9 - LRTI (Pneumonia) Flashcards
What are the clinical signs and symptoms of pneumonia?
- Acute respiratory and systemic signs and sx; infection and inflammation of pulmonary parenchyma
- Cough, sputum production, crackles, consolidation, tachypnea > 24, dyspnea, hypoxia, hemoptysis, pleural pain
- Fever, chills, tachycardia > 100, leukocytosis
How is community-acquired pneumonia diagnosed?
- Clinical signs and sx
- Lung infiltrate on x-ray
Why is the culture yield of sputum poor? What can be done to improve this?
- B/c of poor quality sampling and fastidious or slow-growing pathogens
- Improved yield in endothelial lining fluid (ELF) obtained by bronchoalveolar lavage (BAL)
What are the most common pathogens associated w/ CAP and pathogen-specific risk factors?
- Viral predisposes to secondary bacterial pneumonia
- Strep pneumonia - COPD, CV or renal disease, asplenic, diabetes, immunocompromised
- Mycoplasma pneumoniae - adolescents, young and elderly adults
What are some less common pathogens associated w/ CAP and pathogen-specific risk factors?
- Gram neg bacilli (H. influenzae, moraxella catarrhalis) – COPD, smoking; (klebisella pneumoniae, E. coli, enterobacter) – COPD, smoking, diabetes, alcoholism
- P. aeruginosa – cystic fibrosis, COPD, immunocompromised
- Staph aureus
- Anaerobes - aspiration, neurological disease
Do meropenem and amox-clav have coverage against mycoplasma?
No, b/c these drugs work against the cell wall, which mycoplasma don’t have; so drugs that work against ribosomes will have coverage over mycoplasma
What are some characteristics of pneumonia associated w/ mycoplasma pneumoniae?
- Peak incidence in older children, adolescents, young adults, and elderly
- Incubation 2-3 weeks, associated w/ pharyngitis, tracheobronchitis, pneumonia
- Serology using IgM enzyme immunoassay; respiratory sample PCR
- Gradual onset fever, headache, GI sx, malaise, arthralgia, myalgia, rash, cardiac syndromes for 1-2 weeks, followed by non-productive cough for 3-4 weeks
What are some characteristics of pneumonia associated w/ legionella pneumophila?
- Ubiquitous in water and soil, outbreaks and sporadic cases w/ peak from June to Octboer, associated w/ air ventilation systems
- Rapidly progressive pneumonia w/ multi-system involvement including fever, malaise, arthralgia, pleuritic pain, CNS & GI sx
What are the considerations for antimicrobial therapy in CAP?
- Suspected pathogens and risk for resistance
- Severity of illness; co-morbidities influencing likelihood of pathogen or clinical response
- Availability, formulary, cost
- Potential CI’s, drug interactions & adverse effects
- Appropriate dose (weight, renal and hepatic function)
Antimicrobial options for empirical tx of ambulatory, mild-moderate CAP? Is it given PO or IV?
- PO
- Amox (+/- macro or doxy) for moderate illness, or if not improving w/in 3 days of amox therapy
- Macrolide (concerns regarding resistance)
- Doxy (less clinical data than alternatives)
Antimicrobial options for empirical tx of ambulatory, mild-moderate CAP w/ risk factors for resistance or poor prognosis? Is it given PO or IV?
- PO
- Amox-clav (+/- macro or doxy) - add if not improving w/in 3 days or initial therapy
- Cefprozil/ cefuroxime (+/- macro or doxy)
- Levo/ moxi - restrict to more severe illness, tx failure, or serious beta-lactam allergy
Antimicrobial options for empirical tx of severe CAP? Is it given po or IV?
- IV
- Levo/ moxi
- Cefotaxime/ ceftriaxone + azithromycin
- Cefotaxime/ ceftriaxone + levo/ moxi – seriously ill, ICU admission
Adult dosing of amoxicillin for CAP
1 g q8h (high dose)
Adult dosing of amox-clav for CAP
500/125 mg q8h or 875/125 mg q12h
Adult dosing of macrolides for CAP
- Erythromycin 500 mg q6h
- Clarithromycin 500 mg q12h or 1 g ER q24h
- Azithromycin normal dosing
Adult dosing of doxycycline for CAP
100 mg PO q12h
Adult dosing of cefprozil or cefuroxime for CAP
500 mg q12h
Adult dosing of ceftriaxone or cefotaxime for CAP
- Ceftriaxone = 1 g q24h
- Cefotaxime = 1-2 g q8h
Adult dosing of fluoroquinolones for CAP
- Levo = 500-750 mg q24h
- Moxi = 400 mg q24h
What is the typical response for antimicrobial tx of CAP?
- Clinical improvement w/in 2-3 days
- Complete resolution in 10-14 days
What is the duration of tx for CAP?
5-7 days based on clinical response and resolution
What are some risk factors for LRTI?
- Elderly
- COPD, congestive heart failure, end-stage renal disease, diabetes
- Smoking, alcoholism
- Cerebrovascular or neurological disease, immunocompromised
What are the severity scores of LRTIs?
- PSI (pneumonia severity index)
- CURB-65 – new onset confusion, plasma urea > 7.1 mmol/L, RR > 30, BP < 90/60, or age > 65 years
- Score of 3 or higher = should be admitted to hospital and treated IV
What are the monitoring parameters for treating pneumonia?
- Cough = improved or absent w/in 2-7 days
- HR, RR, and temp = normal w/in 2-3 days
- WBC = normal w/in 5-7 days
- Chest x-ray = repeat if deterioration; normal in over 6 weeks
What should be considered for PO step-down antimicrobial therapy for pneumonia?
- Clinical improvement and hemodynamically stable
- Afebrile x 24-48 h
- Agent w/ appropriate spectrum, reliable bioavailability, adequate concentrations, and good tolerability
Antimicrobial options for pathogen-directed tx for S. pneumoniae CAP?
- PO = amox [levo/ moxi or linezolid]
- IV = Pen G [cefotax/ ceftriax or vanco]
- Combination IV therapy w/ beta-lactam plus macrolide or aminoglycoside suggested for moderate-severe pneumococcal pneumonia
Antimicrobial options for pathogen-directed tx for M. pneumoniae CAP?
PO/IV = macrolide, doxycycline, or levo/ moxi
Antimicrobial options for pathogen-directed tx for H. influenzae CAP?
- PO = amox or amox-clav [cefprozil/ cefuroxime or levo/ moxi/ cipro]
- IV = cefuroxime or cefotaxime/ ceftriaxone [levo/ moxi/ cipro]
What do macrolides inhibit?
CYP 3A4 and the enzyme P-gP
Interaction of macrolides w/ statins
Lovastatin and simvastatin are absolutely contraindicated w/ azithro and clarithro
Interaction of macrolides w/ cyclosporine
- Interaction is variable from pt to pt
- Tacrolimus more susceptible to interaction than cyclosporine
- CI
Interaction of macrolides w/ lorazepam
- Not affected by clarithro
- Medazolam or triazolam are affected by clarithro
- CI
Interaction of macrolides w/ diltiazem
- Applies to all calcium channel blockers
- Significant interaction w/ clarithro (increases levels of CCB => hypotension and bradycardia)
- CI
Interaction of macrolides w/ warfarin
- Broad spectrum antibiotics get rid of gut flora which produce vitamin K, so vitamin K is reduced
- Recommendation to monitor warfarin
Interaction of macrolides w/ digoxin
Absorption can be increased by antibiotic b/c antibiotics inhibit P-gP
Interaction of macrolides w/ colchicine
- Increases absorption b/c of inhibition of CYP 3A4 and P-gP
- Life-threatening b/c is an anti-mitotic drug, so toxicity will cause WBC to dramatically decrease
- Azithro has about 1/4 of the effect of clarithro
- CI
Interaction of quinolone w/ insulin
Quinolones have metabolic effect on glucose, so can cause hypo or hyperglycemia
Interaction of quinolone w/ Maalox (Al, Mg, Fe, sucralfate)?
- Affects absorption
- Most prevalent w/ cipro than levo/ moxi
- Calcium tends to be less affected
What effect does quinolones have on the heart?
- Variable QT prolongation (moxi > levo/ cipro) => can cause Torsade de Pointes, ventricular arrhythmias, or sudden death
- More often in px w/ pre-existing QT prolongation, underlying pro-arrhythmic conditions, class 3 anti-arrhythmics, tricyclic antidepressants, anti-psychotics, and other antibiotics
What are some risk factors for nosocomial pneumonia (hospital acquired)?
- Hospitalization > 3 days, surgery, ICU admission (mechanical ventilation)
- Risk factors for aspiration (immobility, supine positioning, NG tubes)
- Antacids or gastric acid suppression w/ H2 antagonists or PPIs
What are the most likely pathogens in NP?
- Strep pneumoniae (particularly w/in 3 days of admission)
- Staph aureus including MRSA
- K. pneumoniae, E. coli, enterobacter spp
- P. aeruginosa, acinetobacter, stenotrophomonas maltophila
What is the difference between nosocomial pathogens and pathogens that are community-acquired?
- Nosocomial pathogens associated w/ higher rates of resistance leading to delays in appropriate therapy and worse prognosis
- Nosocomial pathogens more common in px undergoing chronic dialysis, from long-term care facilities, or hospitalized w/in 3 months
What are the antimicrobial options for NP that has early onset w/in 3 days of admission? Is it PO or IV?
- IV
- Ceftriaxone/ cefotaxime
- [Levo/ moxi] – allergy
What are the antimicrobial options for NP that occurred w/in 3 days of admission or has risk factors for resistant pathogens? Is it PO or IV?
- IV
- Ceftazadime + vanco (preferred choice b/c least broad)
- Pip-tazo +/- vanco
- Meropenem +/- vanco
- [Cipro/ levo + vanco] - allergy
- [AG + vanco] - allergy and FQ resistance
What are the issues regarding antimicrobial activity in the lungs?
- Blood-bronchus barrier penetration
- Site of infection
- Optimal dosing based on PK-PD to optimize efficacy, minimize adverse effects, and limit resistance
What are the IV antimicrobial options for pathogen-directed MSSA NP?
- Clox or cefazolin
- [Vanco or linezolid]
- Not dapto!
What are the IV antimicrobial options for pathogen-directed MRSA NP?
- Vancomycin
- [Linezolid]
What are the IV antimicrobial options for pathogen-directed enterobacteria NP?
- Cefotaxime/ ceftriaxone
- Cipro/ levo/ moxi
- [Pip-tazo or meropenem/ ertapenem] - as per susceptibilities
What are the IV antimicrobial options for pathogen-directed P. aeruginosa NP?
- Ceftazadime
- Pip-tazo
- Meropenem
- +/- gent/ tobra or cipro/ levo
What is the typical duration of therapy for HAP?
7 days based on pt, clinical status, pathogen, and response to therapy
