Community acquired pneumonia

1. Community Acquired Pneumonia Dr. Saba Khan

2. pneumonia Definition: An acute respiratory illness associated with recently developed radiological pulmonary shadowing in constellation with signs and symptoms (fever, chills, cough, pleuritic chest pain, sputum production, hyper- or hypothermia, increased respiratory rate, dullness to percussion, bronchial breathing, egophony, crackles, wheezes, pleural friction rub) Classification: Community-acquired pneumonia Hospital-acquired pneumonia (nosocomial) Pneumonia occurring in immunocompromised hosts or patients with underlying damaged lung (including suppurative and aspiration pneumonias)

3. Factors that predispose to pneumonia Cigarette smoking Upper respiratory tract infections Alcohol Corticosteroid therapy Old age Recent influenza infection Pre-existing lung disease PATHOLOGY The pathology of pneumonia manifests as four general patterns: lobar pneumonia, bronchopneumonia, interstitial pneumonia, and miliary pneumonia.

4. Lobar Pneumonia A radiological pathological term referring to homogenous consolidation of one or more lung lobes, often with associated pleural inflammation. Four stages of lobar pneumonia may exist: Congestion : Occurs during the 1 st 24 hours; affected lobe is heavy, red and boggy; vascular congestion can be seen, with proteinaceous fluid, scattered neutrophils, and many bacteria in the alveoli. Red Hepatization : The lung lobe has a liver-like consistency; alveolar spaces are filled with neutrophils, red cells, and fibrin; the pleura usually demonstrates a fibrinous or fibrinopurulent exudates. Grey Hepatization : The lung is dry, friable, and gray-brown to yellow as a consequence of a persistent fibrinopurulent exudates, progressive destruction of red blood cells, and the variable presence of hemosiderin. The 2 nd and 3 rd stage last for 2-3 days each, with a 2-6 day duration for maximal consolidation Resolution : Characterized by enzymatic digestion of the alveolar exudates; resorption, phagocytosis, or coughing up of the residual debris; and restoration of the pulmonary architecture. The pleural reaction may similarly resolve or undergo organization, leaving fibrous thickening or pleural adhesions, causing a rub heard by auscultation

5. Bronchopneumonia Refers to patchy alveolar consolidation associated with bronchial or bronchiolar inflammation involving one or several lobes, usually involves the dependent lower and posterior portions of the lung (often bilaterally)—a pattern results in respect to the distribution of aspirated oropharyngeal contents by gravity. Interstitial Pneumonia Defined by histopathologic identification of an inflammatory process predominantly involving the interstitium, including the alveolar walls and the connective tissue around the bronchovascular tree. The inflammation may be patchy or diffuse. Miliary Pneumonia Refers to numerous discrete lesions resulting from the spread of the pathogen to the lungs via the bloodstream (occurs when organisms drain through lymphatics into the lymphatic ducts, which empty into the venous return to the right side of the heart and thence into the pulmonary arteries). Individual lesions are either microscopic or small, visible foci (2-mm) of yellowish-white consolidation are scattered through the lung parenchyma.

6. Chest X-ray RUL RML RLL LUL Lingula LLL RUL RML RLL LUL Lingula LLL

7. Lobar Pneumonia Bronchopneumonia

8. PULMONARY COMPLICATIONS OF PNEUMONIA Uncontrolled infection by particular agents may lead to necrotizing pneumonia, formation of abscesses, vascular invasion with infarction, cavitation, and extension to the pleura with empyema or bronchopleural fistula. Complications of mechanical ventilation and supplemental oxygen administration include interstitial emphysema, pneumothorax, and ARDS. In patients with severe damage, tissue repair may lead to fibrosis with various anatomical distributions, such as organizing pneumonia, bronchiolitis obliterans, and pleural adhesions.

9. Community Acquired Pneumonia Indicates pneumonia in person occuring outside of hospital or extended-care facility The overall rate of pneumonia ranges from 8-15 per 1000 persons per year, with the highest rates at the extremes of age and during the winter months. Rates of pneumonia are higher for men than for women and for black than for white population. CAP is usually spread by droplet infection and most cases occur in previously healthy individuals. Most patients may be safely managed as out-patient, but hospital admission is necessary in 20-40% of patients (5-10% of whom may require intensive care). Mortality rate of adult patients managed as: Out-patients------is very low <1% In-patients---------is between 5 to10% and may be as high as 50% in severe illness.

10. Risk factors for CAP include: Current tobacco smoking or passive exposure to tobacco smoke. Alcoholism Immunosuppression Age >70 years Asthma COPD Congestive heart failure Etiology Common organisms causing CAP are: BACTERIAL Streptococcus pneumoniae Mycoplasma pneumoniae Haemophilus influenzae Chlamydia pneumoniae Legionella pneumophilia Oral anaerobes Moraxella catarrhalis Staphylococcus aureus Mycobacterium tuberculosis Chlamydia psittaci VIRAL Influenza virus Cytomegalovirus Respiratory syncytial virus Measles virus Varicella -zoster virus FUNGAL Histoplasma Coccidiodies Blastomyces spp.

11. Classification: Features Typical Pneumonia Atypical Pneumonia Onset Rapid Slow Organisms Strep. pneumoniae (most common cause of pneumonia) H. infulenza Mycoplasma pneumoniae Legionella pneumoniae Chlamydia pneumoniae Strep. pneumoniae Viral pneumonia C/F Fever a/w chills, and predominant pulmonary features such as productive cough with mucopurulent sputum, pleuritic chest pain ; signs of consolidation such as decreased chest movement, dullness, increased vocal fremitus , egophony, bronchial breath sounds and crepitations . Non-pulmonary features are predominant such as gradual onset of fever and dry cough; myalgia , arthralgia , headache, sore throat, nausea, vomiting and diarrhea. Respiratory signs like chest pain and productive cough, are less prominent. Labs Leucocytosis WBC count may be WNL or marginally raised Chest X-ray Patchy or lobar infiltrates (opacity) Patchy non-lobar infiltrates present bilaterally

12. Physical Examination: General : Patient appears ill with rapid pulse and rapid respiration, high fever, flushed dry skin. Pulmonary Signs: Within 24 hours— Decreased respiratory movements Slight impairment of percussion notes Pleural rub on affected sites On 2 nd and 3 rd day– signs of consolidation appear Decreased chest movement on affected site Increased vocal fremitus Dull note over consolidated area Bronchial or absent breath sounds Fine crepitations Resolution phase— Most signs disappear by the end of second week. When resolution begins numerous coarse crepitations are heard, which indicate liquefaction of alveolar exudates.

13. Investigations: Radiological Examinations— Chest X-ray CT scan Radiological examination is also helpful if complications such as parapneumonic effusion, intrapulmonary abscess formation, or empyema are suspected. Microbiological Investigations– A full range of microbiological tests should be performed on patients with severe CAP. In patients who donot respond to initial therapy, microbiological investigations may lead to the appropriate modification of therapy. It includes: All patients: Sputum---- Gram and Zeihl-Neelsen stain; culture and antimicrobial senstivity testing Blood culture Serology--- acute and convalescent titres to diagnose Mycoplasma , Chlamydia, Legionella and viral infections. Pneumococcal antigen detection in serum. Severe CAP: Above tests plus Tracheal aspirate, induced sputum, bronchoalveolar lavage , protected brush specimen or percutaneous needle aspiration. Serology--- Legionella antigen in urine; Pneumococcal antigen in sputum and blood, immediate IgM for Mycoplasma . Cold agglutinins--- positive in 50% patients with mycoplasma

14. Selected patients: Throat/nasopharyngeal swabs Pleural fluid analysis General blood tests: WBC--- >20,000/mm3 or <4,000/mm3 may be seen in severe pneumonia. Neutophilic leucocytoses of >15,000/mm3 favours a bacterial aetiology . Urea and electrolytes Liver function tests C-reactive protein(CRP)--- is typically elevated. Assessment of Gas Exchange: Pulse oximetry --- non-invasive method to measure arterial oxygen saturation (SaO2), and assists in monitoring response to oxygen therapy. Arterial blood gas: should be sampled if Sao2 <92% or presence of features of severe pneumonia to assess whether the patient has evidence of ventilatory failure or acidosis. NB: an expectorated sample is often inadequate due to contamination from oral flora. Therefore a specimen may be considered adequate if the gram stain shows >25 neutrophils and <10 squamous epithelial cells per low-power field.

15. Differential Diagnosis of Pneumonia Pulmonary infarction Pulmonary/pleural TB Pulmonary edema (can be unilateral) Pulmonary eosiniphilia Malignancy: Bronchoalveolar carcinoma Rare disorders: Cryptogenic organising pneumonia/ Brochiolitis obliterans organising pneumonia (COP/BOOP )

16. Management Approach to the Patient with Community-Acquired Pneumonia 1. Assess pneumonia severity. Pay attention to vital signs, including oxygen saturation. Always count the respiratory rate yourself for 1 min. 2. Ensure adequate oxygenation and support of circulation. 3. Perform etiologic workup (dictated by pneumonia severity). 4. Determine site of treatment: home, hospital (ward or intensive care unit), or long-term-care facility. 5. Institute empirical antibiotic therapy. 6. Rule out empyema in all patients with a pleural effusion of 1 cm on lateral decubitus chest radiography. 7. Never forget tuberculosis and Pneumocystis infection as possible etiologies. 8. Consider pulmonary embolus in all patients with pleuritic chest pain.

17. 9. Consider end-of-life decision-making. 10. Monitor and treat comorbid illnesses. 11. Monitor for achievement of stability of selected physiologic parameters. 12. Assess ability to perform activities of daily living. 13. Assess mental status. 14. Consider preventive measures: a. Smoking cessation counseling (if appropriate) b. Assessment of pneumococcal and influenza vaccination status, with vaccine administration as necessary c. Assessment of risk of aspiration and institution of preventive measures 15. Follow up to ensure radiographic clearance of pneumonia. All patients 40 years old and all tobacco smokers should have a follow-up chest radiograph to document pneumonia resolution.

18. Site of care Can be decided on the basis of pneumonia severity index, that can assessed by following methods: PORT Study

19. The PORT score (based on a pneumonia-specific severity-of-illness scoring system)has been advocated as a tool to guide the decision regarding the site of care (home vs. hospital). Because of the low mortality rates in risk classes I and II, it is recommended that these patients be treated at home. Patients in risk classes IV and V require hospital admission. Patients in class III may benefit from a period of observation in the emergency room before a decision is made regarding the site of care. American Thoracic Society Definition of Severe Pneumonia Category Criteria Major Need for mechanical ventilation Requirement for vasopressors : > 4 h Minor Systolic blood pressure: 90 mmHg PaO /FIO : 250 2 2 Multilobar involvement

20. BRITISH THORACIC SOCIETY RULE FOR DEFINITTION OF SEVERE CAP (CURB-65) Score 0 or 1 Score 2 Score 3 or more

21. Oxygenation: Administered to all patients with tachypnea , hypoxaemia , hypotension or acidosis, with the aim of maintaining PaO2 > 8 kPa (60 mmHg) or SaO2 > 92% Fluid balance: An adequate oral intake of fuids should be encouraged but I.V. fluids should be considered in those with severe illness, elderly patients and those whose systemic features include vomiting. Inotropic support may be required in patient with shock. Antibiotic treatment: Outpatient; no cardiopulmonary disease, no risk factors for DRSP infection Macrolide (e.g., clarithromycin 500 mg bid PO10 days; or azithromycin 500 mg PO once, then 250 mg/d 4 days) or Doxycycline 100 mg bid PO 10 days Outpatient; cardiopulmonary disease and/or risk factors for DRSP infection or high DRSP prevalence in community Quinolone with enhanced activity against Streptococcus pneumoniae—e.g ., levofloxacin 500 mg/d PO, moxifloxacin 400 mg/d PO, or gatifloxacin 400 mg/d PO or B-Lactam (cefpodoxime 200 mg bid, cefuroxime axetil 750 mg tid , or amoxicillin 1000 mg tid , PO; amoxicillin/ clavulanic acid 875/175 mg tid )plus macrolide or doxycycline or Telithromycin 800 mg q24h 10 days (DRSP—drug resistant Streptococcus pneumoniae )

22. Hospital ward Cefuroxime 750 mg q8h IV or ceftriaxone 1 g/d IV or cefotaxime 2 g q6h IV or ampicillin / sulbactam 1.5–3 g q6h IV plus Azithromycin 1 g/d IV followed by 500 mg/d IV or Quinolone with enhanced activity against S. pneumoniae (see above) Intensive care unit no risk factors for Pseudomonas aeruginosa infection--- Azithromycin 1 g IV, then start 500 mg IV 24 h later plus Ceftriaxone 1 g q12h IV or Cefotaxime 2 g q6h IV or Quinolone IV risk factors for P. aeruginosa --- Imipenem (or meropenem )500 mg q6h IV or Piperacillin/tazobactam 3.375 g q6h IV plus Ciprofloxacin 750 mg q8h IV

23. Nursing home Amoxicillin/ clavulanic acid 875/125 mg tid PO plus Macrolide PO (see above) or Quinolone PO with enhanced activity against S. pneumoniae (see above) or Ceftriaxone 500–1000 mg/d IM or cefotaxime 500 mg IM q12h plus Macrolide (see above)

24. Treatment of pleural pain: Mild analgesics such as Paracetamol are rarely adequate; however, opiates must be used with extreme caution in patient with poor respiratory function Discharge and follow up: Discharge from hospital should be contemplated when patients are clinically stable with no more than one of following clinical signs: Temp. >38*C HR >100/MIN Resp. rate > 24/min Systolic BP <90 mmHg SaO2 <90% Inability to maintain oral intake Abnormal mental status Chest X-ray may often take several weeks to months to resolve. Follow-up--- arranged at around 6 weeks and a cxr obtained if there are persistent symptoms.

25. Prevention Influenza vaccination: Recommended to those at high risk of mortality (elderly people) from influenza or pneumonia. Pneumococcal vaccination: Polysaccharide pneumococcal vaccine do not appear to reduce the incidence of pneumonia or death but may reduce the incidence of invasive pneumococcal disease. Protects against 23 serotypes of Strep. Pneumoniae (90% of invasive pneumonia infections) Can be given to anyone over age 65 and/or accompanied with chronic medical problem such as cancer, diabetes, heart disease, lung disease, alcoholism, cirrhosis, sickle cell disease, kidney failure, HIV, damaged spleen or no spleen, CSF leaks Anyone receiving cancer therapy, radiation, steroids Can be given after 5 years from first dose.