Acute Bronchiolitis

Bronchiolitis is a common LRTI in ≤2 years age group and it is also one of the the leading cause for hospitalization in infants. The most common bus associated with bronchiolitis is RSV (other possible agents are human metapneumovirus, adenovirus, influenza, rhinovirus, and parainfluenza viruses. Following an episode, cough may persist for up to 3 weeks. 

Pathophysiology
The viral infection in bronchiolitis causes inflammation of the lower respiratory tract leading to edema, necrosis, increased mucus production and bronchospasm eventually causing  air trapping, atelectasis, and hyperinflation of the lower airways and increased work of breathing. 

Symptoms
The peak of symptoms is often between the third and fifth day after onset

• Coughing. 
• Rhinorrhea, tachypnea
• Wheezing and Crackles 
• Use of accessory muscles and subcostal and intercostal retractions
• Nasal flaring
• Low grade fever 
• Irritability, cyanosis, and poor feeding
• Apnea in infants
• Dehydration due to increased insensible losses

Risk Factors for severe disease

• Chronic Lung Disease
• Age < 3moths
• Premature Birth
• Congenital Heart Disease
• Immunodeficiency 
• Neuromuscular Disorders

Diagnosis

• Bronchiolitis is a clinical diagnosis. 
• No lab tests are useful 
• Blood tests and CXR: indicated only if other diagnoses need to be excluded or in cases of severe disease (high O2 requirement)

Differential Diagnosis

• Asthma
• Pneumonia
• Foreign Body
• Cystic Fibrosis

Treatment 

• Oxygen Target oxygen saturation of >92%.
• Instillation of saline into the nares followed by suctioning
• Frequent and smaller feeds to prevent dehydration
• Caretakers should use frequent hand washing to minimise spread

Controversial Treatment Options:

• Bronchodilators do not offer any clear benefits and thus should not be given routinely.
• Inhaled epinephrine should be considered only in severe disease
• Steroids do not provide any benefit if used alone. However, current guidelines do advocate consideration for steroid use in combination with epinephrine in the treatment of bronchiolitis.
• Nebulized Hypertonic Saline: Mixed evidence and not recommended for routine use. It improve mucociliary clearance by loosening mucous plugs through osmotic draw of fluid from submucosal and adventitial spaces. 
• Ventilatory Support: Noninvasive ventilation may prevent intubation. 
• Heliox: Heliox does not affect the rates of intubation or mechanical ventilation or length of intensive care admission

Admit if:

• Risk Factors for severe disease
• Premature birth
• Persistent symptoms despite therapy
• Dehydration, 
• Spo2 <90% on room air)
• Episodes of apnea 

Take Home: 

• Bronchiolitis affects <2year age group and RSV is the most common bug.
• Supportive Care and Hydration is the key
• Most treatment modalities are controversial and thus are not recommend for routine use. Consider using in rapidly deteriorating

References and Further Reading:

1. Fernandes R, Bialy L, Vandermeer B, et al: Glucocorticoids for acute viral bronchiolitis in infants and young children. Cochrane Database Syst Rev 6: CD004878, 2013. [PMID:23733383]
2. Ralston SL, Lieberthal AS, Meissner HC, et al: Clinical practice guideline: the diagnosis, management, and prevention of bronchiolitis. Pediatrics 134: e1474, 2014. [PMID: 25349312]
3. http://pediatrics.aappublications.org/content/early/2014/10/21/peds.2014-2742
4. https://www.nice.org.uk/guidance/ng9/chapter/1-Recommendations#management-of-bronchiolitis 
5. http://pedemmorsels.com/bronchiolitis-seriously-what-should-i-do/

Posted by:

              

     Lakshay Chanana

     

     Speciality Doctor

     Northwick Park Hospital

     Department of Emergency Medicine

     England

     @EMDidactic