TUTORIALS

موضوع: TUTORIALS الأربعاء مارس 20, 2019 4:43 pm

A 70-year-old woman is brought to your office after her nurse noticed her being apathetic, easily distracted, and starting to urinate in bed. Her medical history is relevant for hypertension, under control with medication. Physical examination reveals a blood pressure of 138/76 mm Hg, a heart rate of 70/min, and a respiratory rate 14/min and regular. On neurological examination, she has a broad-based shuffling gait, an increased muscle tone in her limbs that is reduced by distracting the patient. There is decreased coordination with exaggerated deep tendon reflexes, decreased attention and concentration, and postural tremor. Which of the following additional features would you expect to find in this patient?

A.
Accumulation amyloid plaques and neurofibrillary tangles in the cerebral cortex
B.
Dilation of the ventricular system
C.
Degeneration of the substantia nigra pars compacta
D.
Accumulation of Lewy bodies in cortical cells
E.
Caudate head atrophy
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Correct answer B: The triad of gait difficulty, urinary incontinence, and cognitive disturbances is highly suggestive of normal pressure hydrocephalus (NPH), a condition characterized by a pathological enlargement of the ventricles with normal opening pressure, typically diagnosed in patients over 60 years of age.

The clinical manifestations in NPH (broad-based shuffling gait, paratonia, hyperreflexia) are produced by the pressure that the enlarged ventricles put on the corona radiata and periventricular white matter tracts. Recognizing this condition in an early stage is important, as it is potentially reversible by shunting the cerebrospinal fluid circulation with a ventriculoperitoneal shunt.

Option A: Accumulation of amyloid plaques and neurofibrillary tangles is a characteristic pathological finding in Alzheimer’s disease, the most common type of dementia worldwide. Patients develop impairments in short-term memory which is especially affected (in early stages), mood and psychotic disorders.

Option C: Degeneration of the dopaminergic cells in the substantia nigra pars compacta is the mechanism underlying Parkinson’s disease, a neurodegenerative disorder clinically characterized by bradykinesia, cogwheel rigidity (in contrast to paratonia in NPH), a resting tremor, and, in late stages of the disease, dementia.

Option D: Lewy body dementia is characterized by progressive, degenerative cognitive disturbances secondary to accumulation of round, eosinophilic, intracytoplasmic neuronal inclusions in the deep cortical layers, mainly composed of alpha-synuclein. Motor changes are only seen in the late stages of the disease.

Option E: Caudate head atrophy is seen in Huntington’s disease, an autosomal dominant neurodegenerative disorder, that results from the death of neurons in the caudate nucleus of the basal ganglia. Clinical manifestations appear early in adulthood and include: anxiety, psychosis, depressed mood, which is followed by jerky, random, and uncontrollable movements called chorea.

Learning objective: Normal pressure hydrocephalus is characterized by the triad of gait difficulty, cognitive disturbances, and urinary incontinence. It is caused by compression of the corona radiata and other periventricular white matter tracts by enlarged ventricles.
https://app.lecturio.com/qb-test/shared#test/qotd_20190320/question/1158

TUTORIALS

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