Pneumonia

Pneumonia

1. epidemiology

   • incidence
     • peaks in infancy & old age
     • relatively high in childhood
   • resource-poor countries
     • a major cause of childhood mortality
   • in > 50% of cases no causative pathogen IDed
   • younger kids
     • viruses= most common cause
   • older children
     • bacteria = commonest cause

2. hard to distinguish btw viral and bacterial pneumonia in clinical practice

3. causative pathogens

   • vary with age
     • newborn
       • organisms from mum's genital tract
         • esp group B strep
         • G-ve enterococci
     • infants & young kids
       • respiratory viruses
         • esp RSV
         • commonest
       • bacterial
         • Strep pneumoniae
         • Haem. influenzae
         • Bordetella pertussis
         • Chlamydia trachomatis
         • Staph. aures
           • infrequent but serious cause
     • children > 5 yrs old
       • Mycoplasma pneumoniae
       • Strep pneumoniae
       • Chlamydia pneumoniae
     • all ages
       • Mycobacterium tuberculosis

4. Immunisation

   • Prevenar
     • conjugate vaccine
     • immunogenicity vs 13 commonest serotypes of Strep pneumoniae
   • Hib (Haemophilus type B) vaccine

5. Clinical features

   • consider pneumonia in children with neck stiffness or acute abdo pain
   • URTI followed by
     • fever
       • fever & difficulty breathing are the commonest presenting sx
     • difficulty breathing
   • cough
   • poor feeding
   • of pleural irritation
     • localised chest pain
     • localised abdo pain
     • localised neck pain
     • all suggestive of bacterial infection
   • on examination
     • tachypnoea
       • best sign of pneumonia in kids
         • don't forget to measure resp rate in a febrile child (so that you don't miss silent pneumonia).
     • nasal flaring
     • chest indrawing
     • end inspiratory coarse crackles
       • often don't hear dullness of percussion, decreased breath sounds or bronchial breathing (signs of consolidation) in young children
       • over affected area
     • reduced O2 sats
       • indication for hopsital admission

6. Ix

   • CXR
     • can confirm classic lobar pneumonia
       • characteristic of Strep pneumo
     • can't differentiate btw viral & bacterial pneumonia
     • blunting of costophrenic angle
       • due to assoc pleural effusion
         • empyema & fibrin strands can form from these
           • -> septations
             • make drainage difficult
   • ultrasound of chest
     • tell btw parapneumonic effusion & empyema

7. Mx

   • home
     • most cases can be managed here
   • British Thoracic Society guidelines
   • indications for admission
     • O2 sats <93%
     • severe tachypnoea
     • difficulty breathing
     • grunting
     • apnoea
     • not feeding
     • family unable to provide approp care
   • Abx
     • choice determined by
       • age
       • severity of illness
       • appearance on CXR
     • newborns
       • msot need broadspectrum
     • older infants
       • amoxicillin for most
       • co-amoxiclav
         • for complicated or unresponsive pts
     • > 5 yrs old
       • amoxicillin
       • macrolide
         • e.g. erythromycin
   • parapneumonic effusions
     • resolve with approp Abx
     • empyema developing from this needs drainage
       • insert chest drain
         • +/- fibrinolytic agent
           • into intercostal space
           • e.g. urokinase
             • break down septations
       • surgical decortication

8. prognosis

   • simple consolidation on CXR & recover clinically
     • follow up not needed
   • evidence of lobar collapse, atelactasis or empyema
     • repeat CXR after 4-6 weeks
   • virtually all kids, even those w/ empyema recover fully