Question 58

Increased levels of neurofibrillary tangles

Patients with Alzheimer's disease typically exhibit increased levels of neurofibrillary tangles at autopsy, which are composed of hyperphosphorylated tau protein. These tangles are considered one of the hallmark features of Alzheimer's pathology.

A) Increased levels of neurofibrillary tangles

This option is correct as neurofibrillary tangles are a significant pathological finding in the brains of individuals with Alzheimer's disease. They are formed from the aggregation of tau proteins, and their presence is closely associated with the progression of neurodegeneration and cognitive decline in affected patients.

B) Elevated levels of dopamine

This option is incorrect because Alzheimer's disease is not characterized by elevated dopamine levels. In fact, dopamine levels may be altered in various neurodegenerative diseases, but Alzheimer's is primarily associated with deficits in neurotransmitters such as acetylcholine, not an increase in dopamine.

C) Reduced numbers of neuritic plaques

This option is incorrect as well, as Alzheimer's disease is characterized by the presence of neuritic plaques, which are formed by beta-amyloid peptides. In patients with Alzheimer's, the number of these plaques is generally increased rather than reduced, contributing to the disease's pathology.

D) Increased levels of myelination on axons

This option is incorrect as Alzheimer's disease is associated with demyelination and neurodegeneration, rather than increased levels of myelination. The disease leads to a loss of myelin, which affects neuronal communication and contributes to cognitive decline.

E) Excessive levels of acetylcholine

This option is also incorrect. Alzheimer's disease is known for a decrease in acetylcholine levels due to the degeneration of cholinergic neurons. This deficiency is one of the key factors contributing to the cognitive symptoms observed in patients.

Conclusion

The correct answer is A, as increased levels of neurofibrillary tangles are a defining characteristic of Alzheimer's disease seen at autopsy. All other options fail to accurately represent the pathological findings associated with Alzheimer's, highlighting the specific neurodegenerative changes that occur in the disease.