23. Infectious Disease II Flashcards
Pre-operative abx administration timing
Infuse abx (e.g. cefazolin or cefuroxime) within 60 min before first incision
If quinolone or vancomycin, start infusion 120 min before first incision
In what situations would additional doses of abx be administered during a surgery (intra-operative)?
Longer surgeries (>4hr)
Major blood loss
T/F: Abx are often continued up to 48 hours after surgery
False - abx are usually not needed post-operatively; if used, discontinue after 24 hours
Perioperative abx selection: ____ is preferred for most surgeries to prevent MSSA and streptococcal infections. ___ is an alternative if the patient has a beta-lactam allergy
Cefazolin (or cefuroxime) is preferred
Clindamycin is an alternative
Perioperative abx selection: In GI surgeries, ppx abx regimen needs to cover skin flora plus ___ and ___
Broad GN and anaerobic
Perioperative abx selection: ____ should be included if MRSA colonization or risk is present. This is also an alternative (instead of clindamycin) if the patient has a beta-lactam allergy.
Vancomycin
Perioperative abx selection: Which abx would you recommend for cardiac or vascular procedures? What if they have beta-lactam allergy?
Cefazolin or cefuroxime
Beta-lactam allergy: clindamycin or vancomycin
Perioperative abx selection: Which abx would you recommend for orthopedic (e.g. joint replacement, hip fracture repair) surgery? What if they have beta-lactam allergy?
Cefazolin
Beta-lactam allergy: clindamycin or vancomycin
Perioperative abx selection: What abx would you recommend for GI (e.g. appendectomy, colorectal surgery) surgery? What if they have beta-lactam allergy?
Cefazolin + metronidazole, cefotetan, cefoxitin, or amp/sulb
Beta-lactam allergy: clindamycin or metronidazole + aminoglycoside or quinolone
S/sx of meningitis
Fever, HA, nuchal rigidity (stiff neck), altered mental status
Others:L chills, vomiting, seizures, rash, and photophobia
How is meningitis diagnosed?
Lumbar puncture (LP), sample of CSF is collected and analyzed
Higher CSF pressure during LP procedure is a sign of possible infection
T/F: Meningitis is mostly caused by bacterial infections but can be d/t viral or fungi
False - mostly caused by VIRAL but can be d/t bacterial or fungi
Which bacteria most commonly cause meningitis?
Neisseria meningitidis, Streptococcus pneumoniae, Haemophilus influenzae
The risk of meningitis d/t ___ is higher in which patient populations?
Listeria monocytogenes
Neonates
Pts age>50
Immunocompromised pts
____, administered 15-20 min prior to or with the first abx dose can prevent neurological complications (e.g. hearing loss) and death from pneumococcal meningitis.
Dexamethasone
Adult dosing: 0.15mg/kg (rounded to nearest 10 mg) IV q6hr for 4 days
If S. pneumoniae is not the cause of meningitis, dexamethasone can be d/c
Meningitis: Empiric Treatment: Coverage
Streptococcus pneumoniae and Neisseria meningitidis for most adults
Add Listeria monocytogenes coverage in neonates, age >50yo, and immunocompromised pts
Add vancomycin in pts ≥12 month old for double coverage of Streptococcus pneumoniae
Meningitis: Empiric Treatment: Age <1 month (neonate): Treatment Regimen
Ampicillin (Listeria coverage) + (Cefotaxime or Gentamicin)
Note: CANNOT use ceftriaxone - biliary sludging and kernicterus in neonates
Meningitis: Empiric Treatment: Treatment Regimen: 1 month to 50 yo
(Ceftriaxone or cefotaxime) + Vancomycin
Meningitis: Empiric Treatment: Treatment Regimen: Age >50 or immunocompromised
Ampicillin (for Listeria coverage) + (Ceftriaxone or cefotaxime) + Vancomycin
____ can cause biliary sludging and kernicterus in neonates. Do NOT use in neonates.
Ceftriaxone
Meningitis: Empiric Treatment: Treatment Regimen: Beta-lactam allergy
Quinolone (e.g. moxifloxacin) + vancomycin ± SMX/TMP (for Listeria coverage); obtain ID consult
S/sx of acute otitis media (AOM)
Bulging tympanic (eardrum) membranes, otorrhea (middle ear effusion/fluid), otalgia (ear pain), fever, crying and tugging/rubbing ears
T/F: Most AOM is viral and abx will be ineffective
True
AOM bacterial infection is typically caused by ____
S. pneumoniae, H. influenzae, Moraxella catarrhalis
When is observation for 2-3 days recommended for AOM?
If symptoms are non-severe: otalgia <48 hrs, no otorrhea, temp <102.2ºF (39ºC) and:
Age 6-23 months: only in 1 ear
Age ≥2 years: in one or both ears
If no improvement or worsens, use abx
Observation is not an option for children age ____ and abx should be prescribed
<6 months
AOM: First-line treatment
High-dose amoxicillin 90mg/kg/day, divided into 2 doses OR
Amox/clav 90mg/kg/day, divided into 2 doses (preferred if pts received amoxicillin in the past 30 days)
AOM: Non-severe penicillin allergy
2nd or 3rd gen cephalosporin
Cefidinr, cefuroxime, cefpodoxime, or ceftriaxone
AOM: If treatment fails (not improved after 2-3 days)
Amox/clav 90mg/kg/day, divided in 2 doses (if initial treatment was amoxicillin) OR
ceftriaxone 50 mg/kg IM daily for 3 days
Patient complains of sneezing, runny nose, mild sore throat, cough, and congestion. Should they get abx?
No. This patient most likely has common cold (caused by respiratory viruses like rhinovirus, seasonal coronavirus) and generally resolves in a few days.
Recommend symptomatic care
Patient complains of sudden onset of fever, chills, fatigue, myalgia, dry cough, sore throat, and HA. Should they get abx?
This patient most likely has influenza virus.
Anti-infective care is recommended if suspected or confirmed infection AND (symptoms <48 hrs, severe illness (e.g. hospitalized), OR symptoms plus risk factors for influenza complications)
Recommend symptomatic care with or without antiviral
Patient complains of sore throat, fever, swollen lymph nodes, white patches (exudates) on the tonsils but no cough, runny nose, or congestion. What is their diagnosis?
Pharyngitis (“strep throat”) typically caused by respiratory viruses, Group A Streptococcus (S. pyogenes)
Take rapid antigen test before giving abx
Patient has a positive rapid antigen test for strep throat. What abx do you recommend?
Penicillin or amoxicillin
Mild PCN allergy: 1st or 2nd gen cephalosporin
Severe reaction to PCN: macrolide (clarithromycin, azithromycin) or clindamycin
Patient complains of nasal congestion, purulent nasal discharge, facial/ear/dental pain, HA, and fever. What is their diagnosis?
Acute sinusitis typically caused by respiratory viruses, S. pneumoniae, H. influenzae, M. catarrhalis
Patient is diagnosed with acute sinusitis. When should abx be considered?
≥10 days of persistent symptoms OR
≥ 3 days of severe symptoms (face pain, purulent nasal discharge, temp > 102ºF) OR
Worsening symptoms after initial improvement
Patient is diagnosed with acute sinusitis and symptoms have not improved for 11 days. When abx do you recommend?
Amox/clav OR
symptomatic care for up to 7 days, abx can be used when symptoms worsen or do not improve
What are some key defining features of acute bronchitis?
Cough lasting 1-3 weeks, chest wall tenderness, wheezing and/or rhonchi
Usually preceded by an upper respiratory tract virus, such as rhinovirus, coronavirus, or influenza virus
Chest X-ray findings are typically normal (rules out other causes of acute cough like pneumonia, COPD exacerbation) and cultures are not routinely performed
Acute bronchitis is typically caused by viral infections. While rare, what are some bacterial causes?
S. pneumoniae, H. influenzae, or atypical pathogens (e.g. Mycoplasma pneumoniae)
Patient is diagnosed with acute bronchitis. What is your abx recommendation?
Abx not recommended. Symptoms are generally self-limiting and can be managed with supportive care
Pertussis or “whooping cough” acute bronchitis caused by _____, characterized by forceful coughs followed by an inspiratory “whoop” sound
Bordatella pertussis
How do you confirm dx of pertussis?
Nasopharyngeal swab culture or PCR test for B. pertussis
Pertussis is highly contagious and should be treated with ___
macrolides (azithromycin, clarithromycin)
What are the 3 cardinal symptoms of COPD exacerbation?
Increaed dyspnea
Increased sputum volume
Increased sputum purulence
What causes COPD exacerbations?
Viral infections
Bacterial infections (e.g. H. influenzae, M. catarrhalis, S. pneumoniae)
Environmental pollution or an unknown cause
Supportive treatment (e.g. oxygen, systemic steroids, inhaled bronchodilators) are often adequate but abx is recommended if which criteria are met?
All 3 cardinal symptoms (increased dyspnea, sputum volume, sputum purulence) OR
Increased sputum purulence + 1 additional symptom OR
Mechanically ventilated
If abx is used for COPD exacerbation, what are the preferred abx?
Amox/clav
Others: azithromycin, doxycycline, respiratory FQ
S/sx of community-acquired pneumonia (CAP)
SOB, fever, cough with purulent sputum, pleuritic chest pain, rales (crackling lung sounds), tachypnea (increased respiratory rate), and decreased breath sounds
Gold standard dx test chest x-ray with “infiltrates”, “opacities” or “consolidations”
Which bacteria can cause CAP?
S. pneumoniae, H. influenzae, M. pnuemoniae, and possibly C. pneumoniae
____ is not used for CAP because it is not a respiratory FQ since it does not reliably cover S. pneumoniae
Ciprofloxacin
Typical duration of treatment for CAP is ___
5-7 days
Recommended outpatient empiric regimen for CAP patients who are healthy (no comorbidities)
Amox high dose (1g TID) OR
doxycycline OR
macrolide (azithromycin or clarithromycin) if local pneumococcal resistance is <25%
Recommended outpatient empiric regimen for CAP patients who are high risk with comorbidities
Beta-lactam + macrolide or doxycline:
- amox/clav or cephalosporin (e.g. cefpodoxime, cefuroxime)
OR
Respiratory FQ monotherapy: Moxifloxacin or levofloxacin
Recommended inpatient empiric regimen for nonsevere CAP
Beta-lactam + macrolide or doxycycline
- Preferred beta-lactam: ceftriaxone, cefotaxime, ceftaroline, or amp/sulb
OR
Respiratory FQ monotherapy: moxifloxacin or levofloxacin
Recommended inpatient empiric regimen for severe CAP (in ICU)
Beta-lactam + macrolide
OR
Beta-lactam + respiratory FQ (do NOT use quinolone monotherapy)
Recommended inpatient abx for MRSA coverage (prior respiratory isolation or positive nasal swab)
Vancomycin or linezolid
Recommended inpatient abx for Pseudomonas coverage (prior respiratory isolation)
Pip/tazo, cefepime, fetazidime, imipenem/cilastin, or meropenem
Recommended inpatient abx for previous hospitalization and use of parenteral abx in the past 90 days
Use regimen that covers both MRSA and Pseudomonas
What is the difference between hospital-acquired pneumonia (HAP) vs ventilator-associated pneumonia (VAP)?
HAP = onset > 48 hours after hospital admission
VAP = onset > 48 hours after start of mechanical ventilation - can be reduced by proper hand-washing, elevating head of the bed ≥30 degrees, weaning off ventilator asap, removing NG tubes when possible, and d/c unnecessary stress ulcer ppx (e.g. PPI)
What are common pathogens in HAP and VAP?
Nosocomial pathogens
Increased risk for MRSA, MDR GN rods including P. aeruginosa, Acinetobacter spp. Enterobater spp., E. coli, and Klebsiella spp.
HAP and VAP empiric regimen base
Pseudomonas and MSSA coverage - examples: cefepime, pip/tazo, levofloxacin
HAP and VAP add on regimen if risk for MRSA (IV abx use in past 90 days, MRSA prevalence in hospital unit is >20% or unknown, prior MRSA infection or positive MRSA nasal swab)
Vancomycin or linezolid
Example regimens:
cefepime + vancomycin
Meropenem + linezolid
Aztreonam + vancomycin
HAP and VAP regimen if risk for MDR GN pathogens (IV abx use in past 90 days, prevalence of GN resistance in hospital unit is >10% or unknown, ≥ 5 days prior to the onset of VAP)
Use 2 abx for Pseudomonas
Examples:
Pip/tazo + ciprofloxacin + vancomycin
Cefepime + gentamicin + linezolid
Abx for pseudomonas list used in HAP or VAP
Do NOT use 2 beta-lactams together
Beta-lactams: pip/tazo, cefepime, ceftazidime, imipenem/cilastatin, meropenem
Levofloxacin or ciprofloxacin
Aztreonam
Aminoglycosides (typically tobramycin) - always used in combo with other antipseudomonal drug
Tuberculosis (TB) is caused by _____ (an aerobic, non-spore forming bacillus)
Mycobacterium tuberculosis
With latent disease, the immune system is able to contain the infection and the patient lacks symptoms. Active pulmonary TB is transmitted by _____ and is highly contagious.
aerosolized droplets (e.g. sneezing, coughing, talking)
S/sx of TB
cough/hemoptysis (coughing up blood), purulent sputum, fever, night sweats, and unintentional weight loss
Your patient has active pulmonary TB. What is required of the patient and the healthcare workers?
Patient needs to be in isolation in a single negative-pressure room
Healthcare workers need to wear respiratory mask (N95)
How is latent TB diagnosed?
Tuberculin skin test (TST), also called purified protein derivative (PPD) test, or an interferon-gamma release assay (IGRA) blood test
In which patients can a false-positive TB test occur?
Those who received BCG vaccine
Dx of latent TB: Criteria for positive TST results: ≥5 mm induration
Close contacts of recent active TB cases
HIV infection
Immunosuppression (e.g. transplant, chemotherapy)
Dx of latent TB: Criteria for positive TST results: ≥10 mm induration
Immigrants from high burden countries
clinical risk (e.g. IV drug uses, DM)
Residents/employees of “high-risk” congregate settings (e.g. prisons, healthcare facilities, homeless shelters)
Dx of latent TB: Criteria for positive TST result1s: ≥5 mm induration
Patients with no risk factors
Latent TB treatment options
Isoniazid and rifapentine once weekly x 12 weeks via directly observed therapy (DOT) or self-administered. do NOT use this regimen for pregnant patients
Isoniazid with rifampin daily for 3 months
Rifampin 600mg daily for 4 months
Isoniazid 300mg daily for 6 or 9 months - may be preferred in HIV positive patients taking antiretroviral therapy (lower risk of DDIs); if used, take for 9 months
M. tuberculosis (MTB) is an ___ (AFB). AFB smear can detect but it is not specific to MTB. Definitive dx must be made with PCR or sputum culture results. Final culture and susceptibility results can take up to ___
Acid-fast bacilli
6 weeks (slow-growing organism)
Active TB treatment is divided into 2 phases: ___ and ____
intensive and continuation
TB intensive phase regimen consists of 4 drugs for 2 months. What are they?
Rifampin, isoniazid, pyrazinamide, and ethambutol daily or x5/week
(RIPE therapy)
Note: 4 drugs for 2 months
TB continuation phase (typically ____ months) treatment can be scaled back to 2 drugs (commonly ___ and ___) based on drug susceptibility of the isolate
4 months (may be extended to 7 months in select cases (e.g. sputum culture remains positive after 2 months of treatment, or if intensive phase treatment did not include pyrazinamide)
rifampin and isoniazid daily, 5x/week or 3x/week
Note: 2 drugs for 4 months
T/F: Latent TB is when a patient shows no symptoms but is still contagious
False - patient shows no symptoms and is not contagious, treated with 1 or 2 drugs for 3-4 months (preferably)
Contraindications for rifampin (Rifadin)
Do not use with protease inhibitors
Side effects for rifampin (Rifadin)
Increased LFTs, hemolytic anemia (detected with positive Coombs test), flu-like syndrome, GI upset, rash/pruritus
Orange-red discoloration of body secretions (saliva, urine, sweat, tears); can stain contact lenses, clothing, and bedsheets
Rifampin has many DDIs; ___ has fewer DDIs and can replace rifampin in some cases (e.g. HIV patients taking protease inhibitors), thought a DDI screen is still needed
Rifabutin
You should also take ____ when taking isoniazid to decrease risk of ____
pyridoxine (vit B6) 25-50mg PO daily
decrease risk of isoniazid associated peripheral neuropathy
Boxed warning for isoniazid
severe and fatal hepatitis
Contraindications for isoniazid
Active liver disease, previous serious adverse reaction to isoniazid