Pneumonia is an acute infection of the lung parenchyma and remains a leading cause of hospitalization and preventable mortality globally. Its clinical expression varies substantially across age groups, reflecting differences in airway caliber, immune maturation, exposure patterns, comorbid burden, and pathogen distribution. In children, especially under five years, pneumonia frequently presents with age-specific respiratory signs—tachypnea, nasal flaring, chest indrawing, grunting, and feeding difficulty—whereas adults may present with cough, fever, pleuritic pain, dyspnea, and systemic manifestations such as confusion or functional decline, particularly in older adults. These differences influence triage, diagnostic strategy, antimicrobial choices, and prognosis.1–4

Adult CAP guidance (ATS/IDSA) emphasizes identifying severe CAP, appropriate microbiologic testing, and empiric therapy guided by risk factors for resistant organisms and local epidemiology.1 European guidance for severe CAP similarly recommends structured severity assessment and early escalation when organ dysfunction is suspected.2 Severity tools such as CURB-65/CRB-65 and related validation studies support risk stratification in adults, though sensitivity–specificity tradeoffs persist across settings.5,6

In pediatrics, severity recognition relies heavily on clinical assessment because children may deteriorate rapidly and laboratory markers have variable discriminatory value. While pediatric CAP guidelines historically extrapolated some adult severity concepts, prospective validation work shows that pediatric severity criteria may over-classify severity and require pediatric-specific predictive models.7,8 In low- and middle-income settings, pediatric risk scores such as RISC/mRISC have been evaluated for mortality prediction, supporting structured risk assessment where resources are limited.9

Etiologic patterns also differ. Pediatric CAP frequently involves respiratory viruses and atypical pathogens depending on age and season, with bacterial pneumonia forming a smaller proportion among hospitalized children in many modern cohorts.10 Conversely, adults—especially older adults—carry higher risk for bacterial pneumonia, aspiration events, and severe outcomes due to multimorbidity and frailty.11,12 These age-linked differences justify comparative clinical profiling to refine diagnostic algorithms and optimize early management pathways.

Therefore, this study aimed to compare the clinical profile of pneumonia in children versus adults, focusing on symptom patterns, physical signs, radiographic findings, laboratory biomarkers, microbiologic yield, severity indicators, and short-term outcomes.

Comparative, hospital-based observational study conducted in the Departments of Pediatrics and General Medicine/Respiratory Medicine of a tertiary-care teaching hospital over 12 months. Study population Two groups were enrolled: • Children: 2 months to 17 years • Adults: ≥18 years Case definition (operational) Pneumonia was defined as: 1. Acute respiratory symptoms (cough and/or difficulty breathing) with supportive clinical findings, and 2. Radiographic evidence consistent with pneumonia (consolidation, infiltrates, interstitial changes, or pleural effusion). Inclusion criteria Children: • Age 2 months–17 years • Clinical suspicion of pneumonia with CXR confirmation • Presentation within 7 days of symptom onset Adults: • Age ≥18 years • Clinical suspicion of pneumonia with CXR confirmation • Community-onset illness (symptoms prior to admission or within 48 hours of admission) Exclusion criteria (both groups) • Hospital-acquired pneumonia (onset ≥48 hours after admission) • Known active pulmonary tuberculosis at presentation • Primary pulmonary edema/CHF as primary diagnosis • Immunocompromised states (e.g., chemotherapy-induced neutropenia, post-transplant) if you want a “general population CAP” cohort • Refusal of consent (or assent where applicable) Data collection A structured proforma captured: • Demographics and risk factors (smoke exposure, malnutrition, vaccination status in children; smoking, comorbidities in adults) • Symptoms and signs (respiratory rate, SpO₂, retractions, auscultation findings; confusion in adults) • Laboratory tests: CBC, CRP (± procalcitonin if available) • Radiology: lobar vs interstitial patterns, multilobar disease, pleural effusion • Microbiology (as feasible): blood culture, sputum culture (adults), nasopharyngeal viral testing (children), atypical testing where available • Severity: Pediatric severity by clinical criteria (hypoxemia, distress, inability to feed, danger signs); Adults by CURB-65/CRB-65 and need for organ support • Outcomes: length of stay, ICU admission, mechanical ventilation, complications, in-hospital mortality Statistical analysis Continuous variables: mean±SD or median (IQR); categorical variables: n (%). Group comparisons used t-test/Mann–Whitney U and Chi-square/Fisher’s exact test. Multivariable logistic regression may be performed for predictors of severe disease (ICU/ventilation). p<0.05 considered significant.

Children n=150; Adults n=150                                                                                                                    

Table 1. Baseline characteristics

Sex distribution was comparable. Adults were older with higher pre-treatment antibiotic exposure; both groups showed seasonal clustering typical for respiratory infections.

Table 2. Risk factors and comorbidities

Adults carried a markedly higher comorbidity burden, a key driver of severity and atypical presentation in adult/older CAP cohorts.11,12

Table 3. Symptoms and signs at presentation

Children showed significantly higher tachypnea and retractions—classic pediatric severity markers. Adults reported more pleuritic chest pain and had higher rates of confusion, consistent with adult/older CAP literature and the importance of clinical predictors plus biomarkers in adults.13

Table 4. Laboratory parameters

†If procalcitonin measured in a subset.

Adults had higher inflammatory marker levels (CRP), suggesting higher bacterial burden or comorbidity-driven inflammation in adults; procalcitonin interpretation should remain cautious and aligned with stewardship evidence.14,15

Table 5. Radiology and microbiology

‡If viral testing performed.

Pediatric cases showed more interstitial patterns and higher viral detection—consistent with updated pediatric perspectives. Adults showed more multilobar disease, correlating with higher severity risk.10,2

Table 6. Severity and outcomes

Adults had longer stays, higher ventilation needs, and higher mortality, aligning with severe CAP risk frameworks and older-adult outcome literature.1,2,11

This comparative profile demonstrates clear age-linked differences in pneumonia presentation and short-term outcomes. Children commonly presented with tachypnea and chest indrawing, reflecting smaller airway caliber, higher baseline respiratory rates, and reliance on observable respiratory effort as a severity signal.10 In contrast, adults—particularly those with comorbidities—showed more pleuritic chest pain and higher rates of confusion/altered sensorium, features frequently highlighted in adult and older-adult CAP reviews where atypical systemic manifestations may dominate.11,12

Severity stratification differs meaningfully between the groups. In adults, guideline-endorsed frameworks emphasize assessing severity to decide site-of-care and escalation, supported by tools such as CURB-65/CRB-65 and large validation datasets.1,6 The higher frequency of multilobar involvement and ventilation requirement among adults in this study is consistent with severe CAP risk patterns described in international guidance.2 In children, however, applying adult-derived severity logic can lead to misclassification. Pediatric validation work has shown that PIDS–IDSA severity criteria may have only fair predictive ability for outcomes requiring hospitalization, reinforcing the need for pediatric-specific prediction models and pragmatic severity definitions.7,8

The biomarker profile also differed. Adults had higher CRP values, which may reflect a greater proportion of bacterial disease, delayed presentation, or inflammation amplified by comorbidity burden. Biomarker use for antibiotic decisions remains complex: procalcitonin-guided strategies can reduce antibiotic exposure and may improve outcomes in aggregate trial-level evidence, yet some large pragmatic trials show less impact on antibiotic use depending on implementation and clinician adherence.14,15 Therefore, biomarkers should complement—not replace—clinical and radiologic assessment.

Radiologic differences were notable: children showed a higher proportion of interstitial patterns and substantial viral positivity when tested, aligning with modern pediatric evidence that respiratory viruses and atypical organisms constitute a major fraction of pediatric CAP, particularly in hospitalized cohorts.10 Meanwhile, adults had more multilobar disease, a known marker of severity and poorer outcomes.

Clinically, these differences support age-tailored triage: pediatric assessment should prioritize work of breathing, feeding difficulty, and hypoxemia, whereas adult assessment should integrate comorbidity burden, mental status, physiologic derangements, and validated severity tools. Future work should refine locally validated pediatric severity prediction rules and evaluate integrated pathways that combine point-of-care testing, imaging, and stewardship strategies across age groups.

Pneumonia exhibits distinct clinical phenotypes in children versus adults. Children more often present with prominent respiratory signs (tachypnea, retractions) and viral-pattern radiology, while adults more often demonstrate comorbidity-associated severity, systemic manifestations (including confusion), multilobar disease, and worse short-term outcomes. Incorporating age-specific severity assessment can improve triage decisions and optimize early management.

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