Overview
Definition:
Pneumonia is an infection that inflames the air sacs in one or both lungs
The air sacs may fill with fluid or pus (purulent material), causing cough with phlegm or pus, fever, chills, and difficulty breathing
Pediatric pneumonia is pneumonia occurring in children, a significant cause of morbidity and mortality globally
Procalcitonin (PCT) is a peptide precursor of calcitonin, which has emerged as a valuable biomarker to help differentiate bacterial from non-bacterial causes of inflammation, particularly in respiratory infections.
Epidemiology:
Pneumonia remains a leading cause of death in children worldwide, especially in developing countries
In developed countries, it is a common reason for pediatric hospital admission
Bacterial pneumonia accounts for a substantial proportion of severe cases
Viral etiologies are more common overall but often less severe
Accurate differentiation guides appropriate antibiotic use, crucial for antibiotic stewardship.
Clinical Significance:
Distinguishing bacterial from viral pneumonia is critical for appropriate antibiotic therapy
Unnecessary antibiotic use contributes to antimicrobial resistance, while delayed or inadequate treatment of bacterial pneumonia can lead to severe complications
Procalcitonin offers an objective measure to aid clinicians in this differentiation, potentially reducing antibiotic exposure for viral infections and optimizing treatment for bacterial infections.
Clinical Presentation
Symptoms:
Fever, often high grade
Cough, which may be dry or productive of purulent sputum
Tachypnea and increased work of breathing
Dyspnea or shortness of breath
Chest pain, often pleuritic
Irritability or lethargy in infants and young children
Poor feeding or vomiting
Cyanosis in severe cases.
Signs:
Tachypnea
Grunting respirations
Nasal flaring
Retractions (subcostal, intercostal, suprasternal)
Decreased breath sounds or crackles on auscultation
Bronchial breath sounds
Dullness to percussion over consolidated areas
Increased vocal fremitus
Fever or hypothermia in neonates
Tachycardia.
Diagnostic Criteria:
Clinical diagnosis based on history and physical examination
Chest X-ray showing lobar consolidation, interstitial infiltrates, or pleural effusion suggestive of pneumonia
Laboratory findings may include leukocytosis with a neutrophilic predominance in bacterial pneumonia, and lymphocytosis in viral pneumonia
Procalcitonin levels to aid differentiation.
Diagnostic Approach
History Taking:
Onset and duration of symptoms
Character of cough and sputum
Fever pattern
Associated symptoms like ear pain, sore throat, or gastrointestinal upset
History of recent viral illness or exposure to sick contacts
Immunization status
Presence of underlying chronic conditions like asthma or congenital heart disease
Recent antibiotic exposure.
Physical Examination:
Assess vital signs: temperature, heart rate, respiratory rate, oxygen saturation
Perform a thorough respiratory examination: inspection for work of breathing, palpation for fremitus, percussion for dullness, and auscultation for breath sounds, crackles, and wheezes
Examine other systems, especially ears and throat, to identify potential contributing factors.
Investigations:
Complete Blood Count (CBC) with differential: may show elevated WBC count with neutrophil predominance in bacterial pneumonia, or lymphocytosis in viral pneumonia
C-reactive protein (CRP): a non-specific marker of inflammation, elevated in both bacterial and viral infections
Procalcitonin (PCT): levels are typically significantly elevated in bacterial infections, while remaining low or minimally elevated in viral infections
Chest X-ray: essential for confirming diagnosis, assessing extent, and identifying complications like effusions or abscesses
Blood cultures: indicated in severe cases or for patients with risk factors for bacteremia
Sputum Gram stain and culture: may be helpful in older children with productive cough, but often difficult to obtain and interpret in young children.
Differential Diagnosis:
Bronchiolitis
Asthma exacerbation
Aspiration
Congenital lung abnormalities
Pulmonary edema
Allergic bronchopulmonary aspergillosis
Pneumonitis of non-infectious origin.
Procalcitonin Role
Pct Interpretation:
Normal PCT levels are typically <0.1 ng/mL
Values between 0.1 and 0.5 ng/mL are considered indeterminate or suggestive of mild bacterial infection
Levels >0.5 ng/mL strongly suggest a bacterial etiology
In pediatric pneumonia, PCT levels >0.5-1.0 ng/mL are often used as a threshold to initiate or continue antibiotic therapy
PCT levels typically rise within 2-4 hours of bacterial infection onset and peak at 12-24 hours, declining with effective treatment.
Pct In Bacterial Pneumonia:
In confirmed bacterial pneumonia, PCT levels are significantly elevated, often exceeding 1 ng/mL and sometimes reaching >10 ng/mL in severe sepsis
The magnitude of elevation generally correlates with disease severity
A rapid decline in PCT levels during antibiotic therapy indicates a good clinical response.
Pct In Viral Pneumonia:
Viral pneumonia is typically associated with low or undetectable PCT levels (<0.1 ng/mL)
In some cases of severe viral illness with secondary bacterial superinfection, PCT may be moderately elevated, necessitating careful clinical correlation.
Pct For Antibiotic Stewardship:
PCT assays can guide antibiotic decisions
If PCT is low (<0.1-0.25 ng/mL) in a child with suspected pneumonia, the likelihood of a bacterial infection is low, and antibiotic therapy can often be withheld or discontinued, thus promoting antibiotic stewardship
In contrast, elevated PCT levels support the use of antibiotics.
Management
Initial Management:
Assessment of airway, breathing, and circulation
Supplemental oxygen to maintain adequate oxygen saturation (>92%)
Fluid resuscitation if signs of dehydration or shock
Antipyretics for fever
Close monitoring of vital signs and respiratory status.
Medical Management:
Antibiotic therapy is indicated for suspected or confirmed bacterial pneumonia
Choice of antibiotic depends on age, likely pathogen, local resistance patterns, and severity of illness
For community-acquired pneumonia in children >3 months: Amoxicillin is first-line
For suspected atypical pathogens or failure of first-line therapy: Macrolides (e.g., Azithromycin) may be used
For severe pneumonia requiring hospitalization: Intravenous antibiotics like Penicillin G or Ceftriaxone are often used
Viral pneumonia is managed supportively without antibiotics
Antiviral therapy may be considered for influenza or RSV in specific high-risk populations.
Supportive Care:
Hydration, adequate nutrition, and pain management
Chest physiotherapy may be considered for children with excessive secretions but is not routinely recommended for all
Monitoring for complications such as respiratory failure, sepsis, or empyema
Consider mechanical ventilation if respiratory failure develops.
Monitoring Pct Response:
Serial PCT measurements can be used to monitor response to antibiotic therapy
A significant decrease in PCT levels within 48-72 hours of initiating antibiotics suggests effective treatment
Persistence of high PCT levels may indicate treatment failure, resistant organisms, or an alternative diagnosis.
Complications
Early Complications:
Pleural effusion
Empyema
Lung abscess
Sepsis
Respiratory failure requiring mechanical ventilation
Necrotizing pneumonia.
Late Complications:
Bronchiectasis
Persistent lung infiltrates
Recurrent pneumonia
Reactive airway disease.
Prevention Strategies:
Vaccination against common bacterial pathogens (e.g., Streptococcus pneumoniae, Haemophilus influenzae type b) and influenza
Prompt diagnosis and appropriate treatment of pneumonia
Good hygiene practices to prevent viral transmission
Early identification and management of underlying chronic conditions.
Prognosis
Factors Affecting Prognosis:
Age of the child (neonates and infants have higher risk)
Severity of pneumonia
Presence of comorbidities
Etiological agent (bacterial pneumonia generally has a worse prognosis than typical viral pneumonia if untreated)
Promptness and appropriateness of treatment
Development of complications.
Outcomes:
Most children with community-acquired pneumonia recover fully with appropriate treatment
Outcomes are generally good for uncomplicated bacterial and viral pneumonia
However, severe cases can lead to significant morbidity or mortality, particularly in immunocompromised or very young children.
Follow Up:
Children who have been hospitalized for pneumonia should have a follow-up appointment to ensure complete recovery
Chest X-ray may be repeated if symptoms persist
Close monitoring for any signs of recurrent respiratory issues or complications
Education for parents on recognizing early signs of respiratory distress.
Key Points
Exam Focus:
Procalcitonin is a valuable biomarker to differentiate bacterial from viral pneumonia in children, guiding antibiotic use
Low PCT levels (<0.1-0.25 ng/mL) generally argue against bacterial pneumonia
High PCT levels (>0.5-1.0 ng/mL) strongly suggest bacterial infection
Serial PCT monitoring can track response to antibiotics
Pneumococcal and influenza vaccines are crucial preventive measures.
Clinical Pearls:
Always correlate PCT levels with the clinical picture
a high PCT in a child who is clearly improving with supportive care for a viral illness might prompt reconsideration of the diagnosis or reassessment of the PCT threshold
Consider secondary bacterial infection in viral pneumonia if PCT rises or remains high
PCT is less reliable in neonates and immunocompromised individuals.
Common Mistakes:
Over-reliance on a single PCT value without clinical correlation
Prescribing antibiotics solely based on a slightly elevated PCT without considering the overall clinical context
Not considering viral pneumonia in children with high CRP but low PCT
Failing to consider other causes of inflammation that can elevate PCT, such as severe trauma or surgery.