An 88-year-old man presents with rigidity, diminished facial expression, slowness in walking, and a resting tremor. On physical exam, he also has orthostatic hypotension, and an apparent cerebellar ataxia. He does not have significant impairment in memory or cognitive abilities. Which of the following histological findings would most likely be present on postmortem examination of his brain?
Amyloid beta plaques in the hippocampus
Glial cytoplasmic inclusion bodies in the substatia nigra, cerebellum, and interomediolateral cell column of the spinal cord
Lewy bodies isolated to the substantia nigra
Lewy bodies isolated to the cortex
Neurofibrillary tangles in the entorhinal cortex
Correct answer
Glial cytoplasmic inclusion bodies in the substatia nigra, cerebellum, and interomediolateral cell column of the spinal cord
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correct answer: B
The patient described has multiple system atrophy, a neurodegenerative disease that in addition to features of Parkinsonism (rigidity, diminished facial expression, slowness in walking (bradykinesia), and a “pill-rolling” tremor at rest) also has features of autonomic dysfunction (orthostatic hypotension) and cerebellar ataxia. Answer B lists the characteristic pathological findings found in multiple system atrophy, but is also the only answer choice in which lesions are found in parts of the brain that would produce all the symptoms described:
Parkinsonism, due to lesions in the nigrastriatal dopaminergic system.
Autonomic dysfunction, due to lesions in the cathecholaminergic nuclei of interomediolateral cell column of the spinal cord
Cerebellar ataxia, due to lesions in the cerebellum.
Answer choices A and E are the expected pathological findings in Alzheimer’s disease, which would present with dementia, but not the movement problems described. A good understanding of neuroanatomy is helpful in answering this question, even if you haven’t memorized all the diseases and the pathological findings associated with them. Lesions to the areas of the cortex described would produce cognitive dysfunction, which the patient does not have.
Answer D, which is the pathological finding in dementia with Lewy bodies, would also present with cognitive impairment, and thus can be ruled out using the same logic.
Answer C is the classic description of pathological findings in Parkinson’s disease. (Note: Parkinson’s disease is not the only disease that presents with “Parkinsonism”, which this the constellation of symptoms described above related to damage to the substania nigra, striatum, or drugs that interfere with dopamine such as haloperidol.) This answer choice does not account for the ataxia and the orthostatic hypotension, and thus is less likely to be correct.