Bronchiolitis

Bronchiolitis is a common lung disease usually affecting infants less than six months of age. The disease is common during winter months. Symptoms of bronchiolitis typically last for one to two weeks and spontaneously resolve. If there is underlying health problem, bronchiolitis can become serious which might necessitate hospitalization.^[1]

Epidemiology

Bronchiolitis is a common and sometimes severe disease. It usually affects children under the age of 2, with a peak age of 3 - 6 months. ^[2]   

Causes

The illness is almost always caused by a viral infection. The  Respiratory Syncytial Virus (RSV) accounts for 75% of the cases. Other viruses that may cause bronchiolitis are parainfluenza virus, influenza (flu) virus, adenovirus and rhinovirus.^[3]

When the virus enters the respiratory system, it travels to the bronchioles causing swelling and inflammation. Mucus consequently collects in the airways which hinders free flowing on air through the lungs. Since the infant's bronchioles are much narrower compared to that of adult's, they are more easily clogged hence greater difficulty of breathing is experienced.

Bronchiolitis is contagious as one contracts the virus through air droplets.^[1] Risk factors for bronchiolitis include living in crowded areas, not being breastfed, age of less than 6 months and premature birth.^[2]

Symptoms

Initially, the symptoms of bronchiolitis resemble that of a common cold thus patient has a runny nose and a slight fever for 2 to 3 days. For another 2-3 days, the patient then may begin to cough, breathe fast and wheeze.^[4] Symptoms that may indicate difficulty of breathing are nasal flaring, muscles around the ribs sink in as the patient tries to breathe in and the skin turns bluish (cyanosis) as there is lack of oxygen. When there is cyanosis, emergency treatment is necessary.^[2]

Diagnosis

Diagnosis is often done by getting medical history, assessing the symptoms, and conducting a physical exam.^[5] Chest x-ray, blood gases and culture of nasal fluid may be done.^[2]   

Treatment

Often, no treatment is needed. Supportive therapy like rest and drinking plenty of fluids is advised. In severe cases, antiviral medications, oxygen therapy and intravenous fluids are given.^[2]

References:

1. http://www.mayoclinic.com/health/bronchiolitis/DS00481
2. http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0001970/
3. http://www.nhs.uk/Conditions/Bronchiolitis/Pages/Causes.aspx
4. http://familydoctor.org/familydoctor/en/diseases-conditions/bronchiolitis/symptoms.html
5. http://www.webmd.com/lung/tc/bronchiolitis-topic-overview