Pediatrics (System-Integrated)

Pediatric community-acquired pneumonia

Clinical Overview and When to Suspect Pediatric CAP

— Leading infectious cause of pediatric death worldwide; in the US incidence ~35–40 per 1,000 in children <5 yr.

— Peaks in fall/winter, paralleling viral respiratory season.

— <1 month: Group B Strep, E. coli, Listeria, CMV, HSV — treat as neonatal sepsis.

— 1–3 months: "Afebrile pneumonia of infancy" — Chlamydia trachomatis, RSV, Bordetella, CMV.

— 3 months–5 yr: Viruses dominate (RSV, rhinovirus, influenza, adenovirus, parainfluenza, hMPV, SARS-CoV-2); bacterial → S. pneumoniae #1, then S. aureus, group A Strep.

— ≥5 yr: Mycoplasma pneumoniae and Chlamydophila pneumoniae rise; S. pneumoniae still important.

— Fever + cough + tachypnea (most sensitive sign per WHO).

— Tachypnea thresholds: >60 (<2 mo), >50 (2–12 mo), >40 (1–5 yr), >20 (>5 yr).

— Focal exam findings (crackles, ↓ breath sounds, bronchial breathing, dullness) or hypoxia (SpO₂ <94%).

— Incomplete immunizations (esp. PCV13/PCV15/PCV20, Hib, influenza), prematurity, chronic lung disease, congenital heart disease, immunodeficiency, sickle cell disease, neuromuscular disease, daycare attendance, tobacco-smoke exposure.

Board pearl: Tachypnea is the single most sensitive sign of pneumonia in children — its absence in a well-appearing afebrile child makes CAP very unlikely. Conversely, a febrile toddler with isolated tachypnea (no wheeze, no URI) should prompt CXR consideration even if auscultation is unimpressive.

Definition: Community-acquired pneumonia (CAP) = acute infection of lung parenchyma in a child not hospitalized within prior 14 days, manifesting with cough, fever, tachypnea, and/or respiratory distress.

Epidemiology:

Etiology by age (high yield):

When to suspect CAP:

Risk factors:

Severity spectrum: Outpatient mild → moderate inpatient → severe PICU (hypoxia <90% on room air, apnea, grunting, altered mental status, shock).

Presentation Patterns and Key History

— Abrupt onset high fever (≥39°C), shaking chills, productive cough, pleuritic chest pain, toxic appearance, focal findings.

— May present with referred abdominal pain (RLL pneumonia mimicking appendicitis) or neck stiffness (RUL pneumonia mimicking meningitis).

— School-age/adolescent; gradual onset over days; persistent dry cough, low-grade fever, headache, malaise, sore throat; exam often less impressive than CXR.

— Extrapulmonary clues: bullous myringitis, urticaria, erythema multiforme, cold-agglutinin hemolysis, Stevens-Johnson-like mucositis (MIRM).

— Prodrome of rhinorrhea, congestion, low-grade fever; wheezing common; diffuse findings; often coexisting URI in family contacts.

— Staccato cough, tachypnea, conjunctivitis in 50%, eosinophilia → C. trachomatis from maternal birth-canal exposure.

— Neurologic impairment, dysphagia, GERD, feeding problems; RUL (supine) or RLL (upright) infiltrates; foul-smelling sputum if anaerobic.

— Duration and trajectory of symptoms; fever pattern; oral intake and urine output.

— Immunization status (PCV, Hib, influenza, COVID); recent antibiotics (resistance risk).

— Sick contacts, daycare, school outbreaks; TB exposure, travel, endemic fungi (Ohio/Mississippi → histo; SW US → cocci).

— Prior pneumonia episodes (recurrent → immunodeficiency, CF, sequestration, foreign body).

— Choking episode → foreign body aspiration mimic.

Key distinction: A 6-year-old with 10 days of dry cough, headache, and a CXR worse than the exam → think Mycoplasma (macrolide). A 3-year-old with 1 day of high fever, focal crackles, and lobar consolidation → think pneumococcus (amoxicillin). Trajectory + age + cough character drive the empiric choice on test day.

Typical bacterial (pneumococcal) pattern:

Atypical (Mycoplasma, Chlamydophila) pattern — "walking pneumonia":

Viral pattern:

Afebrile pneumonia of infancy (1–3 mo):

Aspiration pneumonia clues:

Key history points to elicit:

Physical Exam Findings and Respiratory Assessment

— Toxic vs nontoxic; mental status; hydration; capillary refill.

— Pediatric Assessment Triangle: appearance, work of breathing, circulation — abnormal in 2 sides = unstable.

— Fever, age-specific tachypnea, SpO₂ on room air (cornerstone triage variable).

— Tachycardia out of proportion to fever; hypotension is late in children.

— Mild: mild tachypnea only.

— Moderate: nasal flaring, subcostal/intercostal retractions, mild accessory muscle use.

— Severe: grunting, head bobbing, suprasternal retractions, paradoxical breathing, cyanosis, apnea, AMS → escalate immediately.

— Focal crackles (rales) — most specific finding for consolidation.

— Bronchial breath sounds, egophony ("E to A"), increased tactile fremitus, dullness to percussion → lobar consolidation.

— Decreased breath sounds + dullness that doesn't shift → parapneumonic effusion or empyema.

— Diffuse wheeze + crackles → viral or atypical; isolated unilateral wheeze → think foreign body.

— Bullous myringitis → Mycoplasma.

— Conjunctivitis in young infant → Chlamydia.

— Skin findings: erythema multiforme (Mycoplasma), pustular lesions (S. aureus), petechiae (pneumococcal sepsis).

— Clubbing → chronic suppurative process (CF, bronchiectasis).

— Cool extremities, delayed cap refill >3 s, mottling, narrow pulse pressure, lactic acidosis — treat before hypotension develops.

Step 3 management: In a child with respiratory distress, hypoxia, and unilateral decreased breath sounds with dullness, the next step is upright/lateral decubitus CXR or bedside lung US to confirm parapneumonic effusion — do NOT delay with prolonged outpatient observation; admit and consult pulmonology/surgery early.

General appearance:

Vital signs:

Work of breathing (severity grading):

Auscultation:

Extrapulmonary clues:

Hemodynamic red flags (compensated shock):

Diagnostic Workup — Initial Labs and Imaging

— No routine labs or CXR needed if classic features and well-appearing — diagnose clinically (IDSA/PIDS).

— Pulse oximetry mandatory.

— Hypoxia, moderate–severe distress, failed outpatient therapy, suspected complication (effusion), recurrent pneumonia, hospitalization, ambiguous diagnosis.

— PA + lateral preferred; lateral decubitus if effusion suspected.

— Findings: lobar consolidation (typical bacterial), interstitial/peribronchial cuffing (viral, atypical), round pneumonia (pneumococcus in young children — don't mistake for mass), pneumatocele (S. aureus).

— Inpatient labs: CBC, electrolytes, BUN/Cr, glucose, CRP/procalcitonin (adjunctive), blood culture (yield ~3–7% but recommended for moderate–severe disease or complicated CAP).

— SIADH risk with severe pneumonia → check Na⁺.

— Nasopharyngeal viral PCR panel (RSV, flu, SARS-CoV-2, hMPV, adenovirus) — guides isolation and antiviral use.

— Sputum culture rarely obtainable <8 yr; obtain if expectorating.

— Mycoplasma PCR from NP swab in school-age with suggestive presentation.

— Legionella urinary antigen if severe/atypical exposure.

— SpO₂ <90% on room air → admission criterion.

— SpO₂ 90–93% → individualized.

— Increasingly used: sensitivity/specificity comparable to CXR, no radiation; identifies consolidation and effusion.

Board pearl: A routine CBC, blood culture, and CXR are NOT indicated for fully immunized, nontoxic outpatients with mild CAP. Overtesting is a wrong-answer trap on Step 3 — pick "outpatient amoxicillin and clinical follow-up in 48 hours."

Outpatient mild CAP:

When to obtain CXR:

Routine bloodwork — not required for outpatient cases:

Microbiology:

Pulse oximetry triage:

Bedside lung ultrasound:

Diagnostic Workup — Advanced and Confirmatory Studies

— Persistent fever >48–72 h on appropriate antibiotics, worsening distress, or expanding effusion.

— Repeat CXR; add chest ultrasound (best for characterizing effusion — free-flowing vs loculated, septations) or contrast-enhanced chest CT (necrotizing pneumonia, abscess, bronchopleural fistula).

— Diagnostic thoracentesis if moderate–large effusion: pH <7.2, glucose <40, LDH >1000, positive Gram stain/culture, or frank pus = empyema → chest tube ± fibrinolytics (tPA + DNase) or VATS.

— Blood cultures: yield rises in complicated CAP and empyema (~10–20%).

— Pleural fluid PCR (pneumococcal, S. aureus) — higher yield than culture if antibiotics already given.

— Mycoplasma: PCR (preferred) > IgM serology.

— TB: IGRA (≥5 yr) or TST; AFB sputum/gastric aspirates; required if cavitary lesion, hilar adenopathy, or exposure.

— Endemic fungi: urine/serum Histoplasma or Coccidioides antigen; consider with travel + nonresolving infiltrate.

— Reserved for immunocompromised, intubated nonresponders, or suspected foreign body.

— ≥2 episodes in 1 year or ≥3 lifetime → evaluate.

— Sweat chloride (CF), immunoglobulins + IgG subclasses + vaccine titers (CVID, IgA deficiency), HIV testing, ciliary studies (PCD), swallow study (aspiration), CT to rule out sequestration, congenital pulmonary airway malformation, or foreign body.

— Procalcitonin >0.25 ng/mL favors bacterial etiology; low PCT can support de-escalation/stopping antibiotics.

Key distinction: A toddler with same-lobe recurrent pneumonia → think anatomic (sequestration, CPAM, foreign body) → get CT chest. Recurrent pneumonia in different lobes → think systemic (immunodeficiency, CF, aspiration) → workup with sweat test, immunoglobulins, HIV, swallow study.

Complicated or non-responding CAP — escalate workup:

Parapneumonic effusion evaluation:

Pathogen-directed studies:

Bronchoscopy with BAL:

Workup for recurrent or atypical pneumonia:

Biomarkers:

Risk Stratification and Site-of-Care Decision

— Mild-moderate respiratory distress; SpO₂ ≥90% on room air.

— Tolerating oral intake/medications; no dehydration.

— Reliable caregiver and follow-up within 24–48 h.

— Age >3–6 months in most algorithms.

— Age <3–6 months with suspected bacterial CAP.

— Hypoxia (SpO₂ <90%), apnea, severe distress (grunting, retractions).

— Inability to tolerate POs / signs of dehydration.

— Failure of outpatient therapy after 48–72 h.

— Complicated pneumonia (effusion, abscess, necrosis).

— Suspected MRSA or virulent pathogen, sickle cell disease, immunocompromise.

— Unreliable follow-up or social concerns.

— Need for invasive/noninvasive ventilation.

— Sustained tachycardia with poor perfusion, hypotension, or vasoactive needs.

— SpO₂ <92% on FiO₂ >0.5.

— Altered mental status, recurrent apnea, irregular respirations.

— Multilobar disease with rapid progression.

— No single validated pediatric score equivalent to adult PSI/CURB-65; clinical judgment + above criteria drive decisions.

— Sickle cell disease + new infiltrate = acute chest syndrome — admit, broad-spectrum (cefotaxime + macrolide), transfusion if hypoxic.

— Neonates → full sepsis workup + LP, admit, ampicillin + gentamicin (± acyclovir).

CCS pearl: On a CCS case, a 4-month-old with SpO₂ 88%, RR 70, and grunting → advance the clock minimally: order pulse ox + O₂, IV access, CBC/blood culture/CXR, IV ampicillin (or ceftriaxone if older), admit to inpatient ward, recheck in 1–2 hours. Never discharge a hypoxic infant home.

Outpatient management criteria (all must be met):

Admission criteria (any one):

PICU criteria:

Severity scores:

Special-host upgrades:

Pharmacotherapy — First-Line Antibiotic Regimens

— First line: high-dose amoxicillin 90 mg/kg/day divided BID × 5 days (most cases) to 7–10 days.

— Covers S. pneumoniae including most penicillin-nonsusceptible strains.

— Penicillin allergy (non-anaphylactic): cefdinir, cefpodoxime, cefuroxime.

— Anaphylaxis: clindamycin or levofloxacin; macrolide if Mycoplasma suspected.

— Azithromycin 10 mg/kg day 1, then 5 mg/kg days 2–5 (max 500/250 mg).

— If typical bacterial picture coexists or unclear → amoxicillin + azithromycin.

— Rising macrolide resistance in S. pneumoniae (~30–40% US) — amoxicillin still preferred for typical disease.

— Ampicillin 150–200 mg/kg/day IV divided q6h or penicillin G — first line per IDSA/PIDS.

— Add azithromycin if atypical suspected.

— Ceftriaxone 50–100 mg/kg/day IV q24h.

— Add vancomycin or clindamycin (if local clindamycin resistance <10%) to ceftriaxone.

— Afebrile, tolerating POs, improving work of breathing → switch to oral amoxicillin to complete course.

Board pearl: "Fully immunized, outpatient, preschool CAP" → high-dose amoxicillin, period. Macrolide monotherapy is wrong because of resistance; ceftriaxone is wrong because it's overtreatment. Reserve azithromycin for the ≥5-year-old with classic atypical features.

Outpatient (fully immunized, mild-moderate, age 3 mo–5 yr):

Outpatient school-age (≥5 yr) with atypical features:

Inpatient, fully immunized, non-complicated:

Inpatient, not fully immunized or local high pneumococcal resistance:

Severe/complicated or suspected MRSA (pneumatoceles, necrosis, empyema, post-influenza, toxic):

Step-down/oral switch:

Duration: 5 days for uncomplicated CAP (data support short courses); 2–4 weeks for empyema/necrotizing.

Adjunctive antivirals: Oseltamivir if influenza confirmed/suspected, ideally <48 h; treat regardless of duration if hospitalized or high-risk.

Procedures and Management of Complicated Pneumonia

— Small (<10 mm on decubitus, <¼ hemithorax): IV antibiotics alone, monitor.

— Moderate–large or loculated: chest tube drainage + IV antibiotics; if loculated/fibrinopurulent → intrapleural fibrinolytics (tPA + DNase) or VATS — outcomes equivalent, VATS often chosen if available early.

— Send pleural fluid: cell count, pH, glucose, LDH, Gram stain, culture, PCR.

— Most respond to 4–6 weeks IV → oral antibiotics covering anaerobes + S. aureus (clindamycin or ampicillin-sulbactam).

— Percutaneous drainage if no response in 7–10 days or large (>4 cm).

— Common pathogens: S. pneumoniae, PVL-producing S. aureus, group A Strep.

— Prolonged IV antibiotics (3–6 weeks), supportive care; surgery only for bronchopleural fistula or persistent disease.

— Nasal cannula → high-flow nasal cannula (HFNC) for moderate distress and FiO₂ needs >40%.

— NIV (BiPAP) for impending failure without apnea.

— Intubation for apnea, exhaustion, refractory hypoxemia, AMS.

— ARDS pattern → lung-protective ventilation (6 mL/kg IBW, plateau <30, permissive hypercapnia).

— IV fluids — isotonic (LR or NS) to avoid hyponatremia from SIADH; monitor Na⁺.

— Antipyretics, careful airway clearance; bronchodilators only if wheezing present.

— Avoid chest physiotherapy routinely — no benefit shown.

— VTE prophylaxis in adolescents with reduced mobility.

Step 3 management: A child with empyema and persistent fever after 48 h of IV antibiotics → next step is pleural drainage (chest tube + intrapleural fibrinolytics OR VATS), not antibiotic escalation. Source control beats spectrum broadening.

Parapneumonic effusion / empyema management:

Lung abscess:

Necrotizing pneumonia:

Respiratory support escalation:

Supportive care orders:

Special Populations — Comorbid and Organ-Impaired Children

— Any new infiltrate + respiratory symptoms = acute chest syndrome until proven otherwise.

— Empiric ceftriaxone + macrolide, supplemental O₂, incentive spirometry, judicious analgesia (avoid oversedation), simple or exchange transfusion if hypoxic/worsening.

— Hydroxyurea reduces recurrence; ensure pneumococcal and influenza vaccination.

— Broaden empirically: anti-pseudomonal β-lactam (cefepime/pip-tazo) + vancomycin ± antifungal/PJP coverage (TMP-SMX) depending on host.

— Consider PJP (bilateral interstitial, hypoxia out of proportion, elevated LDH) in HIV with low CD4 or chronic steroids.

— Low threshold for bronchoscopy + BAL.

— Cover Pseudomonas (tobramycin + anti-pseudomonal β-lactam) and S. aureus; consult CF center.

— Dose-adjust β-lactams (ampicillin, cefepime), vancomycin (trough/AUC monitoring), aminoglycosides; avoid nephrotoxin stacking.

— Aminoglycoside + vancomycin + contrast = AKI trifecta — minimize.

— Macrolides (esp. erythromycin), clindamycin metabolized hepatically; monitor LFTs; azithromycin generally safe.

— Continue baseline controllers; add systemic steroids only if concurrent asthma exacerbation, not for CAP alone.

— Cover anaerobes — amoxicillin-clavulanate (outpatient) or ampicillin-sulbactam (inpatient).

— Swallow evaluation and feeding-route reassessment.

Key distinction: Children with sickle cell + pulmonary infiltrate → don't call it "pneumonia" and walk away — label and manage as acute chest syndrome, which is a different disease pathophysiologically (vaso-occlusion + infection + atelectasis) requiring transfusion considerations.

Sickle cell disease:

Immunocompromised children (oncology, transplant, primary immunodeficiency, HIV):

Cystic fibrosis:

Renal impairment:

Hepatic impairment:

Chronic lung disease (BPD, asthma):

Neuromuscular/aspiration risk:

Special Populations — Neonates, Young Infants, and Adolescents

— Treat as neonatal sepsis: full sepsis workup (CBC, blood culture, urine culture, LP, CXR), admit, IV ampicillin + gentamicin (or cefotaxime).

— Add acyclovir if HSV concern (vesicles, maternal genital lesions, seizures, transaminitis).

— Pathogens: GBS, E. coli, Listeria, HSV, CMV, Chlamydia (later).

— Staccato cough, tachypnea, conjunctivitis, eosinophilia, hyperinflated CXR → Chlamydia trachomatis.

— Treat: azithromycin × 5 days (monitor for infantile hypertrophic pyloric stenosis — known association); erythromycin alternative.

— Always rule out pertussis (paroxysmal cough, post-tussive emesis, whoop, apnea, lymphocytosis) — azithromycin; admit infants <4 months.

— RSV is dominant viral cause this age — supportive care; consider nirsevimab prophylaxis given in fall.

— Viral predominance; if bacterial → pneumococcus → high-dose amoxicillin.

— Reassess vaccination: PCV15/PCV20, Hib, influenza, COVID.

— Mycoplasma, Chlamydophila common.

— Consider HIV, pregnancy (affects imaging consent and antibiotic choice — avoid doxycycline, fluoroquinolones; macrolides and β-lactams safe).

— Vaping-associated lung injury (EVALI) is a differential — ask about e-cigarette use.

— Influenza in pregnancy → oseltamivir indicated.

— Avoid fluoroquinolones, tetracyclines; use amoxicillin, azithromycin, ceftriaxone.

Board pearl: A 6-week-old with staccato cough, tachypnea, conjunctivitis, and eosinophils on CBC = Chlamydia trachomatis pneumonia → oral azithromycin, counsel parents about the small but real risk of pyloric stenosis and the need to watch for projectile vomiting.

Neonate (0–28 days):

1–3 months ("afebrile pneumonia of infancy"):

3–24 months:

Adolescents:

Pregnancy in adolescents:

Complications and Adverse Outcomes

— Parapneumonic effusion / empyema (most common, ~2–10% of admitted CAP).

— Necrotizing pneumonia — cavitations, often S. pneumoniae serotype 3 or PVL-MRSA.

— Lung abscess — fluid-filled cavity with air-fluid level.

— Pneumatocele — S. aureus classically; usually resolves spontaneously.

— Bronchopleural fistula, pneumothorax.

— Post-infectious bronchiolitis obliterans — especially after adenovirus or Mycoplasma.

— SIADH with hyponatremia — use isotonic IVF.

— Sepsis, septic shock, multi-organ failure.

— Hemolytic-uremic syndrome with pneumococcal pneumonia (esp. serotype 3) — direct Coombs⁺ via T-antigen exposure.

— Acute kidney injury (sepsis, nephrotoxic antibiotics).

— Cold-agglutinin hemolytic anemia, Stevens-Johnson syndrome / MIRM (Mycoplasma-induced rash and mucositis), encephalitis, transverse myelitis, Guillain-Barré, myocarditis, erythema multiforme.

— Sudden worsening 5–7 days into flu → secondary bacterial pneumonia with S. aureus (often MRSA) or S. pneumoniae → add vancomycin.

— Bronchiectasis, recurrent infections, restrictive lung disease (if severe necrotizing).

CCS pearl: Hospitalized child with CAP develops seizures + serum Na⁺ 122 → SIADH from pneumonia. Stop hypotonic fluids, restrict free water, switch to isotonic saline; if symptomatic seizing, 3% hypertonic saline 3–5 mL/kg bolus. Address the underlying pneumonia and avoid rapid correction.

Pulmonary complications:

Systemic/metabolic:

Extrapulmonary Mycoplasma complications:

Post-influenza superinfection:

Long-term sequelae:

Mortality: Low in developed countries (<1%) but rises with delayed care, comorbidity, MRSA, immunocompromise.

When to Escalate Care — ICU and Consults

— Need for invasive mechanical ventilation or sustained HFNC/NIV with worsening parameters.

— SpO₂ <92% on FiO₂ ≥0.5 or PaO₂/FiO₂ <250.

— Hemodynamic instability requiring fluid bolus >40 mL/kg or vasoactive support.

— Altered mental status, recurrent apnea, signs of impending arrest.

— Multilobar/rapidly progressive disease, large effusion compromising ventilation.

— Severe metabolic acidosis (lactate >4), septic shock.

— Complicated CAP (empyema, abscess, necrotizing), recurrent pneumonia, suspected underlying CF/PCD/immunodeficiency.

— MRSA bacteremia, persistent fever despite appropriate therapy, immunocompromised host, unusual pathogens (TB, fungi), outbreak situations.

— Chest tube placement, VATS for empyema, drainage of abscess.

— Sickle cell with ACS — exchange transfusion decisions.

— Use structured handoff (I-PASS) when transferring to PICU.

— Closed-loop communication, document escalation criteria.

— Family-centered rounds; update caregivers at each escalation.

— Recognize early septic shock — IV access ×2, fluid bolus 10–20 mL/kg crystalloid, broad antibiotics within 1 hour, lactate, blood culture.

— Reassess after each bolus; start epinephrine if fluid-refractory.

Step 3 management: A 3-year-old admitted for CAP now has RR 70, retractions, SpO₂ 88% on 4 L NC, lethargic. Next steps simultaneously: escalate to HFNC or NIV, call PICU, repeat CXR (rule out tension pneumothorax/effusion), broaden antibiotics, fluid bolus if hypoperfused, anesthesia/RT at bedside for possible intubation.

PICU transfer triggers:

Pediatric pulmonology consult:

Infectious disease consult:

Pediatric surgery / interventional radiology:

Hematology consult:

Communication and handoffs (Step 3 emphasis):

Rapid response / sepsis bundles:

Key Differentials — Other Lower Respiratory Tract Infections

— <2 yr, viral (RSV, rhinovirus), URI prodrome → wheezing, crackles, retractions; diffuse not focal.

— Treatment supportive: nasal suction, hydration, O₂; no routine bronchodilators, steroids, antibiotics, or CXR.

— Distinction: bronchiolitis = expiratory wheeze + hyperinflation; CAP = focal crackles + consolidation.

— No lower-tract findings, normal pulse ox, no tachypnea.

— Barky cough, stridor, hoarse voice; steeple sign on neck XR; treat with dexamethasone, racemic epinephrine if moderate-severe.

— Wheeze, prolonged expiration, prior episodes, response to bronchodilators; can coexist with viral CAP.

— Paroxysmal cough, whoop, post-tussive emesis, apnea in infants; lymphocytosis; PCR confirms; treat azithromycin.

— Chronic cough >2 weeks, weight loss, night sweats, exposure history; hilar adenopathy; PPD/IGRA.

— Acute choking event → foreign body (often RLL/right mainstem); chronic aspiration in neurologically impaired.

— Histoplasmosis (Ohio/Mississippi River valleys), coccidioidomycosis (SW US), blastomycosis — consider with travel + nonresolving pneumonia.

Key distinction: Wheezing + diffuse crackles + age <2 + URI prodrome → bronchiolitis (no antibiotics). Focal crackles + lobar infiltrate + high fever → bacterial CAP (amoxicillin). The trap on exams is treating bronchiolitis with antibiotics or ordering CXR routinely — both are wrong unless atypical course.

Bronchiolitis:

Viral URI / pharyngitis:

Croup (laryngotracheobronchitis):

Asthma exacerbation:

Pertussis:

Pulmonary TB:

Aspiration syndromes:

Atypical pathogens specific:

Key Differentials — Non-Infectious and Systemic Mimics

— Sudden choking, unilateral wheeze or decreased breath sounds, recurrent same-lobe pneumonia.

— Inspiratory + expiratory or decubitus CXR — air trapping/mediastinal shift on affected side during expiration.

— Rigid bronchoscopy = diagnostic and therapeutic.

— Pulmonary sequestration, congenital pulmonary airway malformation (CPAM), bronchogenic cyst — recurrent same-lobe pneumonia → CT chest with contrast.

— Congenital heart disease, cardiomyopathy, myocarditis; bilateral infiltrates, cardiomegaly, hepatomegaly, gallop; BNP elevated.

— OCPs, immobility, malignancy, hypercoagulable state; pleuritic chest pain, hypoxia with clear CXR; D-dimer, CT angiography.

— Adolescent + e-cigarette use + bilateral ground-glass; exclude infection; treat with steroids.

— Hypersensitivity pneumonitis (bird/mold exposure), eosinophilic pneumonia, pulmonary hemorrhage syndromes (Goodpasture, GPA), pulmonary hemosiderosis (iron-deficiency anemia + hemoptysis + infiltrates).

— Lymphoma with mediastinal mass — SVC syndrome, airway compression; leukemia with leukostasis.

— A round opacity on CXR in a young child with fever is usually pneumococcal round pneumonia, not a mass — antibiotics first, repeat imaging in 4–6 weeks to confirm resolution.

— Often confused with pneumonia; volume loss, fissural shift, no air bronchograms typically.

Board pearl: Recurrent pneumonia in the same lobe = anatomic problem (foreign body, sequestration, CPAM, endobronchial lesion) → CT chest is the next step, not another antibiotic course. Recurrent in different lobes = systemic problem (immunodeficiency, CF, aspiration).

Foreign body aspiration:

Congenital lung malformations:

Heart failure / pulmonary edema:

Pulmonary embolism (adolescents):

Vaping-associated lung injury (EVALI):

Allergic/immunologic:

Malignancy:

Round pneumonia mimic:

Atelectasis:

Secondary Prevention and Discharge Planning

— PCV15 or PCV20 in infants per ACIP schedule (2, 4, 6, 12–15 months).

— Hib vaccine series.

— Annual influenza vaccine ≥6 months.

— COVID-19 vaccine per current ACIP.

— PPSV23 in high-risk children ≥2 yr (sickle cell, asplenia, immunodeficiency, CKD, CSF leak, cochlear implant).

— RSV prevention: nirsevimab for all infants <8 mo entering first RSV season; maternal RSVpreF vaccine in pregnancy.

— Catch-up vaccines for under-immunized children before discharge — high-yield Step 3 quality measure.

— Complete oral antibiotic course (commonly amoxicillin 5 days uncomplicated).

— Inhalers/spacers if asthma component; reinforce technique.

— Avoid OTC cough/cold meds in <6 yr (FDA warning).

— Secondhand smoke counseling — strongly associated with pediatric CAP; offer cessation resources to caregivers.

— Daycare hygiene, hand washing, respiratory etiquette.

— Nutrition optimization, breastfeeding promotion (protective).

— Sickle cell: ensure hydroxyurea, penicillin prophylaxis (until age 5 minimum), pneumococcal vaccines up to date.

— CF: nutrition, airway clearance, CFTR modulators if eligible.

— Primary care follow-up within 1–2 weeks.

— Specialty referral if complicated, recurrent, or underlying condition suspected.

Step 3 management: At discharge after CAP, always review immunization status and administer due vaccines (including catch-up PCV, influenza, COVID) before the child leaves — this is a recurring patient-safety/quality answer on Step 3 stems.

Immunizations (cornerstone of prevention):

Discharge medications:

Risk-factor modification:

Special populations:

Care coordination:

Follow-Up, Monitoring, and Counseling

— Reassess in 24–48 hours for outpatient CAP — telephone or in-person.

— Expect defervescence within 48–72 hours; persistent fever beyond 72 hours → failure of therapy → reevaluate (resistant pathogen, complication, wrong diagnosis).

— PCP visit within 1–2 weeks; pulmonology if complicated.

— Not routine for uncomplicated CAP.

— Indications: recurrent pneumonia, suspected anatomic lesion (round pneumonia), persistent symptoms, complicated CAP — typically 4–6 weeks after illness.

— Also for atelectasis vs lesion clarification.

— Fever often resolves by 48–72 h; cough can persist 2–4 weeks.

— Energy and appetite return gradually; school can usually resume when afebrile 24 h and activity tolerated.

— Worsening breathing, retractions, persistent fever, refusal to drink, dehydration, lethargy, cyanosis, chest pain.

— Inflammatory markers (CRP) can trend response; resolution of effusion clinically and on imaging.

— Pulmonary function testing in adolescents post-necrotizing pneumonia or post-bronchiolitis obliterans suspicion.

— Encourage early mobilization, hydration, incentive spirometry in older children.

— Avoid prolonged bed rest.

— Shorter courses (5 days) for uncomplicated CAP; finish course; don't share antibiotics.

Board pearl: A child treated for CAP who is still febrile at 72 hours on appropriate amoxicillin → don't just switch antibiotics. Reimage to evaluate for parapneumonic effusion, empyema, or wrong diagnosis (TB, foreign body, mass). Re-evaluation precedes escalation.

Outpatient follow-up:

Post-hospital follow-up:

Repeat CXR — when indicated:

Symptom trajectory counseling for families:

Red flags to return immediately:

Monitoring in complicated CAP:

Rehabilitation:

Counseling on antimicrobial stewardship:

Ethical, Legal, and Patient Safety Considerations

— Engage with motivational interviewing; document discussion using presumptive language ("Joey is due for his PCV today").

— In most US states, parents may refuse non-emergent vaccines for non-emergent visits; in emergencies (e.g., post-splenectomy child needing meningococcal vaccine), child welfare consultation may be required.

— Document refusal with informed-refusal forms.

— Chest tube, bronchoscopy, intubation — obtain parental consent; assent from age-appropriate children (~≥7 yr).

— In life-threatening emergencies, proceed under implied consent if guardian unavailable.

— Recurrent aspiration pneumonia in non-ambulatory child raises questions about caregiving; assess feeding safety and access to therapy — refer to social work, not necessarily CPS, unless neglect suspected.

— Severe undervaccination plus medical neglect pattern may trigger CPS reporting per state law.

— ED-to-floor and floor-to-PICU handoffs are highest-risk points for error — use I-PASS structured handoff; reconcile medications.

— Discharge: ensure caregiver understands antibiotic dose, return precautions, and follow-up; teach-back method.

— Overuse drives resistance; avoid antibiotics for viral bronchiolitis or simple URI — both stewardship and quality measure.

— Disparities in pneumococcal disease in Indigenous, Alaska Native, and African American children — ensure timely vaccination.

— Address transportation, language barriers, and food/housing insecurity affecting follow-up adherence.

— Sexual history (HIV risk), substance use (EVALI), pregnancy testing — confidential per state minor-consent laws.

Step 3 management: A non-immunized 4-year-old with pneumonia whose parents refuse PCV at discharge — do not invoke CPS; provide education, offer at next visit, document informed refusal, ensure close follow-up. CPS escalation is for active medical neglect causing serious imminent harm, not vaccine hesitancy alone.

Vaccination refusal / hesitancy:

Informed consent for procedures:

Mandatory reporting and child protection:

Transitions of care (high-yield Step 3):

Antibiotic stewardship and patient safety:

Health equity considerations:

Confidentiality in adolescents:

High-Yield Associations and Rapid-Fire Facts

— Currant-jelly sputum → Klebsiella (rare in kids).

— Salmon-pink sputum / pneumatoceles → S. aureus.

— Rust-colored sputum → S. pneumoniae.

— Bullous myringitis + cold agglutinins → Mycoplasma.

— Staccato cough + conjunctivitis + eosinophilia in 1–3 mo → Chlamydia trachomatis.

— Post-influenza rapid deterioration → S. aureus (often MRSA) or S. pneumoniae.

— Round pneumonia → S. pneumoniae in young children.

— Lobar consolidation + meningismus or abdominal pain → pneumococcal upper- or lower-lobe pneumonia.

— Bilateral diffuse interstitial → viral or Mycoplasma or PJP.

— Lobar consolidation → typical bacterial.

— Pneumatoceles → S. aureus.

— Cavitation → TB, MRSA, anaerobes, fungal, necrotizing pneumococcus.

— Hilar adenopathy → TB, fungal, lymphoma.

— PCV13→15/20 dramatically reduced pneumococcal pneumonia and empyema serotype distribution shifted.

— Hib vaccine virtually eliminated H. influenzae type b pneumonia/epiglottitis in vaccinated children.

— Influenza vaccine reduces both primary viral and secondary bacterial pneumonia.

Board pearl: A previously well preschooler with influenza for 4 days who suddenly worsens with high fever, hypoxia, and pneumatoceles → MRSA secondary bacterial pneumonia → admit, add vancomycin to ceftriaxone, image for empyema, consider PICU.

Pathogen-specific clues:

Radiographic patterns:

Vaccines that reduce pneumonia incidence:

HUS + pneumonia → pneumococcal serotype 3, T-antigen exposure, Coombs-positive.

Vitamin A improves outcomes in measles pneumonia, not routine CAP in well-nourished children.

No role for routine corticosteroids in pediatric CAP (unless asthma comorbid or specific syndromes).

Probiotics, zinc, vitamin C, herbal preparations — not recommended.

Antibiotic duration: 5 days uncomplicated; longer for complicated.

Board Question Stem Patterns

— Fully immunized 3-year-old, 1 day high fever, focal RLL crackles, well-hydrated, SpO₂ 96%.

— Answer: high-dose oral amoxicillin, follow up 48 h. Trap: ordering CXR or ceftriaxone.

— 10-year-old, 10 days dry cough, headache, low-grade fever, CXR with diffuse interstitial infiltrates worse than exam, bullous myringitis.

— Answer: oral azithromycin.

— 6-week-old, staccato cough, tachypnea, conjunctivitis, afebrile, eosinophilia, hyperinflation.

— Answer: oral azithromycin (and warn about pyloric stenosis).

— 5-year-old recovering from flu, sudden re-fever, hypoxia, pneumatoceles on CXR.

— Answer: admit, add vancomycin to ceftriaxone; PICU.

— Admitted child with CAP, persistent fever day 4, decreased breath sounds, large loculated effusion on ultrasound.

— Answer: chest tube + intrapleural fibrinolytics OR VATS. Not "broaden antibiotics."

— 8-month-old, RSV-positive, wheeze, diffuse crackles, mild distress, SpO₂ 94%.

— Answer: supportive care, no antibiotics, no routine CXR.

— 2-year-old, third RLL pneumonia in 9 months, well between episodes.

— Answer: CT chest to evaluate for foreign body, sequestration, CPAM. Not "immunoglobulin levels."

— 7-year-old with HbSS, fever, chest pain, new RLL infiltrate, SpO₂ 89%.

— Answer: admit, O₂, ceftriaxone + azithromycin, simple/exchange transfusion, analgesia, incentive spirometry.

— Hospitalized CAP child develops seizure with Na⁺ 120 on D5½NS maintenance.

— Answer: switch to isotonic fluids, hypertonic saline if seizing.

Key distinction: Stems pivot on age, immunization status, illness course, and CXR pattern — anchoring on those four variables will correctly route nearly every Step 3 pediatric CAP question to the right antibiotic, site of care, and next step.

Stem 1 — Classic outpatient pneumococcal CAP:

Stem 2 — Mycoplasma in school-age:

Stem 3 — Chlamydia trachomatis in infant:

Stem 4 — Post-influenza MRSA:

Stem 5 — Empyema not responding:

Stem 6 — Bronchiolitis distractor:

Stem 7 — Recurrent same-lobe pneumonia:

Stem 8 — Sickle cell acute chest:

Stem 9 — SIADH complication:

One-Line Recap

Pediatric CAP is an age-stratified syndrome where empiric therapy hinges on age, immunization status, illness severity, and pattern of presentation — with high-dose amoxicillin as the cornerstone for fully immunized preschoolers with typical bacterial features, azithromycin for school-age atypical presentations, ampicillin or ceftriaxone for inpatients, and prompt source control plus broadened coverage (vancomycin, drainage) for complicated or post-influenza disease.

Board pearl: When stuck between answer choices on a pediatric CAP question, return to four anchors — age, immunization status, severity (hypoxia/feeding), and CXR pattern — and the next best step on Step 3 will reveal itself.

Triage drives everything: Hypoxia (SpO₂ <90%), age <3–6 months, dehydration, severe distress, or unreliable follow-up = admit; the rest go home on oral amoxicillin with 48-hour reassessment.

Match drug to age and pattern: Preschool typical → amoxicillin; ≥5 yr atypical → azithromycin; inpatient → ampicillin/ceftriaxone; post-flu pneumatoceles or necrosis → add vancomycin; 1–3 mo afebrile + conjunctivitis → azithromycin for Chlamydia (watch pyloric stenosis).

Don't over-test: Skip routine CXR, CBC, and blood cultures in well-appearing outpatient CAP; reserve imaging and labs for moderate-severe, complicated, recurrent, or non-responding cases — and use ultrasound or CT for suspected effusion/empyema.

Source control beats spectrum: Persistent fever on appropriate antibiotics → reimage and drain the empyema rather than reflexively broadening coverage; also reassess for foreign body, TB, or anatomic lesion in recurrent same-lobe disease.

Prevention is the long game: Maximize PCV15/20, Hib, influenza, COVID, and nirsevimab; counsel on secondhand smoke; ensure transitions-of-care safety with structured handoffs, vaccine catch-up before discharge, and 24–48 hour follow-up.