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PEDIATRIC PNEUMONIA - KMTC Exam Notes

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1. DEFINITION

Exam tip: Pneumonia is NOT the same as bronchiolitis (small airways) or bronchitis (large airways).

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2. EPIDEMIOLOGY (Know the Numbers)

Exam tip: Over 2 million children worldwide die annually from acute respiratory tract infections - pneumonia is the single biggest killer.

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3. ETIOLOGY - BY AGE GROUP (MUST KNOW)

Neonates (0-30 days)

• Group B Streptococcus (GBS) - most common, transmitted vertically
• Gram-negative enteric bacteria: E. coli, Klebsiella
• Listeria monocytogenes
• Late onset (7-10 days): Staphylococcus aureus, S. pneumoniae, S. pyogenes
• Chlamydia trachomatis (if mother untreated)

Rule: Every neonate with pneumonia must be evaluated for SEPSIS

Infants 1 month - 2 years

• Viral causes predominate (>70% of hospitalized cases)
• RSV (Respiratory Syncytial Virus) - most important
• Rhinovirus, Parainfluenza, Influenza, Human Metapneumovirus, Adenovirus
• Most common bacterial cause: Streptococcus pneumoniae
• Others: H. influenzae type b (non-immunized), nontypeable H. influenzae
• Less common: S. aureus, Group A Strep, Bordetella pertussis

Children 2-5 years

• Still mostly viral (RSV, rhinovirus, metapneumovirus)
• S. pneumoniae - still key bacterial cause
• H. influenzae type b (non-immunized children)
• Mycoplasma and Chlamydophila pneumoniae - LESS common below age 5

Children 5-13 years (School Age)

• Viruses continue to predominate
• Mycoplasma pneumoniae becomes important (~17% of cases)
• Chlamydophila pneumoniae, S. pneumoniae
• Less common: S. aureus, Group A Strep, nontypeable H. influenzae

Adolescents (>13 years)

• Same as healthy adults
• M. pneumoniae, C. pneumoniae (atypical agents) play significant role
• S. pneumoniae remains important

Exam shortcut - Atypical agents (Mycoplasma, Chlamydophila, Legionella) cause "walking pneumonia" - patient appears less sick, smoldering onset, low-grade fever, dry cough, diffuse interstitial infiltrates on X-ray.

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4. PATHOPHYSIOLOGY

1. Inhalation/aspiration of pathogens (most common)
2. Contiguous spread from nasopharynx (bacterial colonization)
3. Hematogenous spread (rare)

• Nasal hairs/turbinates, cilia, epiglottis, cough reflex
• Secretory IgA (humoral)
• Alveolar macrophages (cellular)

• Alveoli fill with exudate (pus, fluid, debris)
• Atelectasis (lung collapse)
• Impaired oxygenation
• Ventilation-perfusion (V/Q) mismatch

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5. CLINICAL FEATURES

Classic Signs (ALL ages)

• Cough (productive or dry)
• Fever (high in bacterial, low-grade in viral/atypical)
• Tachypnea - EARLIEST and MOST reliable sign
• Respiratory distress: nasal flaring, intercostal retractions, grunting
• Cyanosis (severe cases - sign of hypoxia)

The Earliest Diagnostic Clue in Children:

"Tachypnea disproportionate to the degree of fever"

Signs by Type

Signs of Severe Pneumonia/Hypoxemia

• Inability to feed (infants)
• Altered mental status / lethargy
• Cyanosis
• Head nodding
• Grunting respirations

Physical Exam Findings (After Consolidation)

• Decreased breath sounds on affected side
• Dullness to percussion
• Egophony ("E" sounds like "A" over consolidated lung)
• Bronchial breathing over consolidation
• Tactile fremitus (older children)
• Pleural rub (if pleuritis)

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6. WHO/IMCI CLASSIFICATION (VERY HIGH YIELD FOR KMTC)

Tachypnea Cut-offs (MEMORIZE)

Trick for exams: 60-50-40 decreasing as age increases. Always COUNT for a FULL MINUTE. In infants <2 months, repeat the count if ≥60 because breathing is irregular.

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I. VERY SEVERE DISEASE

• Not able to drink/feed
• Convulsions
• Abnormally sleepy / difficult to wake
• Stridor in a calm child
• Severe malnutrition (visible wasting)

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II. SEVERE PNEUMONIA

• Note: Mild chest indrawing is normal in young infants (soft chest wall)
• A child with chest indrawing + first episode of wheezing may have severe pneumonia
• A child with chest indrawing + recurrent wheezing more likely has asthma

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III. PNEUMONIA (Not Severe)

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IV. NO PNEUMONIA: Cough or Cold

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Young Infants (Under 2 Months) - Different Category

• Fast breathing OR chest indrawing classified as Severe pneumonia
• Because even mild chest indrawing in young infants is abnormal if persistent
• Many cases may also have sepsis - must rule out

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7. DIAGNOSIS

Clinical Diagnosis (Primary for KMTC)

• History + physical examination sufficient in most cases
• Isolation of causative agent is NOT necessary for routine CAP management
• Treatment proceeds empirically (by age and clinical picture)

Investigations

Exam tip: CXR findings of consolidation (lobar) once thought = bacterial. Interstitial infiltrates = viral. This is NO LONGER reliable - both can have either pattern.

Classic CXR Patterns

• Lobar consolidation - classically pneumococcal (S. pneumoniae)
• Interstitial infiltrates (diffuse) - classically viral or atypical (Mycoplasma)
• Perihilar infiltrates - often viral (Chlamydia, Mycoplasma)
• Pneumatoceles / lung abscess - suggest Staph. aureus

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8. MANAGEMENT

A. Supportive Care (All Cases)

1. Supplemental oxygen - maintain SpO2 >90-92%
2. Antipyretics - paracetamol (NOT aspirin in children - risk of Reye's syndrome)
3. Fluids - oral, NG, or IV to offset respiratory losses
4. Bronchodilators - only if wheeze present in the context of asthma (NOT routinely for bronchiolitis in infants <24 months)
5. Positioning - upright/semi-recumbent helps breathing
6. Cough suppressants - NOT generally indicated. Children need cough to clear mucus. Over-the-counter cough syrups NOT recommended in children <5 years.
7. Honey - safe and effective for cough in children (NOT under 1 year - botulism risk)
8. Breastfeeding - continue, protective against respiratory infections

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B. Antibiotic Therapy - By Age

Neonates (<1 month)

• IV Ampicillin + Gentamicin (covers GBS, Listeria + gram-negatives)
• OR IV Ampicillin + Cefotaxime (extended gram-negative coverage)
• Ceftriaxone is CONTRAINDICATED in neonates (displaces bilirubin → kernicterus)
• Always do full sepsis workup: blood, urine, CSF cultures BEFORE antibiotics

Infants 1-3 months (Afebrile pneumonitis syndrome)

• Staccato cough, tachypnea, diffuse infiltrates - think Chlamydia/Ureaplasma
• Treat with Erythromycin or Clarithromycin (macrolide)
• Azithromycin NOT used in this age group (increased risk of infantile hypertrophic pyloric stenosis)

Infants/Children 3 months - 5 years

• First line: High-dose oral Amoxicillin (80-100 mg/kg/day) - covers S. pneumoniae
• If penicillin-resistant S. pneumoniae in community, incomplete immunization, or severe/life-threatening: IV Ceftriaxone or Cefotaxime
• No routine macrolide (Mycoplasma less common in this age group)

Children 5-18 years (School age + adolescents)

• Macrolide antibiotic (Azithromycin, Clarithromycin, Erythromycin) as empiric first line - covers Mycoplasma, Chlamydophila
• If S. pneumoniae suspected: add amoxicillin or amoxicillin-clavulanate
• Hospitalized: IV beta-lactam + macrolide

Duration of antibiotics: 7-10 days

Exam tip: In a child with typical bacterial CAP (lobar consolidation, high fever, toxic-looking), treat with beta-lactam (amoxicillin). In a school-age child with "walking pneumonia" (gradual onset, mild symptoms, diffuse infiltrates), treat with macrolide for Mycoplasma.

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C. Indications for Hospitalization

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D. Treatment for Specific Causes

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E. Follow-up

• Follow-up radiographs are NOT indicated unless clinical condition does not improve
• Transition from IV to oral antibiotics is appropriate after 48 hours of improvement on IV

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9. COMPLICATIONS

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10. PREVENTION

1. Vaccination (most important):

• Pneumococcal Conjugate Vaccine (PCV13) - given from 6 weeks of age; reduces invasive S. pneumoniae disease
• Note: Polysaccharide pneumococcal vaccine is used in adults but is ineffective in children <5 years
• H. influenzae type b (Hib) vaccine
• Influenza vaccine - annually from 6 months of age
• Measles and varicella vaccines (prevent viral pneumonia complications)

1. Breastfeeding - protective against respiratory infections
2. Hand washing and general hygiene - prevent transmission
3. Avoid smoking and secondhand smoke
4. Reduce indoor air pollution - doubles risk of childhood pneumonia

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11. EXAM HIGH-YIELD SUMMARY TABLE

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1. Definition & Epidemiology - global burden numbers (examiners love these)
2. Etiology by age group - the single most-tested topic; organized from neonates to adolescents
3. Pathophysiology - how pneumonia develops, defenses that fail
4. Clinical features - bacterial vs viral comparison table, signs of severity
5. WHO/IMCI Classification - the 60-50-40 tachypnea cut-offs, the 4 categories (Very Severe / Severe / Pneumonia / No Pneumonia), and what to do for each
6. Investigations - what to do and NOT do (CRP/ESR don't distinguish bacterial from viral - very common trap question)
7. Management - supportive care + antibiotic choice by age group, indications for hospitalization, specific organism treatment
8. Complications - empyema, abscess, sepsis
9. Prevention - vaccines (PCV, Hib, influenza) + breastfeeding
10. High-yield summary table - quick revision before your exam

• Ceftriaxone is contraindicated in neonates
• Aspirin is contraindicated for fever in children (Reye's syndrome)
• Azithromycin is not used in infants <3 months (pyloric stenosis)
• Polysaccharide pneumococcal vaccine is ineffective in children <5 years - use the conjugate (PCV)
• CXR cannot reliably distinguish bacterial from viral pneumonia