Pneumonia

PNEUMONIA Dr. Nooruddin Jaffer Professor of Medicine.

Definition Syndrome caused by acute infection caused by a wide variety of microorganisms, characterized by clinical and/or radiological signs of consolidation of a part or parts of one or both lungs .

Definition “ Pneumonitis” is used as synonym for pneumonia when inflammation of lung has resulted from a non-infectious cause e.g chemical or radiation injury.

Clinical Definition Symptoms of acute LRT infection a) Cough, sputum,chest pain b) Fever,sweating,shiver, aches and pains New focal chest signs on examination OR New radiographic pulmonary infiltrates

Epidemiology Common and serious illness despite antibiotics and vaccines Sixth leading cause of death and number one infectious death in USA Overall incidence rate is 170 (per 10,000) and increases with age, with an incidence of 280 for those 65 years of age or older Outpatient mortality 1- 5 % , inpatient mortality approaches 25 %, greater if an ICU admission is required

Epidemiology Risk Factors Advanced age chronic illnesses Cigarette smoking Dementia Malnutrition Previous episode of pneumonia Splenectomy

Etiology of Community Acquired Pneumonia Pathogen not defined in as many as 50 % patients even with extensive diagnostic testing S. pneumoniae is the leading cause of CAP H. influenzae ( type B), S. aureus, and gram (-) bacteria each account for 3 to 10 % Staph aureus CAP is usually seen in the elderly and as post-influenza pneumonia

Etiology of Community Acquired Pneumonia P. aeruginosa causes CAP in neutropenia, cystic fibrosis, HIV infection & bronchiectasis N. meningitidis, M. catarrhalis & S. pyogenes can occasionally cause CAP Anaerobic organisms are implicated in aspiration pneumonia and lung abscess MRSA, M. tuberculosis, and certain viral agents are common in nursing-home patients

Causes of community acquired pneumonia in North America Streptococcus pneumoniae 20 - 60 Hemophilus influenzae 3 - 10 Staphyloccus aureus 3 - 5 Gram-negative bacilli 3 - 10 Aspiration 6 - 10 Miscellaneous 3 - 5 Legionella sp. 2 - 8 Mycoplasma pneumoniae 1 - 6 Chlamydia pneumoniae 4 - 6 Viruses 2 - 15

Four patient categories have been defined on the basis of information collected at the time of initial evaluation

Outpatient Pneumonia without Comorbidity and 60 years or Younger ORGANISMS S. pneumoniae M. pneumoniae Respiratory viruses C. pneumoniae H. influenzae MISCELLANEOUS Legionella S. aureus M.. Tuberculosis endemic fungi anaerobic Gram-negative bacilli

Outpatient Pneumonia with Comorbidity and/or 60 years or Older ORGANISMS S. pneumoniae Respiratory viruses H. influenzae Anaerobic Gram-negative bacilli S. aureus MISCELLANEOUS M. catarrhalis Legionella M. tuberculosis Endemic fungi

Hospitalized Patients with Community Acquired Pneumonia ORGANISMS S. pneumoniae H. influenzae Polymicrobial (including anaerobic bacteria) Anaerobic gram-negative bacilli Legionella S. aureus C. pneumonia Respiratory viruses MISCELLANEOUS M. pneumoniae M. catarrhalis M. tuberculosis Endemic fungi

Severe Hospitalized Community Acquired Pneumonia ORGANISMS S. pneumonia Legionella Anaerobic gram-negative bacilli M. pneumoniae Respiratory viruses MISCELLANEOUS H. influenzae M. tuberculosis Endemic fungi

PATHOGENESIS Predisposing conditions 1-Suppressed cough reflex 2-Impaired mucociliary activity 3-Reduced phagocytic activity of alveolar macrophages and neutrophils 4-Impaired immunoglobulins

Routes of Entry Aspiration Inhalation Colonization Hematogenous spread

Classification Community acquired pneumonia Hospital acquired (nosocomial) pneumonia Aspiration pneumonia Immunocompromised host pneumonia

Typical or Atypical CAP ? Difficult to differentiate on clinical grounds alone The term ‘atypical ’ is used to refer to a group of organisms rather than a clinical picture

Clinical Features Symptoms Respiratory Cough 90% Sputum 70% Dyspnoea 70% Chest pain 65% URT symptoms 33% Haemoptysis 15%

Clinical Features Symptoms Non-Respiratory Fever 90% Vomiting 20% Confusion 15% Diarrhoea 15% Rash 5% Abdominal pain 5%

Clinical Features Signs Fever 90% Tachypnoea 80-90% Tachycardia 80-90% Crackles & 80-90% Bronchial breathing 80-90% Hypotension 20% Confusion 15% Herpes labialis 10%

Investigations In community clinical diagnosis is enough if patient is stable. Patients who do not respond to empiric therapy, consider i-Chest X-ray ii-Sputum gram stain & culture

Test(s) in those who require hospital admission Chest X-Ray Full blood count Urea / Creatinine, Electrolytes, Sugar, LFT’s CRP- if available? (BTS) Arterial Blood Gases / Pulse oximetry Blood culture, Sputum Gram stain & Culture, AFB smear & culture (in selected patients) Routine serologic testing is not recommended

Adequate Sputum Sample Less than10 buccal squamous epithelial cells per low power field More than 25 neutrophils per low power field Leucocyte to squamous epithelial cell ratio greater than 5

Invasive diagnostic techniques Transtracheal aspiration Bronchoscopy with a protected brush catheter Bronchoalveolar lavage with or without balloon protection Direct needle aspiration of the lung

Features of Severe Pneumonia ‘ Core’ clinical adverse prognostic features (CURB) C onfusion U rea > 7 mM (>19.1 mg/dL) R esp.rate >30 /min B lood Pressure: Systolic BP < 90 mm Hg and/or diastolic BP ≤ 60 mmHg NOTE : Patients with 2 or more CURB are at high risk of death

Severity assessment in CAP in the community (CRB-65 score) UPDATED 2004 C onfusion • R espiratory rate = 30/min • B lood pressure (SBP < 90mmHg or DBP = 60mmHg) • A ge = 65 years Score 1 point for each feature present

Severity assessment in CAP in the community (CRB-65 score) UPDATED 2004 1-2 suitable for home treatment 3-4 Needs hospital referral

Additional Clinical Adverse Prognostic Features PO 2 <60 mm or O 2 saturation < 90 % Bilateral or multilobar (>2 lobes) infiltrates on chest radiograph

SEVERE CAP There is no universally accepted definition of severe CAP: 1. Respiratory frequency >30 breaths min at admission 2. Severe respiratory failure defined by a Pao2/Flo2 ratio <250 3. Requirement for mechanical ventilation 4. Chest radiograph showing a) bilateral involvement b) involvement of multiple lobes c) an  in the size of the opacity by  50 % within 48 h of admission 5. Shock ( SBP < 90 mmHg or DBP < 60 mmHg) 6. Requirement for vasopressors for more than 4 h 7. Urine output < 20 ml/h or acute renal failure requiring dialysis

Management (subset of patients) Group I : Outpatients with no h/o cardiopulmonary disease and no modifying factors. Group II : Outpatients with cardiopulmonary disease (eg. CCF or COPD) and/or other modifying factors.

Management (subset of patients) Group III : Inpatients not admitted to the ICU, who have the following: a) Cardiopulmonary disease, and/or other modifying factors including being from a nursing home) b) No cardiopulmonary disease, and/or other modifying factors.

Management (subset of patients) Group IV : ICU-admitted patients who have the following: No risk for Pseudomonas aeroginosa Risks for Pseudomonas aeroginosa

General Management of CAP In the community Not to smoke , to rest and drink plenty of fluids Pleuritic chest pain should be relieved using simple analgesics like Paracetamol Review of patients in the community is recommended after 48 hours, those who fail to improve should be considered for hospital admission

Decision to Hospitalize 1. Age over 65 yr 2. Presence of coexisting illnesses or other findings a. COPD, bronchiectasis, cystic fibrosis b. Diabetes mellitus c. Chronic renal failure d. Congestive heart failure e. Chronic liver disease of any etiology f. Previous hospitalization within 1 yr g. Suspicion of aspiration h. Altered mental status i. Postsplenectomy state j. Chronic alcohol abuse or malnutrition

Decision to Hospitalize 3. Physical findings a. Respiratory rate > 30 breaths/min b. DBP 60 mmHg or a SBP 90 mmHg c. Temperature >38.3º C (101º F) d. Extrapulmonary sites of disease e.g, presence of septic arthritis, meningitis, etc. e. Confusion and/or decreased level of consciousness

Decision to Hospitalize 4. Laboratory findings a. WBC <4,000/mcL or >30,000/mcL b. Pao2 <60 mmHg or Paco2 of >50 mmHg on room air. c. Need for mechanical ventilation. d. Serum creatinine >1.2 mg/dl or BUN >20 mg/dl (>7 mmol/L) e. Unfavorable chest radiographic findings: - more than one lobe involvement - presence of a cavity - rapid radiographic spread - pleural effusion f. Hct of <30 % or hemoglobin <9 g/dl g. Evidence of sepsis or organ dysfunction as manifested by a metabolic acidosis, an increased PT, an increased PTT, decreased platelets, fibrin split products > 1:40

General Management of CAP In hospital All patients should receive supplemental oxygen Assess for volume depletion CXR should be repeated in patients not showing clinical response Role of Bronchoscopy ? (Retained secretions, Samples for culture, Exclude endobronchial abnormality)

Therapy Principles All admitted patients should receive first antibiotic dose within 8 hours of arrival to the hospital All populations should be treated for the possibility of atypical pathogens Upto 10% of all CAP patients will not respond to initial therapy. A diagnostic evaluation is mandatory

What antibiotics to use ? Group 1: Outpatients, age < 60, no cardiopulmonary disease Erythromycin or other Macrolides (Erythromycin is not active against H.influenzae and newer macrolides are better tolerated) Amoxicillin (high dose) Amoxicillin/Clavulanate Doxycycline (many isolates of S.pneumo are resistant to tetracycline)

What antibiotics to use? Group 2: Outpatients, age >60, with co-existing diseases and/or modifying factors Amoxicillin + Macrolide Amox/Clav + Macrolide Cefuroxime + Macrolide Antipneumococcal fluoroquinolone (used alone)

What antibiotics to use? Group 3: Inpatients, not in ICU Intravenous Beta-lactam (Cefotaxime, Ceftriaxone) + Intravenous/Oral Macrolide Intravenous antipneumococcal FQ used alone (Levofloxacin, Sparfloxacin, Grepafloxacin)

What antibiotics to use? Group 4: ICU-admitted patients No risk for Pseudomonas aeruginosa Intravenous Beta Lactam (Cefotaxime, Ceftriaxone, Penicillin/Beta lactamase inhibitor) + IV Macrolide or IV Fluoroquinolone

What antibiotics to use? Group 4: ICU-admitted patients Risks for Pseudomonas aeruginosa Selected intravenous antipseudomonal Beta-lactam (Cefepime, Imipenem/Meropenem, Piperacillin/Tazobactam) + Intravenous antipseudomonal quinolone (Ciprofloxacin) or Intravenous aminoglycoside

ORAL OR PARENTERAL ANTIBIOTICS ? Parenteral Severe Pneumonia Impaired consciousness Loss of swallowing reflex Malabsorption, functional or anatomical Oral Community managed Hospital managed, non-severe with no other contraindications

Clinical Response Most patients with CAP will have an adequate response within 3 days

Switch to oral therapy Resolution of fever for >24 hrs. Resolution of tachypnoea Pulse < 100 beats /min Resolution of hypotension Hydrated and taking oral fluids Absence of hypoxia Improving white cell count Non-bacteremic infection No concern over GI absorption

Duration of therapy Patients managed in community and admitted non-severe uncomplicated pneumonia: 07 DAYS THERAPY IS ENOUGH

Duration of therapy Patients with severe microbiologically undefined pneumonia: 10 DAYS THERAPY IS PROPOSED Patients suffering from legionella, staphylococcal, or Gram negative enteric bacilli pneumonia: 14-21 DAYS THERAPY IS RECOMMENDED

Non Resolving Pneumonia Consider other diagnosis TB Lung Cancer Fungal pneumonia Foreign body inhalation BOOP, Eosinophilic pneumonias, Sarcoidosis Pulmonary embolism Pulmonary hemorrhage Heart failure

Correct Diagnosis but Fail to Respond Host : Obstruction, Foreign body, Superinfection, Empyema Drug : Error in drug selection, dose or route, Compliance, Drug interaction Pathogen : Nonbacterial, Resistant

SOME FACTS ABOUT CAP The etiologic agent causing CAP cannot be accurately predicted from clinical or radiological features The term ‘ atypical pneumonia ’ should be abandoned Elderly patients with CAP more frequently present with non specific symptoms and are less likely to have fever Radiological resolution lags behind clinical improvement Radiological resolution is slow in the elderly and cases of multilobar involvement.

Prevention 23-valent polysaccharide pneumococcal vaccine 90 percent of the serotypes are included in the 23 valent vaccine 70 % response in the general population Lower in immunocompromised patients and those on maintenance dialysis

Prevention Target hosts at greatest risk for pneumococcal disease - > 65 yrs - Chronic cardiovascular and pulmonary disease - Metabolic diseases, alcoholism, cirrhosis, nephrotic syndrome - Immunosuppression, asplenia - Lymphoma, multiple myeloma

Prevention Influenza vaccine Younger patients at risk - Chronic cardiovascular and pulmonary diseases - Renal and metabolic disease - Immune deficiency - Nursing home residents and health care workers

Pneumonia

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