Antimicrobials — MCQs

An 8-year-old boy is brought to the emergency department by his parents because of sudden onset of abdominal pain beginning an hour ago. The parents report that their son has also had an episode of dark urine earlier that morning. Three days ago, he was diagnosed with a urinary tract infection and was treated with trimethoprim-sulfamethoxazole. He emigrated from Liberia to the US with his family 3 years ago. There is no personal history of serious illness. His immunizations are up-to-date. Vital signs are within normal limits. Examination shows diffuse abdominal tenderness and scleral icterus. The spleen is palpated 1–2 cm below the left costal margin. Laboratory studies show: Hemoglobin 10 g/dL Mean corpuscular volume 90 μm3 Reticulocyte count 3% Serum Bilirubin Total 3 mg/dL Direct 0.5 mg/dL Haptoglobin 20 mg/dL (N=41–165 mg/dL) Lactate dehydrogenase 160 U/L Urine Blood 3+ Protein 1+ RBC 2–3/hpf WBC 2–3/hpf Which of the following is the most likely underlying cause of this patient's symptoms?

A 45-year-old male presents to his primary care doctor complaining of abdominal pain. He reports a three-month history of intermittent burning pain localized to the epigastrium that worsens 2-3 hours after a meal. He attributes this pain to increased stress at his job. He is otherwise healthy and takes no medications. He does not smoke or drink alcohol. His temperature is 98.8°F (37.1°C), blood pressure is 130/85 mmHg, pulse is 90/min, and respirations are 18/min. Physical examination reveals mild epigastric tenderness to palpation. A urease breath test is positive. Which of the following treatments is most appropriate first-line therapy for this patient?

A 47-year-old woman comes to the physician because of easy bruising and fatigue. She appears pale. Her temperature is 38°C (100.4°F). Examination shows a palm-sized hematoma on her left leg. Abdominal examination shows an enlarged liver and spleen. Her hemoglobin concentration is 9.5 g/dL, leukocyte count is 12,300/mm3, platelet count is 55,000/mm3, and fibrinogen concentration is 120 mg/dL (N = 150–400). Cytogenetic analysis of leukocytes shows a reciprocal translocation of chromosomes 15 and 17. Which of the following is the most appropriate treatment for this patient at this time?

A 51-year-old woman presents to her primary care doctor with diarrhea. She has had 3-10 malodorous and loose bowel movements daily for the last 6 months, though she recalls that her bowel movements started increasing in frequency nearly 2 years ago. She was otherwise healthy until 2 years ago, when she had multiple elevated fasting blood glucose levels and was diagnosed with type 2 diabetes mellitus. She was also hospitalized once 6 months ago for epigastric pain that was determined to be due to cholelithiasis. She is an avid runner and runs 3-4 marathons per year. She is a vegetarian and takes all appropriate supplements. Her body mass index is 19 kg/m^2. She has lost 10 pounds since her last visit 18 months ago. On exam, she has dry mucous membranes and decreased skin turgor. A high-resolution spiral computerized tomography scan demonstrates a 5-cm enhancing lesion in the head of the pancreas. Additional similar lesions are found in the liver. Further laboratory workup confirms the diagnosis. The patient is offered surgery but refuses as she reportedly had a severe complication from anesthesia as a child. This patient should be treated with a combination of octreotide, 5-fluorouracil, and which other medication?

An investigator is studying the genetic profile of an isolated pathogen that proliferates within macrophages. The pathogen contains sulfatide on the surface of its cell wall to prevent fusion of the phagosome and lysosome. She finds that some of the organisms under investigation have mutations in a gene that encodes the enzyme required for synthesis of RNA from a DNA template. The mutations are most likely to reduce the therapeutic effect of which of the following drugs?

A 23-year-old woman on prednisone for lupus presents to her primary care physician because she experiences a burning sensation with urination. She has also been urinating more frequently than normal. The patient denies fever, chills, nausea/vomiting, abdominal or back pain, or other changes with urination. Her vital signs and physical exam are unremarkable, and her urine analysis is positive for leukocyte esterase and nitrites. The patient receives a diagnosis and is then prescribed an antimicrobial that acts by inhibiting DNA gyrase. Which adverse effect should the patient be counseled about?

A 21-year-old male presents after several days of flatulence and greasy, foul-smelling diarrhea. The patient reports symptoms of nausea and abdominal cramps followed by sudden diarrhea. He says that his symptoms started after he came back from a camping trip. When asked about his camping activities, he reports that his friend collected water from a stream, but he did not boil or chemically treat the water. His temperature is 98.6°F (37°C), respiratory rate is 15/min, pulse is 67/min, and blood pressure is 122/98 mm Hg. Stool is sent for microscopy which returns positive for motile protozoans. Which of the following antibiotics should be started in this patient?

The patient is admitted to the hospital. A stereotactic brain biopsy of the suspicious lesion is performed that shows many large lymphocytes with irregular nuclei. Which of the following is the most appropriate treatment?

A 55-year-old man presents to his primary care physician for diarrhea. He states that he has experienced roughly 10 episodes of non-bloody and watery diarrhea every day for the past 3 days. The patient has a past medical history of IV drug abuse and recently completed treatment for an abscess with cellulitis. His vitals are notable for a pulse of 105/min. Physical exam reveals diffuse abdominal discomfort with palpation but no focal tenderness. A rectal exam is within normal limits and is Guaiac negative. Which of the following is the best initial treatment for this patient?

A 21-year-old man presents to the office for a follow-up visit. He was recently diagnosed with type 1 diabetes mellitus after being hospitalized for diabetic ketoacidosis following a respiratory infection. He is here today to discuss treatment options available for his condition. The doctor mentions a recent study in which researchers have developed a new version of the insulin pump that appears efficacious in type 1 diabetics. They are currently comparing it to insulin injection therapy. This new pump is not yet available, but it looks very promising. At what stage of clinical trials is this current treatment most likely at?