Paediatric Pneumonia

Introduction

• Diagnose clinically when wheezing syndromes ruled out
• Always consider pneumonia in acute abdomen presentation
• Consider foreign body if acute onset, lack of fever or recurrent lobar pneumonia
• Tachypnoea is most sensitive and specific sign of pneumonia
• Meningismus may be due to upper lobe pneumonia
• Wheezing common in RSV, influenza and mycoplasma
• Pneumococcal tends to be abrupt while atypical/viral presentations have a more indolent course with less fever and more malaise, headache, arthalgia and rash
• Coryza, wheeze, diffuse crackles and minimal CXR findings (if performed) suggests viral pneumonitis and antibiotics can be witheld with close follow-up

Clinical Definition

• Persistent or repetitive fever, cough and tachypnoea at rest (and retractions in younger children) when clinical wheezing syndromes ruled out

Aetiology

• Pathogen can be identified in 65-85% of cases (BTS)
  • 30-67% due to viruses
  • Mixed viral-bacterial in 22-33%
• Age is the best predictor. CXR findings are not reliably predictable of aetiology
• Virus is most common in children <5 using nasopharynx PCR testing
  • RSV most common in infants
  • Adenovirus and human metapneumovirus also common under 5yo
• Atypical organisms most common in children >5 (also seen in pre-schoolers)
  • Chlamydia
  • Mycoplasma
• Bacterial
  • Strep pneumoniae, staphylococcus aureus, Hib, Pertussis, Moraxella catarrhalis
  • Klebsiella/E. coli/Salmonella in malnourished children
  • Consider S. aureus , Group A streptococcus and CA-MRSA in indigenous and Pacific Islander children
• Neonatal
  • Group B strep, E. coli, Listeria, gram-negatives

Incidence and risk factors

• 30-40/1000 children <5yo in developed world
• 15/1000 children age 5-14 in developed world
• Risk factors
  • Male
  • Age <5 and Birth at 24-28 weeks associated with risk of severe disease
  • Day care
  • Malnutrition
  • Low birth weight
  • Non-exclusive breastfeeding in first 4 months of life
  • Unimmunised
  • Indoor air pollution
  • Overcrowding
  • Parental smoking
  • Zinc deficiency

Recurrent pneumonia

• Risk factors
  • Aspiration syndrome
  • Immunodeficiency
  • Congenital heart disease
  • Asthma
  • Pulmonary anomalies
  • GORD
  • Sickle cell disease

Diagnosis

• Pneumonia unlikely in absence of fever or tachypnoea
• CXR, FBC, BC, inflammatory markers and serology not necessary in most cases
• Indications for CXR
  • Suspicious but inconclusive clinical diagnosis
  • Prolonged or unresponsive
  • Severe
  • High-risk for complications or suspected complications e.g. empyema
• Indications for nasopharyngeal swab/aspirate PCR
  • Young infants in whom identification of viral pathogen may alter course of antibiotics
  • Severe or complicated cases
  • Testing for atypical bacteria is not helpful as cannot distinguish asymptomatic carriage from symptomatic infection
• Indications for BC
  • Less than 2 months old or severe
  • Positive in only 2-3% of pneumonia cases, higher in severe pneumonia

Severity assessment

• Severe pneumonia if 2 or more of:
  • Severe respiratory distress
  • Severe hypoxaemia or cyanosis
  • Marked tachycardia
  • Altered mental status
  • Clinical signs of empyema (ALWAYS PERCUSS)

Differential diagnosis

• Asthma
• Croup
• Bronchiolitis
• Foreign body aspiration
• Heart failure
• Cystic fibrosis
• Nephrotic syndrome
• Viral URTI
• Tonsillitis
• Epiglottis/bacterial tracheitis
• Sepsis

CXR findings

• Lobar pneumonia
  • Spread from alveolus to next via pores of Kohn
• Bronchopneumonia
  • Acute bronchitis spread to multiple alveoli leading to multifocal densities
• Focal consolidation more suggestive of bacterial
• Focal atelectasis with diffuse non-specific and perihilar findings suggestive of viral
• Round pneumonia more likely pneumococcal
• Empyema more likely staphylococcal
• Pleural effusion – Strep. Pneumoniae still remains more likely and does not necessarily indicate more severe disease
• Lung abscess

Treatment

• Antibiotics
  • Neonates – Ampicillin 50mg/kg QID and Gentamicin 5mg/kg daily
  • Mild to moderate
    • Amoxicillin 25mg/kg (max 1g) PO q8h (Roxithromycin if penicillin allergic)
    • BenPen 60mg/kg (max 2.4g) IV q6h if unable to tolerate orals
    • If mycoplasma suspected add Roxithromycin PO 4mg/kg BD
    • If staph suspected add Flucloxacillin 50mg/kg IV q4h
    • A 3 day course is as effective as 5 days in non-severe pneumonia in children under 5yo
  • Severe pneumonia
    • <5yo: Cefotaxime 50mg/kg q6h + IV flucloxacillin 50mg/kg
    • >5yo: Cefotaxime +- Azithromycin
    • If empyema or nmMRSA suspected add lincomycin 15mg/kg TDS
    • If life-threatening or multi-resistant MRSA suspected add vancomycin 30mg/kg load then 15mg/kg q6h

• Resistant strains of pneumococcus are becoming more common but clinical outcomes are the same between strains treated with penicillins
• Third-generation cephalosporins provide no additional benefit beyond penicillins and should be reserved for severe cases to cover beta-lactamase producers and gram-negatives

• Fluids – NG or IV. ½ to 2/3 maintenance recommended (RCH)
• Risk factors for MRSA
  • Concurrent skin infections due to MRSA
  • ATSI or pacific islander descent
  • Necrotising pneumonia
  • Previous MRSA colonisation
• Oseltamivir
  • Consider for inpatients with complicated disease, ICU admissions in flu season and child with suspected influenza at high risk of complications i.e. CF, congenital heart disease or immunosuppression
• Bronchodilators
  • Can consider trial if suspect significant bronchospasm

Disposition

• Admit
  • Infants <2mo
  • Moderate to severe work of breathing
  • O2 requirement (target >92%)
  • NG feed/IV fluid requirement
  • History of apnoea
  • Immunocompromised
  • High-risk family
  • Chronic lung disease
  • Failed outpatient therapy

• ICU if:
  • Impending respiratory failure
  • Shock
  • SpO2 <92% on FiO2 >0.50
  • Altered mental status
• Discharge criteria
  • Maintaining adequate oxygenation, mild work of breathing and fluid intake
• Follow-up CXR: Only recommended if not recovered fully at 4-6 weeks, complicated pneumonia, persistent signs, anatomical abnormality or foreign body

Complications

• Lung abscess
• Parapneumonic effusion
• Empyema
• Respiratory failure
• Septic shock
• Necrotising pneumonia (Pneumococcus, staphylococcus, GAS, Mycoplasma)
• Apnoea – RSV and pertussis in infants <48 weeks post-conception
• Hyponatraemia
• Dehydration
• ARDS
• Obliterative bronchiolitis/bronchiectasis

Bronchiectasis

• Irreversibly dilated, thick-walled bronchi due to muscle and elastic tissue destruction
• Can be widespread or localised
• Persistent and progressive condition
• Acquired
  • Allergic bronchopulmonary aspergillosis
  • Complication of childhood pneumonia
  • Foreign body
  • HIV
  • IBD
  • Recurrent aspiration
  • Tuberculosis

• Congenital
  • Alpha-1 AT deficiency
  • Bronchomalacia
  • Ciliary dyskinesia
  • Cystic fibrosis
  • Marfan syndrome
  • Primary immunodeficiency
• Idiopathic in 50% of non-CF cases

• Presentation
  • Chronic cough with purulent sputum exacerbations
  • Haemoptysis
  • Clubbing (rare)
• Investigation – CT/bronchoscopy and testing to identify cause
• Treatment
  • Prolonged antibiotics reduce exacerbation frequency in non-CF bronchiectasis
  • Postural drainage

Specific organisms

• S. pneumoniae
  • Most common bacterial agent
  • Risk factors include immune deficiency, chronic renal disease, functional or anatomic asplenia and ATSI descent
• S. aureus
  • More severe and 70% of cases in first year of life
  • Foreign body aspiration, immunosuppression and skin infections are at increased risk
  • Rapid progression with 90% suffering empyema, 50% pneumatocoeles and 25% pneumothorax
• H.influenzae
  • Reduced in frequency by 90% since immunisation
  • Mostly older children now (non-type B)
  • 25-75% rate of effusions and bacteraemia (75-95%)
  • More commonly has other foci of infection (meningitis, septic arthritis, epiglottitis, pericarditis, soft tissue infection and otitis media)

• Group A streptococcal pneumonia
  • Sporadic and may complicate varicella
  • High toxicity, rapid progression and high fatality rate
• Mycoplasma pneumoniae
  • Classically 5-14yo but is actually fairly common over 1 yo
  • Typically gradual onset but some have abrupt onset
  • Prodromal fever, headache, malaise then non-productive, barking cough
  • Coryza is unusual
  • Rash is seen in 10%
  • CXR often more impressive than physical examination
  • Complications include haemolytic anaemia, myopericarditis, meningoencephalitis, GBS, transverse myelitis, cranial neuropathy, arthritis and rash but are very rare

Last Updated on October 27, 2021 by Andrew Crofton