Internal Medicine Infectious Disease Management Questions and Answers — Questions and Answers
Question 1: A 65-year-old male with diabetes presents to the emergency department with fever, confusion, and a blood pressure of 85/50 mmHg. He is diagnosed with septic shock from a urinary source. After an initial 30 mL/kg crystalloid fluid bolus, his mean arterial pressure (MAP) remains 55 mmHg. According to the Surviving Sepsis Campaign guidelines, what is the most appropriate next step?
- Administer an additional 1-liter fluid bolus before considering other therapies.
- Initiate a norepinephrine infusion. (Correct answer)
- Add vasopressin to the current regimen.
- Obtain a central venous oxygen saturation (ScvO2) measurement to guide resuscitation.
Correct answer: Initiate a norepinephrine infusion.
The Surviving Sepsis Campaign guidelines recommend initiating vasopressors if hypotension persists after initial fluid resuscitation to maintain a MAP of ≥65 mmHg. Norepinephrine is the first-line vasopressor of choice. While further fluid administration may be considered, vasopressor therapy should not be delayed in patients with persistent shock. Vasopressin is typically added as a second-line agent if the patient is refractory to norepinephrine. Routine monitoring of ScvO2 is no longer a primary resuscitation target.
Question 2: A 45-year-old female with no significant comorbidities and no recent antibiotic use is diagnosed with outpatient community-acquired pneumonia (CAP), confirmed by chest X-ray. According to the most recent IDSA/ATS guidelines, which of the following is a recommended first-line empiric antibiotic regimen for this patient?
- Levofloxacin
- Azithromycin monotherapy
- Amoxicillin-clavulanate
- Doxycycline (Correct answer)
Correct answer: Doxycycline
For healthy outpatients with CAP and no risk factors for resistant pathogens, the IDSA/ATS guidelines recommend monotherapy with amoxicillin, doxycycline, or a macrolide (only if local pneumococcal resistance is <25%). Due to widespread macrolide resistance, doxycycline and amoxicillin are often preferred. Levofloxacin is a respiratory fluoroquinolone, which is typically reserved for patients with comorbidities or recent antibiotic use. Amoxicillin-clavulanate is broader than necessary for this patient and is typically recommended in combination with another agent for patients with comorbidities.
Question 3: A 72-year-old man is diagnosed with his first episode of non-severe *Clostridioides difficile* infection (CDI). According to the most recent IDSA/SHEA guidelines, which of the following is the preferred first-line treatment?
- Oral Metronidazole for 14 days
- Oral Vancomycin for 10 days
- Oral Fidaxomicin for 10 days (Correct answer)
- Fecal Microbiota Transplantation (FMT)
Correct answer: Oral Fidaxomicin for 10 days
The 2021 IDSA/SHEA guidelines suggest fidaxomicin as the preferred agent over oral vancomycin for an initial episode of CDI, based on evidence showing lower rates of recurrence. Oral vancomycin is considered an acceptable alternative. Metronidazole is no longer recommended as a first-line agent for initial episodes due to inferior efficacy. FMT is generally reserved for patients with multiple recurrent infections.
Question 4: A 35-year-old asymptomatic healthcare worker undergoes routine annual screening and has a positive Interferon-Gamma Release Assay (IGRA) test. A subsequent chest X-ray is normal. What is the most appropriate next step in the management of this patient?
- Reassure the patient that this is likely a false positive and repeat the test in 6 months.
- Obtain three morning sputum samples for AFB smear and culture.
- Start a four-drug regimen for active tuberculosis.
- Offer a recommended treatment regimen for latent TB infection (LTBI). (Correct answer)
Correct answer: Offer a recommended treatment regimen for latent TB infection (LTBI).
A positive IGRA in the context of a normal chest X-ray is diagnostic for latent TB infection (LTBI). For individuals like healthcare workers who are at increased risk of exposure, treatment for LTBI is recommended to prevent progression to active disease. Sputum samples and active TB treatment are only indicated if active disease is suspected based on symptoms or radiographic findings. Assuming a false positive is not appropriate without further evaluation.
Question 5: A 28-year-old surgical resident sustains a deep needlestick injury from a hollow-bore needle used on a patient with a known high HIV viral load and no documented drug resistance. According to current CDC guidelines, what is the most appropriate regimen for post-exposure prophylaxis (PEP) that should be initiated as soon as possible?
- Zidovudine (AZT) monotherapy for 28 days.
- A two-drug regimen with tenofovir and emtricitabine for 28 days.
- A three-drug regimen with tenofovir, emtricitabine, and an integrase inhibitor (e.g., raltegravir or dolutegravir) for 28 days. (Correct answer)
- No prophylaxis is needed if the resident's baseline rapid HIV test is negative.
Correct answer: A three-drug regimen with tenofovir, emtricitabine, and an integrase inhibitor (e.g., raltegravir or dolutegravir) for 28 days.
For a high-risk occupational exposure to HIV (e.g., deep injury, hollow-bore needle, high viral load source), a three-drug PEP regimen is the standard of care. The preferred regimen for adults typically includes two nucleoside reverse transcriptase inhibitors (like tenofovir and emtricitabine) plus an integrase inhibitor (like raltegravir or dolutegravir). Two-drug regimens are no longer preferred for most exposures, and monotherapy is outdated. PEP should be initiated as soon as possible, ideally within 2 hours of exposure, and should not be delayed pending the results of the healthcare worker's baseline tests.
Question 6: A 68-year-old male from a nursing home with a long-term indwelling urinary catheter presents with fever and flank pain. He was treated with levofloxacin for a UTI two months ago. He is admitted for pyelonephritis. Which of the following is the most appropriate empiric intravenous antibiotic while awaiting urine culture results?
- Ceftriaxone
- Ciprofloxacin
- Piperacillin-tazobactam (Correct answer)
- Ampicillin-sulbactam
Correct answer: Piperacillin-tazobactam
This patient has a complicated UTI (pyelonephritis with an indwelling catheter) and several risk factors for a multidrug-resistant organism: nursing home residence, indwelling hardware, and recent fluoroquinolone use. Empiric therapy should cover common uropathogens as well as *Pseudomonas aeruginosa*. Piperacillin-tazobactam provides this broad-spectrum coverage. Ceftriaxone lacks reliable Pseudomonas coverage. Ciprofloxacin is a poor choice due to recent use and high resistance rates. Ampicillin-sulbactam has limited activity against many common gram-negative uropathogens in this setting.
Internal Medicine Infectious Disease Management Questions and Answers
A 65-year-old male with diabetes presents to the emergency department with fever, confusion, and a blood pressure of 85/50 mmHg.
He is diagnosed with septic shock from a urinary source.
After an initial 30 mL/kg crystalloid fluid bolus, his mean arterial pressure (MAP) remains 55 mmHg.
According to the Surviving Sepsis Campaign guidelines, what is the most appropriate next step?