Neumonía adquirida en la comunidad

Community Acquired Pneumonia

Renato T. Stein, MD Porto 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 FACTORS Especially in Low Income Countries • • • • • •

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

Pneumonia • 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)

DIAGNOSIS Consider:

• • • • • •

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 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 life are viral declining afterwards (Heiskanen-Kosma T et al. Pediatr Infect Dis J 1998)

• The association of viral and bacterial pneumonias 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 â&#x20AC;˘ RSV is the major agent <2y causing viral CAP; Rhinovirus is highly prevalent thereafter â&#x20AC;˘ Influenza, HMPV, Adenovirus, Paraflu may 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 â&#x20AC;˘ 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)

â&#x20AC;˘ 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 â&#x20AC;˘ PJP has also been described in malnourished children as well as young HIV-exposed uninfected infants â&#x20AC;˘ 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 â&#x20AC;˘ Routine immunization against Hib has decreased the incidence of pneumonia due to this bacterium; non-typable strains are still responsible for a small proportion of pneumonia in South Africa (Zar HJ et al 2006)

â&#x20AC;˘ 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 â&#x20AC;˘ Empirical treatment with cotrimoxazole, amoxicillin and an aminoglycoside should also be considered for older HIV infected children with features of severe AIDS who are not on cotrimoxazole prophylaxis.