Last Updated on Jul 29, 2016

What is Bronchiolitis?

Bronchiolitis is an acute lower respiratory infection, which is common among children less than 2 years of age. It is due to an inflammatory reaction in the bronchioles (the smaller airways).

The bronchioles are narrowed due to the swelling of its walls and increased secretions in the bronchioles. It is common during winter. It is the frequent cause of hospitalizations in children.


What are the Causes of Bronchiolitis?

  • It is mainly due to viral infection. Respiratory Syncytial Virus (RSV) is the main causative organism. Other organisms that cause bronchiolitis include rhino virus, parainfluenza virus, adeno virus, influenza virus, coronavirus and human metapneumovirus (hMPV).
  • The children at high risk include those:
    • Exposed to cigarette smoke (passive smoking)
    • Younger than 6 months
    • Living in the over-crowded places
    • Who had a premature birth
    • Non-breastfed babies
    • With low immunity
    • Children with underlying heart problems.
  • The mode of transmission is airborne through infected droplets and also via contact with the secretions from the nose and mouth of an infected child.

What are the Symptoms of Bronchiolitis?

Initially, the affected children present with symptoms similar to common cold like running nose, sneezing, cough and mild fever. Later, the patient may develop wheezing (whistling noise during exhalation). In some patients, the respiratory difficulty progresses and the child may present with chest retractions, tachycardia (rapid heart rate), rapid breathing, lethargy, drowsiness, irritability, dehydration, inability to feed and cyanosis (child may turn blue due to lack of oxygen).

Symptoms of Bronchiolitis Common Cold

How do you Diagnose Bronchiolitis?

The diagnosis is frequently made from a thorough history and examination. Investigations may not always be essential. When the child’s condition is suggestive of bronchiolitis, the following investigations may be ordered by the physician depending on the child’s condition.

Blood Urea and Serum Electrolytes: These tests are ordered if the child seems to be dehydrated.

Pulse Oximetry: If hypoxia (a decrease in the oxygen supply to the tissues) is suspected, pulse oximetry is required. This test finds the levels of oxygen saturation in the blood.

Arterial Blood Gas (ABG) Analysis: It is essential in patients with severe respiratory distress and mechanical ventilation.

Nasopharyngeal Aspirate: The nasopharyngeal secretions are collected using various methods. The aspirate is used to find the causative agent using polymerase chain reaction (PCR) or viral immunofluorescence. The diagnostic test helps confirm RSV bronchiolitis.

Urine Analysis: This test is done to measure the level of dehydration.

Chest X-ray and Blood Test are not usually necessary.

How do you Treat Bronchiolitis?

At Home: In children with bronchiolitis the treatment is mostly conservative.

  • Hydration: Adequate hydration is essential. Mother should try to feed her baby with liquids frequently; adequate breast feeding is encouraged. Mothers should keep a watch on the symptoms. Also, note for the signs of dehydration by monitoring the urine and the wet diaper count.
  • Antibiotics are not prescribed for bronchiolitis because it is caused by the viruses. In patients with associated pneumonia they may be prescribed.
  • Acetaminophen helps reduce the temperature.
  • Nasal blocks should be cleared with the help of saline drops and bulb syringes before feeding the baby and putting the baby to sleep.
Saline Drops to Clear Nasal Blockage


Hospitalization is required in children who develop cyanosis dehydration, respiratory distress, lethargy, apnea (temporary pause of breathing) and uncontrollable fever.

  • Hydration: In severe dehydration, fluids are provided intravenously. 
  • Oxygen: Oxygen saturation levels are monitored. Humidified oxygen is administered if needed. In children with severe respiratory depression, intubation (inserting a tube into the airway) may be required to provide ventilator support. 
  • Nebulized Racemic Epinephrine may be helpful to relieve spasm of the respiratory tract.
  • The use of steroids is controversial.
  • Hypertonic Saline: It is administered with a nebulizer.
Nebulizer Used for the Treatment of Bronchiolitis

How do you Prevent Bronchiolitis?

  • Regular hand wash can prevent the infection to some extent.
  • Prevent the child from exposure to smoke.


  1. Ralston, S.L., et al., Clinical practice guideline: the diagnosis, management, and prevention of bronchiolitis. Pediatrics, 2014. 134(5): p. e1474-502.
  2. Bronchiolitis - (
  3. About Bronchiolitis - (
  4. Hypertonic Saline for the Treatment of Bronchiolitis in Infants and Young Children: A Critical Review of the Literature - (
  5. Recent advances in the management of acute bronchiolitis - (
  6. Acute bronchiolitis - (

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