Nokea
A 40 year old man is HIV positive with CD4 count of 200/ cu.mm . After 2 months of therapy, he develops a peripheral WBC count of 1000 and hemoglobin of 9. Which of the following drugs most likely cause d this hematologic abnormality?
- A. Zidovudine
- B. Acyclovir
- C. Foscarnet
- D. Amantadine
Correct Answer: A
Rationale: The correct answer is A: Zidovudine. Zidovudine is known to cause bone marrow suppression, leading to decreased white blood cell and red blood cell counts. In this case, the patient's peripheral WBC count of 1000 and low hemoglobin after starting therapy are indicative of hematologic abnormalities consistent with zidovudine use. Acyclovir, Foscarnet, and Amantadine do not typically cause bone marrow suppression and are not associated with the hematologic abnormalities seen in this patient.
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Which of the following cephalosporins has activity against gram negative anaerobic bacteria like Bacteroides fragilis, and the only cephalosporins that cross the blood brain barrier and enter the brain?
- A. Ceftriaxone
- B. Cefoxitin
- C. Cephalexin
- D. Cefixime
Correct Answer: A
Rationale: Rationale:
1. Ceftriaxone is a third-generation cephalosporin known for broad-spectrum coverage.
2. It has excellent activity against gram-negative anaerobes such as Bacteroides fragilis.
3. It is also one of the cephalosporins that can penetrate the blood-brain barrier.
4. The other choices do not have the same anaerobic coverage or BBB penetration.
Summary:
- B: Cefoxitin is a second-generation cephalosporin with anaerobic coverage but does not cross the BBB.
- C: Cephalexin is a first-generation cephalosporin with limited anaerobic activity and no BBB penetration.
- D: Cefixime is a third-generation cephalosporin with no anaerobic activity or BBB penetration.
A patient with HIV-AIDS being treated with combined antiviral drugs and * immunosuppressive agents, develops an opportunistic infection caused by Pneumocystis caranii. Which of the following drugs most likely be used in the treatment of pulmonary infection caused by P, caranii?
- A. Metronidazole
- B. Carbenicillin
- C. Trimthoprim /Sulfametoxazole
- D. Penicillin G
Correct Answer: C
Rationale: The correct answer is C: Trimethoprim/Sulfamethoxazole. This combination is the first-line treatment for Pneumocystis carinii pneumonia in patients with HIV-AIDS due to its efficacy against the organism. Trimethoprim inhibits bacterial folic acid synthesis, while sulfamethoxazole inhibits bacterial dihydrofolic acid formation. These drugs work synergistically to target different steps in the folic acid synthesis pathway of Pneumocystis carinii, leading to its effective eradication. Metronidazole (A) is used for anaerobic bacterial infections, Carbenicillin (B) is a penicillin derivative mainly used for Gram-negative bacteria, and Penicillin G (D) is not effective against Pneumocystis carinii.
A 30-year-old woman presents to the clinic with a complaint of a delayed period and abdominal discomfort. The nurse suspects pregnancy. Which of the following is the earliest and most reliable sign of pregnancy?
- A. A missed period.
- B. Positive urine pregnancy test.
- C. Changes in breast size.
- D. Abdominal tenderness and bloating.
Correct Answer: C
Rationale: The correct answer is C: Changes in breast size. This is because hormonal changes in early pregnancy can cause breast tenderness, swelling, and darkening of the areola. This typically occurs before a missed period or a positive urine pregnancy test. A missed period (choice A) is a common sign of pregnancy, but not the earliest. A positive urine pregnancy test (choice B) confirms pregnancy but may not be the earliest sign. Abdominal tenderness and bloating (choice D) can occur due to various reasons and are not specific to pregnancy. Therefore, changes in breast size are the earliest and most reliable sign of pregnancy in this scenario.
The penicillin G preparation with the longest duration of action is:
- A. Benzathine penicillin
- B. Sodium penicillin
- C. Potassium penicillin
- D. Procaine penicillin
Correct Answer: A
Rationale: The correct answer is A: Benzathine penicillin. Benzathine penicillin has the longest duration of action among the choices because it is formulated as a salt that releases the active drug slowly over an extended period. The benzathine salt forms a depot at the injection site, leading to a sustained release of penicillin into the bloodstream. This results in a prolonged therapeutic effect and less frequent dosing compared to other penicillin preparations.
Summary:
- Choice B: Sodium penicillin has a shorter duration of action as it gets rapidly absorbed and eliminated from the body.
- Choice C: Potassium penicillin is not a standard form of penicillin and does not exist as a distinct preparation.
- Choice D: Procaine penicillin has an intermediate duration of action compared to benzathine penicillin due to the addition of procaine for local anesthesia, but it is not as long-acting.
A 2-month-old uncircumcised infant has been brought to the clinic for a well-baby checkup. How would the nurse proceed with the genital examination?
- A. Eliciting the cremasteric reflex is recommende
- C. The glans is assessed for redness or lesions.
- D. COM
Correct Answer: C
Rationale: The correct answer is C: The glans is assessed for redness or lesions. This is the appropriate step for a genital examination in a 2-month-old uncircumcised infant to check for any signs of infection or abnormalities. Eliciting the cremasteric reflex (choice A) is not necessary for a routine well-baby checkup and is more relevant in assessing testicular descent. Choices B and D are incomplete or irrelevant, not addressing the specific aspect of the genital examination needed in this scenario.