Download Case Study, Porth Chapter 16, Mechanisms of Infectious Disease

Case Study, Porth
Chapter 16, Mechanisms of Infectious Disease
Jason is a 32-year-old general laborer who fell ill shortly after working on a job
digging up old water pipes for the town he lived in. The task involved working around
shallow pools of stagnant water. Ten days after the contract ended, Jason developed a
fever and aching muscles. He also had nausea, vomiting, and diarrhea. Jason’s friend
took him to his physician, who listened carefully to Jason’s history. She told him she
suspected West Nile fever and ordered serologic testing. Jason went home to recover
and was feeling better by the end of the week. (Learning Objectives 2, 4, 6, 7)
1.
West Nile fever is caused by the West Nile virus. Describe the emergence of
novel disease in the Western hemisphere. Provide some examples of sources
of infection for novel diseases, including the mode of transmission for WNV.
2.
Jason’s physician ordered serologic tests. Describe how antibody titers would
assist the doctor in confirming her diagnosis.
3.
When Jason was feeling at his worst, he had extreme malaise, vomiting, and
diarrhea. What stage of the illness was he experiencing at that time? Explain
the physiologic mechanisms that give rise to the signs and symptoms of
infectious illness.
4.
West Nile virus has a single-stranded RNA genome. Explain how this virus is
able to replicate. In general terms, what are the various effects viruses can
have on host cells?
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Case Study, Porth
Chapter 17, Innate and Adaptive Immunity
Melissa is a 15-year-old high school student. During the past week, she had been
feeling tired and had found it difficult to stay awake in class. By the time the weekend
had arrived, she developed a sore throat that made it difficult to eat and even drink.
Melissa was too tired to get out of bed, and she said her head ached. On Monday
morning, her mother took her to her doctor. Upon completing the physical exam, he
told Melissa the lymph nodes were enlarged in her neck and she had a fever. He
ordered blood tests and told Melissa he thought she had mononucleosis, a viral
infection requiring much bed rest. (Learning Objectives 2, 5, 11)
1.
Innate and adaptive immune defenses work collectively in destroying invasive
microorganisms. Describe the interaction between macrophages and T
lymphocytes during the presentation of antigen.
2.
Melissa’s illness is caused by a virus. Where are type I interferons produced,
and why are they important in combating viral infections?
3.
Humoral immunity involves the activation of B-lymphocytes and production
of antibodies. What are the general mechanisms of action that make antibodies
a key component to an immune response?
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Case Study, Porth
Chapter 18, Inflammation, Tissue Repair, and Wound Healing
Carlton, a 6-year-old boy, was playing on a sandy beach with his mother. He began to
run along the shoreline when he stepped on the sharp edge of a shell, giving himself a
deep cut on his foot. His mother washed his foot in the lake and put on his running
shoe to take him home. One day later, Carlton’s foot looked worse. The gash was red
and painful. The foot was warm to touch and appeared swollen. Carlton’s mom put
some gauze over the wound and prepared to take him to the local community health
clinic. (Learning Objectives 1, 2, 11, 12)
1.
Describe the physiologic mechanism causing the wound to become red, hot,
swollen, and painful. How is this different from the inflammatory response
that might occur in an internal organ?
2.
Describe the immunologic events that are happening at the local level during
Carlton’s acute inflammatory response. Consider the movement of leukocytes
to the wound and the cells that would be particularly prevalent in this type of
injury.
3.
Nutrition plays an important factor in wound healing. Predict what stages of
wound healing would be affected by a deficiency in vitamins A and C and
explain your answers.
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Case Study, Porth
Chapter 19, Disorders of the Immune Response
Ahmed has worked as a phlebotomist in the local hospital for the past 7 years. Last
year, he began to complain of watery eyes, nasal congestion, and wheezing whenever
he went to work. He suspected he was allergic to something at the hospital because
his symptoms abated when he was at home over the weekends. One day he arrived at
work for the morning shift and put on his gloves. Within minutes, he went into severe
respiratory distress requiring treatment in the emergency ward. It was determined at
that time his allergic response was due to latex exposure. (Learning Objectives 5, 6, 8)
1.
Ahmed experienced a type I, IgE-mediated hypersensitivity response. Explain
how this can be determined by his signs and symptoms. How might another
type of latex hypersensitivity reaction present?
2.
Describe how TH2 cells, mast cells, and eosinophils function to produce the
signs and symptoms typical of a type I hypersensitivity disorder.
3.
How is it that someone who does not come into direct contact with latex can
still have a hypersensitivity response to the material? What do food allergies
have to do with latex allergies?
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Case Study, Porth
Chapter 20, Acquired Immunodeficiency Syndrome
Patience is 29 years old and has been HIV positive for 9 years. She has remained
asymptomatic and is not taking antiretroviral medication. Recently she was at the
drop-in clinic to talk to a public health nurse about having a baby through artificial
insemination. She said she had met a man who wanted to marry her and have children
with her, but she was concerned about the baby contracting her HIV infection. Her
latest blood tests indicated her CD4+ count was 380/µL. The PCR test indicated her
viral load was 850. The nurse referred her to the physician to discuss antiretroviral
therapy during her pregnancy. (Learning Objectives 3, 7, 8, 9, 15)
1.
Outline the factors that increase the chance of HIV transmission from mother
to infant and how transmission occurs.
2.
Patience was told that after she became pregnant she would begin HAART
therapy. Describe what this therapy is and what particular antiretroviral
medication would be particularly useful to her during her pregnancy. What
concern is there about administering certain antiretrovirals early in the
pregnancy?
3.
Individuals infected with HIV are prone to contracting opportunistic
infections. Define opportunistic infection and outline the risk factors that leave
an individual with HIV infection prone to contracting this type of illness.
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