Author Question: John is 63 years old and receives home care by an occupational therapist twice a week. His therapist ... (Read 99 times)

jCorn1234 · **on:** Jun 25, 2018

John is 63 years old and receives home care by an occupational therapist twice a week. His therapist is currently working with John on maintaining joint flexibility and balance.

John demonstrates resting tremor, so his therapist is also working on adaptive techniques, so John can continue to use his hands to write, use the computer, and cook simple meals. John's wife assists with his mobility and walks slowly beside him, holding his arm. Sometimes she needs to help him open his prescription bottles, so he can take his medicine, a combination of levodopa and carbidopa.

What motor disease does John demonstrate? One of his signs is resting tremor. What is the difference between a resting tremor and an intention tremor?

What is the advantage of combining levodopa with carbidopa? What is the benefit of anticholinergic drugs in the management of Parkinson disease?

Parkinson disease involves the destruction of the substantia nigra and the nigrostriatal pathway. Where are these structures anatomically?

The patient with Parkinson disease typically presents with a masklike facial expression. Why does he or she have a masklike facial expression? How are the eyes, mouth, and laryngopharynx affected by this disease?

Question 2

Bonnie is a 70-year-old woman who lives alone. One evening, she felt light-headed and dizzy. When her head began to ache, she decided to take an analgesic and go to bed early.

The following morning, upon awakening, she was unable to move the bed sheets with her right arm. At this point she was experiencing tingling sensations in her limbs, and she had difficulty keeping her balance. She dialed 911 for help, and by the time the ambulance arrived, she was confused and unable to articulate her words although she knew what information he was asking of her. In the hospital, she was examined and treated for ischemic stroke.

Stroke, or brain attack, involves brain tissue injury. Describe ischemic penumbra and what factors contribute to the survival of the neurons involved. What happens if the cells of the penumbra are unable to be preserved?

Compare and contrast hypoxia and ischemia. What condition is more dangerous to the brain? Explain your answer.

Knowing what you do about the effects of ischemia on the brain, why would someone with ischemic stroke develop cerebral edema?

What type of aphasia was Bonnie exhibiting when talking to her care givers? Explain your answer.

frogdreck123456 · **Reply #1 on:** Jun 25, 2018

Answer to Question 1

John is expressing the signs and symptoms of Parkinson disease. The resting tremor that exists in Parkinson disease is a rhythmic movement that occurs when the limb is inactive. When an intended movement is initiated in the limb, the tremor disappears. The tremor is also absent when the individual is asleep. Intention tremor, on the other hand, is absent when the limb is at rest. When an intended movement is initiated, the tremor worsens. Intention tremor is a result of cerebellar dysfunction and the inability for the cerebellum to control the movement of the limb to the intended target.

Levodopa, when administered alone, is largely metabolized before it enters the brain. When this happens, it can no longer cross the blood-brain barrier and produce its therapeutic effect. Carbidopa is beneficial because it inhibits decarboxylase, the enzyme responsible for metabolizing levodopa to dopamine in the systemic circulation. As a result, more levodopa is available to enter cerebral circulation and a smaller dose is needed to have therapeutic value.

Unlike levodopa, which acts to increase dopamine levels, anticholinergic drugs inhibit cholinergic activity in the central nervous system. They function to reduce the effects that occur when cholinergic neurons work without the inhibitory action of dopamine.

The substantia nigra is a dopamine-producing center of the midbrain. The axons of these cells form a tract, called the nigrostriatal pathway, to the striatum of the basal ganglia. This tract carries dopamine to the striatum and modulates basal ganglion activity.
As muscle rigidity and bradykinesis progress, voluntary and involuntary movement of the facial muscles is lost. The result is a masklike facial appearance and inability to express emotion through facial movements. Blinking becomes impaired, and in conjunction with altered autonomic function, excess lacrimation and tearing occur. The muscles of the tongue, mouth, and throat are also affected by rigidity. Eating, speaking, and swallowing become increasingly difficult. With autonomic change, there is excessive salivation and drooling.

Answer to Question 2

The ischemic penumbra is a band of neurons surrounding a core of dead or dying cells created by the vascular accident. The cells of the penumbra are physically intact but functionally impaired from a marginalized blood flow. The penumbra may avoid further insult depending on the speed of circulatory restoration, alterations in local blood flow, the amount of toxins released by damaged neighboring cells, and the extent of cerebral edema. If noxious conditions persist, the cells of the penumbra die and the core of dead tissue enlarges.

Both hypoxia and ischemia are conditions that involve alterations in oxygen availability at the tissue level. Hypoxia is a term used to describe a lack of oxygen at a given site although blood circulation to the area is intact. Ischemia, on the other hand, describes a lack of blood circulation to an area. In ischemia, tissues are vulnerable not only to oxygen deficiency but also to glucose deficiency and the accumulation of metabolic wastes.

The brain is able to maintain limited cellular activity by anaerobic metabolism and is therefore able to survive for some time in a state of hypoxia. With ischemia, nutrient stores are rapidly depleted and not replenished. The lack of blood supply also means that metabolic waste accumulates at the cellular level, creating a state of acidosis. Ischemia is therefore more detrimental to brain tissue than hypoxia. Normal metabolism in the brain is needed, in part, to produce ATP for the normal function of ion pumps in the cellular membranes. When perfusion is inadequate, ATP production declines and active transport pumps, like the Na+/K+ pump, fail. Sodium flows down the concentration gradient into the cell as a result, creating an osmotic gradient that causes the development of interstitial and intracellular edema.

Bonnie was expressing expressive or nonfluent aphasia. This type of speech is characterized by verbalizations that are meaningless and performed in a halting, limited manner. Communication in someone with expressive aphasia requires effort and is not spontaneous. Comprehension, however, is unaffected, and the individual knows what is being said by others. Bonnie was aware of what was being asked, but was answering in ways that were incomprehensible.