Pediatric Pneumonia: Pathogenesis and clinical findings

Pediatric pneumonia: Pathogenesis and clinical findings
Immunological: immunization status, immune compromise
Environmental: second-hand smoke, air pollution
Hospitalization: length of stay, recent antibiotics, mechanical ventilation
Neonates, immunocompromise, underlying lung disease (ciliary dysfunction, Cystic Fibrosis, bronchiectasis)

Exposure to pathogen: inhalation, hematogenous, direct, aspiration
Susceptible host and/or virulent pathogen
Infection and proliferation of pathogen in lower respiratory tract/parenchyma
Pediatric pneumonia: Inflammatory response to proliferation of microbial pathogens at the alveolar level
Authors: Nicola Adderley Reviewers: Midas (Kening) Kang Usama Malik Eric Leung* * MD at time of publication
Notes: • Additional findings in pediatric pneumonia may include nausea, otitis, headache • Viral pathogens most common in children <2yrs; bacterial pathogens most common in children >2yrs • Interstitial pattern: suspect Mycoplasma pneumoniae, Influenza A + B, Parainfluenza • Lobar pattern: suspect S. pneumonia, H. influenzae, Moraxella, S. aureus
Local inflammatory response: neutrophils recruited to site of infection (LOBAR or INTERSTITIAL PATTERN, depending on pathogen) by epithelial cytokine release
At– Irritation of contiguous structures and/or referred pain (mechanism unclear)
Acute abdominal pain
Accumulation of plasma exudate (from capillary leakage at sites of inflammation), cell-debris, serous fluid, bacteria, fibrin
Irritation of airways and failure of ciliary clearance to keep up with fluid buildup Cough
Crack es, 4• breath sounds
Pathophysiology Mechanism
Fluid buildup in spaces between alveoli (INTERSTITIAL PATTERN)
Interstitial opacity on CXR
Fluid buildup in alveoli (LOBAR PATTERN)
J, efficiency of gas exchange (I` diffusion distance in INTERSTITIAL, J, surface area in LOBAR)

Lobar consolidation on CXR
Sign/Symptom/Lab Finding
Systemic inflammatory response:
Cytokine release (eg. TNF, IL-1)
1` respiratory drive

Disruption of hypothalamic thermoregulation
Respiratory accessory muscle use (chest indrawing, paradoxical breathing, muscle retractions)