VIRAL AND BACTERIAL PNEUMONIA IN CHILDREN 林口長庚醫院 急診醫學部 吳孟書 醫師 吳孟書 醫師

PNEUMONIA  Defined pathologically as an inflammation of lower tract lung tissue.  Defined clinically by pulmonary infiltrations in a chest radiography + clinical signs and symptoms + abnormal auscultatory findings  Viruses : parainfluenza in fall, RSV in winter, influenza in spring  Pneumococcus

PATHOPHYSIOLOGY  Aerosolized particles  Nasal cavity : filter and entrap  Laryngeal reflex and coughing  Alveolar macrophage  Activation of complement and Ab  Lymphatic drainage

Signs and Symptoms of Pneumonia  Cough  Fever  Chest pain  Short of breath  Tachypnea  Malaise  Abdominal pain  hypoxia

Typical Pneumonia  Abrupt onset  High grade fever/chillness  Pleuritic chest pain  Productive cough  Toxic appearance with dyspnea  Local findings on chest examination  Usually bacterial infection

Atypical Pneumonia  Gradual onset (over days)  Prodromal phase of headache, malaise, nonproductive cough, and rhinorrhea  Low grade fever  Wheezing  Conjunctivitis  Pharyngitis  Rash  Usually viral in origin  Mycoplasma infection may mimic this pattern but also can present with acute symptoms including skin rash.

Pneumonitis Syndrome  Very young infants (1 to 3 mo)  Afebrile  Cough  Tachypnea or even respiratory distress  Bilateral diffuse pulmonic infiltrates with air trapping on CxR  RSV, other virus  Chlamydia trachomatis -- maternal  Bordetella pertussis  Ureaplasma urealyticum

Risk Factors for Pneumonia  Young age  Male  Pollution  Nutritional status  Immunodeficiency  Anatomic airway abnormalities  Metabolic diseases  Socioeconomic factors

Diagnosis  Solely on clinical histories and positive physical examination  Diffuse interstitial filtrates, hyperinflation, peribronchial thickening, and areas of atelectasis on CxR --- viral  Segmental or lobar consolidation on CxR --- bacterial  Pneumatocele formation and a combination pneumothorax and empyema --- S. aureus  M. pneumonia --- lower lobe streaky or patchy infiltrates, but usually variable

Laboratory Studies  CBC/DC  Blood culture – rarely positive  Sputum culture  Cold agglutinin test for M. pneumoniae  Serologic test for viruses if indicates  Skin test for suspecting tuberculosis  Other invasive studies in more severe cases or unresponsive to empiric antibiotics

Differential Diagnosis  Congestive heart diseases  Atelectasis  Primary or metastatic tumors  Congenital pulmonary abnormalities  Radiologic imaging problems  Collagen vascular disorders, or allergic alveolitis  Cystic fibrosis  Asthma

Pathogens and Empiric Therapy in Pediatric Pneumonia Age Bacterial Pathogens Viral Pathogens Other Pathogens Empiric Therapy ＜ 1 mo Group B streptococcus E. coli KlebsiellaPseudomonasListeria Varisella, RSV Chlamydia* Ampicillin + Aminoglycoside or Ampicillin + Cefotaxime* 1-3 mo H. Influenza, S. pneumoniae, Group A Streptococcus, Pertusis, Group B Streptococcus RSV, Parainfluenza, Influenza, Adenovirus Chlamydia* Ampicillin + Cefotaxime* 3 mo to 5 yrs S. pneumonia, H. influenza, S. aureus, Group A Streptococcus, Pertusis RSV, Parainfluenza, Influenza, Enterovirus, RhinovirusChlamydia* Cephalosporin or ampicillin + chloramphenicol or antistaphyloccal rhinovirus agent if course indicates* ＞ 5yrs S. pneumoniae, H influenza, Group A Streptococcus Parainfluenza, Influenza, Adenovirus,RhinovirusMycoplasma Penicillin or ampicillin or cephalosporin or antistaphylococcal agent if course indicates or erythromycin or azithromycin if course suggests Mycoplasma

Special Considerations  All age with severe pneumonia: 1.S. pneumoniae 2.S. aureus : rapidly progressive pulmonary abscess 3.Group A streptococcus : necrotizing fasciitis with pneumonia and empyema 4.Hemophilus influenza type B (HIB) 5.M. pneumonia : in sickle cell disease 6.Adenovirus GNB including Pseudomonas : recent hospitalization GNB including Pseudomonas : recent hospitalization Anaerobic infections : aspiration Anaerobic infections : aspiration

Special Considerations  All ages with immunocompromised disease: 1.All of above All of aboveAll of above 2.P. carinii 3.Cytomegalovirus 4.Fungi

Treatment  Assessment for hyoxia and O 2 supplement  Hydration status consideration  Empiric antibiotics for suspected bacterial pneumonia as table 12 table 12table 12  Acyclovir for varicella in immunocompromised patients  Ribavirin in selective high-risk patients for severe RSV pneumonia  Ganciclovir and gammaglobulin for cytomegaloviral pneumonia in patients with bone marrow or solid organ transplantation  Bronchodilator for bronchiolitis-like syndrome and pulmonary toilet

Disposition  Admission criteria: 1.Hypoxia – SaO 2 ≦ 90% 2.Respiratory distress 3.A history of apnea or cyanosis 4.Toxic appearance 5.Dehydration 6.Age less than 3 months 7.Impaired immune function 8.Presence of pleural effusion or pneumatocele 9.Infection unresponsive to oral therapy 10.Socioeconomic consideration

Disposition  Discharge instructions: a)Specific advise on the dosage and scheduling of medications b)Specific advise on the signs of worsening respiratory distress c)Children who become unable to ingest adequate amounts of fluid or prescribed antibiotics should be instructed to return for further care. d)Follow-up within 24 to 48 h