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46 Cards in this Set
- Front
- Back
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Upper respiratory tract defense mechanisms
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-mechanical - air filtration, epiglottic and cough reflexes, tracheobronchial secretions, patency of conducting airways, upper airway turbulence, cough and mucociliary clearance
-secretory IgA - may impair microbial adherence to mucosal surfaces, or neutralize viral activity |
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Lower respiratory tract defense mechanisms
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-Humoral immunity - (B lymphocytes, IgG antibodies, Complement) IgG antibodies diffuse freely into mucosal secretions and the alveoli; complement activation generates opsonins, chemotactic factors, etc.
-Cell-mediated immunity - alveolar macrophages (and PMNs) inactivate bacteria (i.e. Staph) deposited in the terminal bronchioles; antigenic stimulation of T-lymphocytes leads to the production of lymphokines, which activate the macrophages, and enhance their bactericidal activity -Polymorphonuclear neutrophils |
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Methods by which airways become infected
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-Aspiration of upper airway resident flora (how most bacterial pneumonias develop)
-Inhalation of aerosolized material (second most common pathogenic pathway) -Hematogenous seeding (embolic staph pneumonia in IVDA with tricuspid endocarditis) -Contiguous spread (spread of infection across diaphragm into pleural space and lung from a subdiaphragmatic or hepatic abscess) -Reactivation - predominantly associated with TB and fungal pneumonias |
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Acute bronchitis - General
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Acute bronchitis is characterized by inflammation of the bronchi and evidence of concurrent upper airway infection. It is one of the most common conditions seen in clinical practice.
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Microbiology of Acute Bronchitis
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-Viral - 50% (influenza A and B, parainfluenza, coronavirus, rhinovirus, respiratory syncytial virus, human metapneumoniae)
-Mycoplasma pneumoniae - 10-20% -Chlamydia pneumoniae - 10-20% -Bordetella pertussis (whooping cough) - Rare |
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Clinical Features of Acute Bronchitis
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The most common symptom is cough, usually with sputum production. Fever is relatively uncommon, but may occur. Cough plus fever may suggest influenza or pneumonia.
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Supportive treatment of Acute Bronchitis
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-NSAIDs, aspirin, acetaminophen
-Iprotropium (beta-2 agonists not effective for the treatment of acute bronchitis) -Nasal decongestants |
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Antibiotic treatment of Acute Bronchitis
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Acute bronchitis is the most common cause of antibiotic abuse. Although acute bronchitis is generally caused by a virus, antibiotics are commonly prescribed (>70% who seek medical care). There is no proven benefit of antibiotics in the treatment of acute bronchitis.
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Epidemiology of Community-Acquired Pneumonia
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Each year, 2-3 million cases of CAP result in ~10 million physician visits, 500,000 hospital admissions, and 45,000 deaths in the US. The mortality rate for hospitalized patients is ~14%, and <1% for non-hospitalized patients. CAP occurs more frequently during the winter months.
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Most common etiologies of CAP patients who can be treated outpatient
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-Stretptococcus pneumoniae
-Mycoplasma pneumoniae -Haemophilus influenzae -Chlamydophila pneumoniae -Respiratory viruses |
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Most common etiologies of CAP in patients who must be treated inpatient (non-ICU)
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-S. pneumoniae
-M. pneumoniae -C. pneumoniae -H. influenzae -Legionella species -Aspiration (Gram-negative bacilli) -Respiratory viruses |
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Most common etiologies of CAP in patients who must be treated inpatient (ICU)
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-S. pneumoniae
-Staphylococci aureus -Legionella species -Gram-negative bacilli -H. influenzae |
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Risk factors for developing CAP
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-Alcoholics (S. pneumoniae, oral anaerobes, gram-negative bacilli like Klebsiella)
-Nursing home (S. pneumoniae, H. influenzae, gram-negative bacilli, S. aureus) -COPD (S. pneumoniae, H. influenzae, M. catarrhalis) -Postinfluenza (H. influenzae, S. aureus, S. pneumoniae) -Exposure to water (Legionella) -Poor oral hygiene (oral anaerobes) -HIV infections (PCP, S. pneumoniae, M. pneumoniae, Mycobacterium) |
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Clinical features of CAP
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Common clinical features of CAP include new cough (90%), sputum, pleurisy, and dyspnea. Chest discomfort occurs in 50% of cases, chills in 40-50%, and rigors in 15%. Eighty percent of patients are febrile (although frequently absent in older patients). A respiratory rate >24 breaths/minute is noted in 45-70% of patients.
The most frequent lab abnormality is leukocytosis (typically 15-30K) |
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Diagnosis of CAP
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The presence of an infiltrate on plain chest radiograph is considered the "gold standard" for diagnosing pneumonia (when clinical and microbiologic features are supportive). Patients with suspected CAP should have blood cultures and sputum Gram stain and culture. However, the benefit of these tests is controversial.
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CURB-65 Score when trying to determine treatment of CAP
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One point for each
-confusion -BUN > 20 mg/dL -respiratory rate > 30 breaths/minute -blood pressure (SBP < 90 or DBP < 60) -Age > 65 years Number of risk factors determines treatment -manage outpatient if 0-1 points -admitted to medicine ward 2 points -admit to ICU if 3 or more |
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Empiric Treatment of CAP in Outpatients with no other risk factors
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Macrlide (azithromycin, clarithromycin/erythromycin)
Doxycycline |
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Empiric Treatment of CAP in Outpatients with comorbidities (antibiotic treatment in last 3 months or other risk factors for DRSP)
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Respiratory fluoroquinolones (moxifloxacin, levofloxacin 750 mg)
Beta-lactam plus a macrolide |
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Empiric Treatment of CAP in Outpatients who have a penicillin allergy
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Respiratory fluoroquinolone (moxifloxacin, levofloxacin 750 mg)
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Empiric Treatment of CAP for Inpatients (Non-ICU admission)
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-Respiratory fluoroquinolone (moxifloxacin, levofloxacin)
-Beta-lactam plus macrolide |
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Empiric Treatment of CAP for Inpatients (ICU admission)
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-Beta-lactam plus fluoroquinolone
-Beta-lactam plus azithromycin |
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Empiric Treatment of CAP for Inpatients (ICU admission and P. aeruginosa an issue)
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-Antipneumococcal, antipseudomonas beta-lactam with [ciprofloxacin or levofloxacin] or [an aminoglycoside and azithromycin] or [an aminoglycoside and antipneumococcal, antipseduomonas fluoroquinolone]
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Recommended Antibiotics for Outpatients with CAP
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-Macrolide (azithromycin, clarithromycin, or erythromycin)
-Doxycycline -Respiratory fluoroquinolone (moxifloxacin, gemifloxacin, or levofloxacin) -Beta-lactam (high-dose amoxicillin or amoxicillin-clavulanate; alternatives include ceftriaxone, cefpodoxime, and cefuroxime) |
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Recommended Antibiotics for Inpatients with CAP
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-Respiratory fluoroquinolone (moxifloxacin, gemifloxacin, or levofloxacin)
-Macrolide (azithromyin 500 mg, clarithromycin, or erythromycin) -Doxycycline (alternative to Macrolide) -Beta-lactam (cefotaxime, ceftriaxone, and ampicillin-sulbactam; ertapenem for selected patients) |
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Recommended Antibiotics for ICU patients with CAP
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-Beta-lactams (cefotaxime, ceftriaxone, and ampicillin-sulbactam)
-Macrolide (azithromycin) -Respiratory fluoroquinolone (moxifloxacin, gemifloxacin, or levofloxacin) -Antipseudomonal fluoroquinolone (ciprofloxacin or levofloxacin) -Antipseudomonal beta-lactams (aztreonam, piperacillin-tazobactam, cefepime, imipenem, or meropenem) |
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When can you switch from IV to PO in a patient with CAP?
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Patients should be switched from IV to oral therapy when they are hemodynamically stable and improving clinically, are able to ingest medications, and have a normally functioning GI tract.
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What is the duration of therapy when treating CAP? What are the criteria for clinical stability?
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Patients should be treated for a minimum of 5 days (level I evidence), should be afebrile for 48-72 hours, and should have no more than 1 CAP-associated sign of clinical instability before d/c'ing therapy.
-Criteria for clinical stability Temp < 100 F (37.8 C) Heart rate < 100 beats/min Respiratory rate < 24 breaths/min Systolic BP > 90 mm Hg Arterial oxygen saturation > 90% or pO2 > 60 mm Hg on room air Ability to maintain oral intake Normal mental status |
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In which groups is it recommended to get pneumococcal vaccine?
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-all persons >65 years of age
-current smokers -high risk patients including: chronic CV, pulmonary, renal or liver disease diabetes mellitus cerebrospinal fluid leaks alcoholism asplenia immunocompromised Native Americans and Alaskans Long-term care residents |
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In which groups is it recommended to get inactivated influenza vaccine?
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influenza vaccination has been shown to reduce pneumonia, hospitalization and death rate
-all persons >50 years old -health care providers -children 6-23 months -high risk patients including: asthma or other pulmonary chronic metabolic disease (DM) renal dysfunction hemoglobinopathies immunocompromised compromised respiratory function pregnancy long-term care residents aspirin therapy in persons <18 years old |
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Hospital-acquired pneumonia - Definition
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HAP is defined as penumonia that occurs 48 hours or more after admission, which was not incubating at the time of admission
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Ventilator-associated pneumonia - Definition
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VAP refers to pneumonia that arises more than 48 to 72 hours after endotracheal intubation
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Healthcare-associated pneumonia - Definition
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HCAP includes any patient who was hospitalized in an acute care hospital for two or more days within 90 days of the infection; resided in a nursing home or long-term care facility; received recent intravenous antibiotic therapy, chemotherapy, or wound care within the past 30 days of the current infection; or attended a hospital or hemodialysis clinic
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Sources of pathogens for HAP
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-healthcare devices
-the environment (air, water, equipment, and fomites) -transfer of microorganisms between patient and staff (or other patients) -stomach and sinuses are potential reservoirs (controversial) |
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Important colonization factors in the pathogenesis of HAP and VAP
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-severity of the patient's underlying disease
-prior surgery -exposure to antibiotics, other medications -exposure to invasive respiratory devices and equipment |
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Primary routes of bacterial entry into lower respiratory tract
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-aspiration of oropharyngeal pathogens
-leakage of secretions containing bacteria around the endotracheal tube cuff -infected biofilm in the endotracheal tube, with subsequent embolization to distal airways, may be important in the pathogenesis of VAP |
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What are the most common organisms in nosocomial infections
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Pseudomonas aeruginosa (17%)
Staphylococcus aureus (16%) Enterobacter sp (11%) |
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Common MDR pathogens in HAP
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-Pseudomonas aeruginosa (most common)
-Klebsiella -Enterobacter -Citrobacter -MRSA |
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Risk factors for MDR pathogens causing HAP, CAP, and HCAP
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Antimicrobial therapy in preceding 90 days
Current hospitalization of 5 days or more High frequency of antibiotic resistance in the community Presence of risk factors for HCAP: -Hospitalization for 2 days in more in the preceding 90 days -Residence in nursing home or extended care facility -Home infusion therapy (including antibiotics) -Chronic dialysis within 30 days -Home wound care -Family member with MDR pathogen Immunosuppressive disease and/or therapy |
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Clinical Features of HAP
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Common clinical features of nosocomial pneumonia include a new or progressive radiographic infiltrate, along with:
-new onset fever -purulent sputum -leukocytosis -decline in oxygenation |
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Treatment of HAP - General
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The key decision in initial empiric therapy is whether the patient has risk factors for MDR organisms. Empiric therapy of patients with severe HAP or VAP requires antibiotics at optimal doses, to ensure maximum efficacy. Combination therapy should be used if patients are likely to be infected with MDR pathogens.
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Initial empiric antibiotic therapy for HAP/VAP in patients with no known risk factors for MDR pathogens and early onset
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ceftriaxone OR
levofloxacin, moxifloxacin, or ciprofloxacin OR ampicillin/sulbactam OR ertapenem |
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Initial empiric therapy for HAP/VAP in patients with known risk factors for MDR pathogens or late onset
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antipseudomonal cephalosporin (cefepime, ceftazidime) OR
antipseudomonal carbapenem (imipenem or meropenem) OR beta-lactam/beta-lactamase inhibitor (piperacillin-tazobactam) PLUS antipseudomonal fluoroquinolone (ciprofloxacin or levofloxacin) OR aminoglycoside (amikacin, gentamicin, or tobramycin) PLUS linezolid OR vancomyxin |
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Dosing of piperacillin-tazobactam for HAP
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4.5 g every 6 hours
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Dosing of levofloxacin for HAP
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750 mg daily
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Trough levels for vancomycin for HAP
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trough levels should be 15-20 mcg/mL
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Duration of therapy when treating HAP
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The duration of therapy is based upon the clinical response. Antibiotic course should be kept short to avoid colonization with resistant organisms.
-If patients receive an initially appropriate antibiotic regimen, efforts should be made to shorten the duration of therapy to periods as short as 7 days. -If the pathogen is S. aureus, P. aeruginosa, or Acinetobacter spp. or there is multilobar involvement, a longer course of treatment (14 to 21 days) probably is needed |
