Community Acquired Pneumonia

pediatrics.uchicago.edu

Community Acquired Pneumonia

Community Acquired

Pneumonia

Morning Report

August 2005


Epidemiology

Annual incidence in children < 5y is 34-40 34 40

per 1000; 7 per 1000 in adolescents

More common and more severe in

developing countries

Definition varies widely and features of

pneumonia overlap with bronchiolitis in

infants

Defined as presence of fever, acute

respiratory symptoms, or both, plus

evidence of parenchymal inflitrates on CXR


HOST DEFENSE

MECHANISMS

Nasopharyngeal air filtration

Hairs in anterior nares, nares,

ciliated epithelium

Laryngeal protection of airway

Helps prevent aspiration

Mucociliary clearance

Impairment of ciliary function can be caused by exposure to

cigarette smoke

Normal cough reflexes and strength

Neuromuscular disorders higher risk

Anatomically normal airway

Normal humoral and cellular immunity

Also affected by cigarette smoke; immunodeficiency


COMMON CAUSES

VIRUSES

RSV, Influenza A or B

Parainfluenza 1,2,3

Adenovirus

Rhinovirus

MYCOPLASMA

Mycoplasma

pneumoniae

CHLAMYDIA

Chlamydia

trachomatis

C. pneumoniae

BACTERIA

Strep pneumo

Staph aureus

Mycobacterium TB

Nontypable H

influenza


NEONATES (Birth to 20d)

Difficult to distinguish from RDS or TTN

Treat empirically for E. coli, GBS, H. flu, Strep pneumo, pneumo,

Listeria with Ampicillin/Gentamicin with or without 3 rd

generation cefotaxime

GBS pneumonia onset is first 12-24 12 24 hr, usually severe,

bilateral, diffuse

CXR may exhibit diffuse reticular nodular appearance,

may have pleural effusions associated with GBS

BCX commonly grow offending organism

Obtain UCX and CSF

Consider CMV if unresponsive to therapy, other signs


INFANTS (3 wks to 3 mo)

Bacterial Pneumonia

Strep pneumo most common cause; other organisms

include S. aureus, aureus,

Moraxella catarrhalis, catarrhalis,

H. influenzae

(non-typeable

(non typeable)

If suspected, BCX, UCX and CSF advisable

CXR with focal consolidation is characteristic, but not

required for diagnosis

BCX less likely to be positive (20-30%) (20 30%)

If suspected, empiric IV antibiotics with ampicillin and

cefotaxime unless concern for Staph aureus (clinical

course, presence of large effusion) add Clindamycin or

Vancomycin

Once defervesced and stable, high dose Amox to

complete 10d

Bordetella pertussis (paroxysmal cough, whoop,

lymphoctoysis);

lymphoctoysis);

tx with erythromycin or

azithromycin


INFANTS (3 wks to 3 mo)

RSV (2mo-7mo, (2mo 7mo, mid-winter/spring)

mid winter/spring)

Parainfluenza (slightly older, not epidemic)

Chlamydia trachomatis

acquired by maternal genital infection

suspect in afebrile, afebrile,

non-toxic non toxic patient with dry cough

and tachypnea, tachypnea,

not hypoxic

Peripheral eosinphilic pleocytosis

Tx with erythromycin or azithromycin


4 MONTHS to 4 YEARS

Viruses are the most common cause of pneumonia in

the younger children

RSV, parainfluenza, parainfluenza,

influenza, adenovirus, rhinovirus

Severe viral pneumonia may result in secondary

bacterial pneumonia

Mycoplasma pneumoniae may be present in older

patients in this age group

Strep pneumo still most common cuase of bacterial

pneumonia in pre-school pre school age children

CXR in febrile, tachypneic child with cough, particularly

in presence of focal crackles, wheezing or history of

asthma


4 MONTHS to 4 YEARS

Outpatient therapy if bacterial pneumonia is

suspected: oral Amoxicillin (80-100mg/kg/day)

(80 100mg/kg/day)

x 10 days with close follow up

Inpatient: if hypoxic, in distress without lobar

infiltrate or effusion, can observe if viral

etiology is likely; otherwise treat with IV

ceftriaxone +/- +/ clindamycin

Inpatient with signs of sepsis, large pleural

effusion, alveolar infiltrate treat with IV

ceftriaxone + clindamycin or vancomycin


5 YEARS to 15 YEARS

Mycoplasma pneumoniae and C pneumonia

(controversial) become important pathogens

Strep pneumoniae continues to be important pathogen

PE tools more reliable

Bacterial pneumonia characterized by abrupt onset of

high fever and productive cough

Can obtain sputum; adequate if > 25 leukocytes and

fewer than 25 squamous epitherlial cells per lpf

Tx with high dose amoxicillin if bacterial pneumonia is

suspected; if requires inpatient can use IV ceftriaxone

(pneumococcus

pneumococcus resistance – intermediate still ok to

use high dose penicillins) penicillins

Tx Mycoplasma with macrolide or tetracycline (older

child)


PLEURAL EFFUSIONS

Pneumococcus is most common cause

of pneumonia in children and also most

common cause of pleural fluid

accumulation

Large pleural fluid collection and

empyema are frequent in cases of S.

aureus pneumonia


Imaging Studies - CXR

PA/AP

Blunting of diaphragmatic

borders or costophrenic

angles

Pleural mass without air

bronchogram

View CXR’s

http://www.utdol.com/application/image.asp?file

=pulm_pix/pleura9.gif

DECUBITUS

Thin mobile fluid “layers layers

out” out on dependent side

If film demonstrates fluid

> 10 mm, perform a

diagnostic thoracentesis

Failure of liquid shift

indicates loculation


Other Imaging

Ultrasound

Distinguishes loculated pleural fluid

from infiltrate

Can identify best site for thoracentesis

or placement of thoracostomy tube

CT

Delineates pleural fluid loculations

Detects airway or parenchymal

abnormalities


Classification

Uncomplicated parapneumonic

effusion

Complicated parapneumonic effusion

Thoracic empyema

Or

Exudative Stage

Fibropurulent Stage

Organization Stage


Uncomplicated Effusion

(Exudative

Exudative Stage)

Interstitial fluid increases during pneumonia

and accumulates in pleural space because:

↑permeability permeability of interstitium

absorptive capacity of pleural space is

exceeded

Effusion characteristics

exudative

neutrophilic

low WBC and LDH

normal glucose and pH


Complicated Effusion

(Fibropurulent

Fibropurulent stage)

Bacterial invasion of the pleural space

Effusion characteristics

↑Neutrophils

Neutrophils

↑ cellular debris

↑LDH LDH

Lower pH and glucose

Sterile because of rapid bacterial clearance

Tendency toward loculation


Thoracic empyema

(Organization stage)

Fibroblasts grow into the exudates from both the

visceral and parietal pleural surfaces, producing

pleural peel

Effusion characteristics

thickened pleural fluid

aspiration of pus on thoracentesis

bacterial organisms on Gram stain

positive culture is not required for diagnosis


Antibiotic Therapy

Broad spectrum antibiotics to cover the

most common pathogens for the child’s child s age

group

Tailor antibiotic therapy according to

cultures, if possible

IV antibiotics until afebrile for 7 – 10 days,

weaned from O2 and not ill appearing

Oral antibiotics continued for total of 1 to 3

weeks


Beyond Antibiotics

Uncomplicated parapneumonic effusions

Resolve with antibiotics alone

Thoracentesis recommended only if patient has

persistent fever, toxicity, respiratory

compromise

Repeat the thoracentesis if condition worsens

Serial radiography or PE to document resolution

Complicated parapneumonic effusions

Variable response to antibiotics alone

If gram stain is + or effusion is characteristic of

complicated effusion, tube thoracostomy is

recommended

Empyema

Immediate tube thoracostomy

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