Infectious Diseases 2 Flashcards
A female patient comes to the clinic with a urinary
tract infection (UTI), and you are asked by the nursing student to explain the patient’s urinary dipstick
test because the student is confused by the results.
The patient’s results are positive for nitrite, leukocyte
esterase, protein, and blood in the urine. Specifically,
the student nurse asks which urine dipstick result, if
positive, is most indicative of a UTI?
A. Nitrite positive.
B. Leukocyte esterase positive.
C. Positive for protein.
D. Positive for blood.
Leukocyte esterase, proteinuria, and hematuria are not
specific for a UTI. Although leukocyte esterase indicates
the presence of WBCs in the urine, it could be a sign of
inflammation in the urinary tract (Answer B is incorrect).
Proteinuria and hematuria could also be present in other
disease states (Answers C and D are incorrect). A positive nitrite test result indicates the presence of nitrate-reducing bacteria, such as E. coli; therefore, it would be most indicative of a UTI (Answer A is correct).
Correct Answer: A
R.T. is an 18-year-old woman who presents to the
clinic with a 2-day history of urinary frequency and
burning, and fatigue. She noticed pain on urination
this morning. She also describes widespread muscle
aches, especially in her back. Which is the best treatment for R.T.?
A. Nitrofurantoin.
B. Fosfomycin.
C. Ciprofloxacin.
D. Amoxicillin/clavulanate.
This patient has systemic symptoms that indicate likely
pyelonephritis. Because of systemic disease, nitrofurantoin and fosfomycin are not appropriate options owing to a lack of sufficient tissue penetration (Answers A and B are incorrect). Answer D, amoxicillin/clavulanate, is incorrect because although the causative pathogen might be susceptible, amoxicillin/clavulanate is insufficient for empiric coverage because of generally high resistance rates. Answer C, ciprofloxacin, is correct because it is a preferred drug for pyelonephritis, it has excellent tissue penetration, and the organism is probably susceptible.
Correct Answer: C
Which of the following antibiotics provides sufficient
coverage against atypical organisms in community acquired pneumonia?
A. Amoxicillin/clavulanate.
B. Linezolid.
C. Doxycycline.
D. Cefuroxime.
The best answer is C, doxycycline. Tetracyclines are one of three drug classes (the others being macrolides and fluoroquinolones) that have activity against atypical organisms. Linezolid (answer B) and penicillin (answer A) and cephalosporins (answer D) do not have activity against atypical organisms.
Correct Answer: C
A 7-year-old girl is brought to the clinic in October
with a 1-day history of a red left eye. She says that she
could barely take her test today at school because her
eye is itchy and watery, and it feels like something is
in it. On physical examination, she is afebrile, and her
left conjunctiva is red and inflamed. No foreign objects
or visual changes are noted. She is given a diagnosis
of conjunctivitis. Which is the best treatment for her
conjunctivitis?
A. Supportive care only, with warm, moist compresses as needed.
B. Azithromycin 1%, one drop in left eye twice daily
for 2 days, followed by one drop once daily for
5 days.
C. Ofloxacin 0.3%, one or two drops in left eye once
daily for 14 days.
D. Ketotifen 0.025%, one drop in left eye twice daily
for 7 days.
Although conjunctivitis can be caused by many things, such as allergens, bacteria, and, more commonly, viruses, this 7-year-old girl goes to school; therefore, she should automatically be treated with topical antibiotics. Azithromycin would cover the most likely organisms of S. pneumoniae and H. influenzae; thus, it would be a good choice (Answer B is correct). Supportive care would be good in addition to antibiotics, but this should not be the only treatment (Answer A is incorrect). Antihistamines might help, but again, topical antibiotics are warranted in this case (Answers C and D are incorrect). Ofloxacin would be a good choice, but it should be given four times daily and for only 7 days unless there is reinfection or persistence.
Correct Answer: B
A 45-year-old man comes to the clinic with a red rash
on his neck that started about a week ago, the day he
flew back from his camping trip in Maine. He states
that although he picked off a few ticks while he was
there, he does not remember any ticks on his neck.
On examination, he has an erythematous rash with a
bull’s-eye pattern on the right side of his neck. He has
no other symptoms. His laboratory tests are positive
for Borrelia burgdorferi antibodies, and he is given a
diagnosis of Lyme disease. Which is the most appropriate management for his disease?
A. Watch and wait to see if more symptoms develop.
B. Give ceftriaxone 2 g intravenously daily for 14
days.
C. Give doxycycline 200 mg orally once.
D. Give doxycycline 100 mg orally twice daily for
10 days.
This patient presents to the clinic with early localized
Lyme disease, a classic bull’s-eye rash, and positive B.
burgdorferi antibodies. Treatment is imperative to prevent the development of late Lyme disease (Answer A is incorrect). Ceftriaxone intravenously would not be used for early disease but for cardiac or neurologic disease (Answer B is incorrect). Treatment for 10 days with doxycycline would be the treatment of choice (Answer C is incorrect; Answer D is correct).
Correct Answer: D
H.J. is a 19-year-old man who returns to the clinic with
worsening nasal congestion, headache, and severe
tooth pain. He has just completed a 10-day course of
amoxicillin/clavulanate 2 g/125 mg orally twice daily.
H.J. says his symptoms improved for a few days but
then worsened during the past week. He states that he
took his antibiotic as prescribed and has not missed
any doses. He has no known drug allergies. Which
regimen is the best recommendation for the treatment
of H.J.’s sinusitis?
A. Amoxicillin 1 g three times daily for 21 days.
B. Azithromycin 500 mg daily for 21 days.
C. Moxifloxacin 400 mg daily for 10 days.
D. Linezolid 600 mg orally twice daily for 10 days.
This patient is not responding to his current regimen of
high-dose amoxicillin/clavulanate. According to the current guidelines, his medication should be switched to a respiratory fluoroquinolone, such as moxifloxacin, and because the patient’s first-line therapy has failed, treatment would be extended to 7–10 days (Answer B is incorrect; Answer C is correct). Amoxicillin is no longer recommended for sinusitis (Answer A is incorrect). Linezolid would not cover the possibility of infections with gram-negative pathogens, such as H. influenzae or M. catarrhalis, and its adverse effects and cost would be problems (Answer D is incorrect).
Correct Answer: C
D.T. is a 13-year-old boy who presents to the pediatrician’s office with a 4-day history of severe sore throat and a temperature of 101°F (38.3°C). He states he
can barely swallow because his throat hurts so badly.
On physical examination, he weighs 41.2 kg, and his
tonsils are erythematous and swollen. A throat swab
is taken, and the rapid antigen detection test (RADT)
comes back positive for Streptococcus pyogenes. D.T.
has no known drug allergies. Which treatment recommendation is most appropriate for D.T.?
A. No treatment necessary.
B. Penicillin benzathine 0.6 million units intramuscularly once.
C. Trimethoprim/sulfamethoxazole 1 double-strength
tablet orally every 12 hours for 10 days.
D. Penicillin benzathine 1.2 million units intramuscularly once.
This patient has a positive strep antigen test result; therefore, treatment with antimicrobial therapy is necessary (Answer A is incorrect). Penicillin is the treatment of choice for group A Streptococcus, and an intramuscular shot of benzathine penicillin would be appropriate. The patient weighs more than 27 kg; therefore, the adult dose of 1.2 million units would be needed (Answer B is incorrect; Answer D is correct). Group A Streptococcus has a high rate of resistance to trimethoprim/sulfamethoxazole, which would not be a good choice (Answer C is incorrect).
Correct Answer: D
J.K. is a 45-year-old man who presents to the clinic
with a 48-hour history of severe diarrhea. His medical
history includes type 2 diabetes and hypertension. He
has two children younger than 4 years living at home.
He is on day 12 of his 14-day amoxicillin/clavulanate
therapy for the treatment of the carbuncles (boils) he
had drained 12 days ago. Physical examination reveals
significant improvement in the drained boils, and stool
studies are positive for Clostridioides difficile toxins
A and B. Which risk factor is most likely responsible
for J.K.’s development of C. difficile diarrhea?
A. Type 2 diabetes.
B. Recent surgery.
C. Living with children younger than 5 years.
D. Current amoxicillin/clavulanate treatment.
One of the most modifiable risk factors for C. difficile diarrhea is the exposure to antimicrobial agents. Although some antimicrobials may give the impression of being more associated with C. difficile, almost all antimicrobials can be potential risks because of the changes they can produce on the gut flora. Changes in gut flora will increase the risk of toxin-producing C. difficile (Answer D is correct). Health care exposure (e.g., recent surgery) can be a risk, as can immunosuppression or exposure to other individuals with C. difficile diarrhea, but these would not be the most likely causes in this case (Answers A, B, and C are incorrect).
Correct Answer: D
F.H. is a 62-year-old man who presents to the clinic
with a weeklong history of a blister on the side of his
right foot that has increased in redness and oozing for
the past 24 hours. His medical history includes type 2
diabetes for 25 years, coronary artery disease, hypertension, chronic kidney disease (estimated creatinine clearance [CrCl] was 22 mL/minute/m2), and amputation of his right middle finger 3 years ago as a result of infection. He reports a rash to “sulfa drugs.” Physical examination reveals a foul-smelling blister with surrounding erythema on the inside of the right foot with no necrosis. Radiographic study findings are negative for osteomyelitis. Sensitivities are pending. F.H. is being sent for wound debridement and outpatient antibiotic therapy. Which regimen is the best empiric
coverage for F.H.’s diabetic foot infection?
A. Trimethoprim/sulfamethoxazole, one double strength tablet orally twice daily for 14 days.
B. Levofloxacin 250 mg orally daily for 14 days.
C. Vancomycin 1 g intravenously every 12 hours for
14 days.
D. Levofloxacin 750 mg orally daily for 14 days.
Diabetic foot infections are usually polymicrobial;
therefore, empiric antimicrobial therapy should cover
gram-negative organisms, gram-positive organisms, and anaerobes. Levofloxacin has coverage against most of these organisms and would be the best choice (Answer B is correct). The patient has a CrCl of 22 mL/minute/1.73 m2; therefore, levofloxacin at 750 mg daily would be too high (Answer D is incorrect). Vancomycin has mainly gram-positive coverage, and the 1-g dose every 12 hours might be too aggressive because of this patient’s renal function (Answer C is incorrect). Trimethoprim/sulfamethoxazole does not offer adequate coverage for polymicrobial infections, and the patient reports a past allergic reaction to sulfa drugs (Answer A is incorrect). More severe infections may require broader coverage and/or hospitalization; however, this patient has a mild infection.
Correct Answer: B
S.O. is an 18-year-old high school senior who comes
to the clinic worried she is going to be sick. Her best
friend just received a diagnosis of meningitis caused
by Neisseria meningitidis. S.O. is an otherwise healthy
teenager with no known drug allergies, and she shows
no signs of infection today. She has not yet received
her meningococcal vaccination because she was going to wait until she went to college. Which would be the best recommendation for S.O. at this time?
A. Ceftriaxone 1 g intramuscularly once daily for 14
days.
B. Meningococcal conjugate vaccination only.
C. Rifampin 600 mg orally twice daily for 4 days.
D. Ciprofloxacin 500 mg orally once.
This patient has had close contact with someone who has meningococcal meningitis, and she is unvaccinated; therefore, she requires prophylaxis. Ceftriaxone could be used, but the dose should be 125–250 mg intramuscularly once (Answer A is incorrect). This patient will require the vaccine at some point, but not without receiving prophylaxis (Answer B is incorrect). Rifampin is a good choice, but the dose should be 600 mg twice daily for 2 days (Answer C is incorrect). Ciprofloxacin 500 mg orally once is fine for adult prophylaxis, and the patient is 18 years old; therefore, she could receive this regimen (Answer D is correct).
Correct Answer: D
Uncomplicated cystitis, name 3 treatments
Nitrofurantoin
TMP/SMX
Fosfomycin
What is dose nitrofurantoin and who to avoid giving it too
100mg bid for 5 days
Do not use pyelonephritis
Effectiveness decreases with renal impairment
Dose TMP/SMX 160/800
160/800 BID x3 days
No Longer first line due to E coli resistance
May use in pyelonephritis to secondary to flouroquinolone
What is the dose of fosfomycin
3 grams (single dose)
Expensive
Avoid in pyelonephritis
Not as effective as the others
What is the dose of fluoroquinolones for treatment of uncomplicated cystitis
Cipro 500mg ER daily or 250mg BID
Levofloxacin 250mg daily
Reserve for complicated disease, intolerance, pyelonephritis
