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Pediatric Lower Respiratory Infections

Pediatric Lower Respiratory Infections. Michael J. Muszynski, M.D., F.A.A.P. Age. Community-Acquired Pneumonia Frequency. Cases/1000 Population. Pneumonia Etiologies. Age Epidemiological factors Clinical Presentation Hospitalized Ambulatory X-ray appearance.

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Pediatric Lower Respiratory Infections

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  1. Pediatric Lower Respiratory Infections Michael J. Muszynski, M.D., F.A.A.P.

  2. Age Community-Acquired Pneumonia Frequency Cases/1000 Population

  3. Pneumonia Etiologies Age Epidemiological factors Clinical Presentation Hospitalized Ambulatory X-ray appearance

  4. Pneumonia Etiology(Juvan et al: Pediatr Infect Dis J 19:293-8, 2000) Streptococcuspneumoniae 37% Respiratory syncytial virus 29% Rhinovirus 24%

  5. Ambulatory PneumoniaWubbel et al: Pediatr Infect Dis J 18:98-104, 1998

  6. Human Metapneumovirus • Cough 69% • Rhinorrhea 69% • Fever 63% • Wheezing 50% • Hypoxia 31% • (O2 sat < 90%) • CXR: Peribronchial cuffing, prominent hilum, focal infiltrates Esper et al 2003

  7. Suspected Aspects of Metapneumovirus • Causes pneumonitis and bronchiolitis similar to RSV • Acts much like influenza virus bronchiolitis • May be a co-pathogen with other viruses • may worsen disease • Preterm infants may be particularly prone • Virtually everyone by age 5 years has been infected (serologic data) • Similar epidemiology to RSV but with more strain variation geographically • Winter distribution most likely

  8. Human Bocavirus • Cough 78% • Fever 67% • Sore throat 44% Emerg Infect Dis.12(5):848-50, 2006.

  9. Undiagnosed Respiratory Viruses in Children • Metapneumovirus+HBoV 9 11.8/10.9 • HBoV+RSV 9 10.9/5.2 • Adenovirus+RSV 5 5.7/2.9 • Adenovirus+HBoV 4 4.6/4.9 • Metapneumovirus+RSV 3 3.9/1.7 • Adenovirus+MPV 1 1.1/1.3 Emerg Infect Dis.12(5):848-50, 2006

  10. Pneumonia EtiologyHospitalized children, 5-14 yrs of age (n = 75) • Viruses 65% • Adenovirus 12% • Parainfluenza 8% • Influenza 7% • RSV 3% • Metapneumovirus 1% • Rhinovirus 45% CID 39(1):681-6, 2004

  11. Other Emerging Viruses Human Corona Viruses NL63, HKU1 1-9% of respiratory disease: upper tract, croup and bronchiolitis Less virulent SARS relatives Adenovirus AD14 Reemergence of an strain identified in 1955 Causes severe pneumonia Surveillance ongoing

  12. Other Emerging Viruses Influenza Disproportion of severe disease and mortality in patients < 5 years of age (and especially < 2 years)

  13. Pneumonia EtiologyHospitalized children, 5-14 yrs of age (n = 75) • Bacteria 40% • Pneumococcus 7% • Mycoplasma 35% • Chlamydophila 3% Note that mixed infections (virus + bacteria) occurred in 5% CID 39(1):681-6, 2004

  14. “Afebrile Pneumonitis Syndrome”“Infant Tachypnea Syndrome” • Infants 1-3 months of age • Non-seasonal or seasonal • Subacute presentation • Tachypnea • Afebrile or low-grade fever • Variable cough, crackles, wheezes • CXR - Bilateral, perihilar, +/- hyperinflation

  15. “Afebrile” Pneumonitis SyndromeEtiologies • RSV • Chlamydiatrachomatis • Bordetellapertussis • CMV Alone or in any combination

  16. C. trachomatis “Clues” History of maternal STD Conjunctivitis under four weeks of age Eosinophilia Staccato cough Afebrile and tachypneic with diffuse rales +/- retractions

  17. Pertussis in Infants • Classic presentation (less common) • Catarrhal, paroxysmal, convalescent stages • Atypical under 6 months of age (common) • Pneumonitis • Tachypnea • Apnea

  18. Diagnosis of Pertussis Which testing method do you use in your practice? • History and physical examination only • History and physical examination plus CBC and differential only • Culture • Direct Fluorescent Antibody (DFA) • B. pertussis PCR

  19. Pertussis DiagnosisA tough problem • Culture • Special media required; time is of the essence • Insensitive, but specific • Negated by antibiotic treatment • DFA • High specificity (90%), but low sensitivity (< 50%) • Lymphocytosis • Very sensitive (Near 100%), but not at all specific • PCR is a reasonable method • Sensitivity & accuracy vary between laboratories

  20. RSV • Wide spectrum of disease presentations • URI • Croup • Bronchiolitis • Sepsis • Apnea • Combined with other etiologies

  21. Other Factors To Assess Etiology • Epidemiology • Age • Season • Immunization status • Influenza, Hib, pneumococcal conjugate • Radiographs

  22. Para 1 Para 3 Para 2 Seasonal Considerations

  23. Seasonal Considerations Specimens tested RSV +

  24. Radiology Generality and Reality

  25. Radiology • Lobar process tends to be Bacterial • Effusion • S. pneumoniae • S. aureus • GABHS • Rarely Mycoplasma • H. influenzae type b if not immunized

  26. Radiology • Pneumatocele • S. pneumoniae • Penicillin resistance • S. aureus • MRSA • Rarely Klebsiella

  27. Radiology • Abscess • S. aureus • MRSA • Anaerobes • Non-ID • CAML • Foreign body

  28. Radiology • Bilateral + air trapping +/- atelectasis • Bronchiolitis • RSV • Parainfluenza • Influenza (during outbreaks) • Non-ID • Asthma

  29. Radiology • Bilateral findings tend to be • Viruses • Mycoplasma pneumoniae • Chlamydophila pneumoniae and C. trachomatis (infants)

  30. Radiological AppearanceThe bottom line • Inter-observer correlation is fair at best • Etiology determination difficult at best • Bacterial process can be diffuse and with interstitial appearance in very young infants • Mycoplasma can be lobar in older children

  31. Radiological AppearanceThe bottom line • CXR very helpful in defining pulmonary complications, extent of disease, but not necessarily severity • Confirms diagnosis in some cases, but a normal CXR doesn’t necessarily rule out pneumonia in other cases • CXR may point the clinician in a direction, but can never replace clinical judgment

  32. Radiographic Findings • High fever • Sudden onset • Additional symptoms • Diarrhea • Rash • Low platelet count GABHS Toxic Shock

  33. Streptococcus pneumoniae

  34. Pneumonia Diagnostic Methods

  35. Pneumonia DiagnosisClinical • Coughing infants • Abnormal chest exam • Tachypnea • Most sensitive clinical finding • > 50 breaths/min < 1 y.o. • > 40 breaths/min > 1 y.o.

  36. Pneumonia Diagnosis

  37. Pneumonia DiagnosisBacterial Etiology • Bacteria Cultures • Blood: extremely specific, extremely insensitive • < 1-10% positive rate • Sputum: Only in older patients • Unreliable in infants and children • No correlation with lower respiratory tract • Major exception: Cystic fibrosis patients • Throat or sputum = excellent correlation

  38. Nasopharyngeal WashesViruses and Chlamydia

  39. Pneumonia Diagnosis • Virus culture and rapid virus tests • Upper respiratory specimens correlate well with lower respiratory tract • Upper respiratory specimen has higher yield than lower • Positive result doesn’t totally rule out bacterial etiology • PCR on the horizon

  40. Pneumonia Diagnosis • Bronco-Alveolar Lavage (BAL) in severe illness or immune compromised • Thoracentesis for effusions • The emergence of CA-MRSA

  41. Pneumonia TreatmentOutpatient and Cases of Mild-moderate Severity • Approaches to therapy • To treat or not to treat with antibiotics • Treat all since bacteria, mycoplasma, chlamydia can’t be completely ruled out in any scenario and mixed infections do occur • Withhold treatment for mildly ill patients in whom viral illness is likely • Withhold therapy where diagnosis of bronchiolitis is obvious McCracken: Pediatric Infect Dis J 19:924-8, 2000

  42. Streptococcus pneumoniae

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