Pneumonia

Introduction 

Aside from the neonatal period, lower respiratory tract infections are the most common cause of death in children under 5. The term lower respiratory tract infection (LRTI) refers to infection below the level of the larynx, including the trachea, bronchi, bronchioles and alveoli. LRTI is an umbrella term for several conditions such as pneumonia, acute bronchitis and bronchiolitis.

In this article, we will focus on pneumonia and the pathophysiology, clinical features, management and complications of this disease in childhood.

Epidemiology

Although incidence of pneumonia peaks at the extremes of age, it is still high during childhood, with around 3% of children over the age of 12 months having a LRTI each year¹. Pneumonia is the commonest cause of mortality and hospital admissions in children².

Pathophysiology

Pneumonia can be caused by both viruses and bacteria. The causative organism often goes undetected; however, the age of the child, alongside any co-morbidities they may have, can make certain pathogens more likely.

Mycobacterium tuberculosis should always be considered as a causative organism¹.

Pathogens enter the lower respiratory tract via inhalation, aspiration, invasion of the respiratory epithelium or haematogenous spread³. If anatomical and immunological “barriers to infection” are overcome, the presence of pathogens in the lung can cause localised inflammation. This results in damage to alveoli and epithelial cells. Subsequently, inflammatory cells cluster around the infected area. This exudative mechanism impairs oxygenation³.

By BruceBlaus - Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=44806756

Comparison of normal alveoli to an alveoli during pneumonia

Risk Factors

• Younger in age
• Malnourishment
• Immunocompromised
• Exposure to cigarette smoke
• Air pollution⁴
• Ill contacts
• Immunisations not up to date
• Recent travel ^1,4

Clinical Features

History^1,4

• High temperatures
• Shortness of breath
• Cough
• Post-tussive vomiting
• Lethargy
• Aches and pains, specifically around the abdomen, chest and neck, due to the effects of the pleural effusion
• Reduced feeding

Examination

• Tachypnoea⁵ – this is the most sensitive clinical sign¹
  • >60 for 0-5 months
  • >50 for 6-12 months
  • >40 for over >12 months
• Signs of cyanosis
• Signs of increased work of breathing
  • Nasal flaring
  • Tracheal tug
  • Intercostal and subcostal recession
  • Abdominal breathing
• Auscultation Findings
  • End inspiratory crackles
  • Bronchial breathing
  • Absent breath sounds
  • Decreased breath sounds
• Percussion Findings
  • Dullness to percussion due to consolidation
  • Stony dullness due to effusion or empyema

Differential Diagnosis

• Bronchiolitis
• Acute bronchitis
• Asthma
• Cystic fibrosis
• Congenital heart disease

Investigations

The SPUR acronym is a useful aid to determine if investigations are necessary ⁸

• Severe
• Persistent
• Unusual
• Recurrent

Laboratory⁶

• Nasopharyngeal secretions +/- swabs for viral PCR
• Sputum for microscopy and culture
• Serology for Respiratory viruses, chlamydia and mycoplasma
• Pleural fluid sent for microscopy and culture
• Investigate for TB and HIV in areas with high disease prevalence ⁸
• Blood investigations – Full blood count, Inflammatory markers like CRP.

Imaging⁶

• Chest X-ray
• Ultrasound scan can be considered if signs of complications, such as pleural effusion or empyema.

Management

Children with pneumonia benefit from early investigations (if necessary) and management to prevent future acute and chronic complications of pneumonia ².

Immunisation

• Pneumococcal vaccine for children in at-risk groups ⁷
• Haemophilus influenzae type B ⁸

Initial management

NICE CKS – 999 or hospital admission if any of the below ^4,5

• Oxygen saturations consistently below 92% on air
• Respiratory rate >60
• Signs of cyanosis
• The child is unarousable or struggles to stay awake
• A temperature of 38 degrees or higher in a child less than 3 months old
• Signs of a clinically unwell child
• Apnoea

NICE CKS consider hospital admission if ⁵

• Increased respiratory rate
• Signs of cyanosis
• Increased effort breathing (such as grunting, nasal flaring, marked recession)
• Fluid intake reduced to 50-75% normal or clinical signs of dehydration, such as fewer wet nappies
• Less responsive or difficult to rouse
• Persistent worsening of fever, or if it does not settle within 48 hours, or initiation of antibiotic treatment

If the child does not require hospital admission ⁵

• Oral antibiotics (may vary depending on local guidelines)
  • 1st line: 5-day course of amoxicillin
  • If no response to amoxicillin, add on a macrolide such as clarithromycin
  • Association with influenza – co-amoxiclav
• If the child is distressed, use paracetamol (note: not indicated solely for fever)
• Regular fluids
• Check on the child regularly
• Safety netting advice to the parents.

Management in hospital ⁶

• IV antibiotics, initially broad-spectrum and then rationalised based on microbiology
• IV fluids if the child is unable to manage oral intake (ensure urea and electrolytes are monitored daily)
• Chest physiotherapy
• Management of complications will be based on the clinical picture, blood markers and imaging.
  • Children with complications such as a para-pneumonic effusion or an empyema may benefit from insertion of a small-bore chest drain under ultrasound, flushed regularly with a fibrinolytic ⁶.
  • If the patient develops a lung abscess, they may require surgical drainage ⁹. In severe cases, a VATS procedure or thoracotomy may be indicated ⁶.

Follow up – the 4 C’s of follow up ⁸

• Follow up Chest X-ray to ensure resolution 4-6 weeks after the initial episode if
  • Continued symptoms
  • Collapse
  • Consolidation
  • Complications (abscess / empyema / effusion)

Complications

• Para-pneumonic effusion is present in a third of children and resolves with the resolution of the pneumonia¹
• Pleural empyema is when the pleural fluid becomes infected. Fibrin strands can form within the empyema, causing septations.
• Intrapulmonary abscess
• Post infectious bronchiectasis⁸ – Common in children with recurrent or severe infection.

References