Infectious Diseases 1 Flashcards
A.A. is a 21-year-old college student who presents in
the clinic with penile discharge and burning with urination. He reports drinking too much the past weekend (about 6 days ago) and having unprotected intercourse with a woman he met at a party. A.A. is otherwise healthy with no comorbidities, chronic medications, or known drug allergies. A physical examination is performed, and urethral discharge is noted. However, testing for sexually transmitted infections (STIs) is not immediately available. Which is the most appropriate treatment recommendation for this patient?
A. Ceftriaxone 250 mg intramuscularly once.
B. Doxycycline 100 mg orally twice daily for 7 days
plus ceftriaxone 500 mg intramuscularly once.
C. Ceftriaxone 250 mg intramuscularly once plus
azithromycin 1 g orally once.
D. Ceftriaxone 500 mg intramuscularly once plus
doxycycline 1 g orally once.
This patient is at risk of multiple STIs, including gonorrhea and chlamydia, given his history and clinical presentation. Because testing is not immediately available, he should be empirically treated for both gonorrhea (ceftriaxone 500 mg intramuscularly once) and chlamydia (doxycycline 100 mg orally twice daily for 7 days), making Answer B correct. The previously recommended empiric treatment was ceftriaxone 250 mg intramuscularly once plus azithromycin 1 g orally once, but this recommendation changed in 2021 because of increased resistance (Answer C is incorrect). Ceftriaxone alone would treat only gonorrhea, and 250 mg is no longer the recommended dose; also, the patient needs empiric treatment for chlamydia (Answer A is incorrect). Answer D is incorrect because the doxycycline dose should be 100 mg orally twice daily for 7 days.
Correct Answer: B
B.B. is a 20-year-old woman who presents to her
primary care provider with painful, ulcerative
lesions on her labia bilaterally. Her physician makes
the presumptive diagnosis of herpes labialis and
requests your opinion on treatment. Which is the most
appropriate therapy for this patient’s first episode?
A. Valacyclovir 1 g orally three times daily for 7
days.
B. Valganciclovir 900 mg orally once daily for 7
days.
C. Acyclovir 800 mg orally twice daily for 7 days.
D. Acyclovir 400 mg orally three times daily for 7
days.
For first episodes of herpes labialis, acyclovir 400 mg orally three times daily is a reasonable first-line option (Answer D is correct). Increasing the acyclovir dose to 800 mg is not necessary (Answer C is incorrect), and the correct valacyclovir dose for HSV is 1 g orally twice daily (Answer A is incorrect). Although valganciclovir is active against HSV, its spectrum is broader than necessary (Answer B is incorrect).
Correct Answer: D
C.C. is a 30-year-old health care worker who is stuck
by a needle that was being used to perform a venipuncture in a known HIV-seropositive patient. Which is the most important determinant with respect to the efficacy of postexposure prophylaxis (PEP)?
A. The time elapsed since the needlestick injury
occurred.
B. The sex of the source patient.
C. The nonprescription drug history of the source
patient.
D. The source patient’s CD4+
cell count.
One of the most critical factors involved in the efficacy of
PEP to prevent HIV infection is the time elapsed since the actual exposure. The earlier the PEP is administered, the greater the likelihood of efficacy (Answer A is correct). Most experts agree that the use of PEP beyond 72 hours of time zero is unlikely to reduce the risk of HIV transmission. The gender, medication history, and CD4+
cell count of the source patient do not affect the efficacy of PEP (Answers B, C, and D are incorrect).
Correct Answer: A
D.D. is a 30-year-old African American man with
newly diagnosed HIV infection; his viral load is
250,000 copies/mL, and his CD4+ count is 220 cells/ mm3. Which is the most appropriate next step in managing his disease?
A. Obtain a genotype.
B. Obtain a phenotype.
C. Administer hepatitis B virus (HBV) vaccine.
D. Administer influenza vaccine.
It is recommended to obtain a genotype for all patients
when they begin to receive HIV care, regardless of initiation of ART (Answer A is correct). A phenotypic resistance test is reserved for patients with known or suspected complex drug resistance mutations (Answer B is incorrect). Vaccinations are also important but would not be the first priority (Answers C and D are incorrect).
Correct Answer: A
E.E. is referred to the pharmacotherapy clinic for the
management of ongoing hyperlipidemia that has not
responded to 6 months of diet and exercise. He is
HIV seropositive and takes the following antiretroviral (ARV) regimen: tenofovir alafenamide fumarate/
emtricitabine plus darunavir/ritonavir. The only other
medications the patient currently takes are citalopram
for depression and zolpidem as needed for sleep. E.E.’s primary care physician is concerned about his elevated low-density lipoprotein cholesterol concentrations. Which intervention is most appropriate currently?
A. Initiate therapy with pravastatin.
B. Initiate therapy with simvastatin.
C. Discontinue tenofovir alafenamide fumarate/
emtricitabine.
D. Continue lifestyle modifications only.
Human immunodeficiency virus and certain ARV agents
have been associated with a propensity to induce hyperlipidemia. Typically, the management of hyperlipidemia in patients with HIV infection is similar to that in uninfected patients, except for certain limitations in the selection of drug therapy with statins. Many of the statin agents will interact with PIs, increasing the risk of rhabdomyolysis. If statins are indicated to lower low-density lipoprotein cholesterol, preferred agents include those with a lowerpropensity for CYP interactions (e.g., pravastatin, atorvastatin, rosuvastatin; Answer A is correct; Answer B is incorrect). Tenofovir alafenamide fumarate/emtricitabine is likely contributing only minimally to the increased lipids, so discontinuing it is not appropriate (Answer C is
incorrect). The patient should continue lifestyle modifications, but because this intervention has not worked over a 6-month period, a statin should be initiated (Answer D is incorrect).
Correct Answer: A
F.F. is a 26-year-old white man with HIV who presents
today to begin a new ARV regimen. The patient has not
previously been treated for HIV, and a genotypic resistance assay shows no resistance to any available ARV medication; his viral load is 76,300 copies/mL, and his CD4+ count is 355 cells/mm3. The patient is a graduate student who has a hectic work and school life. F.F. also has severe insomnia, which he attributes to “racing thoughts.” He will consider only a once-daily regimen. Which is the best once-daily option for this patient?
A. Emtricitabine/tenofovir disoproxil fumarate/
rilpivirine.
B. Emtricitabine/tenofovir disoproxil fumarate/
efavirenz.
C. Emtricitabine/tenofovir alafenamide/bictegravir.
D. Emtricitabine/tenofovir alafenamide/cobicistat/
elvitegravir
Current guidelines recommend an INSTI plus a two-NRTI
backbone as initial treatment for HIV infection. Answer C, emtricitabine/alafenamide/bictegravir, is therefore correct. Emtricitabine/tenofovir DF/efavirenz and emtricitabine/ tenofovir DF/rilpivirine are listed as alternative agents, not recommended agents, in the current guidelines (Answers A and B are incorrect). In addition, the use of efavirenz is not recommended in this patient because it might further exacerbate this patient’s difficulty sleeping; efavirenz has been associated with vivid dreams and CNS disengagement. Emtricitabine/tenofovir alafenamide fumarate/elvitegravir/cobicistat is an INSTI-based regimen, but this specific regimen is not recommended as initial therapy because it contains a boosting agent, which would place the patient at a greater risk of drug-drug interactions (Answer D is incorrect).
Correct Answer: C
G.G. is a 49-year-old female renal transplant recipient
who presents to the clinic for a routine follow-up. She
has no food or drug allergies. G.G.’s allograft is functioning well, and she has not been treated for rejection. Because the influenza season has just begun, which is the most appropriate means of prevention for this patient?
A. Oseltamivir 75 mg orally once daily for the duration of the influenza season.
B. Inactivated influenza vaccine (IIV) and oseltamivir 75 mg orally once daily for 2 weeks.
C. IIV.
D. Live attenuated influenza vaccine (LAIV).
Vaccination is the most effective method for preventing
influenza (Answer A is incorrect). The inactivated vaccine is preferred for this patient because she is a transplant
recipient (Answer C is correct; Answer D is incorrect).
The use of oseltamivir for 2 weeks at the time of influenza vaccination (to provide protection until immunity is established) can be considered if a patient has an influenza exposure (Answer B is incorrect because the patient did not report an influenza exposure).
Correct Answer: C
H.H. is 62-year-old woman who presents to her primary care provider for an annual follow-up. She states that she cannot recall ever having chickenpox or shingles. Which is the best option to prevent herpes zoster in this patient?
A. Obtain assay for varicella zoster virus immunoglobulin G, and if negative result, give Varivax; if positive result, give Zostavax.
B. Give Varivax.
C. Give Shingrix.
D. Give varicella zoster immune globulin (VariZIG).
The ACIP guidelines recommend Shingrix for all patients age 50 and older, regardless of herpes zoster history or previous vaccination with Zostavax. (Answer C is correct). It is thus unnecessary to obtain VZV serologic testing for this patient, and Zostavax is also no longer available in the United States (Answer A is incorrect). Varivax is recommended as a routine childhood vaccine, and it can be given to certain immunocompromised patients who are VZV negative (Answer B is incorrect). The VariZIG vaccine is recommended only as PEP in high-risk VZV-negative patients (Answer D is incorrect).
Correct Answer: C
J.J. is a 22-year-old man with a 4-month history of
pain and itching on the toes of both feet, with noticeable peeling and scaling. In the past month, he has lost both toenails from his great toes. J.J. is otherwise in excellent health because he regularly competes in amateur triathlons. His primary care provider diagnoses tinea pedis. Which is the most likely cause of this patient’s infection?
A. Malassezia spp.
B. Dermatophytes.
C. Sporothrix schenckii.
D. Candida albicans.
Tinea pedis is a type of ringworm caused by the dermatophytes Trichophyton, Microsporum, and Epidermophyton species (Answer B is correct). The other listed fungal pathogens are not dermatophytes (Answers A, C, and D are incorrect).
Correct Answer: B
Which organism best fits the following description:
endemic in the Ohio and Mississippi River Valleys and
can manifest as an acute pulmonary, chronic pulmonary, or disseminated infection?
A. Blastomyces dermatitidis.
B. Histoplasma capsulatum.
C. Coccidioides immitis.
D. Coccidioides posadasii
H. capsulatum is endemic in the Ohio and Mississippi
River valleys (Answer B is correct). B. dermatitidis is
endemic around the Great Lakes (Answer A is incorrect), whereas Coccidioides spp. are endemic in the desert
Southwest (Answers C and D are incorrect).
Correct Answer: B
Which HIV treatment also treats Hep B
Tenofivir
What is the drug for primary prophylaxis for opportunistic infections in HIV? Prevents both PJP and toxoplasmosis
Tmp/smx 1 dose daily or 3 days a week
For treatment it’s 21 days for PJP ( for toxoplasmosis, treatment is sulfadiazine plus pyrimethamine plus leucovorin )
Discontinue prophylaxis when CD4 is greater than 200 for 3 months
When CD4 < 50, at risk for MAC
Rare in United States
May see prophylaxis with azithromycin
Treatment clarithromycin with ethambutol
Discontinue prophylaxis when CD4 >150
Post exposure prophylaxis (PEP), description
Initiate as soon as possible Ideally within 72 hours of exposure
Give combination of three drug regimen for 28 days
Dolutegravir or raltegravir plus TDF/emtricitabine
Pre-exposure prophylaxis (PrEP), describe
My screen for HIV prior to initiation and then every 3 months
Tenofovir/emtricitabine
TAF or TDF can be used
New treatment approved, injectable cabotegrivir
