Community Acquire Pneumonia (CAP)

Community Acquire PNEUMONIA (CAP) Respiratory Infection Pneumonia develops when an organism invades the lung parenchyma and the host defenses are depressed Causes: bacterial, viral, fungal, rickettsial, or parasitic organisms; inflammatory process; and inhalation of toxic substances CAP – acute infection of the pulmonary parenchyma acquired outside of a health care setting Viral Pneumonia Bacterial Pneumonia ¥ ¥ ¥ In most adult (75%) and child cases, Streptococcus pneumoniae is the most common causative organism In neonates, Group B streptococci is often the leading causative organism. Chlamydia trachomatis can be another causative organism seen in this age group Haemophilus influenza and Moraxella catarrhalis are less common causative organisms seen in patients with underlying lung disorders Viral pathogens: Influenza Virus (most common causative organism), Respiratory Syncytial Virus (RSV), Parainfluenza virus and Rhinovirus Viruses are identified in 18-36% of pneumonia cases Viruses travel via droplets of fluid (sneeze, cough) from an infected individual and obtain access through the nose or mouth Viral pneumonia may depress host defenses and can lead to secondary bacterial pneumonia ¥ ¥ ¥ ¥ Risk Factors ¥ ¥ ¥ ¥ ¥ ¥ ¥ ¥ ¥ Age <2 years old or > 65 Lifestyle o Alcoholism o Smoking (including second-hand exposure) Underlying diseases o Chronic heart disease o Chronic renal disease o Chronic liver disease o Chronic respiratory disease o Metabolic disease o CNS disease Previous pneumonia Recent antibiotic use Recent upper respiratory infection Immunosuppression o HIV, Chemotherapy Overcrowded living conditions Malnutrition Atypical Pneumonia ¥ ¥ Atypical pathogens: Legionella pneumophila, Mycoplasma pneumoniae, Chlamydophila pneumoniae, and viral infections. Atypical pneumonia tends to have milder symptoms than typical pneumonia Pathophysiology CAP – acute infection of the pulmonary parenchyma acquired outside of a health care setting ¥ ¥ Streptococcus pneumonaie – organism most commonly found in pneumonia Clinical Presentation: cough, dyspnea, tachypnea, sputum production, fever, abnormal breath sounds (crackles), malaise, dehydration, pleuritic chest pain Introduction of organism (Streptococcus pneumonaie) into the lung parenchyma & Host defenses are depressed/compromised ↓ Adherence to alveolar macrophages (activation of adaptive then humoral immunity) ® release of TNF-a and IL-1 from macrophages and chemokines from mast cells/fibroblasts ↓ Inflammatory response: Neutrophil attraction from capillaries of the lungs into the alveoli; release of inflammatory mediators; accumulation of bacteria, red blood cells, and fibrinous exudate ↓ Red hepatization (presence of erythrocytes, neutrophils, desquamated epithelial cells, and fibrin within alveoli) ® [Leukocyte infiltration (neutrophils and macrophages) ® Gray hepatization (fibrinopurulent exudate, disintegration of RBCs, and hemosiderin) and disposition of fibrin on pleural surfaces; phagocytosis in alveoli References: McCance, K. L., & Huether, S. E. (2019). Pathophysiology: The biologic basis for disease in adults and children (8th ed.). St. Louis, MO: Elsevier. ↓ Macrophages in alveoli ingest and remove degenerated neutrophils, fibrin, and bacteria ® Resolution of infection Alyssa Bernstein Pharmacology Macrolide Antibiotics [Azithromycin, Clarithromycin, or Erythromycin] – used to treat CAP that occurs in previously healthy adults with no history of comorbidities, no risk factors for drug-resistant streptococcal pneumonia (DRSP), and no known drug allergies ↓ Doxycycline – used to treat CAP that occurs in previously healthy adults with no history of comorbidities, no risk factors for DRSP, and known allergy to Macrolide antibiotics ↓ Respiratory Fluoroquinolones [Levofloxacin, Moxifloxacin, or Gemifloxacin] – used to treat CAP that occurs in patients with comorbidities [heart disease, COPD, liver or renal disease, DM, alcoholism, malignancies, immunosuppression, asplenia], risk for DRSP [age >65, etc.], and/or recent use of antimicrobial within 3 months ↓ Beta Lactam + Macrolide [Augmentin (amoxicillin/clavulanate) or high dose Amoxicillin; alternatives: Ceftriaxone, Cefpodoxime, and Cefuroxime] – used to treat CAP that occurs in patients with comorbidities (see above mentioned), risk for DRSP, and/or recent use of antimicrobial within 3 months, and known allergy to Fluroquinolones [Doxycycline can be used as an alternative to the Macrolide if an allergy is present] ↓ Respiratory Fluoroquinolones or Beta Lactam + Macrolide – used to treat CAP that occurs in patients that reside in regions where a high (>25%) Macrolide resistant S. pneumoniae is present. [Indicated by local antibiogram] [Doxycycline can be used as an alternative to the Macrolide if an allergy is present] Macrolides [Azithromycin, Clarithromycin, or Erythromycin] MOA: bacteriostatic/bactericidal (in high concentrations). Inhibits RNA-dependent protein synthesis and reversibly binds to the P site on 50S ribosome subunits on susceptible organisms Indication: used to treat CAP that occurs in previously healthy adults with no history of comorbidities, no risk factors for drug-resistant streptococcal pneumonia (DRSP), and no known drug allergies Dosing: Azithromycin 500 mg PO tab on Day 1, then 250 mg PO tab daily on days 2-5. Child Dosing: 10mg/kg on Day 1, followed by 5mg/kg on days 2-5. Safety: Pregnancy Category B. hypersensitivity, hepatotoxicity, QT prolongation, clostridium difficile – associated diarrhea (CDAD) ADRs: palpitations, chest pain, dyspepsia, vomiting, vaginitis, nephritis, dizziness, HA, vertigo, fatigue, photosensitivity, angioedema, rash (Steven’s-Johnson Syndrome) ¥ ¥ ¥ ¥ ¥ ¥ ¥ ¥ ¥ ¥ ¥ ¥ ¥ ¥ ¥ Respiratory Fluoroquinolones [Levofloxacin, Moxifloxacin, or Gemifloxacin] MOA: bactericidal, active against gram-positive and gram-negative bacteria, interferes with the enzymes required for synthesis and repair of bacterial DNA. By inhibiting DNA gyrase, the bacteria are prevented from relaxing the supercoiled DNA which is required for normal transcription and replication. Inhibition of topoisomerase IV results in the inhibition of separating the replicated DNA from the parent cell into the daughter cells. Indication: used to treat CAP that occurs in patients with comorbidities, risk for DRSP, and/or recent use of antimicrobial within 3 mo. Inpatient or outpatient use. Dosing: Levofloxacin (Levaquin) 750mg tab PO every 24 hours for 7-14 days. [6mo-18yrs Dosing]: 8 to 10 mg/kg/dose PO every 24 hours (Max: 750 mg/dose) for 10 days Safety: Pregnancy Category C. Renal impairment (CCr <50 mL/min) consider dose reduction. ADRs: Black Box warning - risk of tendon rupture/tendonitis and to avoid this class in patients with a hx of myasthenia gravis. hepatotoxicity, CDAC, prolongation of the QT interval, blood glucose disturbances, photosensitivity, and CNS disturbances (tremors, restlessness, seizures, and confusion) Beta-Lactam [Augmentin (amoxicillin/clavulanate) or high dose Amoxicillin, Penicillin] MOA: bactericidal, inhibits the synthesis of the peptidoglycan layer (responsible for structural integrity) of the bacterial cell wall. β-lactam antibiotics also block the division of bacteria, including cyanobacteria and cyanelles (photosynthetic organelles of the glaucophytes), and the division of chloroplasts of bryophytes. Indication: used to treat CAP that occurs in patients with comorbidities (see above mentioned), risk for DRSP, and/or recent use of antimicrobial within 3 months, and known allergy to Fluroquinolones Dosing: Amoxicillin/Clavulanate (Augmentin) 875mg tab PO every 12 hours for 10-14 days. Child dosing: <3 mo: 30mg/kg/d of amoxicillin divided q12h; > 3mo: 80-90 mg/kg/d of amoxicillin divided q12h. Safety: Pregnancy Category B. Renal impairment (CCr <50 mL/min) consider dose reduction. ADRs: Hepatic dysfunction (hepatitis, jaundice, " in AST and/or ALT), CDAD, dermatitis, anemia, thrombocytosis, tooth discoloration References: Woo, T. M. & Robinson, M. (2015). Pharmacotherapeutics for advanced practice nurse prescribers (4th ed.). Philadelphia, PA: F.A. Davis Company. Monitoring Patients should see an improvement in clinical presentation with 48 to 72 hours if treatment is effective. The practitioner should monitor patient’s respiratory status, fever, hydration, and activity tolerance during antibiotic therapy. Patients should come back in for a follow up appointment within 72 hours of antibiotic initiation. During f/u: obtain CBC to check for leukocytosis, CMP to monitor renal and liver function, check skin for rash/jaundice. Diagnosis: chest x-ray, sputum culture if patient is unresponsive to treatment within 72 hours