Wednesday, April 28, 2021
Wednesday, April 14, 2021
Tuesday, April 13, 2021
Saturday, April 3, 2021
Tuesday, March 9, 2021
Frontotemporal dementia (FTD) is a heterogeneous spectrum of disorders marked by degeneration in the frontal and anterior temporal lobes, resulting in various symptoms of disturbed personality, behavior, and language. FTD is the third most common form of neuro- degenerative dementia, ranking after Alzheimer disease and dementia with Lewy bodies, accounting for perhaps 5% of all dementia cases. FTD generally presents at a younger age than Alzheimer disease and has a mean age at onset of 58 years.
DEMENTIA WITH LEWY BODIES
Dementia with Lewy bodies (DLB) is the second most common cause of dementia, accounting for 10% to 15% of dementia cases. The pathologic hallmark of DLB is the presence of Lewy bodies in neurons of the brainstem, primarily the substantia nigra, and through-out the cerebral cortex. Lewy bodies are primarily composed of abnormal aggregations of the synaptic protein alpha-synuclein. Interestingly, brain changes of Alzheimer disease (plaques and tangles) frequently co-occur with typical Lewy body pathology.
Vascular dementia is interesting in that many of those who do have a true vascular dementia are not diagnosed with it, while many who probably do not have a vascular dementia are diagnosed with it. The most straightfor-ward presentations are those in which an individual with normal cognition has a large stroke that causes a combination of cognitive signs, such as aphasia and a memory retrieval problem. If the patient cannot resume their prestroke day-to-day level of function because of these new cognitive deficits, the criteria for vascular dementia are met, but because the stroke so clearly caused the deficits, they are held to simply represent the consequences of a stroke (as opposed to a frank vascular dementia). On the other hand, some patients will present with a gradually progressive dementia, a retention-type memory deficit, no motor signs, no history of sensory or motor changes, and a neuroimaging study that shows subcortical changes that could be consistent with “small vessel cerebrovascular disease.” In the elderly, such patients almost always have the plaques and tangles that are expected in Alzheimer disease. In such cases, despite the neuroimaging changes, it is probably more appropriate to consider Alzheimer disease as the primary etiology. Still, the frequent association between Alzheimer disease and cerebrovascular pathology suggests these conditions may be linked in some way.
Although in some ways cognitive performance abilities evolve throughout adulthood, many elderly people remain mentally sharp into their ninth and tenth decades. The emergence of uncharacteristic changes in an individual’s cognition that impacts their usual activities should, therefore, trigger an evaluation for possible etiologies.
Because Alzheimer disease is the most common cause of intellectual decline in later life, symptoms or signs that are unusual in Alzheimer disease should particularly alert the physician to a different diagnosis and the possibility of reversing the dementing process. Such features include early age at onset; prominent headache; disturbances of gait or incontinence early in the course of the illness; epileptic seizures; fever; precipitous decline over a period of weeks or months; alteration of consciousness, especially sleepiness, stupor or delirium; history of head trauma; focal neurologic signs, such as lateralized visual, motor, or sensory abnormalities; accompanying dysfunction of peripheral nerves characterized by paresthesias and absent distal reflexes; and known systemic cancer, collagen vascular disease, or endocrinopathy. The presence of any of these features should dictate further evaluation and consideration of the following treatable dementias.
Metabolic Disease with Encephalopathy. When intellectual decline is caused by systemic metabolic disease, there are usually four associated features: diminished alertness; asterixis; a global decrease in mental function, often with a flight of ideas; and variability of intellectual function during the day. The metabolic dysfunction can be either endogenous or exogenous. An endogenous abnormality indicates too much or too little of a substance or metabolite usually found in the body, such as calcium, sodium, thyroid hormone, sugar, and so forth, may be responsible.
ALZHEIMER DISEASE: CLINICAL MANIFESTATIONS, PROGRESSIVE PHASES
The earliest stages of Alzheimer disease are generally marked by cognitive changes in multiple domains of cognition, including memory, executive function, language, and visuospatial function. Of importance, these cognitive changes are often well-compensated, and individuals may still be independent in many activities in the community, and their symptoms may not be readily apparent in casual conversation. Observations from an attentive family member, relative, or friend describing cognitive changes interfering even mildly with the subject’s usual function is a sensitive indicator of the earliest stages of AD.
Thursday, February 18, 2021
PYELOPLASTY AND ENDOPYELOTOMY
A pyeloplasty or endopyelotomy may be performed to treat an obstruction of the ureteropelvic junction (UPJ, see Plate 6-6). A pyeloplasty consists of surgical reconstruction of the UPJ, whereas endopyelotomy consists of intraluminal, endoscopic incision of the obstruction.
ALZHEIMER DISEASE: PATHOLOGY
Alzheimer disease (AD) is the most common neurodegenerative disorder and affects 10% of people older than age 65 years and nearly 50% of those 85 years and older. The brain affected by AD has gross changes of brain atrophy accompanied by microscopic changes of amyloid plaques and neurofibrillary tangles.
Wednesday, February 17, 2021
NONDOMINANT HEMISPHERE HIGHER CORTICAL DYSFUNCTION
When it comes to stroke-induced lateralized deficits, patients with left-sided hemiplegia caused by damage to the nondominant right cerebral hemisphere frequently do not recover as well as patients with similar left hemisphere lesions, despite the fact that they are not aphasic. Return to the work place and previous home and family participation occur less frequently after a stroke causing left-sided hemiplegia. Although disturbances of higher cortical function and behavior in patients with right hemisphere disease are more subtle, they are equally or more functionally disabling than the more obvious aphasia caused by left hemisphere disease. Deficits in right hemisphere disease include the following.
DOMINANT HEMISPHERE LANGUAGE DYSFUNCTION
Aphasia, a disorder of language usage and comprehension, should be distinguished from dysarthria, impaired articulation, and mutism, the absence of speech. Usually, the presence of aphasia accurately localizes dysfunction to the cerebral hemisphere concerned with speech.