis of anorexia, depression, and sleep disorders. (Choice D) Atrophy of the caudate nucleus is seen in Huntington disease. (Choice E) The locus ceruleus is thought to play a role in the pathogenesis of panic attacks and panic disorder. It is located in the pons and contains cell bodies of noradrenergic neurons that synthesize norepinephrine. Educational objective: Alzheimer disease is characterized by decreased levels of acetylcholine in the nucleus basalis of Meynert and the hippocampus, caused by diminished activity of choline acetyltransferase. __________ References: Alzheimer's disease: targeting the cholinergic system. (http://www.ncbi.nlm.nih.gov/pubmed/26813123)

A 72-Year-Old Woman Comes to the Office for a Routine