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What is the pathophysiologic process responsible for the decreased glomerular filtration rate in a patient with acute glomerulonephritis?
- A. Decreased renal-induced constriction of the renal arteries
- B. Immune complex deposition, increased capillary permeability, and cellular proliferation
- C. Necrosis of 70% or more of the nephrons secondary to increased kidney interstitial hydrostatic pressure
- D. Scar tissue formation throughout the proximal convoluted tubule secondary to toxin-induced collagen synthesis
Correct Answer: B
Rationale: The correct answer is B: Immune complex deposition, increased capillary permeability, and cellular proliferation. Acute glomerulonephritis is characterized by inflammation of the glomeruli in the kidneys. This inflammation leads to the deposition of immune complexes, increased capillary permeability, and cellular proliferation, which collectively contribute to a decreased glomerular filtration rate. Choice A is incorrect as decreased renal-induced constriction of the renal arteries would not directly result in decreased glomerular filtration rate. Choice C is incorrect as necrosis of nephrons due to increased kidney interstitial hydrostatic pressure would affect kidney function differently. Choice D is incorrect as scar tissue formation in the proximal convoluted tubule due to toxin-induced collagen synthesis is not a typical feature of acute glomerulonephritis.
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Which of the following types of vitamin or mineral deficiency can cause megaloblastic anemia and is associated with lower extremity paresthesias?
- A. Vitamin B12
- B. Folate
- C. Iron
- D. Vitamin K
Correct Answer: A
Rationale: The correct answer is Vitamin B12. Vitamin B12 deficiency can lead to megaloblastic anemia, a condition characterized by the production of abnormally large and immature red blood cells. Lower extremity paresthesias, such as tingling or numbness, are common neurological symptoms associated with vitamin B12 deficiency. Folate deficiency can also cause megaloblastic anemia but is not typically linked to lower extremity paresthesias. Iron deficiency leads to microcytic anemia, not megaloblastic anemia. Vitamin K deficiency is associated with bleeding tendencies, not megaloblastic anemia or paresthesias.
In a patient with a subconjunctival hemorrhage due to allergic rhinitis, which statement is accurate?
- A. The hemorrhage will resolve without treatment within 2 weeks.
- B. The patient should be referred for immediate ophthalmologic examination.
- C. Oral antihistamines should be started to prevent further complications.
- D. Topical corticosteroids may be considered to reduce inflammation.
Correct Answer: A
Rationale: In a patient with a subconjunctival hemorrhage secondary to allergic rhinitis, the hemorrhage is typically self-limiting and will resolve on its own within 2 weeks without the need for specific treatment. Referring the patient for immediate ophthalmologic examination is not necessary unless there are other concerning symptoms. Starting oral antihistamines may help manage the underlying allergic rhinitis but is not specifically indicated for the hemorrhage. Topical corticosteroids are not routinely prescribed for subconjunctival hemorrhage as they may have limited benefit and could potentially cause complications.
Anemia of chronic inflammation is generally classified as:
- A. Hypochromic and microcytic.
- B. Hypochromic and macrocytic.
- C. Normochromic and microcytic.
- D. Normochromic and normocytic.
Correct Answer: D
Rationale: Anemia of chronic inflammation is typically characterized by normochromic (normal hemoglobin content) and normocytic (normal cell size) red blood cells. Choice A, hypochromic and microcytic, is incorrect because hypochromic refers to reduced hemoglobin content and microcytic refers to smaller than normal red blood cells, which are not typically seen in anemia of chronic inflammation. Choice B, hypochromic and macrocytic, is also incorrect as macrocytic refers to larger than normal red blood cells. Choice C, normochromic and microcytic, is incorrect because microcytic red blood cells are smaller than normal. Therefore, the correct classification for anemia of chronic inflammation is normochromic and normocytic.
Women who have breast cancer due to a BRCA1 gene mutation are usually:
- A. positive for human epidermal growth factor receptor 1 and 2.
- B. negative for estrogen receptor.
- C. positive for estrogen receptor, progesterone receptor, and human epidermal growth factor receptor 2.
- D. negative for estrogen receptor, progesterone receptor, and human epidermal growth factor receptor 2.
Correct Answer: D
Rationale: Women with breast cancer due to a BRCA1 gene mutation commonly have a triple-negative breast cancer subtype, which means they are negative for estrogen receptor, progesterone receptor, and human epidermal growth factor receptor 2 (HER2). This subtype tends to be more aggressive and harder to treat. Choice A is incorrect as they are typically negative for HER2. Choice B is incorrect because they are usually negative for estrogen receptor. Choice C is incorrect as they are usually negative for progesterone receptor and HER2.
A 65-year-old man is admitted to the intensive care unit from the operating room after a triple coronary artery bypass graft. He is intubated and on a ventilator. Lactic acid levels were normal postoperatively, but now they are rising. The increased level could be an indication of:
- A. excessive sedation
- B. bowel ischemia
- C. excessive volume infusion in the operating room
- D. mild hypothermia postoperatively
Correct Answer: B
Rationale: In this scenario, the rising lactic acid levels in a 65-year-old man after a coronary artery bypass graft could indicate bowel ischemia. Bowel ischemia can lead to anaerobic metabolism, causing an increase in lactic acid levels. Excessive sedation may cause respiratory depression but would not directly lead to rising lactic acid levels. Excessive volume infusion in the operating room might cause fluid overload but would not typically result in rising lactic acid levels. Mild hypothermia postoperatively could lead to shivering and increased oxygen consumption, but it is less likely to be the primary cause of rising lactic acid levels in this context.