PNEUMONIA

PNEUMONIA

ALOK SINHADepartment of Medicine

Manipal College of Medical SciencesPokhara, Nepal

• Acute respiratory illness of varied aetiology associated with recently developed radiological opacities which can be-• Segmental• Lobar• Multilobular

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Pneumonia is parenchyma/alveolar inflammation of lungs and abnormal alveolar filling with fluid.

Pneumonia is parenchyma/alveolar inflammation of lungs and abnormal alveolar filling with fluid.

Type of V/Q mismatch ??

ClassificationClassificationAnatomic or Pathologic • Lobar (or segmental) pneumonia

• infection of a single lobe often due to Streptococcus pneumoniae (some times segmental)

• Multilobar pneumonia(Broncho pneumonia) • involves more than one lobe, and it often

causes a more severe illness

• Interstitial pneumonia • involves the areas in between the alveoli

Atypical pneumonia • caused by agents such as

Mycoplasma Legionella Chlamydia Coxiella burnetii

• clinical features of these pneumonias can differ from pneumococcal disease

• Account for 20% cases of pneumonia

Combined clinical classificationCombined clinical classification

• Community-acquired pneumonia (CAP)

• Hospital-acquired pneumonia(nosocomial)

Community-acquired pneumonia (CAP) is an infection of the alveoli, distal airways, and interstitium of the lungs that occurs outside the hospital setting

Characterized clinically by: • Fever • Chills• Cough • Pleuritic chest pain • Sputum production • At least one opacity on chest radiography

Epidemiology Incidence:

• 800–1500 cases per 100,000 persons annually

~20% require hospitalization Age

• Incidence highest at extremes of age

Sex • Rate higher among men than among women

Seasonality • More common during the winter/spring months

• Low mortality rate in adults < 1% at home

• Is high in children-20% of childhood deaths

• Most cases in previously healthy persons

• Impairment of local defense mechanism predisposes to Pneumonia

Risk Factors Independent risk factors for CAP include:

• Alcoholism [relative risk (RR) 9] • Cigarette smoking

• Asthma (RR 4.2)

• Immunosuppression (RR 1.9)

• Corticosteroid therapy• Multiple myeloma• Spleenectomy• H.I.V.

• Age >70 years (RR 1.5 vs. 60–69 years)

• URTIs• Pre existing lung disease

Etiology

Common S. pneumoniae - most common cause of

community-acquired bacterial pneumonia H. influenzae K. pneumoniae

Uncommon S. aureus S. pyogenes P. aeruginosa N. meningitidis

Rare Y. pestis B. pseudomallei Acinetobacter calcoaceticus

• S pneumoniae -common cause of bacterial pneumonia. Colonizes upper respiratory tract and can cause the following: • a) disseminated invasive infections, including

bacteremia and meningitis• b) pneumonia and other lower respiratory tract

infections• c) upper respiratory tract infections, including otitis

media and sinusitis

• H influenzae often is associated with debilitating conditions such as asthma, COPD, smoking, and a compromised immunesystem

• K pneumoniae -severe necrotizing lobar pneumonia in patients with chronic alcoholism,diabetes, or COPD

• S aureus in intravenous drug users. in hospitalized patients, with prosthetic

devices, people with a recent influenza virus infection, and in individuals with cystic fibrosis

• L pneumophila infections occur either

sporadically or as local outbreaks from contaminted air conditioners

Microaspiration of oropharyngeal secretions colonized with pathogenic microorganisms • S. pneumoniae• H. influenzae

is most common route – Community acquired pneumonia

Gross aspiration • Central nervous system disorders that affect

swallowing (e.g., stroke, seizures) • Impaired consciousness (e.g., in alcoholism,

IV drug use) • Anesthesia or intubation • Pathogens include anaerobic organisms and

gram-negative bacilli -Common in Hospital acquired pneumonia

Other less important Aerosolization Hematogenous spread Contiguous spread from another site

Clinical features = Symptoms + SignsClinical features = Symptoms + Signs

Stages of pneumonia

Consolidation Red hepatization Gray hepatization resolution

History

Most typical signs/symptoms – depends upon the stage of diseaseFever Cough

• Nonproductive initially • productive of purulent sputum latter

stages Pleuritic chest pain

• Occasionally referred to the shoulder or anterior abdominal wall & associated with upper abdominal tenderness

Chills and/or rigors Dyspnea

Frequent signs/symptoms

Headache Nausea Vomiting Diarrhoea Fatigue Arthralgia/myalgia new-onset or worsening confusion (in elderly patients)

herpes labialis

endobronchial plug of blood, sputum, mucus & debris

Character of sputum produced may suggest a particular pathogen • Pneumococcal pneumonia bloody or

rust-colored

• Pseudomonas, Haemophilus- green sputum

• Anaerobic infections- foul-smelling and

bad-tasting • Klebsiella or pneumococcal species-

Currant-jelly

Physical examination

• Fever • Tachypnea (Accessory muscles – active)• Tachycardia• Cyanosis

Chest examination • Chest expansion – restricted • Percussion - impaired • Increased tactile and vocal fremitus• BRONCHIAL BREATH SOUNDS present • Egophony & Whispering pectoriloquy • Crackles • Pleural friction rub

Differential Diagnosis Infections

• Lung abscess • Bronchitis

Noninfectious illnesses • Pulmonary embolism • Pulmonary hemorrhage • Pulmonary edema • Pulmonary fibrosis/scarring • Inflammatory disorders

• Sarcoidosis • Wegener’s granulomatosis • Other rheumatologic/vasculitic diseases

• Lung cancer • Hypersensitivity pneumonitis • Bronchiolitis obliterans organizing pneumon (BOOP)

Assess pneumonia severity • Pay attention to vital signs, including oxygen

saturation • Always count the respiratory rate yourself for

1 min The single most useful clinical sign of

severity is a respiratory rate of >30/min in a person without underlying lung disease

CURB65 SCORECURB65 SCORE

7 mmol/l or 42mg/dl (Blood Urea Nitrogen>19)

The main objectives of investigating patients with a clinically based diagnosis of pneumonia are: • to obtain radiological confirmation of diagnosis

• exclude other conditions that mimic pneumonia

• to obtain a microbiological diagnosis • to assess the severity of pneumonia• to identify the development of complications

Good morning !

Where we stopped last time ?

INVESTIGATIONSDepends on the severity of diseasesCURB65 score 0 can be managed empiricallyScore 1-2:

a. Sputum examination with gram & ZN stain b. Blood culturec. Serology-Acute & convalescent titers

Score > 2: All the bove +a. Tracheal aspirateb. B.A.L.c. Serology-Legionella antigen in urine Pneumococcal in sputum & bloodd. Throat swab and pleural fluid if present

Laboratory Tests

Nonspecific studies Complete blood count Serum electrolyte and glucose measurements

Blood urea nitrogen (BUN) and creatinine measurements

Arterial blood gas & Pulse oximetry

Sputum stains and culture Gram’s stain

• Useful in screening a sputum sample for suitability for culture and in making a presumptive etiologic diagnosis

A sputum sample with

• >25 white blood cells (WBCs) • <10 squamous epithelial cells per low-power field is suitable for culture

• Most common: presence of gram positive diplococci – S. Pneumonae

Other sputum stains that may be helpful in some patients • Stains for

•Acid-fast bacilli •Pneumocystis •Fungi •Cytology (malignancy)

• Rapid antigen testing for viral pathogens (e.g.Influenza)

Sputum culture

Results should always be correlated with those of Gram staining (of sputum)

If an organism is isolated from sputum and is morphologic correlate is not seen on Gram staining, the isolate may be colonizing the upper airway

Certain microorganisms, if isolated from sputum, should always be considered pathogens. These include:• M. tuberculosis• Legionella spp.• Blastomyces dermatitidis• Histoplasma capsulatum• Coccidioides immitis

(Only about one-third of elderly patients admitted with CAP produce sputum suitable for culture)

Blood culture

Indications: • Hyperthermia (body temperature >38.5°C)• Hypothermia (body temperature <36°C)• Homeless• Alcohol abuse

All patients admitted to the hospital for CAP should have 2 sets of blood cultures done before initiation of antibiotic therapy (positivity rate: 6–20%)

Most common isolates• S. pneumoniae (~60%) • S. aureus• Escherichia coli

Detection of antigens of pulmonary pathogens in urine

S. pneumoniae • The antigen detected for up to 1 month after

the onset of pneumonia• results can be available in 15 min

L. pneumophila • when Legionnaires’ disease is strongly suspected• Rapidly progressive pneumonia

Urine antigen test most frequently used diagnostic method for Legionnaires’ disease

Serology Detection of IgM antibody 4-fold rise in titre of antibody to a

particular agent between acute & convalescent phase indicates is the cause of CAP

Useful for epidemiological study

ImagingImaging

Chest x-ray • Diagnostic test of choice for pneumonia

• May show Lobar or segmental consolidationBronchopneumonic pattern Interstitial infiltrates Cavitation Associated pleural fluid, etc

The common patterns in pneumonia are-

segmental or lobar pneumonia – • Strep. pneumoniae • Mycoplasma. pneumoniae • Legionella. pneumophila • Staph. aureus • C pneumoniae • Mycobacterium tuberculosis

Right upper lobe pneumonia

Segmental pneumonia

Air bronchogram

Left upper lobe pneumonia

Left upper lobe consolidationSame patient as in previous one

3rd segment left upper lobe

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• Multifocal bilateral segment or lobar opacities (Broncho pneumonia) – S aureusC burnetiiS pneumoniae

Broncho pneumonia

•Pneumatoceles (thin-walled cavities) S aureusStreptococcus pyogenesP carinii

Pneumatoceles

High-resolution CT • Occasionally detects pulmonary

opacities in patients with symptoms and signs suggestive of pneumonia and negative chest x-ray

• More likely than chest radiography to show bilateral involvement, pleural fluid/empyema, adenopathy, etc.

Bronchoscopy/ bronchoalveolarlavage /lung biopsy

(BAL)

• To obtain material for further studies when the diagnosis defies other diagnostic efforts

• patient does not improve despite empirical therapy

1. Oxygen

2. Fluid balance 3. Antibiotic treatment

4. Treatment of pleural pain

5. Physiotherapy

Oxygen Should be administered to all patients to

maintain • PaO2 ≥ 60 mmHg

• SpO2 ≥ 92%

High concentrations (> 35%) & humidified oxygen used in all patients (who do not have hyper capnia associated with COPD)

Assisted ventilation should be considered at an early stage in those who remain hypoxaemic despite adequate oxygen therapy

Risk factors for antimicrobial resistance

Age >65 years, β-lactam therapy within the past 3 months

Alcoholism Immunosuppressive illness Multiple medical comorbidities Severity of illness

Outpatient Patients with no comorbidities and no risk

factors for drug-resistant S. pneumoniae (DSRP) infection

Macrolides

• Clarithromycin (250 - 500mg PO bd for 7 days)

• Azithromycin (500 mg PO once, then 250 mg/d PO for 4 days or 500 mg/d PO for 3 days or 2 g PO once)

Doxycycline (100 mg PO bid for 7–10 days)

or

or

Patients with comorbidities • COPD • diabetes• renal or congestive heart failure • malignancy • Risk DRSP infection or a high DRSP prevalence in

the community • One of the following

Quinolone with enhanced activity against S. pneumoniae

• Levofloxacin (500–750 mg PO qd) or • Moxifloxacin (400 mg PO qd) or • Gatifloxacin (400 mg PO qd)

Cefpodoxime 200 mg PO bid third generation cephalosporin active against most Gram

positive and Gram negative organisms except Pseudomonas

Cefprozil 500 mg PO bid second-generation cephalosporins greater Gram-negative

spectrum & some activity against Gram + cocci

Amoxicillin 1000 mg PO tid; or Amoxicillin/Clavulanic acid 625 mg PO tid

+• Macrolide (clarithromycin or azithromycin dosed as

above) or • Doxycycline dosed as above

or

or

Severely ill patients

Consider coverage for methicillin-resistant S. aureus (MRSA) as well • vancomycin (1 g IV q12h)

until microbiology data become available Monotherapy with a quinolone is not

recommended for severely ill patients with CAP

In most patients • 7-10-day course is adequate

Treatment usually required for longer in patients with • Legionella • staphylococcal • Klebsiella pneumonia

How long to treat ?

Oral antibiotics adequate unless the patient has • Severe illness • Impaired consciousness • Loss of swallowing reflex • Malabsorption

MonitoringMonitoring

Outpatients Follow up within 48 h

warning signs of pneumonia exacerbation:• Symptoms not improving or new symptoms

Shortness of breath while walking on level ground (assuming no underlying lung disease)

Temperature of >38.5°C (101.3°F) New onset of confusion or pleuritic chest pain Hemoptysis

Inpatients

• Monitor Temperature curve WBC count for resolution

• Follow up on culture results and adjust therapy accordingly Watch for superinfection with S aureus

Monitor comorbid conditions (e.g., COPD, renal disease)

Follow up to ensure radiographic clearance of pneumonia

•Radiological resolution in pneumonia lag behind clinical improvement for several weeks

• Time taken for radiological resolutionNonsmokers <50 years who lack underlying lung disease: 6 weeks

Elderly patients with COPD: 8–12 weeks

• Up to 2% of patients hospitalized with CAP have cancer in the lung (with pneumonia distal to an obstructed bronchus)

50% of these cancers are evident on the initial chest film

50% manifest as failure of pneumonia resolution & are diagnosed at broncho scopic evaluation for unresolving pneumonia

When pneumonia fails to improve despite treatment

1.Reconsider the diagnosis • Is another illness presenting as pneumonia? • treating the wrong pathogen?

Treated for conventional bacterial causes of pneumonia, but is actually due to M. tuberculosis or to Pneumocystis or another fungus?

2. Treating the right pathogen with wrong drug? • using nafcillin or cloxacillin to treat S. aureus

and patient is infected with MRSA, should be using vancomycin or linezolid

3. Complicated pleural effusion Pleural effusion is seen in ~40% of patients

hospitalized for CAP – parapneumonic effussion

Indication for draining • pH of <7• glucose level of <2.2 mmol/L (40 mg%)• LDH content of >1000 units • positive on Gram’s staining or culture • If the effusion is >1 cm in lateral decubitus X ray

4. Is there a mechanical reason for the patient’s failure to improve

an obstructed bronchus due to carcinoma

5. Have you overlooked an undrained or metastatic pyogenic focus • empyema • brain abscess • endocarditis • splenic abscess • Osteomyelitis ?

Since most patients are elderly & havemultiple comorbid conditions, complicationsduring hospital stay are not uncommonThe most common complications are:

1. Acute type I respiratory failure2. Congestive heart failure3. Septicemia & shock

• Leading to multiorgan failure

4. Dysrhythmias (arrhythmias) due to • hypoxia• dyselectrolytemia

5. Gastrointestinal bleeding• Stress or Curling’s ulcers

6. Renal insufficiency

Due to severe/uncontrolled infection: 7. lung abscess

• Not a common complication of CAP• may occur in association with

aspiration with Klebsiella & staphylococcal infections

8. Complicated pleural effusion leading to empyema

9. Metastatic infection brain abscess endocarditis

• Requires immediate attention & proper treatment

10. Retention of sputum causing lobar collapse

11. Super infection with gram-negative organisms

12. Acute respiratory distress syndrome 13. Of all complicationsDeath

Findings predicting severe disease

1. WBC count <4000/μL or >30,000/μL,2. Absolute neutrophil count <1000/μL 3. Abnormal renal function - serum creatinine

>1.2 mg/dL or blood urea> 45 mg/d

4. ABG determinations- • PaO2 of <60 mm Hg • PaCO2 > 50 mm Hg on room air

5. Evidence of sepsis or organ dysfunction as manifested by • Metabolic acidosis• Increased prothrombin time• Picture of disseminate intravascular

coagulation • Increased partial thromboplastin time, • Decreased platelets

X ray findings for: multilobar involvement presence of a cavity rapid radiographic progressionpresence of a pleural effusion

Influenza and pneumococcal vaccination

smoking cessation

attention to oral hygiene in patient prone to aspiration

Hospital

acquired

Hospital acquired (nosocomial) Pneumonia

• Pneumonia acquired during or after hospitalization for another illness or procedure with onset at least 72 hrs after admission

• causes, microbiology, treatment and prognosis

are different from Community acquired pneumonia

• Up to 5% of patients admitted to hospital for

other causes subsequently develop pneumonia

FACTORS PREDISPOSING TO NOSOCOMIAL PNEUMONIA

Reduced host defences against bacteria

•Reduced immune defences (e.g. corticosteroid treatment, diabetes, malignancy) •Reduced cough reflex (e.g. post-operative) •Disordered mucociliary clearance (e.g. anaesthetic agents) •Bulbar or vocal cord palsy

Aspiration of nasopharyngeal or gastric secretions

•Immobility or reduced conscious level •Vomiting, dysphagia, achalasia or severe reflux •Nasogastric intubation

Bacteria introduced into lower respiratory tract•Endotracheal intubation/tracheostomy •Infected ventilators/nebulisers/bronchoscopes •Dental or sinus infection

Bacteraemia

•Abdominal sepsis •Intravenous cannula infection •Infected emboli

.

• The microorganisms a person is exposed to in a hospital are often different from those at home

• Hospital-acquired microorganisms include resistant bacteria • Escheresia• Pseudomonas• Klebsiella• MRSA (Multidrug Resistant Staphylococcusaureus)• Anaerobic organism

• Ventilator-associated pneumonia (VAP) a subset of hospital-acquired pneumonia. • pneumonia which occurs after at least 48

hours of intubation and mechanical ventilation

Treatment

Started empirically till the investigation reports

Are availableInitial therapy determined by

• severity of illness• risk factors• length of hospitalization• day of onset- latter is more severe

Patients With Mild-to-Moderate Hospital-Acquired Bacterial Pneumonia With Risk Factors, Onset Any Time

Anaerobes recent abdominalsurgery, witnessed

aspiration

Clindamycin or beta-lactam/beta-lactamase inhibitor

S aureus coma, head trauma,

diabetes mellitus, renal failure

+/-vancomycin (until methicillin-resistant S aureus is excluded

Legionella high-dose steroids Erythromycin +/- rifampin

P.Aeruginosa prolonged ICU staySteroidsantibioticsstructural lungdisease

Aminoglycoside or ciprofloxacin +

Anti pseudomonal penicillinBeta-lactam/beta-lactamase

inhibitorCeftazidime or cefoperazone

Atypical pneumonia

Pneumonia caused by Atypical pathogens:

caused by one or a combination of the following organis

Legionella pneumophila • Causes a severe form of pneumonia with a relatively high

mortality rate, known as legionellosis or Legionnaires' disease

Mycoplasma pneumoniae • Usually occurs in younger age groups and may be associated

with neurological and systemic (e.g. rashes) symptoms Chlamydophila pneumoniae

Atypical clinical features: In general few physical signs Patient looks worse than the

symptoms suggest No signs and symptoms of lobar

consolidation, • affection is restricted to small areas,

rather than involving a whole lobe

Absence of leukocytosis Extrapulmonary symptoms, related to

causative organism

Atypical therpeutic response: No response to common antibiotics as

sulfonamide and beta-lactams like penicillin