Community-Acquired Pneumonia

SAMIR EL ANSARY

Objectives

Diagnosis and management of CAP

Differentiate between healthcare-associated pneumonia (HCAP) and CAP

Identify risk factors for resistant organisms and less common causes of pneumonia

CAP - Epidemiology

Very common

5 million cases/year in North America

At least 1 million hospitalizations/year

9th leading cause of infectious death in US

30 day morality for hospitalized patients is up to 23%

$17 billion/year in healthcare costs in US

Which of these patients have community-acquired pneumonia (CAP)?

34 yo hospital employee, previously healthy, admitted for acute pneumonia.

56 yo man admitted with CHF, noted to have pneumonia the day after admission.

76 yo bedridden man transferred from a nursing home for acute confusion, noted to have a new infiltrate on CXR.

Alphabet Soup of Terms

• CAP: Community-acquired pneumonia– Outside of hospital or extended-care facility

• HCAP: Healthcare-associated pneumonia– Long-term or extended care facility, hemodialysis, outpatient

chemo, wound care, etc.

• HAP: Hospital-acquired pneumonia– ≥ 48 h from admission

• VAP: Ventilator-associated pneumonia– ≥ 48 h from endotracheal intubation

What differentiates acute bronchitis (or other causes of fever/cough) from pneumonia : –Clinical definition requires chest imaging – air space disease.

HCAP includes the following patients with pneumonia: hospitalized in an acute care hospital for more than 2 days within 90 days of the pneumonia; resided in a long-term care facility (e.g., nursing home); received recent parenteralantimicrobial therapy, chemotherapy, or wound care within 30 days of pneumonia; or received treatment in a hospital or hemodialysis clinic.

Pneumonia - DefinitionsSpecturm of pneumonia.

Clinical Presentation

Acute cough (>90%)

Fevers/chills (80%)

Sputum production (66%)

Dyspnea (66%)

Pleuritic chest pain (50%)

Tachypnea (RR > 24)

Egophony

Bronchial breath sounds

Percussion dullness

Diminished breath sounds

Clinical Presentation

Acute cough (>90%)

Fevers/chills (80%)

Sputum production (66%)

Dyspnea (66%)

Pleuritic chest pain (50%)

Tachypnea (RR > 24)

Egophony

Bronchial breath sounds

Percussion dullness

Diminished breath sounds

Lung physical examSensitivity 47-69% ; Specificity 58-75%

CXR

To Admit or Not?Pneumonia Severity & Deciding Site of Care

Objective criteria to risk stratify & assist in decision re outpatient vs inpatient management

Pneumonia Severity Index (PSI)

CURB-65

Caveats

Other reasons to admit apart from risk of death

Not validated for ward vs ICU

Not validated in some populations (i.e. HIV+)

Criteria for Severe CAP(Admit to ICU)

Minor criteria

Respiratory rate ≥30 breaths/minPaO2/FiO2 ratio ≥ 250Multilobar infiltratesConfusion/disorientationUremia (BUN ≥20 mg/dL)Leukopenia (WBC <4000 cells/mm3)Thrombocytopenia (platelets <100,000 cells/mm3)Hypothermia (core T <36C)Hypotension requiring aggressive fluid resuscitation

Major criteria

Invasive mechanical ventilationSeptic shock with the need for vasopressors

Microbiology

TYPICAL

– Streptococcus pneumoniae

– Haemophilus influenzae

– Moraxella catarrhalis

– Klebsiella pneumoniae

ATYPICAL

– Mycoplasma pneumoniae

– Chlamydophila pneumoniae

– Legionella pneumophila

2/3 are typical; 1/3 are atypical

Microbiology of CAP among hospitalized patients

Outpatient Streptococcus pneumoniae

Mycoplasma pneumoniae

Haemophilus influenzae

Chlamydophila pneumoniae

Respiratory viruses

Inpatient (Ward) S. pneumoniae

M. pneumoniae

H. influenzae

C. Pneumoniae

Legionella species

Respiratory viruses

Aspiration

Inpatient (ICU) S. pneumoniae

Legionella spp.

Staphylococcus aureus

Gram-negative bacilli

Age-specific Rates of Hospital

Admission by Pathogen

Marsten. Community-based pneumonia incidence study group.Arch Intern Med 1997;157:1709-18

Two-thirds of deaths due to a known CAP pathogen is due to Strep pneumoniae.

Comorbidities & Associated Pathogens

Alcoholism

COPD and/or

Tobacco

Strep pneumoniae

Oral anaerobes

Klebsiella pneumoniae

Acinetobacter spp

M. tuberculosis

Haemophilus influenzae

Pseudomonas aeruginosa

Legionella spp

S. pneumoniae

Moraxella catarrhalis

Chlamydophila pneumoniae

Aspiration

Lung Abscess

Structural lung

disease (e.g.

bronchiectasis)

Advanced HIV

Gram-negative enteric pathogens

Oral anaerobes

CA-MRSA

Oral anaerobes, microaerophilic streptococci, Actinomyces, Nocardia spp

Endemic fungi

M. tuberculosis, atypical mycobacteria

P. aeruginosa

Burkholderia cepacia

S. aureus

Pneumocystis jirovecii

Cryptococcus

Histoplasma

Tuberculosis

Aspergillus

P. aeruginosa

MRSAModern-day CAP pathogen

Must consider MRSA, MSSA coverage in severe CAP, esp during flu season!

MRSA CAPClinical Features

Cavitary infiltrate or necrosis

Rapidly increasing pleural effusion

Gross hemoptysis (not just blood-streaked)

Concurrent influenza

Neutropenia

Erythematous rash

Skin pustules

Young, previously healthy patient

Severe pneumonia during summer months

Is sputum culture helpful?

Sputum Gram stain and culture

Low sensitivity (25-40%)

Considered optional for outpatients

Blood culture

Positive < 10%

May help guide antibiotic therapy

Diagnosis: Cultures

Pre-abx Blood Cultures

Yield 5-15%

Stronger indication for severe CAP

Host factors: cirrhosis, asplenia, complement deficiencies, leukopenia

Only 25-30% can actually provide a decent expectorated sample.Endotracheal aspirate: Intubated patients who were too sick to be

able to produce sputum.

Diagnosis: Cultures

Pre-abx expectorated sputum Gs & Cx

Yield can be variable

Depends on multiple factors: specimen collection, transport, speed of processing, use of cytologic criteria

Adequate sample

Pre-abx endotracheal aspirate Gs & Cx

Pleural effusions > 5 cm on lateral upright CXR

Diagnosis: Other testing

Urinary antigen tests

S. pneumoniae

L. pneumophila serogroup 1

60-80% sensitive, >90% specific in adults

Pros: rapid (15 min), simple, more sensitive than Cx, can detect Pneumococcus after abxstarted

Cons: no susceptibility data, not helpful in patients with recent CAP (prior 3 months)

Diagnosis: Other testing

• Acute-phase serologies–C. pneumoniae, Mycoplasma, Legionella

spp

–Not practical given slow turnaround & single acute-phase result unreliable

Diagnosis: Other testing

• Influenza testing– Hospitalized patients: Severe respiratory illness (T> 37.8°C with

SOB, hypoxia, or radiographic evidence of pneumonia) without other explanation and suggestive of infectious etiology should get screened during season

– NP swab or nasal wash/aspirate

– Rapid flu test (15 min) - Distinguishes A vs B

• Sensitivity 50-70%; specificity >90%

– Respiratory virus DFA & culture - reflex subtyping for A

– Respiratory viral PCR panel - reflex subtyping for A

– Epidemic Influenza PCR panel – screens for A & B with reflex subtyping for A

Outpatient Empiric CAP Abx

• Healthy; no abx x past 3 months– Macrolide: azithromycin

– 2nd choice: doxycycline

• Comorbidities; abx x past 3 mon– Respiratory fluoroquinolone: Moxifloxacin, levofloxacin 750

mg, gemifloxacin

– Beta-lactam (preferred: amoxicillin 1 g3 or amox/clav 2 g2; alternative: ceftriaxone, cefuroxime 500 mg2), + macrolide

• Regions with >25% high-level macrolide-resistant S. pneumo(MIC ≥16), consider alternative agents

Inpatient Empiric CAP Abx1

• Inpatients in ward

– Respiratory fluoroquinolone

– ß-lactam (cefotaxime/ceftriaxone or ampicillin/sulbactam) + macrolide

• Inpatients in ICU

– ß-lactam + macrolide

– Respiratory fluoroquinolone for PCN-allergic pts

Inpatient Empiric CAP Abx1

• Pseudomonas (if concerns exists)

– Anti-pneumococcal & anti-pseudomonal ß-lactam + azithromycin + cipro/levofloxacin (750 mg)

– Can substitute quinolone with aminoglycoside

– PCN-allergic: can substitute aztreonam

• CA-MRSA: Add vanco or linezolid* (or ceftaroline2)

• CA-MSSA: Nafcillin or cefazolin or ceftriaxone

Risk Factors for Multidrug Resistance (MDR)

Antibiotics in the past 90 daysHigh frequency of antibiotic resistance in communityImmunosuppressive disease or medicationsHCAP Risk Factors:• Hospitalization for at least 2 days in the past 90 days• Residence in a SNF• Home infusion therapy• Dialysis within 30 days• Family member with MDR infection

Influenza pneumoniaTreatment

First-line Tx is neuroaminidase inhibitors for both

influenza A and B:

Oseltamavir 75-150* mg PO BID x 5+ days

Zanamavir 10 mg INH BID x 5+ days

NOTE: influenza A resistant to adamantanes

(amantadine, rimantadine)

* There is limited data in support of double dosing. But we do it anyway.

Antiviral Therapy for Influenza

CDC Guidelines for Influenza 2012-2013

Should be started ASAP in:

Anyone hospitalized with suspected or confirmed

influenza

Anyone with severe, complicated or progressive

respiratory illness

Anyone at higher risk of complications from influenza

Individuals at Higher Risk for Influenza Complications

CDC Guidelines for Influenza 2012-2013

• Extremes of age: children <2, adults ≥65 years

• Comorbid conditions:

– Chronic pulmonary

– Cardiovascular (except HTN alone)

– Renal, hepatic, hematologic, metabolic (DM)

– Neurologic, neuromuscular (cerebral palsy, epilepsy, CVA, SCI)

• Immunosuppression (caused by meds, HIV infection)

• Pregnant or post-partum (<2 wks) women

• Persons <19 years on long-term aspirin

• American Indians & Alaskan Natives

• Morbidly obese (BMI ≥40)

• Residents in NH or chronic-care facilities

Influenza pneumoniaWhat about the 48-hr rule?

Antiviral treatment within 48 hrs

Reduce likelihood of lower tract complications & antibacterial use in outpatients

Hospitalized patients likely benefit even if started up to 3-5 days from illness onset

Additional exceptions to <48 h rule:

Immunocompromised patients

Severe, complicated or progressive illness

Follow-up ResponseExpected improvement?

Clinical improvement w/ effective abx: 48-72 hrs

Fever can last 2-5 days with Pneumococcus, longer with other etiologies, esp Staph aureus

CXR clearing

If healthy & <50 yo, 60% have clear CXR x 4 wks

If older, COPD, bacteremic, alcoholic, etc. only 25% with clear CXR x 4 wks

Switch from IV to PO

Hemodynamically stable, improving clinically

Able to ingest meds with working GI tract

Question…

What is far & away the most common reason for non-response to antibiotics in CAP?

1. Cavitation

2. Pleural effusion

3. Multilobar involvement

4. Discordant antibiotic/etiology

5. Host factors

•

• A 58 y/o man with advanced liver disease,

construction worker in outdoor excavation

• C/O acute fever, cough, pleuritic chest pain,

WBC 23,000.

• CXR and chest CT show RML nodule. No

response to Unasyn + Levo.

• Concern for pneumococcal pneumonia.

Coccidioides immitis

- Endemic to the desert southwest

- Dissemination more common in non-Caucasians, pregnant, immunocompromised

- Acute & chronic pulmonary syndromes (“valley fever”—fever, cough, arthralgias, Erythema nodosum)

- Diagnosis based on serology, culture, or histopathology

NW Infections: Coccidioides

Exposures & Associated Pathogens

Hotel or cruise ship, built water

sources

Travel or residence in SW US

Travel or residence in SE or E

Asia

Travel or residence in Arabian

Peninsula

Influenza active in community

Cough >2 wks with whoop or

posttussive vomitting

Legionella spp

Coccidioides spp

Hantavirus pulmonary syndrome (Sin Nombre virus)

Burkolderia pseudomallei

Avian influenza A (H7N9)

MERS-CoV

Bordetella pertussis

Influenza

S. pneumoniae

Staph aureus (MSSA, MRSA)

H. influenzae

- Legionella: 1-5% CAP. L. pneumophila serogroup 1 responsible for 70-90%. U Ag(+) – contact Micro lab; specialized testing/media.

- Sin Nombre virus: activity put you in contact with rodent droppings, urine, saliva, nesting matter.

- B. pertussis rarely causes pneumonia in adults

Zoonotic Exposures & Associated Pathogens

Bat or bird

droppings

Histoplasma capsulatum

Birds Chlamydophila psittaci

Avian influenza (H7N9)

Rabbits Francisella tularensis

Farm animals or

parturient cats

Coxiella burnetti (Q fever)

Take Home Points

Ask patients about co-morbidities and travel/other potential exposures when they present with a respiratory illness

Evaluate patients for MDR risk factors when managing patients in the community with respiratory illness

GOOD LUCK

SAMIR EL ANSARYICU PROFESSOR

AIN SHAMSCAIRO

elansarysamir@yahoo.com