Bronchiolitis in Children

Bronchiolitis in Children

• Bronchiolitis is a viral illness affecting infants under two years old.
• Peak incidence is between November and March.
• Respiratory Syncytial Virus (RSV) is the most common cause, accounting for approximately 75% of cases.
• Other viruses, such as Adenovirus, Metapneumovirus, Influenza, and Parainfluenza, can also cause bronchiolitis.
• Pathologically, bronchiolitis is characterized by bronchiolar obstruction due to edema and mucus. This leads to overinflation, atelectasis, and impaired gas exchange.

Presenting Features

• History: Coryzal symptoms (e.g., runny nose) peak around 5 days before illness. Common presentations include dry, wheezy coughs (often without a fever). Wheezing is commonly observed, as is difficulty breathing. Cyanosis and apnoeas (cessation of breathing) are also observed, as is poor feeding.
• Examination: Low oxygen saturations are a common presenting feature. Tachypnea (rapid breathing) is usually seen on examination. Respiratory recession (drawing in of the soft tissues on chest during inhalation) and/or tracheal tug are also common. Wide spread fine inspiratory crackles and wheezing may be heard. Although a fever above 38°C is not usually present, a fever above 39°C should warrant investigation for other potential causes. The absence of wheezing does not rule out a diagnosis.

Admission Criteria

• Bronchiolitis is diagnosed clinically, and admission criteria can be used.
• Factors that may lead to hospital admission include:
  • Oxygen saturations below 94%
  • Respiratory rate above 70 breaths per minute
  • Severely reduced breathing volume associated with respiratory distress and grunting
  • A history of apneas
  • Taking less than 50% of usual feeding amounts
  • Infants appearing listless or unwell
• Duration of illness is also a factor, and infants exhibiting moderate symptoms for 4-5 days should be admitted.

High Risk Infants

• Infants younger than 6 weeks old have an increased risk of severe illness and should trigger a lower evaluation/admission threshold.
• Premature babies (ex-preterm infants) constitute a high-risk group
• Infants with Chronic Lung Disease are also considered high-risk.
• Congenital heart disease is another condition requiring careful monitoring.
• Immunodeficiencies, Trisomy 21 and other syndromic associations may also indicate high risk.

Investigations

• Nasopharyngeal aspirate (NPA) is a routine examination.
• Pulse oximetry should be obtained for all patients.
• Chest radiography is not routinely performed, but may be considered if there is a sudden clinical deterioration.
• Blood tests are generally not needed, unless sepsis is suspected.
• Blood gas analysis may be useful if advanced respiratory support is deemed necessary.

Recommended Management

• Supportive Management: Essential for most cases, including:
  • Oxygen therapy: supplemental oxygen may be given to improve oxygen saturation to 92% or higher (aim to keep oxygen saturation 92% or more). Humidified head box oxygen should be used, if possible. Larger infants may be treated with nasal cannulae at 1L/min if oxygen requirement is less than 35% oxygen.
  • Apnea monitoring: Important for evaluating and monitoring breathing patterns.
  • Feeding: Small, frequent feedings may be used for mild cases; however, nasogastric feedings may be necessary for infants struggling to maintain a proper feeding rate, or those with respiratory rates over 60 breaths per minute or receiving supplementary oxygen. Intravenous fluids should only be considered for severe illness accompanied by severe respiratory distress or when no other feeding method can be sustained.
• Specific Treatments:
  • Nebulized hypertonic saline: Shown to shorten hospital stays in mild/moderate cases. Should be co-administered with salbutamol for therapeutic effect.
  • Bronchodilators: Adrenaline nebulisers show short-term benefits in reducing admission rates for bronchiolitis. Combined treatment with adrenaline and dexamethasone can also reduce admission rates for 7 days after discharge.
  • Ribavirin (antiviral): May be given in some severe cases.
  • Inhaled/Oral Corticosteroids: Use is not routine, but a trial may be considered.

Outcome/Advice to Parents

• Coughs may persist for up to 2-4 weeks.
• Wheezing episodes in the future may be more common.
• Exposure to cigarette smoke should be avoided, particularly during the infant's development.