Antifungals Practice Questions

Question 1

You are taking care of a patient with renal failure secondary to anti-fungal therapy. The patient is a 66-year-old male being treated for cryptococcal meningitis. This drug has a variety of known side effects including acute febrile reactions to infusions, anemia, hypokalemia and hypomagnesemia. What is the mechanism of action of this drug?

Accepted Answer

Pore formation secondary to ergosterol binding

Answer

Inhibition of squalene epoxidase

Answer

Binding of the 50S subunit

Answer

Disruption of microtubule formation

Answer

Inhibition of 1,3-beta-glucan synthase

Question 2

A 37-year-old woman with a history of anorectal abscesses complains of pain in the perianal region. Physical examination reveals mild swelling, tenderness, and erythema of the perianal skin. She is prescribed oral ampicillin and asked to return for follow-up. Two days later, the patient presents with a high-grade fever, syncope, and increased swelling. Which of the following would be the most common mechanism of resistance leading to the failure of antibiotic therapy in this patient?

Accepted Answer

Production of beta-lactamase enzyme

Answer

Intrinsic absence of a target site for the drug

Answer

Use of an altered metabolic pathway

Answer

Altered structural target for the drug

Answer

Drug efflux pump

Question 3

An 18-year old college freshman presents to his university clinic because he has not been feeling well for the past two weeks. He has had a persistent headache, occasional cough, and chills without rigors. The patient’s vital signs are normal and physical exam is unremarkable. His radiograph shows patchy interstitial lung infiltrates and he is diagnosed with atypical pneumonia. The patient is prescribed azithromycin and takes his medication as instructed. Despite adherence to his drug regimen, he returns to the clinic one week later because his symptoms have not improved. The organism responsible for this infection is likely resistant to azithromycin through which mechanism?

Accepted Answer

Insertion of drug efflux pumps

Answer

Mutation in topoisomerase II

Answer

Methylation of ribosomal binding site

Answer

Presence of a beta-lactamase

Answer

Decreased binding to RNA polymerase

Question 4

A 57-year-old florist presents to his family physician with nodular lesions on his right hand and forearm. He explains that he got pricked by a rose thorn on his right "pointer finger" where the first lesions appeared, and the other lesions then began to appear in an ascending manner. The physician prescribed a medication and warned him of gynecomastia as a side effect if taken for long periods of time. Which of the following is the mechanism of action of the medication?

Accepted Answer

Inhibits ergosterol synthesis

Answer

Inhibits squalene epoxidase

Answer

Binds to ergosterol, forming destructive pores in cell membrane

Answer

Disrupts microtubule function

Answer

Inhibits formation of beta glucan

Question 5

A 74-year-old man is admitted to the medical ward after he developed a fungal infection. He has aplastic anemia. The most recent absolute neutrophil count was 450/µL. An anti-fungal agent is administered that inhibits the fungal enzyme, (1→3)-β-D-glucan synthase, and thereby disrupts the integrity of the fungal cell wall. He responds well to the treatment. Although amphotericin B is more efficacious for his condition, it was not used because of the side effect profile. What was the most likely infection?

Accepted Answer

Candidemia

Answer

Invasive aspergillosis

Answer

Mucormycosis

Answer

Histoplasmosis

Answer

Paracoccidioidomycosis

Question 6

A 32-year-old woman presents with three-days of vaginal burning, itching, and pain with intercourse. She is in a monogamous relationship with her husband and has an intrauterine device for contraception. Her past medical history is unremarkable, except for recently being treated with antibiotics for sinusitis. Pelvic exam is remarkable for vulvar excoriations, vaginal wall edema, and thick, white discharge in the vault. Wet mount with KOH staining reveals budding filaments with pseudohyphae and hyphae. Which of the following is the most appropriate treatment?

Accepted Answer

Fluconazole

Answer

Voriconazole

Answer

Posaconazole

Answer

Metronidazole

Answer

Itraconazole

Question 7

A 31-year-old female undergoing treatment for leukemia is found to have a frontal lobe abscess accompanied by paranasal swelling. She additionally complains of headache, facial pain, and nasal discharge. Biopsy of the infected tissue would most likely reveal which of the following?

Accepted Answer

Irregular non-septate hyphae

Answer

Yeast with pseudohyphae

Answer

Septate hyphae

Answer

Spherules containing endospores

Answer

Budding yeast with a narrow base

Question 8

A 28-year-old male presents to his primary care physician with complaints of intermittent abdominal pain and alternating bouts of constipation and diarrhea. His medical chart is not significant for any past medical problems or prior surgeries. He is not prescribed any current medications. Which of the following questions would be the most useful next question in eliciting further history from this patient?

Accepted Answer

"Can you tell me more about the symptoms you have been experiencing?"

Answer

"Does the diarrhea typically precede the constipation, or vice-versa?"

Answer

"Is the diarrhea foul-smelling?"

Answer

"Please rate your abdominal pain on a scale of 1-10, with 10 being the worst pain of your life"

Answer

"Are the symptoms worse in the morning or at night?"

Question 9

A 55-year-old woman presents to the physician because of a fever 4 days after discharge from the hospital following induction chemotherapy for acute myeloid leukemia (AML). She has no other complaints and feels well otherwise. Other than the recent diagnosis of AML, she has no history of a serious illness. The temperature is 38.8°C (101.8°F), the blood pressure is 110/65 mm Hg, the pulse is 82/min, and the respirations are 14/min. Examination of the catheter site, skin, head and neck, heart, lungs, abdomen, and perirectal area shows no abnormalities. The results of the laboratory studies show:
Hemoglobin 9 g/dL
Leukocyte count 800/mm3
Percent segmented neutrophils 40%
Platelet count 85,000/mm3
Which of the following is the most appropriate pharmacotherapy at this time?

Accepted Answer

Imipenem

Answer

Valacyclovir

Answer

Vancomycin

Answer

Caspofungin

Answer

Ciprofloxacin

Question 10

A 72-year-old man is brought to the emergency room by his daughter with complaints of a productive cough, rust-colored sputum, and fever for 1 week. He denies any breathlessness or chest pain. The past medical history is unremarkable. The vital signs include a pulse rate of 103/min, respiratory rate of 34/min, and blood pressure of 136/94 mm Hg, with an axillary temperature of 38.9°C (102.0°F). The SaO2 is 86% on room air. The chest examination revealed a dull percussion note and coarse crepitations over the left mid-chest. The patient was admitted to the medical unit and intravenous antibiotics were started. He responded well, but after 2 days an elevated temperature was noted. The patient deteriorated and he was transferred to the intensive care unit. A few days later, his temperature was 39.0°C (103.2°F), the respiratory rate was 23/min, the blood pressure was 78/56 mm Hg, and the SaO2 was 78%. He also had a delayed capillary refill time with a pulse of 141/min. Blood was drawn for the white cell count, which revealed a total count of 17,000/µL. The attending physician decides to begin therapy for the low blood pressure. After administration of the medication, hemodynamic monitoring reveals an increase in mean arterial pressure, increased venous return (reflected by increased central venous pressure), and increased cardiac output. Which of the following medications was most likely administered to the patient?

Accepted Answer

Norepinephrine

Answer

Captopril

Answer

Low-dose dopamine

Answer

Phenoxybenzamine

Answer

Isoproterenol

Antifungals

Study Resources

Lessons

Questions

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Polyenes (amphotericin formulations)

Azoles (imidazoles and triazoles)

Echinocandins

Flucytosine

Griseofulvin

Terbinafine

Topical antifungal agents

Antifungal prophylaxis protocols

Antifungal spectrum of activity

Antifungal resistance mechanisms

Antifungal therapeutic drug monitoring

Drug interactions with antifungals

Treatment guidelines for invasive fungal infections

Practice Questions

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About Antifungals for USMLE

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