Transcript
CHAPTER 27 </P></ANS></ANSSET></MCQSET>
Clinical Reasoning Checkpoint Answers
Case Scenario: Angela M., a 28-year-old middle school teacher, is brought to the urgent treatment center by her husband with complaints of fever, chills, and a productive cough of 2 days duration. Following appropriate evaluation, she is diagnosed with right lower lobe pneumonia. Her husband, Mark, is currently recovering from cancer chemotherapy for treatment of Hodgkin disease. His most current complete blood cell count shows evidence of moderate bone marrow depression.
1. Assuming that Angela has an intact immune system, describe neutrophils and explain their role in destroying her bacterial pneumonia.
Answer: Neutrophils are small, rapid-turnover granulocytes (only surviving for 6 to 8 hours). They are the first immune cells to arrive at a sight of inflammation or infection (within 1 to 1.5 hours of injury). Rather than being phagocytes that engulf bacteria, they contain powerful granules that destroy bacteria or other foreign substances through expression of powerful enzymes. The enzymatic activity causes breakdown and liquefaction of local cells and foreign substances, forming pus.
2. In order to combat Angela’s pneumonia, the immune cells have to be able to move to the site of the infection. Explain how this is accomplished by describing margination, diapedesis, migration, and chemotaxis.
Answer: When an injury or infection occurs, circulating WBCs begin accumulating and adhering to the capillary wall near the injury/infection site—this is margination. The cells then develop pseudopods and squeeze their way out of the capillary through ameboid movement – this is diapedesis. Once the WBC has escaped the capillary, it will follow a chemical trail to the site of injury—this is chemotaxis.
3. As the nurse interviewing and assessing Angela, do you have any concerns about her husband, Mark?
Answer: Yes, you should have some concerns. Mark has bone marrow depression, which means that he is not producing sufficient numbers of immune cells to protect himself fully from infections. He is at significant risk of becoming contaminated from his wife’s pneumonia. Her productive cough tells you that she can spread the infection by airborne spread and through direct contact spread from objects that she touches in their shared environment.
4. While you are interviewing Angela, Mark asks you to give him some advice. He tells you that he has been having frequent nosebleeds that are difficult to stop. Considering his recent history, why might he be having epistaxis (nose bleeds)?
Answer: His chemotherapy has resulted in bone marrow depression and thrombocytopenia—abnormally low levels of platelets. Platelets are a crucial part of the initial clotting mechanism and when levels are low, bleeding can occur, often experienced as bleeding gums or nose, and easy bruising.
5. Assume for a moment that Mark has thrombocytopenia. Briefly describe the role of platelets in hemostasis.
Answer: Platelets are the cellular component of hemostasis. They circulate continuously in an inactive state until being called as a result of endothelial injury. When activated, they accumulate at the site of injury, becoming sticky, and clump together, forming a mass, the platelet plug that ideally halts blood leaking through the vessel. The platelet plug is then followed by formation of a fibrin clot, which forms a strong seal to the injured vessel.
