Bronchiolitis: Types, Symptoms, Risks & Diagnosis

Bronchiolitis is an inflammatory respiratory condition. It is caused by a virus which affects the smallest air passages in the lungs. Bronchioles control the airflow in the lungs. When they become infected or damaged, they can swell or become clogged. This blocks the flow of oxygen. Although it’s generally a childhood condition, bronchiolitis can also affect adults.

Types of Bronchiolitis:

There are two main types of bronchiolitis:

Viral Bronchiolitis

Viral bronchiolitis appears in infants. Most cases of viral bronchiolitis are due to respiratory syncytial virus (RSV). Viral outbreaks occur every winter and affect children under the age of one.

Bronchiolitis Obliterans

Bronchiolitis obliterans is a rare and dangerous condition seen in adults. This disease causes scarring in the bronchioles. This blocks the air passages creating an airway obstruction that can’t be reversed.

Symptoms of Bronchiolitis:

Viral bronchiolitis and bronchiolitis obliterans have similar signs and symptoms. These include:

  • Shortness of breath
  • Wheezing
  • Bluish appearance of the skin from lack of oxygen
  • Crackling or rattling sounds heard in the lungs
  • Fatigue
  • Ribs that appear sunken during attempts to inhale (in children)
  • Nasal flaring (in babies)
  • Fast breathing
  • Cough

Exposure to certain chemicals may cause bronchiolitis to appear within two weeks to a month. A lung infection can take several months to several years to produce symptoms.

Causes of Bronchiolitis:

There are different causes of viral bronchiolitis and bronchiolitis obliterans.

Causes of Viral Bronchiolitis:

Viruses that enter and infect the respiratory tract cause viral bronchiolitis. Viruses are microscopic organisms that can reproduce rapidly and challenge the immune system. The following are common types of viral infections that may cause bronchiolitis:

Respiratory syncytial virus (RSV):

RSV is the most common cause of bronchiolitis. RSV usually strikes children by the age of 2 but is most common in babies less than 1 year of age. Contagious infection can also cause inflammation, mucus, and swelling in the airways.

Adenoviruses:

These viruses target mucous membranes. They cause about 10 percent of acute respiratory tract infections in children.

Influenza viruses:

These viruses cause inflammation in the lungs, nose, and throat. Influenza affects both adults and children. It’s especially dangerous for babies who don’t have strong immune systems.

Causes of bronchiolitis obliterans:

This rare condition that sometimes occurs for no known reason. Severe cases can lead to death if left untreated. A few cases have been identified and include:

  • Fumes from chemical like ammonia, bleach, and chlorine
  • Respiratory infections
  • Adverse reactions to medications

Risks:

Viral bronchiolitis can affect children up to 2 years old. It generally occurs in infants of  3 to 9 months of age. A few risk factors for viral bronchiolitis in babies and young children are:

  • Not being breastfed
  • Being born prematurely or born with a heart or lung condition
  • Having a suppressed immune system
  • Being exposed to cigarette smoke

Risks for Bronchiolitis Obliterans in Adults are:

  • Working conditions can expose you to dangerous chemicals
  • Having a heart, lung, or bone marrow transplant
  • Smoking tobacco containing nicotine
  • Having an autoimmune connective tissue disease

Diagnosis:

There are several ways to diagnose the bronchiolitis. Imaging tests, including chest X-rays that help doctors to diagnose this bronchiolitis. A common tool used for adults is spirometry. This measures how much and how quickly you take in air with each breath. Arterial blood gas tests are used to test both types of bronchiolitis and measure how much oxygen and carbon dioxide are present in the blood.

Samples of mucus or nasal discharge can help the doctor to diagnose the type of virus causing the infection. This testing method is common with babies and small children.

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