Infectious Diseases Flashcards
For the majority of cases, the recommended treatment for a patient with latent TB infection (LTBI) in order to reduce the risk of TB developing is:
a) Isoniazid 900mg twice weekly (directly observed therapy)
b) Pyrazinamide 50mg/kg twice weekly
c) Levofloxacin 500mg daily
d) Ethambutol 50mg/kg twice weekly
e) Rifabutin 300mg daily
A. Patients with LTBI have a 10% risk of developing TB, and isoniazid can reduce this risk by >90%. Pyrazinamide was formerly used for prophylaxis in conjunction with rifampin, but this combination is no longer used due to a 7.3% risk of liver injury. The other agents are used in various combinations to treat active TB.
Reasons for non-adherence to TB medications, leading to drug resistance, include:
a) Complicated dosage regimens
b) Frequent and uncomfortable side effects
c) Long treatment periods
d) All of the above
e) None of the above
D. Patients can be on as many as 4 medications at a time and therapy can last 4 to 12 months, leading to treatment fatigue. All of the anti-tubercular agents have a high incidence of side effects, including GI upset, rash, myalgia, confusion, urticaria, flu-like illness, etc.
Which of the following agents cannot be used to treat active TB during pregnancy?
a) Isoniazid
b) Rifampin
c) Ethambutol
d) Pyrazinamide
e) Streptomycin
E. The combination of isoniazid, rifampin and ethambutol is the preferred initial treatment regimen for a pregnant woman. Teratogenicity with pyrazinamide has not been determined, though the risk is thought to be unlikely. Streptomycin has been associated with congenital deafness and is contraindicated
Post-exposure prophylaxis against meningitis caused by N. meningitidis in an adult can include:
a) Rifampin 600mg daily x 4 days
b) Ciprofloxacin 500mg as a single dose
c) Ceftriaxone 250mg IM as a single dose
d) All of the above
e) None of the above
D. The listed agents are all options for post-exposure prophylaxis (page 1309, CTC, 7th edn).
In the treatment of sexually transmitted infections, all of the following are true EXCEPT:
a) Metronidazole interacts with alcohol
b) Single-dose fluconazole can be an effective treatment
c) Fluconazole interacts with warfarin
d) Intravaginal metronidazole is effective against trichomoniasis
e) Clindamycin can cause C. difficile diarrhea
D. Only oral metronidazole is effective against trichomoniasis. Alcohol has a disulfiram-like reaction with metronidazole and should be avoided during therapy and for at least 24 hours afterwards. Fluconazole may cause an elevated prothrombin time when given to women on warfarin; a single dose of 150mg is effective against symptomatic vulvovaginal candidiasis, but may need to be given for 3 days if the problem is recurrent. C. difficile diarrhea is a known ADR of clindamycin and may appear up to 2 months after the antibiotic is finished.
In which of the following would you NOT routinely treat the sexual partner?
a) Trichomoniasis
b) Candidiasis
c) Chlamydia
d) Pelvic inflammatory disease
e) Gonorrhea
B. Candidiasis is not usually considered sexually transmitted, though the treatment of the sexual partner could be considered in recurrent infections (>4/year). All of the others are sexually transmitted diseases and both partners must be treated (Table 2, page 1466, CTC, 7th edn).
Which of the following would damage a latex condom?
a) Metronidazole vaginal gel
b) Miconazole vaginal ovule
c) Nystatin vaginal cream
d) Clotrimazole vaginal tablet
e) Miconazole vaginal cream
B. Miconazole vaginal ovules contain hydrogenated vegetable oil and mineral oil and these decrease the efficacy latex condoms or diaphragms. This also applies to econazole and terconazole ovules and butoconazole cream. None of the other agents contain these ingredients (Table 5, page 1476, CTC, 7th edn).
When treating recurrent cold sores, it is important that oral therapy be started:
a) Within 1 hour of first symptoms
b) Within 2 hours of first symptoms
c) Within 12 hours of first symptoms
d) Within 48 hours of first symptoms
e) Within 72 hours of first symptoms
A. Therapy should be initiated within 1 hour of the first symptoms to reduce the duration of pain and/or accelerate healing.
Which of the following statements about travellers’ diarrhea are CORRECT?
A) Antibiotics are required even if fever and blood or mucous in the stool are absent
B) Loperamide is a good treatment to prevent travellers’ diarrhea
C) Azithromycin 500mg daily x 3 days is the antibiotic of choice in Asia and India
D) Choleravaccineisroutinelyrecommended
E) Mild travellers’ diarrhea usually resolves in 72 hours with ORS and loperamide
A. Mild diarrhea can be managed with fluids and antimotility agents, and antibiotics are only recommended if there are signs of a bacterial infection. Prophylactic antimotility agents (loperamide) have no effect in reducing the incidence of travellers’ diarrhea. Azithromycin is the antibiotic of choice in Thailand, India, Indonesia and Nepal as the causative agent is usually a fluoroquinolone-resistant Campylobacter. Cholera vaccine (Dukoral) is only recommended for travellers at unusually high risk working in cholera risk zones (page 1514, CTC, 7th edn).
Which of the following statements about malaria prevention is FALSE?
a) Chloroquine should be started 2 weeks before departure
b) Primaquine is known for its severe neuropsychiatric reactions
c) Mefloquine should be continued for 4 weeks after leaving a malarious area
d) Primaquine must be taken daily
e) Chloroquine is safe to use during pregnancy
B. Primaquine has few side effects with the most common being severe haemolytic anemia in those with G6PD deficiency (blacks, Mediterraneans, Asians). Chloroquine and Mefloquine are taken once weekly, starting 2 weeks before departure and continuing for 4 weeks after leaving the malarious area. Primaquine must be taken daily but is only started 1 to 2 days before entry to the area and continued for 3 days after leaving the area. Chloroquine and hydroxychoroquine are safe to use during pregnancy; mefloquine is safe during the 2nd and 3rd trimesters. All other agents are contraindicated during pregnancy.
Red Flags by condition and drug induced conditions: Influenza
INFLUENZA VACCINE
> INR in warfarin therapy
High dose amoxicillin is chosen as the first line therapy for otitis media in children because:
a. it has an excellent safety profile
b. it is effective against penicillin-resistant S.
pneumoniae
c. it decreases pain within 24 hours
d. it covers S. pneumonia and M. catarrhalis,
common strains associated with otitis media
D is correct
a) is incorrect, causes allergic reaction, GI upset, anaphylaxis, vasculitis, eosinophilia, pseudomembranous coli
b) it is not effective against penicillin-resistant S. pneumoniae, that is amoxicillin-clavulanate
c) pain reduces within 2-7 days (Rx Files)
When would a clarithromycin be an appropriate choice for otitis media?
a. penicillin allergy
b. recent treatment with antibiotic
c. history of erythromycin GI effects
d. in non-type I hypersensitivity to penicillin i) a and b
ii) b and d
iii)a, b and c
iv)a, c, and d
iii) is correct
What methods are useful for pain reduction in otitis media
a. acetaminophen 10-15 mg/kg q 8-12 hr
b. ibuprofen 20 mg/kg q 6-8 hr
c. ASA 10-15 mg/kg q 4-6 hr
d. ibuprofen 5-10 mg/kg q 6-8 hr
i) a and b
ii) d and b
iii) a and c
iv) a
v) a and d
vi) d
vi)
- technically acetaminophen is best dosed every 4-6 hours for pain and so a is not exactly correct for the first 48 hours, d) is the only correct answer
What does the concept of watchful waiting refer to in otitis media?
a) Giving a child lots of fluid to see if their ear
infection gets worse
b) Treating pain symptoms to see if the otitis
media resolves
c) Treating with antibiotics as soon as there
are signs of infection
d) Treating by giving pain medications
initially, and giving an antibiotic script to fill if symptoms do not resolve in >48 hours
i) b
ii) d
iii) a and c
iv) c
v) a and d
ii)
True or false:
On physical examination, a swab of the tonsils should not be completed unless there is a sign of quinsy
False
Strep throat, in non-penicillin allergic patients, is best treated with a combination of:
1. steroids and penicillin V
2. acetaminophen and amoxcillin
3. steroids and azithromycin
4. acetaminophen and clindamycin 5. acetaminophen and penicillin V
- acetaminophen and penicillin V
True or false:
Erythromycin estolate salt can be used in both children and pregnant women for treatment of S. pyogenes
FALSE - erythromycin estolate salt cannot be used in pregnancy
What is the one thing that you need to be sure of before treating a child with amoxicillin for strep throat?
1. penicillin allergy
2. Quinsy and fever
3. Cough, fatigue, and diarrhea
4. A previous treatment with antibiotics
- Checking for cough, fatigue and diarrhea suggests a viral etiology. You need to rule out that the viral etiology is not EBV (mononucleosis)
Your patient is at 33 weeks gestation, and she develops strep throat. She is allergic to penicillin. What would be the most appropriate interventions to support her at this time?
1. ibuprofen and amoxicillin
2. clindamycin and acetaminophen
3. azithromycin and acetaminophen
4. azithromycin and acetaminophen with
codeine
3
Which of the following is correct? When a person is diagnosed with HIV, a priority should be:
a) Measuring their viral load and picking a dug according to the results
b) Assessing HIV drug resistance
c) Screen all patients for HLA-B 27
d) Screen all patients for HLA-B 5701
b, d
Combination antiretroviral therapy (cART) is the standard of care and is defines as the combination of at least 3 active antiretroviral drugs. To make this a first line therapy recommendation, it should include 2 nucleoside (or nucleotide) reverse transcriptase inhibitors and
a) non-nucleoside reverse transcriptase inhibitor
b) a ritonavir-boosted protease inhibitor
c) integrase inhibitor
d) all of the above
Any of these can be added
Fusion inhibitors and entry inhibitors should be reserved for which patients?
a) Poor compliers, as they are less effective, but one a day/ dosing provides moderate therapeutic benefit
b) Treatment experienced patients who demonstrate drug resistance
c) Patients who experience intolerable adverse effects with cART therapy
d) Patients in whom cART therapy is contraindicated
b,c,d
HLA-B 5701 testing should be done
a) Only initially, to get a baseline level
b) Monthly, to monitor disease
c) Before starting and restarting Abacavir
d) Annually, to monitor disease
C
In which patients should you consider cART therapy?
a) All patients, irrespective of their CD4 count
b) Pregnant patients should receive this urgently
c) Patients with symptomatic HIV
d) HIV patients who are asymptomatic and have a CD4 count >500 cells/uL
a-c
d- <500
If the viral load rebounds to >200copies/mL, despite ongoing cART Tx
a) Consider non-adherence
b) Consider Drug interaction that decrease the effect of the drug
c) Consider the patient a fast metabolizer, rendering the drug less effective
C
Before prescribing Maraviroc, you should
a) Try Abacavir for 3 months, If the patients viral load is not improved, you should switch to Maraviroc
b) Do an HLA-B 5701 test to assess for allergy
c) Do a tropism test to see if he/she is CCR5 or CXCR4 or dual mixed
d) Consult with an HIV tertiary clinic
C
ART therapy offers what benefits?:
a) improved quality of life
b) reduces the incidence of opportunistic infections
c) reduces the incidence of some cancers
d) reduces transmission from mom to her baby
e) all of the above
E
A person who demonstrates the presence of the HLA-B 5701 allele at baseline means:
a) the patient is allergic to Maraviroc
b) the patient is sensitive to Maraviroc but is a good candidate for Abacavir
c) The patient is allergic to Abacavir
d) The patient is a good candidate for Abacavir
C
Maraviroc is only indicated in:
a) Patients who are CXCR 4 tropic
b) Patients who demonstrate dual/mixed tropism
c) Patients who are Dual/mixed Tropic
d) Patients who are CCR5 Tropic
D
T/F “Drug holidays” are recommended to reduce long-term toxicity and treatment costs for patients
f. 1
Which of the following are true?
a) All Non-Nucleoside Reverse Transcriptase Inhibitors are metabolized by CYP 450
b) All Protease Inhibitors are metabolized by CYP 450
c) All Nucleotide Reverse Transcriptase inhibitors are not metabolized by CYP 450, but they have the potential for many drug interactions
d) All of the above
D
Why are protease inhibitors boosted with ritinavir?
2- below
This drug demonstrates pharmacologic antagonism with zidovudine
3-stavudine
There is only 1 NtRTI, this is…
tenofovir
This HIV drug is known to have rare reports of SJS reactions
etavirine
Preferred NtRTI/NTRTI combos are
a) emtricitabine/tenofovir
b) lamivudine/tenofovir
c) abacavir/lamivudine
a-c
Preferred Drugs for the 3rd Drug in the regimen include:
a) NNRTI: efavirenz
b) PIs: atazanivir/ritonavir or darunavir/ritonavir
c) IIs: dolutegravir, elvitegravir/cobicistat or raltegravir
a-c
These Integrase Inhibitors are only available as a combination
Elvitegravir
/cobicistat
This drug should not be used in patients with creatine clearance <70mL/min
This drug may be effective against NNRTI-Resistant HIV
etravirine
All protease inhibitors carry a risk of this adverse effect
PR interval prolongation
This drug is know for both QT and PR interval prolongation
saquinavir
This protease inhibitor should be reserved for treatment- experienced patients with limited options:
tipranavir
This drug may have cross sensitivity with sulfonamides
tipranavir
