Community Acquired Pneumonia

Renato T. Stein, MDPorto Alegre, Brazil

Pneumonia in Developing Countries

• Incidence of pneumonia is 10 times higher in developing than in developed countries;

• ~5 million deaths occur yearly in children younger than 5 years.

• Nutritional status, age, and the presence of an underlying condition are major risk factors

MOST SIGNIFICANT RISK FACTORSEspecially in Low Income Countries

• low birth weight• malnourishment• no breast feeding• failure in vaccination schedule • low maternal education• air pollution / ETS

PneumoniaPneumonia

• Gold standards– lower Aw aspirate or lung biopsy

• Clinical dx with radiological component• Age-specific prevalent species are

important for logical approach at ethiology

Diagnosis

• Fever, cough, tachypnea (overlap w/ bronchiolitis in young children)

• WHO RR signs: sensitivity 74%, specificity 67%• PPV of clinical signs is greater in developing

countries: higher prevalence of pneumonia• NPV is greater in developed countries where

prevalence is lower• Margolis e Gadomski, JAMA, 1998; 279(4)

DIAGNOSISConsider:

• Epidemiology• Clinical presentation• Radiology• Age of child• Immune status• How infection was acquired

Diagnostic Tests

• Very low yield of positive tests; in complete trials 70% positive (serology, culture, nucleic acid amplification tests, immunofluorescence)

• Overall, respiratory viruses account for 20–45% of all infections

• S. pneumoniae is the agent in 27-44% of cases of CAP in children

• Observe local seasonal epidemics

Chest X-Ray DiagnosisChest X-Ray Diagnosis

• BTS guidelines: consider in children < 5y with fever > 39o C of unknown origin

• Interpersonal variability• Can be normal at beggining of the

infection• Alveolar/lobar infiltrates w/ air space

opacification: not sensitive but valuable

Chest X-rays

• May be useful for confirming presence of pneumonia and detecting complications such as a lung abscess or empyema

• Not useful for discriminating causative agents; cannot accurately discriminate between viral and bacterial pneumonia

• Great inter-observer variability

Indications for CXRs

• Clinical pneumonia unresponsive to standard ambulatory management

• Suspected pulmonary TB• Suspected foreign body aspiration • Hospitalized children to detect

complications

Viral and Bacterial Pneumonias

• Most pneumonias in the first 3y of lifeare viral declining afterwards(Heiskanen-Kosma T et al. Pediatr Infect Dis J 1998)

• The association of viral and bacterialpneumonias is not frequent (~5 -10%)

• Co-infection may be more frequent in non-affluent communities

Validation Score to Distinguish Bacterial from Viral Pneumonia

Moreno L. et al. Ped Pulm 2006

Moreno L. et al. Ped Pulm 2006

Viral Agents

• RSV is the major agent <2y causing viral CAP; Rhinovirus is highly prevalent thereafter

• Influenza, HMPV, Adenovirus, Paraflumay also be present

Pneumococcal Pneumonia

• Most prevalent agent in hospital admissions • Resistant strains: low to 40’s%• Typical picture

– ill appearance, fever of 39°C or higher, leukocytosis, and lobar or segmental consolidation, pleural effusions

– ~25% may have no respiratory symptoms (GI)

Impact of HIV Epidemic

• Increased the incidence, severity and case fatality of childhood pneumonia (Jadavji T et al. Can Med Ass J 1997; Zar HJ. Curr Opin Pulm Med. 2004)

• CAP accounts for between 30-40% of hospital admissions with associated case fatality rates of between 15-28%

HIV Infected Children

• Pneumocystis jiroveci pneumonia (PJP) is common and serious infection and associated with high mortality

• Infants aged 6 weeks to 6 months are at highest risk for infection

• PJP is the predominant cause of pneumonia mortality in HIV-infected children less than 6 months of age.

HIV-related Agents

• PJP has also been described in malnourished children as well as young HIV-exposed uninfected infants

• M. tuberculosis was positive in 8% of HIV infected/uninfected children hospitalized for acute pneumonia in S.A. (Zar HJ et al.Acta Paediatr 2001)

Always Consider Tuberculosis…

• Tuberculosis should always be considered as a possible diagnosis, especially in endemic areas

• May clinically mimic common viral or bacterial CAPs

Other Agents

• Routine immunization against Hib has decreased the incidence of pneumonia due to this bacterium; non-typablestrains are still responsible for a small proportion of pneumonia in South Africa (Zar HJ et al 2006)

• S. aureus causing CAP is more frequent in developing countries

Mycoplasma Pneumonia

• More prevalent over the age of 5y• Fever, cough, wheezing are most

prominent features• “No typical” radiological findings

– Pulmonary infiltrates, lobar or segmental consolidation, pleural effusions

Tx Choices

• ~20% of children with suspected viral pneumonia receive antibiotics (Friis B. et al. Arch dis child 1984)

• WHO suggest co-trimoxazole as a first choice for CAP; concerns on resistence

• Oral Amoxacilin may be the most reasonable choice for empyrical Tx

Hale KA, Isaacs, D. Paed Resp Rev 2006

Children at Risk for HIV or Symptomatic HIV disease

• Add Aminoglycoside to empirical treatment; or be covered against Gram-negative bacteria.

• If PJP is suspected add cotrimoxazole. • All HIV exposed children <6 mo should be

treated empirically for PJP if hospitalized for severe pneumonia, unless HIV infection status is confirmed to be negative and the child is not breast-fed

Special Conditions

• Empirical treatment with cotrimoxazole, amoxicillin and an aminoglycosideshould also be considered for older HIV infected children with features of severe AIDS who are not on cotrimoxazoleprophylaxis.