Pneumonia Anak

01Pathophysiology

Pneumonia is an acute infection of the lung parenchyma that results in inflammation and damage to lung tissue (PNPK Pneumonia Anak 2025). The infectious agent, whether bacterial, viral, or atypical, reaches the lower airways through inhalation or aspiration, triggering an inflammatory cascade within the alveoli.

In bacterial pneumonia (prototypically S. pneumoniae), the organism colonizes the nasopharynx and descends into the lower respiratory tract when mucociliary clearance or immune defenses are compromised. Once in the alveoli, bacteria multiply and provoke a neutrophilic inflammatory response. The alveolar spaces fill with exudate containing neutrophils, fibrin, red blood cells, and cellular debris. This process, called consolidation, replaces the air within the alveoli. Because gas exchange depends on air filling the alveolar space, consolidation directly leads to ventilation-perfusion mismatch and subsequent hypoxemia. This is why the child becomes tachypneic: the respiratory center responds to low oxygen and rising carbon dioxide by increasing respiratory rate. The physical exam findings follow logically: crackles are the sound of air moving through fluid-filled alveoli, and decreased breath sounds occur where alveoli are completely collapsed (atelectasis).

In viral pneumonia (RSV, adenovirus, parainfluenza, influenza), the primary target is the bronchiolar epithelium and interstitial tissue rather than the alveolar space. The resulting interstitial inflammation and peribronchiolar edema cause airway narrowing, air trapping, and diffuse infiltrates on imaging. This explains why viral pneumonia in young children often overlaps clinically with bronchiolitis, making the distinction a frequent exam challenge.

Atypical pneumonia caused by Mycoplasma pneumoniae or Chlamydia pneumoniae warrants separate attention. These organisms damage the respiratory epithelium through a cell-mediated inflammatory response rather than the classic pyogenic process. This is why the clinical presentation is often indolent, subacute, and non-toxic appearing. The PNPK Pneumonia Anak 2025 explicitly notes that atypical pneumonia can range from asymptomatic to severe, and its clinical picture is "tidak khas" (non-characteristic). Exam vignettes targeting this entity will often describe a school-age child with a persistent dry cough, low-grade fever, and a CXR that looks worse than the patient appears clinically.

The concept of age-dependent etiology is critical for test purposes. The reason viruses dominate in children under 5 years is tied to their immature adaptive immunity and smaller airway caliber, while Mycoplasma and Chlamydia predominate in older children because school-age populations have greater person-to-person close-contact transmission and a more mature immune system that generates the cell-mediated inflammation characteristic of atypical infection.

02Classification and Clinical Manifestation

The PNPK Pneumonia Anak 2025 adopts the WHO classification, which stratifies pneumonia by age group and severity. This classification is central to exam questions because it determines disposition (outpatient vs. inpatient vs. ICU) and antibiotic choice.

Respiratory Rate Thresholds for Tachypnea

These cutoffs are among the most frequently tested numbers. They define "napas cepat" (fast breathing) and are the cornerstone of the WHO classification below.

WHO Classification of Pneumonia

Infants <2 Months

Children 2 Months to 5 Years

Key teaching point: The distinguishing line between "pneumonia" and "severe pneumonia" in the 2-month-to-5-year group is the presence of chest wall retraction. If the vignette describes tachypnea alone, it is pneumonia. If retraction is added, it becomes severe pneumonia. If danger signs are layered on top, it becomes very severe pneumonia. Test writers frequently build vignettes that escalate through these tiers.

Note that for infants <2 months, there is no "plain pneumonia" category. Any pneumonia in this age group is at minimum classified as severe, reflecting the higher morbidity and mortality risk in neonates.

03Diagnostic Workup

The workup for pediatric pneumonia is deliberately conservative. The PNPK Pneumonia Anak 2025 emphasizes that chest X-ray is not routinely recommended for outpatient, uncomplicated pneumonia. This is a commonly tested concept: a well-appearing child with cough, fever, and tachypnea who is being treated as an outpatient does not need imaging. The diagnosis is clinical.

For hospitalized or severe cases, a chest X-ray in the AP view is recommended. The lateral view is explicitly noted as not routinely necessary. On imaging, the classic bacterial pattern shows a lobar or segmental consolidation, while viral pneumonia tends to produce bilateral, diffuse interstitial or peribronchial infiltrates. However, exam questions will sometimes remind you that imaging alone cannot definitively distinguish bacterial from viral etiology.

Repeat imaging is not indicated when the patient is improving clinically. The indication for repeat CXR is failure to respond to antibiotics within 48 to 72 hours, which should prompt evaluation for complications such as empyema, necrotizing pneumonia, or pneumothorax. A repeat film may also be considered if the initial imaging showed extensive lung involvement.

$Sp{O}_{2}SpO\_2$ monitoring with pulse oximetry is the single most important bedside assessment tool. An oxygen saturation of $\le 92\mathrm{\%}\backslash leq\; 92\backslash \%$ on room air is both an admission criterion and a trigger for supplemental oxygen.

A critical "trap" for students: CRP, ESR, and procalcitonin cannot differentiate viral from bacterial pneumonia and are not recommended as routine investigations. This is stated explicitly in the PNPK Pneumonia Anak 2025. A vignette that offers elevated CRP as an answer choice to "confirm bacterial etiology" is testing whether you know this limitation.

Blood culture is positive in fewer than 10% of pediatric pneumonia cases. Its utility is limited to hospitalized patients and those with complications. Do not select blood culture as a routine test for an outpatient vignette.

If pleural effusion is present, the PNPK Pneumonia Anak 2025 recommends thoracentesis with full pleural fluid analysis including protein, LDH (in both fluid and serum), microscopy, culture, and bacterial antigen detection when available.

04Management and Treatment

Admission Criteria

Infants

Children

PICU Admission Criteria

Antibiotic Summary Table

General Supportive Care. The PNPK Pneumonia Anak 2025 states that oxygen therapy should be initiated when $Sp{O}_2\le 92\mathrm{\%}SpO\_2\; \backslash leq\; 92\backslash \%$ on room air, with saturation monitoring every 4 hours. Chest physiotherapy is explicitly described as not beneficial and not recommended. Antipyretics and analgesics should be given when indicated. Fluid balance must be carefully maintained.

Nutritional support deserves emphasis. If the child can take food orally, do not insert a nasogastric tube solely to increase intake. In children with severe respiratory distress, oral feeding should be avoided entirely, and fluids should be delivered via an oro- or nasogastric tube in small, frequent volumes. When supplemental oxygen and a nasogastric tube are both needed, both should be placed in the same nostril. Use the smallest available tube size to minimize airway compromise, particularly in infants.

Outpatient antibiotic strategy. The first-line agent is amoxicillin at 80 mg/kg/day (given as 40 mg/kg every 12 hours) for 3 to 5 days. If the patient does not improve, escalate to amoxicillin-clavulanate at the same amoxicillin dose component. If atypical pneumonia is suspected (school-age child, subacute cough, minimal exam findings), add a macrolide, with azithromycin as the most commonly tested choice.

Inpatient antibiotic strategy. The first-line combination is ampicillin plus gentamicin. This is a frequently tested pairing. Ampicillin covers S. pneumoniae and other gram-positive organisms, while gentamicin extends gram-negative coverage. If benzylpenicillin is used instead of ampicillin, the dosing is 50,000 units/kg every 6 hours. This combination should be given for a minimum of 5 days.

If there is no clinical improvement within 48 to 72 hours, escalate to a third-generation cephalosporin. The PNPK Pneumonia Anak 2025 recommends ceftriaxone at 80 mg/kg/day (once daily, max 2 g/day) or cefotaxime at 50 mg/kg per dose every 8 hours. A high-yield contraindication: ceftriaxone should not be given to neonates, premature infants, or patients with hypoalbuminemia due to the risk of bilirubin displacement and precipitation with calcium-containing solutions.

For suspected or confirmed MRSA pneumonia, add vancomycin (40-60 mg/kg/day) or clindamycin (40 mg/kg/day) to the empiric regimen. For S. aureus pneumonia without MRSA suspicion, flucloxacillin or cloxacillin is appropriate.

In immunocompromised patients with suspected Mycoplasma infection, the PNPK Pneumonia Anak 2025 permits levofloxacin. Note the age-based dosing difference: children 6 months to <5 years receive 8-10 mg/kg every 12 hours, while children >5 years receive 10 mg/kg every 24 hours. Fluoroquinolones are not first-line in immunocompetent children.

Step-down principle: Once the patient improves clinically on IV antibiotics, transition to an oral antibiotic of the same class. This is a commonly tested management concept.

Discharge Criteria

05Differential Diagnosis and Distractors

06Traps and High-Yield Pearls

Trap 1: Ordering a CXR on every child with pneumonia. The most common error is selecting chest X-ray as the "best initial test" for a well-appearing child with cough and tachypnea managed as an outpatient. The PNPK Pneumonia Anak 2025 is clear: CXR is NOT routine for uncomplicated community-acquired pneumonia. A CXR is indicated for patients who require hospitalization (severe pneumonia) or who fail to respond to initial antibiotic therapy. If a vignette describes a child with mild tachypnea, no danger signs, and adequate oral intake, the best initial step is empiric amoxicillin, not imaging.

Trap 2: Relying on CRP or procalcitonin to distinguish viral from bacterial pneumonia. This is a high-yield negative pearl. The PNPK Pneumonia Anak 2025 explicitly states that CRP, ESR, and procalcitonin cannot differentiate between viral and bacterial etiology and should not be used for that purpose. A vignette offering "elevated CRP confirms bacterial pneumonia" as an answer choice is testing your understanding of this limitation.

Trap 3: Missing the 48-to-72-hour reassessment window. If a hospitalized patient does not improve within 48 to 72 hours on first-line therapy (ampicillin + gentamicin), the next step is twofold: obtain a repeat chest X-ray to evaluate for complications (effusion, necrotizing pneumonia, pneumothorax) AND escalate antibiotics to ceftriaxone or cefotaxime. Many students jump directly to antibiotic escalation without considering complications, or they repeat imaging too early.

Trap 4: Giving ceftriaxone to a neonate. Ceftriaxone is contraindicated in neonates, premature infants, and hypoalbuminemic patients. If the vignette features a young infant requiring second-line therapy, the correct choice is cefotaxime, not ceftriaxone.

Trap 5: Forgetting age-based etiology when selecting empiric therapy. A child under 5 years with pneumonia is most likely to have a viral or S. pneumoniae infection, making amoxicillin (outpatient) or ampicillin (inpatient) appropriate. A child over 5 years with a subacute, non-toxic presentation and persistent dry cough is more likely to have Mycoplasma or Chlamydia, requiring macrolide coverage. The age and presentation pattern determine the empiric choice.

Trap 6: Confusing the classification tiers. In children aged 2 months to 5 years, the dividing line between "pneumonia" and "severe pneumonia" is chest wall retraction. Tachypnea alone without retraction is pneumonia (outpatient). Tachypnea with retraction is severe pneumonia (inpatient). A vignette that describes "subcostal retractions" in a 3-year-old with cough and tachypnea is indicating severe pneumonia and hospital admission, even if the child appears otherwise well.

Trap 7: Overlooking tuberculosis. The PNPK Pneumonia Anak 2025 recommends a tuberculin skin test for any child with pneumonia who has a history of close contact with a pulmonary tuberculosis patient. In Indonesia, where TB is endemic, this is a relevant clinical step and may appear as a "next best step" question.

The core competency being tested across pneumonia questions is the ability to classify severity using age-appropriate respiratory rate thresholds, correctly triage between outpatient and inpatient management, select the right empiric antibiotic for the right age group, and recognize when to suspect complications versus when to stay the course. The exam rewards pattern recognition of the classic cough-tachypnea-crackles triad, combined with disciplined avoidance of unnecessary investigations.