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🫁 PEDIATRIC PNEUMONIA - COMPREHENSIVE EXAM NOTES

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1. DEFINITION & EPIDEMIOLOGY

• Infection rates vary inversely with age: ~40/1000 in preschool-age, decreasing to ~7/1000 in 12-15 year-olds
• Viral agents cause up to 90% of all pediatric pneumonias - more common in younger children
• Most deaths from pneumonia result from bacterial infections
• Leading bacterial cause beyond neonatal period = Streptococcus pneumoniae (all age groups)

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2. ETIOLOGY BY AGE GROUP

🧠 MNEMONIC: "NEONATES LOVE GRAPES, BABIES CATCH COLDS, SCHOOL KIDS GET MYCOPLASMA"

Special Organisms to Remember:

• Chlamydia trachomatis: Unique cause in 3-19 weeks of age - classic "staccato cough," afebrile pneumonitis, conjunctivitis
• Bordetella pertussis: Classically <1 year, but can occur in older children/adolescents
• Mycoplasma pneumoniae: Most common in >5 years - "walking pneumonia"
• Pneumocystis jiroveci: Immunocompromised patients
• Aspiration pneumonia: Anaerobes, Pseudomonas (consider in neuromuscular disorders, CF)

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3. CLASSIFICATION

🧠 MNEMONIC: "WHERE" = WHO classification

WHO Classification (Developing World - High-Yield for Exams)

WHO Tachypnea Thresholds (THE most tested fact)

🧠 MNEMONIC: "50-40-30" → Under 1 / 1-5 / Over 5

Classification by Setting

Classification by Pathology

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4. CLINICAL FEATURES

General Symptoms (Age-Dependent)

• Fever (may be low-grade or absent in neonates)
• Grunting, nasal flaring, head bobbing
• Apnea - can be the ONLY presenting sign in infants <3 months (RSV, Chlamydia, pertussis)
• Inability to feed (surrogate marker of dyspnea)
• Cyanosis
• Posttussive vomiting

• Fever + cough (productive in older children)
• Chest pain / pleuritic pain
• Abdominal pain (lower lobe pneumonia can mimic appendicitis - classic exam question!)
• Neck pain/stiffness (pleural irritation - can mimic meningitis)
• Malaise, headache

Physical Signs

1. Tachypnea (most sensitive sign)
2. Nasal flaring
3. Intercostal retractions
4. Subcostal/lower chest ("abdominal") indrawing = more severe
5. Tracheal tug
6. Grunting
7. Use of accessory muscles
8. Head nodding (severe)
9. Cyanosis (late, severe)

🧠 MNEMONIC for Hypoxemia signs: "INCA"

Auscultation Findings:

• Fine crackles (rales) = localized → bacterial
• Rhonchi (coarse breath sounds)
• Diminished breath sounds → effusion/consolidation
• Wheezing → viral, Mycoplasma, atypical

Classic Presentations (High-Yield for Exams):

Key Diagnostic Pearl:

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5. INVESTIGATIONS

🧠 MNEMONIC: "BICCUP" = Basic workup

Chest X-Ray

• Not routinely needed for mild, uncomplicated outpatient CAP
• Indicated when: Hospitalization considered, severe disease, failure to respond to treatment, complications suspected
• Not the gold standard - can be falsely negative (clinical disease precedes radiographic changes) or falsely positive (poor inspiration, rotation)
• Does NOT reliably distinguish bacterial vs viral etiology
• CXR patterns:

Blood Culture

• NOT routinely recommended in healthy children with mild CAP (bacteremia rates low)
• Recommended in: Toxic-appearing child, severe disease requiring hospitalization, complicated pneumonia
• Obtain before antibiotic administration
• Low yield - reserve for targeted patients

CBC

• Useful for severe disease to evaluate complications (e.g., pneumococcal HUS)
• NOT useful for reliably distinguishing bacterial vs viral etiology

Inflammatory Markers (CRP, ESR, Procalcitonin)

• Current evidence does NOT support routine use to distinguish bacterial from viral pneumonia
• May be useful to trend disease resolution and guide continued antibiotic therapy in severe disease

Other Tests

• Nasopharyngeal swab (PCR panel): RSV, influenza, parainfluenza, adenovirus, Mycoplasma
• Cold agglutinins (bedside): Positive in >50% of Mycoplasma pneumonia - titer ≥1:64 or 4-fold rise is significant
• Sputum culture: Rarely useful in young children (cannot produce sputum)
• Pleural fluid culture: For large effusions or severe compromise
• TB workup: Gastric aspirate (infants) or induced sputum (older children) when TB suspected

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6. TREATMENT PROTOCOLS

General Principles

• All children with suspected bacterial pneumonia → prompt empiric antibiotics
• Treat viral pneumonia supportively (antivirals rarely indicated except influenza)
• Oral antibiotics = adequate for most mild-to-moderate bacterial CAP
• Parenteral therapy = neonates + severe pneumonia requiring hospitalization

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EMPIRIC ANTIBIOTIC TABLE (THE Most Exam-Critical Section)

🧠 MNEMONIC: "NAB-MAC"

Important Antibiotic Notes:

• Ceftriaxone is CONTRAINDICATED in neonates (displaces bilirubin → kernicterus)
• Azithromycin NOT approved <6 months (risk of pyloric stenosis)
• Fluoroquinolones not routinely recommended in children (theoretical arthropathy risk)
• Doxycycline only for adolescents/adults (permanent tooth staining in young children)
• Macrolide resistance to S. pneumoniae = 7.5-50% in Europe and North America - growing concern
• If child fails amoxicillin after 48-72 hours → add a macrolide (cover Mycoplasma)

Antibiotic Duration:

• Outpatient: typically 7-10 days (standard)
• Azithromycin: 5 days (Z-pack)
• Recent meta-analyses (JAMA Pediatr 2022 [PMID 36374480]): Short-course (3-5 days) may be equivalent for nonsevere CAP
• IV → oral transition: appropriate after 48 hours of improvement on IV therapy

Adjunct/Supportive Therapy:

• Supplemental oxygen if SpO2 <92%
• Oral hydration or IV fluids if dehydrated
• Antipyretics (ibuprofen/paracetamol)
• NO routine corticosteroids (except specific indications: Mycoplasma with macrolide failure, severe refractory disease)
• Chest physiotherapy: Not routinely recommended
• Bronchodilators: Only if significant wheezing/bronchospasm component

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7. HOSPITALIZATION CRITERIA

🧠 MNEMONIC: "SHOP for ICU"

Outpatient (Mild CAP):

• SpO2 >92%, able to take oral fluids, non-toxic, reliable caregiver, good follow-up access

Inpatient:

• SpO2 <92% on room air
• Moderate-severe respiratory distress (retractions, RR significantly elevated)
• Dehydration, inability to take fluids/medications orally
• Failure to improve after 48h outpatient ABx
• Toxic appearance
• Infants <3-6 months
• Suspected or confirmed complicated pneumonia (effusion, empyema)
• Underlying comorbidities (CF, immunodeficiency, sickle cell, CHD, BPD)
• Uncertain diagnosis
• No reliable caregiver / poor social circumstances

ICU Admission:

• Impending respiratory failure / need for mechanical ventilation
• SpO2 persistently <90% despite supplemental O2
• Hemodynamic instability / septic shock
• Altered consciousness
• Extensive bilateral disease

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8. COMPLICATIONS

🧠 MNEMONIC: "PLEASE" = Pneumonia complications

Pulmonary Complications:

Extrapulmonary Complications:

• Dehydration - most common systemic complication overall
• Sepsis / bacteremia → hematogenous spread: meningitis, septic arthritis, pericarditis, epiglottitis, soft tissue infections
• Hemolytic-Uremic Syndrome (HUS) - pneumococcal pneumonia
• Extrapulmonary Mycoplasma: arthritis, meningitis, encephalitis, myocarditis, hemolytic anemia, erythema multiforme (Stevens-Johnson)
• Apnea: RSV, Chlamydia, Pertussis - especially <3 months

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9. MYCOPLASMA PNEUMONIA - DEDICATED SECTION (High-Yield)

🧠 MNEMONIC: "MY COLD WALKING PNEUMONIA"

• Most common in 5-18 year-olds ("walking pneumonia")
• Youth/school-age predominance
• Clinically mild - non-toxic appearance
• Onset gradual/insidious (prodrome: fever, headache, malaise)
• Low WBC (normal or slightly elevated)
• Dry hacking nonproductive cough
• Worse on CXR than clinical exam (CXR out of proportion to examination)
• Associated findings: pharyngitis, conjunctivitis, otitis media, cervical LAD
• Lower lobe consolidation on CXR (most common)
• Kold agglutinins (cold) - positive in >50%
• IgM serology: 4-fold rise diagnostic
• No coryza (unlike viral URIs)
• Generally self-limited and benign
• Problematic in asthma (triggers exacerbation)
• No cell wall (not visible on Gram stain, NOT sensitive to β-lactams)
• Extrapulmonary complications: arthritis, meningitis, erythema multiforme, hemolytic anemia, myocarditis
• Use macrolide (azithromycin/clarithromycin) for treatment
• Macrolide-resistant Mycoplasma: add corticosteroids (meta-analysis 2019: benefit in macrolide-refractory cases)
• Occurs year-round (not seasonal)
• Note: Rash in 10% - EM, urticaria, maculopapular, vesicular
• Incubation: 2-3 weeks
• A - PCR NPS is diagnostic test of choice

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10. NEONATAL PNEUMONIA - DEDICATED SECTION

Risk Factors (Perinatal):

• Prolonged rupture of membranes (PROM)
• Prematurity
• Maternal GBS colonization / chorioamnionitis
• Meconium aspiration (chemical/bacterial pneumonia within 24-72h)
• Intrapartum fever

Organisms:

• Early onset (<72h): Group B Strep (#1), E. coli, Listeria
• Late onset (>72h): S. aureus, coagulase-negative Staph, gram-negatives
• Viral neonatal: CMV, Herpes simplex, Rubella

Treatment:

• Ampicillin + Gentamicin (standard first line)
• Cefotaxime (not ceftriaxone) if gram-negative coverage needed
• Ceftriaxone CONTRAINDICATED in neonates
• Outpatient management NOT recommended for neonatal pneumonia

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11. PREVENTION & VACCINATION

Key Vaccines:

Vaccine Impact:

• PCV7 (2000-01): Dramatic decrease in invasive disease but increase in severity from non-included serotypes
• PCV13 (2010-11): Further decline in incidence and severity worldwide
• Hib vaccine: Dramatic reduction in H. influenzae invasive disease since 1985

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12. SPECIFIC SCENARIOS (Exam Traps)

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13. RADIOLOGY PEARLS

• Poor inspiration in young children creates false appearance of pulmonary infiltrates and cardiomegaly - ALWAYS get technically adequate film
• Bronchiolitis vs Pneumonia CXR: Bronchiolitis = hyperinflation + atelectasis patches (can be misread as bacterial infiltrates → unnecessary antibiotics)
• Staphylococcal pneumonia: Empyema + abscess on same CXR (Fig reference from Rosen's)
• Viral pneumonia: Hyperinflation + peribronchial thickening + diffuse interstitial infiltrates
• Atelectasis ≠ infiltrate (common mistake with right middle/upper lobe)

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14. QUICK REVIEW TABLE - AGE vs BUGS vs DRUGS

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15. HIGH-YIELD ONE-LINERS FOR EXAM

1. Tachypnea is the single most sensitive sign of pneumonia in children
2. 50-40-30 rule for tachypnea: <1yr/>50, 1-5yr/>40, >5yr/>30
3. Ceftriaxone is CONTRAINDICATED in neonates (bilirubin displacement)
4. Azithromycin NOT approved <6 months (pyloric stenosis)
5. S. aureus → pneumatoceles + empyema (post-influenza)
6. Mycoplasma → CXR worse than clinical exam + normal WBC
7. Chlamydia trachomatis → afebrile, staccato cough, eosinophilia, 3-19 weeks
8. Lower lobe pneumonia can mimic appendicitis in young children
9. Apnea alone in infants <3 months can be the only sign of RSV/Chlamydia/Pertussis
10. Blood cultures NOT routine for mild CAP; get BEFORE antibiotics in severe/hospitalized cases
11. CXR does NOT reliably distinguish bacterial from viral pneumonia
12. Viral pneumonia = 90% of all pediatric pneumonias but bacterial = most deaths
13. Failure to respond in 48-72h on amoxicillin → add macrolide (Mycoplasma)
14. PCV13 = 85% protection against serotype-specific pneumococcal pneumonia
15. HUS is a systemic complication of pneumococcal pneumonia

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16. SUMMARY FLOWCHART

Child with Cough + Fever
         |
    Assess Severity
         |
    ┌────┴────┐
   Mild     Severe
    |           |
 Tachypnea?  SpO2 <92%?
 Retractions? Toxic appearance?
    |           |
   YES → CAP  Hospitalize
    |           |
   Age?       Age?
    |
 <3 mo → High risk → Consider admission
 3mo-5yr → Amoxicillin (80-100 mg/kg/d) × 7-10d
 5-18yr → Amoxicillin ± Macrolide × 7-10d
    |
 Follow-up in 48-72h
    |
 No improvement → Add macrolide / reassess

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17. RECENT EVIDENCE UPDATES (2022-2024)

• JAMA Pediatr 2022 [PMID 36374480]: Short-course (3-5 days) antibiotics may be equivalent to long-course for nonsevere CAP - not yet standard practice
• Clin Infect Dis 2023 [PMID 35579504]: 5 days vs 10 days for outpatient CAP in children - comparable outcomes, supports shorter courses in uncomplicated cases
• Lancet Child Adolesc Health 2022 [PMID 35636455]: Respiratory viruses found in up to 81% of pediatric CAP cases - reinforces viral predominance
• Ital J Pediatr 2024 [PMID 39427174]: Italian intersociety consensus recommends amoxicillin as first-line for mild-moderate CAP in otherwise healthy children; macrolides only when atypical suspected

⚠️ Exam Warning: Always use IDSA/PIDS guidelines as primary reference. Short-course therapy evidence is emerging but not yet universally adopted in standard protocols.

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