Antibiotics + Infections Flashcards
What abx cover mycoplasma and chlamydia?
Macrolides (clarithromycin, azithromycin, erythromycin)
Tetracyclines (tetracycline, doxycycline, minocycline)
Which abx prolong QT?
QT MF - QT Makes u Flutter
Macrolides (clarithromycin, azithromycin, erythromycin)
Fluoroquinolones (ciprofloxacin, norfloxacin, levofloxacin, moxifloxacin)
Rx pinworms
Mebendazole
Albendazole
Pyrantel
Folliculitis, Carbuncles, complicated carbuncles, impetigo Rx
Folliculitis = mupirocin 2%
Carbuncles or cellulitis = cephalexin 500mg BID x 7 days
Complicated = septra 1-2DS tabs
Impetigo = mupirocin 2%
Common pathogens UTI
E coli + enterobacteriaceae, Klebsiella, proteus mirabilis
UTI abx - simple
Nitrofurantoin 1st line
2nd line: septra, ciprofloxacin, cephalexin
rx of UTI in pregnancy
avoid quinolones (no cipro), repeat UC monthly during pregnancy
Out vs inpt rx for pyelonephritis
Outpatient: 1 dose ceftriaxone or gentamycin, 10 days amox-clav, Septra or cefixime, or 7 days cipro
Inpatient: 10 days ceftriaxone or gentamycin
cellulitis abx
cephalexin 5 days or cefazolin IV 5 days (can be done as outpatient with probenecid to increase half life and make it last 24 hrs)
difference between erysipelas + cellulitis + rx for erysipelas
difference is clear demarcation and raised edge - caused by group A strep, treat with penicillin V or amoxicillin
abscess management - when to give abx vs not
<2cm w/ no systemic sx + no surrounding cellulitis in otherwise healthy pt = drained, no need for abx
All other abscesses = antibiotics
>2cm or multiple
Immunocompromised
Systemic sx = fever
Surrounding cellulitis
Risk of endocarditis
Indwelling medical device
Risk of community transmission
Abx - cephalexin
Common pathogens for abscesses
group A strep, staph aureus, group B, C, G strep
types of impetigo + what bacteria causes them + what sx
Bullous impetigo - common in kids, vesicles enlarge to form flaccid bullae with clear yellow fluid that turns darker and turbid over time, commonly over thorax. Staph aureus
Non bullous impetigo - evolves over a week w/ lesions turning into papules into vesicles with surrounding erythema, form blisters that burst with honey crusted lesions, commonly face + extremities. Group A strep
Ecthyma - deeper punch lesions into dermis with surrounding erythema + yellow crust
rx impetigo
Tx - mupirocin 2% TID topically, if unresponsive to topical or if extensive involvement or if ecthyma = flucloxacillin 500mg PO QID treat until resolved (max 7 days). If MRSA suspected = Septra, clindamycin or doxycycline
What test to do if adult presents with impetigo?
HIV
When may CXR be falsely negative for PNA?
Immunocompromised pts
Need CT
common CAP pathogens
strep pneumonia, mycoplasma pneumonia, chlamydophyllia pneumonia, Hemophilus influenza
Rx for CAP
amoxicillin 1g PO TID x 5 days or doxycycline
If pt smokes, has comorbidities or recent abx use - amox-clav + azithromycin
Sx of bacterial sinusitis vs viral
nasal discharge, facial pain, fever, viral sx
Bacterial if fever >39, discharge/ facial pain for >3 days, or if URTI sx >10 days worsening around day 5. Unilateral facial pain, cacosmia, pain in teeth
common sinusitis pathogens
strep pneumonia, H influenza, moraxella catarrhalis
rx sinusitis (+ what is it if there is black necrotic discharge - who is more at risk and what should you do?)
Tx: amoxicillin 500-1g TID x5-7 days, nasal saline rinses
If black necrotic discharge, and diabetes or immunosuppression = mucormycosis (fungal infection). Needs ENT consult urgently
Sx UTI
dysuria, suprapubic discomfort, frequency
fever or flank pain = pyelo
cellulitis sx
redness, warmth, swelling, pain and unilateral involvement. Redness must not disappear with elevation of area
CAP sx
cough, fever, tachypnea, dyspnea, tachycardia
OM sx + signs on exam
commonly kids, unilateral otalgia, decreased hearing, fever
bulging Tym Membrane, yellow or red membrane, perforation of Tym membrane with purulent discharge, impaired tympanic mobility
Rx OM - when to give abx + what to give
Tx: if fever >39, moderately to severe systemic sx, severe otalgia or if ill for >48 hrs. Otherwise, delayed script for abx.
All adults with OM should be treated
amoxicillin 90mg/kg/day divided BID x 10 days for kids under 2, older kids x 5 days
common OM pathogens
strep pneumonia, H influenza, moraxella catarrhalis
sx conjunctivitis
redness, purulent DC in one or both eyes, mild discomfort. Pain UNLIKELY
Bacterial vs viral - bacterial has white milky purulent discharge that reappears when wiped away within few mins
common conjunctivitis pathogens
staph aureus, strep pneumonia, H influenza, moraxella catarrhalis
Rx conjunctivitis
Usually resolves spontaneously
If given early, abx can resolve issue quicker
Contact lens wearers always require abx
bacitracin polymyxin, tobramicin, arithromycin
what is a hyperacute conjunctivitis?
develops within 12 hrs, copious discharge, redness, pain, conjunctival edema, lid swelling and tender pre-auricular lymphadenopathy
Site threatening infection with neisseria gonorrhea or neisseria meningitidis
How do you manage a hyperacute conjunctivitis?
swab purulent dc for GC+S + PCR NAAT
2g ceftriaxone IV + 1 dose azithromycin or 7 days doxycycline
Opthalmology consult
Reportable to public health
Partners to treat
H pylori management
CLAMET/PAMC:
Amoxicillin 1000mg BID
Clarithromycin 500mg BID
Metronidazole 500mg BID
PPI BID
14 days
Quadruple (for penicillin allergy)
Bismuth subsalicylate 2 tabs QID
Metronidazole 500mg BID
Tetracycline 500mg QID
PPI BID
14 days
rx c diff in adults + kids
Vancomycin 125mg QID x 10 days
Fidaxomicin 200mg BID x 10 days
Peds: metronidazole + vanco
who gets IE prophylaxis + what do they get?
Pts needing prophylaxis:
Prosthetic heart valve
Prev bacterial IE
During first 6mo of repair of congenital heart defect
Dental procedures needing gingival manipulation
Tonsillectomy, bronchoscopy
Cystoscopy on pts with known enterococcal UTI
Abx:
Amoxicillin 2g or
Cephalexin 2g
OE rx
Polysporin eye + ear drops 2 drops QID
Ciprodex otic suspension 4 drops BID if perforated
What are common interactions with abx?
Oral contraceptives (rifampin can make OCP less effective)
Alcohol use (avoid metronidazole)
Methotrexate or allopurinol (avoid amoxicillin)
Warfarin interacts with ciprofloxacin, metronidazole, clarithromycin, Septra, arithromycin
Antifngals, ciclosporin, diuretics, muscle relaxants (avoid gentamicin and tobramicin d/t renal and hearing injury)
Tetracyclines, fluoroquinolones, macrolides = interact with multiple meds
Fluoroquinolones (achilles tendon rupture)
how to approach viral illness w/ pts
Explain likely viral nature of URTI + that abx will have no effect on duration of sx
Explain that abx are potentially harmful, with increased colonization and infection with resistant pathogens in pts with prior abx therapy, increased antimicrobial resistance in community, unwanted allergic reactions and SE, cost of unnecessary treatment
Empathise with pts about effect of sx on ADLs + provide educational materials and provide therapy for these sx. Offer FU if sx not improving
how to approach abx allergy w/ pts
R/O intolerance to side effects, viral exanthum, drug-drug interaction
Allergy to penicillin can wane over time
No cross-reactivity between sulfa abx and other sulfa drugs
Consider referral to allergy testing if allergic reaction was a long time ago or if story not convincing
When to order cultures in:
systemic illness
UTI
cellulitis
abscess
pharyngitis
immunocompromised
Any systemic illness = culture
UTIs if patient pregnant or other complicating factors (pyelo, structural abnormalities, stones), or if multiple recent infections
Impetigo when dx is unclear
Cellulitis with systemic illness
Abscess if initial therapy failed
Pharyngitis - swab needed to r/o group A strep
Gonoccocal cultures for community resistance
Immunocompromised pts or pts who have had abx in last 3 months
rx for meningitis (<3mo, 3mo-50y/o, >50y/o)
Meningitis 3 months - 50 y/o = ceftriaxone + vancomycin
If >50 y/o or with comorbidities, add ampicillin
If <3 months, ampicillin, cefataxime + call peds
rx for febrile neutropenia
Stable - Pip-tazo
Unstable - pip-tazo, vancomycin + gentamicin then treat like sepsis
When to treat candida empirically (before results)?
Recent abx use
What ill-defined issues in pts could be caused by infection?
Elderly with confusion
FTT
Unexplained pain (necrotising fasciitis, abdo pain in kids w/ PNA)
Rx for shingles
72 Hour Window for Shingles Treatment
Oral Antivirals (rash)
Topical Steroids (keratitis/iritis)
Analgesics
Complication of shingles + physical sign name
Post Herpetic Neuralgia
Hutchinson’s Sign - nose
Sensitivity calculation
true positive / true positive + false neg
Specificity calculation
true neg/ false positive + true neg
TNFPTN
Positive predictive value calculation
true positive / true positive + false positive
Sensitivity calculation
Positive predictive value calculation
Specificity calculation
Negative predictive value calculation
true neg/ false neg + true neg
SENS - TPTPFN Positive predictive value - TPTPFP - switch N to P
SPEC - TNFPTN Negative predictive value - TNFNTN - switch P to N
Tinea pedis rx
azoles, allylamines, terbinafine cream, keep feet cool + dry, wear sandals, air out shoes
Soft tissue infections requiring surgery
nec fas, pyomyositis
Sx of soft tissue infections
edema beyond erythema, hemorrhagic bullae, pain out of proportion to exam, cutaneous anesthesia
Types of nec fas (in terms of what bugs cause them)
polymicrobial (typically in people w/ chronic dz)
monomicrobial (usually group A strep)
Rx for purulent cellulitis + what bug is most likely
clindamycin, usually staph, need to cover for MRSA
Rx for non-purulent cellulitis + what bug is most likely
keflex, septra, doxy, usually strep
Septra + ACEi + elderly = what?
AKI
Complications of cellulitis
recurrent cellulitis, nec fas
Complications of pyelo
renal abscess, obstructing stone, emphysematous pyelo
How to choose UTI abx
based on local guidelines, whichever abx does the local e coli have <10% resistance to
