25 Lower Respiratory Tract Infections Cupro Flashcards
What is the definition of Community-Acquired Pneumonia (CAP)?
An acute infection of the pulmonary parenchyma that is associated with at least some symptoms of an acute infection, accompanied by the presence of an acute infiltrate on a chest radiograph, or ausculatory findings consistent with pneumonia, in a patient not hospitalized
What is the epidemiology of CAP?
Incidence of the disease is increasing. Aging of the population. Age-adjusted mortality increasing (increased proportion of population w/ underlying disease)
How are the pathogens of pneumonia acquired?
Via inhalation of aerosolized particles. Via aspiration of oropharyngeal contents. Via seeding the bloodstream from extrapulmonary source
What are the normal host defenses against pneumonia?
Anatomical/mechanical (mucocilary clearance, coughing/gag reflex). Cellular immunity (pulmonary macrophages and lymphocytes). Humoral immunity
What are some alterations in host defenses that can increase the risk of pneumonia?
Altered level of consciousness (stroke, seizures, anesthesia, alcohol). Decreased mucociliary clearance (smoking, EtOH). Increasing age (Immune senescence). Immunocompromised (cancer, HIV, steroids)
What are the risk factors for CAP?
Age. Alcoholism. Smoking. Underlying lung disease (asthma, COPD). Immunosuppression. Other comorbidities (CKD, CHF, ESLD). Splenectomy
What is the difference between CAP and Bronchitis?
Bronchitis is an inflammation of bronchial tubes vs. pneumonia (inflammation of lungs)
What is seen on a physical exam for Bronchitis?
Purulent cough (can be productive), rhonchi, rales. CXR normal lungs
What is seen on a physical exam for Pneumonia?
Fever, Increased RR, decreased breath sounds, wheezes, rhonchi, rales, dullness to percussion. Can have productive cough. CXR with infiltrates
What is the Clinical Presentation (Symptoms) of Pneumonia?
Fever. Chest pain. Shortness of breath (dyspnea). Cough (productive). Malaise (very common in elderly)
What is the Clinical Presentation (Signs) of Pneumonia?
CXR with infiltrates. Sputum w/ WBCs. Sputum w/ bacteria. Increased temperature, Increased WBC. Chest ausculation w/ fluid sounds (rales/rhonchi)
What labs are done for a CAP evaluation?
CBC w/ differential. Basic metabolic panel. Oxygen saturation. Chest X-Ray. Blood and sputum cultures
What is looked at in a sputum analysis?
Squamous epithelial cells (reflect oropharngeal contamination, < 10/HPF). WBCs (reflect infection, > 25/HPF). Predominant organism
What are the different types of Pneumonia?
CAP. Atypical. Nosocomially-Acquired. Aspiration (community, nosocomial)
What organisms cause CAP?
S. pneumoniae most common, M. pneumoniae, H. influenzae, Viral, C. pneumoniae, Legionella pneumophilia. Note: S. aureus, K. pneumoniae, P. aeruginosa not seen in typical hosts (seen more in patients with underlying lung disease (i.e. CF)), K. pneumoniae often seen in aspiration pneumonia
What are the characteristics of Atypical Pneumonia caused by Mycoplasma?
Walking pneumonia. Usually effects young adults, and is treated as an outpatient. Chest X-Ray has diffuse infiltrates, cough is usually non-productive
What does therapy for Atypical Pneumonia caused by Mycoplasma consist of?
Macrolides (Azithromycin!, Clarithromycin). Doxycycline. Fluoroquinolone (reserved for pts. w/ hyper-sensitivity to the others)
What are the characteristics of Atypical Pneumonia caused by Chlamydia?
Estimated 5-15% of CAPs. Usually outpatient (unless underlying illness). Chest X-Ray with diffuse infiltrates, cough is usually non-productive
What does therapy for Atypical Pneumonia caused by Chlamydia consist of?
Macrolides (Clarithromycin, Azithromycin). Doxycycline. Fluoroquinolone
What are the characteristics of Atypical Pneumonia caused by Legionella?
Not very common, often mis-diagnosed. Can be treated outpatient if recognized early, but often end up in ICU. Chest X-Ray with diffuse infiltrates, cough is usually non-productive. Urine antigen test is most sensitive
What does therapy for Atypical Pneumonia caused by Legionella consist of (in ICU)?
IV Quinolone (Cipro) or Macrolide (Azithromycin) for ~3 weeks
What are the CAP treatment options?
B-Lactam (Amoxicillin, Cefotaxime). Macrolide (Azithro, Clarithro). Fluoroquinolone (Levo, Moxi). Ketolid (Telithromycin)
What are the factors influencing antimicrobial choice?
Susceptibility patterns. Severity of disease. Tolerability. Allergy history
What are the new categories for susceptibility for S. pneumoniae isolates to amoxicillin, cefotaxime, ceftriaxone, and cefepime?
MIC < 1 (S). MIC ~ 2 (I). MIC > 4 (R)
What is the new dosage formulation for Amoxicillin/Clavulanate for specific treatment of less susceptible strains of S. pneumoniae?
2g po Q12h
What are the organisms involved in CAP - Group I (low risk = outpatient Rx)?
S. pneumoniae, Mycoplasma pneumoniae, Chlamydia pneumoniae, Haemophilus influenzae. Viruses
What are the therapy options for CAP - Group I (low risk = outpatient Rx)?
Macrolides OR Doxycycline OR Telithromycin. Monotherapy is ok since most likely not resistant Strep
What are the organisms involved in CAP - Group II (Moderate risk = outpatient Rx)?
S. pneumoniae. Mycoplasma pneumoniae. Chlamydia pneumoniae. Mixed infection (bact and atypical or viral). H. influenzae. Enteric Gram (-). Viral
What are the therapy options for CAP - Group II (Moderate risk = outpatient Rx)?
B-Lactam (oral or one time IV/IM Ceftriaxone followed by oral) + Macrolide or Doxy
What items get points in the CURB-65 mortality risk assessment?
Assigned 1 point for each: Confusion, Urea level > 19. Respiratory rate > 30. SBP < 90 or DBP < 60. Age > 64
What do the points from CURB-65 mean?
Score 0-1: Outpatient. Score 2: Inpatient. Score 3+: ICU status
What are the organisms involved in CAP - Group IIIA (Mod/Inpatient, w/ Cardiopulmonary)?
S. pneumoniae, H. influenzae, Mycoplasma, Chlamydia, Mixed infection, Enteric Gram (-), Aspiration