Community Acquired Pneumonia Supplemental Notes PDF

# How to Risk Stratify Community Acquired Pneumonia? ## CAP ### Risk Stratification - **Any of the following:** - RR ≥30/min - PR ≥125/min - T ≥40°C or ≤36°C - SBP <90mmHg or DBP ≤60mmHg - Altered mental status of acute onset - Suspected aspiration - Unstable co-morbid...

# How to Risk Stratify Community Acquired Pneumonia? ## CAP ### Risk Stratification - **Any of the following:** - RR ≥30/min - PR ≥125/min - T ≥40°C or ≤36°C - SBP <90mmHg or DBP ≤60mmHg - Altered mental status of acute onset - Suspected aspiration - Unstable co-morbid conditions - Chest x-ray: multilobar pleural effusion, abscess - **If YES:** High-Risk CAP, ICU admission. - **If NO:** Severe sepsis and septic shock? - **If YES:** High-Risk CAP, ICU admission. - **If NO:** Need for mechanical ventilation? - **If YES:** High-Risk CAP, ICU admission - **If NO:** Moderate-Risk CAP, Ward admission ## Etiology/Pathogens ### Risk Based on Etiology - **Low Risk:** - *Streptococcus pneumoniae* - *Haemophilus influenzae* - *Chlamydophila pneumoniae* - *Mycoplasma pneumoniae* - *Moraxella catarrhalis* - Enteric Gram-negative bacilli (among those with co-morbid illness) - **Moderate Risk:** - Same as low-risk PLUS - *Legionella pneumophila* - Anaerobes (among those with aspiration risk) - **High Risk:** - Same as moderate risk PLUS - *Staphylococcus aureus* - *Pseudomonas aeruginosa* ### Details - *Streptococcus pneumoniae* is the most common cause of CAP. - **Atypical pathogens:** *Mycoplasma, Chlamydia and Legionella* - Stay in hotel or on cruise ship in previous 2 weeks = think of *Legionella*! - Stroke, Dementia, decreased consciousness = think of anaerobes, gram (-) enteric bacteria! - Recent antibiotic use, malnutrition, steroid use, bronchiectasis = think of *Pseudomonas* ## Clinical Manifestation ### Symptoms - Fever, tachycardia, chills and sweat - Non-productive to productive cough (mucoid, purulent, or blood-tinged) - Pleuritic chest pain if the pleura is involved - 20% may have nausea, vomiting or diarrhea - Fatigue, headache, myalgia, arthralgia ### Physical Examination - Unable to speak in full sentences - Increased respiratory rate - Use of accessory muscles of respiration - Increased or decreased tactile fremitus - Dull to flat percussion note - Crackles ### Details - The clinical findings that best differentiate CAP from other acute respiratory tract infections are cough, fever, tachypnea, tachycardia, and pulmonary crackles. CAP is present in 20% to 50% of persons who have all five factors. - In older patients, especially those with multiple comorbidities, pneumonia may present with general weakness, decreased appetite, altered mental status, incontinence, or decompensation due to underlying disease. - The "atypical" pneumonia is characterized as having a more insidious onset, with a dry cough, prominent extrapulmonary symptoms such as headache, myalgias, sore throat, and a chest radiograph that appears much worse than the clinical or auscultatory findings. ## Etiology ### Most Common Cause of CAP - *Streptococcus pneumoniae* ### Typical Agents Causing CAP - *S pneumoniae, H influenzae, S aureus, K pneumoniae, P aeruginosa* ### Atypical Agents Causing CAP - *M pneumoniae, C pneumoniae, Legionella, Respiratory viruses* ### Complicates Previous Influenza Infection Associated with Pneumatocoles - *S aureus (may cause necrotizing pneumonia)* ### COPD, Bronchiectasis, Cystic Fibrosis - *P aeruginosa* ### Stay in Hotel, Cruise Ship - *Legionella* ### Exposure to Birds - *Chlamydia psittaci* ### Exposure to Rabbits - *Francisella tularensis* ### Exposure to Sheep, Goats - *Coxiella burnetti* ### Associated with Aspiration - Oral anaerobes ### Details - Atypical organisms of CAP has the following features: 1) cannot be cultured on standard media/Gram stain; 2) intrinsically resistant to B-lactam agents ## Diagnostics - Chest x-ray is the best initial test - Sputum gram stain and culture - Urinary antigen tests: to detect pneumococcal and *Legionella* antigen - Polymerase chain reaction tests - Serology - Biomarkers: - CRP - Procalcitonin ### Details - Radiographic evaluation is necessary to establish the presence of pneumonia, because there is no combination of historical data, physical findings, or laboratory results that reliably confirms the diagnosis. - Sensitivity and specificity of sputum GSCS is around 50%. Only 5-14% of cultures of blood from patients hospitalized with CAP are positive, and the most frequently isolated pathogen is *S. pneumoniae*. - CRP may be of use in the identification of worsening disease or treatment failure, and PCT may play a role in distinguishing bacterial from viral infection, determining the need for antibacterial therapy, or deciding when to discontinue treatment. - The main purpose of getting a sputum GS is to ensure the adequacy for culture. An adequate sputum sample is seen when neutrophils >25 per low-power field: <10 squamous cells per low-power fluid. This yield is indicative of a sample coming from the lower respiratory tract. - Neutrophils represent the alveolar infiltrates, while squamous cells represent oral epithelium. Recall that the epithelium of the lower respiratory tract is composed of ciliated pseudostratified columnar epithelium. ## Pathology ### Series of Pathologic Changes Seen in Classic Lobar Pneumonia - Edema → Red hepatization → Gray hepatization → Resolution ### Phase Rarely Evident in Pathology Slides - Edema ### Phase Corresponding to Successful Containment Of Infection, Gas Exchange Improvement - Gray hepatization ### Phase Corresponding to Clearance Of Inflammation - Resolution ### Dominant Cell in Edema Phase - Bacteria ### Dominant Cell in Red Hepatization - RBCs ### Dominant Cell in Gray Hepatization - Neutrophils ### Dominant Cell in Resolution Phase - Macrophage ### Radiograph Pattern in Bacterial CAP - Lobar pneumonia ### Radiograph Pattern in Nosocomial Pneumonia - Bronchopneumonia ### Radiograph Pattern in Vital, *Pneumocystis pneumonia* - Interstitial pneumonia ### Details - Recall your Pathology! Neutrophils are your first responders. After 6-24 hours, Macrophage will dominate and will largely focus on clearing inflammation (hence, predominant in the resolution phase). ## Treatment Based on CAP Guidelines 2016 ### Risk Based Treatment - **Low Risk:** - No co-morbid illness: - Amoxicillin (drug of choice) - Extended Macrolides (Azithromycin, Clarithromycin) - Stable co-morbid: - B-lactam/BLIC combination (Co-amoxiclav, Sultamicillin), or - 2nd gen Cephalosporins (Cefuroxime) - + Extended macrolides - **Moderate Risk:** - IV non-antipseudomonal B-lactam (Ampicillin-sulbactam, Ceftriaxone, Ertapenem) PLUS either extended macrolide or fluoroquinolone (Levofloxacin, Moxifloxacin) - w/o risk for *Pseudomonas*: - IV non-antipseudomonal B-lactam (BLIC, Cephalosporins, Carbapenem) PLUS IV Extended macrolide or Fluoroquinolone - w/ risk for *Pseudomonas*: - IV antipneumococcal/antipseudomonal B-lactam (Pip-Tazo, Cefepime, Meropenem, Imipenem-Cilastatin) PLUS extended macrolide and aminoglycoside (gentamicin, amikacin) or - IV antipneumococcal + antipseudomonal B-lactam (BLIC, Cephalosporins or Carbapenem) PLUS IV ciprofloxacin or IV levofloxacin - **High Risk:** - MRSA suspected, add any of the following - Vancomycin, Linezolid or Clindamycin ### Response to Treatment - 1 week = fever should have resolved - 4 weeks = chest pain and sputum production should have substantially reduced - 6 weeks = cough and breathlessness should have substantially reduced - 3 months = most symptoms should have resolved; fatigue may still be present - 6 months = most people will feel back to normal ### Lack Of Response to Treatment - Resistant pathogen - Sequestered focus (Lung abscess or empyema) - Wrong treatment - Correct drug but wrong dose or frequency ### Details - The first evidence of response to treatment are resolution of fever within a week and decreasing WBC count within 2-4 days. The chest x-ray infiltrates clears in 4-12 weeks hence it is not reliable marker of response to treatment. You may expect cough and breathlessness to substantially reduce in 6 weeks. ## Duration of Antibiotic Use Based on Etiology | Etiologic Agent | Duration of Therapy (Days) | |:---------------------------------------|:------------------------:| | Most bacterial pneumonias except enteric Gram-negative pathogens *S. aureus* (MSSA and MRSA), and *P. aeruginosa.* | 5-7 days | | Enteric Gram-negative pathogens, *S. aureus* (MSSA and MRSA), and *P. aeruginosa.* | 3-5 (azalides) for *S. pneumoniae* | | *Mycoplasma* and *Chlamydophila* | 10-14 days | | *Legionella* | 14-21; 10 (azalides) | ### Shortcut - MSSA/ *Staph aureus*: 10-14 days - Gram Negatives enteric/ non-enteric?: 7 days - *If using Azithromycin (5 days)* - *Pseudomonas* or MRSA/MSSA?: 14 days - Bacteremic?: Double the usual - Atypical?: Double the usual duration (usual 7 days) = 14 days - *If using Azithromycin (usual 5 days) x 2 = 10 days* ### Details - During the 24 hours before discharge, the patient should have the following characteristics (unless this represents baseline status): - Temperature of 36-37.5°C - Pulse <100/min - Respiratory rate between 16-24/minute - Systolic BP >90mmHg - Blood oxygen saturation >90% - Functioning gastrointestinal tract ## Reasons for a Lack of Response to Treatment of CAP - Correct organism but inappropriate antibiotic choice or dose - Resistance of organism to selected antibiotic - Wrong dose (e.g., in a patient who is morbidly obese or has fluid overload) - Antibiotics not administered - Correct organism and correct antibiotic but infection is loculated (e.g., most commonly empyema) - Obstruction (e.g., lung cancer, foreign body) - Incorrect identification of causative organism - No identification of causative organism and empirical therapy directed toward wrong organism - Non-infectious cause - Drug-induced fever - Presence of an unrecognized, concurrent infection # CAP-HR / CAP-MR / CAP-LR ## CAP-HR - Always evaluate if with risk for MRSA in CAPHR ## CAP-MR | Risk for *Pseudomonas* | Treatment | |:-----------------------|:---------------------------------------------------------------------------------------------------------------| | No | IV non-antipseudomonal B-lactam (Ampicillin-sulbactam, Ceftriaxone, Ertapenem) + Extended macrolide/ Fluoroquinolone (Levofloxacin, Moxifloxacin) | | Yes | IV antipneumococcal/antipseudomonal B-lactam (Pip-Tazo, Cefepime, Meropenem, Imipenem-Cilastatin) + extended macrolide and aminoglycoside (gentamicin, amikacin) | ## CAP-LR | Comorbids | Treatment | |:----------|:-------------------------------------------------------------------------------------------------------------------------| | No | Amoxicillin (drug of choice); Extended Macrolides (Azithromycin, Clarithromycin). | | Stable | B-lactam/BLIC combination (Co-amoxiclav, Sultamicillin), or 2nd gen Cephalosporins (Cefuroxime) + Extended macrolides. | | Unstable | IV non-antipseudomonal B-lactam (Ampicillin-sulbactam, Ceftriaxone, Ertapenem) + Extended macrolide/ Fluoroquinolone (Levofloxacin, Moxifloxacin) | ### Details - MRSA suspected, add any of the following: Vancomycin, Linezolid or Clindamycin.