Transcript Pneumonia
Pneumonia Disease Definition Pathological Clinical infiltrate(s) on CXR is need CAP HAP VAP HCAP Typical and Atypical Pathogenesis HOST DEFENSES Routes of Infection Gross aspiration Microaspiration Aerosolization Hematogenous spread from a distant infected site Direct spread from a contiguous infected site PATHOLOGY Lobar Pneumonia Bronchopneumonia Interstitial Pneumonia Miliary Pneumonia Risk Factors Impaired Host defense Anatomical defects such as obstructed bronchus, bronchiectasis, or sequestration Alcoholism , asthma , immunosuppression , age of >70 , dementia, seizures, CHF, CVD, alcoholism, COPD , chronic illness, smoking, and passive smoking Epidemiology Extremes of age During the winter months Rates of pneumonia are higher for men than for women and for black than for white persons ETIOLOGY Common respiratory pathogens S. pneumoniae, H. influenzae, S.aureus, Moraxella catarrhalis C. pneumoniae, M. pneumoniae Legionella spp. Influenza viruses, adenoviruses, and respiratory syncytial virus S. pneumoniae meta-analysis of CAP 1966 – 1995 S. pneumoniae 66% of 7000 cases 66% of fatalities Fine JAMA 1996:275;134 Atypical Pathogens M. pneumoniae, C. pneumoniae and Legionella sp. ranked 2nd 3rd and 4th of over 2700 hospitalized CAP patients with a definite etiologic diagnosis. Marston et al Arch Intern Med 157:1709,1997 CLINICAL MANIFESTATIONS Symptoms Signs Examination Auscultatory findings Severity CURB CURB 65 PORT Mortality P. aeruginosa >50% Klebsiella spp., E. coli, S. aureus, and Acinetobacter spp. 30 to 35% Serotype 3 pneumococcus is associated with a much higher mortality rate than serotype 1 M serotypes 1 and 3 of group A Streptococcus Mortality The in-hospital mortality rate from pneumonia is ~8%. The most common causes: respiratory failure heart disease Infections Half of deaths are related to pneumonia, and the other half are due to comorbid illnesses. DIAGNOSIS CXR CT scan Sputum smear Sputum culture Serology Ag study PCR Blood Culture Outpatient or Inpatient CURB-65 criteria:(confusion, uremia, respiratory rate, low blood pressure,age 65 years or greater) For patients with CURB-65 scores 2, hospitalization is usually warranted. ICU admission decision 2 major criteria (need for mechanical ventilation and septic shock), Minor criteria (respiratory rate, 130 breaths/min; arterial oxygen pressure/fraction of inspired oxygen (PaO2/FiO2) ratio <250; multilobar infiltrates; confusion; blood urea nitrogen Level>20 mg/dL; leukopenia resulting from infection; thrombocytopenia;hypothermia; or hypotension requiring aggressive fluid resuscitation. The presence of at least 3 of these criteria suggests the need for ICU care CXR resolve Age Co morbidity Lung disease Pathogen 4-8 weeks Resistant pneumococci To Penicillin To Macrolides To Tetracyclines To FQ MIC<0.06 0.12<MIC<1 MIC >2 mg/mL Duration Patients with CAP should be treated for a minimum of 5 days should be afebrile for 48–72 h should have no more than 1 CAP-associated sign of clinical instability before discontinuation of therapy A longer duration of therapy may be needed if initial therapy was not active against the identified pathogen or if it was complicated by extrapulmonary infection, such as meningitis or endocarditis. PO Therapy & Discharge Switched from intravenous to oral therapy when they are hemodynamically stable Improving clinically are able to ingest medications have a normally functioning gastrointestinal tract. Patients should be discharged as soon as they are clinically stable have no other active medical problems have a safe environment for continued care Inpatient observation while receiving oral therapy is not necessary. Complications Pleural effusion Empyema Lung abscess Recurrent pneumonia No response Aspiration Pneumonia The usual causes of aspiration pneumonia in the elderly are Enterobacteriaceae, S. aureus, S. pneumoniae, and H. influenzae. In the setting of aspiration of oropharyngeal contents and poor dental hygiene, anaerobic bacteria may be present, and lung abscess is not an uncommon complication. Particulate matter may be aspirated, with consequent mechanical obstruction of the airway. NOSOCOMIAL PNEUMONIA Acquired by a patient in the following settings: in a hospital or long-term-care facility after being admitted for >48 hours or <7 days after a patient is discharged from hospital ( patient’s initial hospitalization should be 3 days duration ) Risk Factors Host factors ( e.g. extremes of age, severe underlying disease ) Colonization by gram-negative microorganisms Aspiration or reflux Prolonged mechanical ventilation Factors that impede adequate pulmonary toilet Nosocomial Bacterial Pneumonia - Etiology Gram-negative enteric bacilli (predominant) Gram-positive cocci, including: Staphylococcus aureus ( e.g., MRSA ), Streptococcus pneumoniae Anaerobes Others Prevention Inactivated influenza vaccine Pneumococcal polysaccharide vaccine Respiratory hygiene measures, including the use of hand hygiene and masks or tissues for patients with cough, should be used in outpatient settings and EDs as a means to reduce the spread of respiratory infections.