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A 14-year-old boy presents with cough, shortness of breath, and difficulty lying down. His face and neck swell when his arms are raised. Chest x-ray reveals a large mediastinal mass. A tissue diagnosis is desired. A biopsy is performed with local anesthesia because the anesthesiologist thinks that the patient has a very high general anesthesia risk. Which of the following findings does not make general anesthesia unsafe?
- A. Tumor diameter greater than 45% of transthoracic diameter
- B. Tracheal cross-sectional area less than 50% of predicted
- C. Peak expiratory flow rate less than 50% of predicted
- D. A malignancy of hematopoietic origin
Correct Answer: D
Rationale: The correct answer is D because a malignancy of hematopoietic origin does not inherently increase the risk of general anesthesia. Hematopoietic malignancies such as leukemia or lymphoma do not directly impact the respiratory system or airway, unlike the other choices. A: Tumor size affecting transthoracic diameter can compress airways, leading to respiratory compromise. B: Tracheal cross-sectional area affects air flow and can be a concern during intubation. C: Peak expiratory flow rate indicates respiratory function; lower values suggest increased risk under general anesthesia. Therefore, D is the correct answer as it does not pose a direct risk to general anesthesia.
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Bone marrow responds to iron therapy by increasing erythropoietic activity. Which of the following in bone marrow would most likely indicate erythropoiesis?
- A. Myelocytes
- B. Reticulocytes
- C. Ring sideroblasts
- D. Target cells
Correct Answer: B
Rationale: The correct answer is B: Reticulocytes. Reticulocytes are immature red blood cells released by the bone marrow into the bloodstream in response to increased erythropoietic activity. They indicate ongoing erythropoiesis as they mature into fully functional red blood cells. Myelocytes (A) are immature granulocytic precursors, not involved in erythropoiesis. Ring sideroblasts (C) are seen in conditions like sideroblastic anemia and indicate abnormal iron metabolism. Target cells (D) are red blood cells with a central bull's eye appearance and are associated with conditions like liver disease and thalassemias, not specifically erythropoiesis.
A patient with abdominal injuries from a motor vehicle crash is scheduled for surgery to remove the spleen. What bodily function will be affected by the removal of this organ?
- A. Filtration of waste products
- B. Removal of old red blood cells from circulation
- C. Clearance of mucous in the tracheobronchial tree
- D. Facilitation of glucose to be used by the cell for energy
Correct Answer: B
Rationale: The correct answer is B: Removal of old red blood cells from circulation. The spleen plays a crucial role in filtering and removing old or damaged red blood cells from circulation. When the spleen is removed, this function is compromised, leading to a decrease in the body's ability to clear out these cells efficiently. This can result in an increased risk of anemia and other complications related to the buildup of old red blood cells in the bloodstream.
A: Filtration of waste products - While the spleen does play a role in filtering blood, its primary function is related to red blood cells, not waste products.
C: Clearance of mucous in the tracheobronchial tree - This function is primarily carried out by the respiratory system, particularly the cilia and mucous membranes in the airways, not the spleen.
D: Facilitation of glucose to be used by the cell for energy - This function is primarily related to the pancreas and insulin production, not the
Which of the following best characterizes the function of ferroportin in iron metabolism?
- A. A form of storage iron in intestinal mucosal cells
- B. A transport protein in the plasma
- C. A receptor protein on the surface of erythroid progenitors
- D. Transmembrane iron exporter
Correct Answer: D
Rationale: The correct answer is D: Transmembrane iron exporter. Ferroportin is a transmembrane protein that functions as an iron exporter, allowing iron to move out of cells. This is crucial in iron metabolism as it facilitates the release of iron from cells into the bloodstream for transport to other tissues.
A: A form of storage iron in intestinal mucosal cells - This is incorrect as ferroportin is not involved in storing iron in cells.
B: A transport protein in the plasma - This is incorrect as ferroportin is not primarily a plasma protein but rather a transmembrane protein.
C: A receptor protein on the surface of erythroid progenitors - This is incorrect as ferroportin is not a receptor protein but an exporter protein.
Increase serum iron:-decrease IBC a feature of:
- A. Hookworm infestation
- B. sideroblastic an.
- C. alcoholic liver dis.
- D. th.major
Correct Answer: B
Rationale: The correct answer is B: sideroblastic anemia. In sideroblastic anemia, there is impaired heme synthesis leading to the accumulation of iron in the mitochondria of red blood cell precursors. This results in increased serum iron levels due to the release of iron from the mitochondria. Decreased Iron Binding Capacity (IBC) occurs as a compensatory mechanism due to the increased serum iron levels.
Choice A, hookworm infestation, would typically result in iron deficiency anemia with decreased serum iron levels and normal to increased IBC. Choice C, alcoholic liver disease, is associated with decreased serum iron levels and normal to increased IBC due to impaired iron metabolism. Choice D, thalassemia major, presents with normal to decreased serum iron levels and normal to increased IBC due to ineffective erythropoiesis.
A patient is scheduled for upcoming surgery. He is on nonsteroidal anti-inflammatory drugs (NSAIDs) for rheumatoid arthritis. You are being asked what to do with his medications for the surgery. What is the mechanism of action of NSAIDS?
- A. Irreversible inhibition of cyclooxygenase 1
- B. Irreversible inhibition of cyclooxygenase 2
- C. Reversible inhibition of cyclooxygenase 1
- D. Reversible inhibition of cyclooxygenase 2
Correct Answer: C
Rationale: Step 1: NSAIDs inhibit cyclooxygenase (COX) enzymes to reduce prostaglandin synthesis.
Step 2: Reversible inhibition means the effect is temporary and can be reversed.
Step 3: COX-1 inhibition leads to GI side effects, which can be concerning in surgery.
Step 4: COX-2 inhibition is more targeted for inflammation but can still pose cardiovascular risks.
Step 5: Reversible COX-1 inhibition allows for temporary discontinuation before surgery to minimize bleeding risk.
Summary: Choice C is correct as reversible COX-1 inhibition allows for safer management pre-surgery compared to irreversible inhibition in choices A and B, and COX-2 inhibition in choice D.