Bronchiolitis

Overview

Bronchiolitis is the swelling of bronchioles (tiny airways of the lungs) caused by respiratory syncytial virus (RSV) infection. Acute viral illness causes mucus build-up in the small airways, restricting breathing abilities. Younger children and infants under the age of 2 are affected primarily by the disease.
Common types of bronchiolitis include acute viral bronchiolitis, follicular bronchiolitis, bronchiolitis obliterans and transplant-related bronchiolitis. Symptoms of this condition are fever and common cold, which may manifest into difficulty breathing, wheezing and coughing.

Diagnosis includes physical examination, blood tests, nasal swabs, X-rays and sputum culture. This disease can be treated at home by ensuring hydration and breathing monitoring. However, individuals with adverse symptoms may require prompt medical attention at a hospital.

What is Bronchiolitis?

Bronchiolitis is the inflammation of the small airways of the lungs (known as bronchioles), caused by an acute viral infection. Children below 2 years of age often develop this lower respiratory tract infection. The viral infection caused the build-up of mucus in the bronchioles, making breathing challenging.
Symptoms start like a common cold and progress to wheezing, coughing and difficulty breathing which may last for up to a month. Affected individuals can get better through at-home bronchiolitis treatments, while medical attention may be required for individuals with worsened symptoms.

Types of Bronchiolitis

Acute bronchiolitis is a common and viral lower respiratory tract infection, affecting young children and infants. The other types of bronchiolitis include the following:

Follicular Bronchiolitis

Hyperplasia of the bronchial-associated lymphoid tissue (BALT), or bronchiolar nodular lymphoid hyperplasia, is a rare lung disease that causes inflammation of the bronchioles. It is characterised by the occurrence of hyperplastic lymphoid follicles having germinal centres across the walls of bronchioles.

Diffuse Panbronchiolitis

An idiopathic inflammatory disease, characterised by sinusitis, bronchiolitis and diffuse bilateral micronodular pulmonary lesions. DPB develops in individuals who are susceptible to this disease-causing viruses and bacteria. It predominantly affects people front he East Asia, including Japan, Korea and China.

Bronchiectasis

A chronic lung disease that causes the walls of the bronchi to widen and thicken permanently, leading to excess mucus build-up and frequent severe infections. Symptoms may include a persistent cough that brings up phlegm, wheezing and shortness of breath. It is caused by any lung infection and is categorised into two types including cystic fibrosis bronchiectasis and non-cystic fibrosis bronchiectasis.

Bronchiolitis obliterans (constrictive bronchiolitis)

Also known as obliterative bronchiolitis or popcorn lung, it is a chronic allograft rejection or scarring of the lung after lung transplantation. Long-term survivors who have undergone transplantation often develop this rare syndrome. It is caused by breathing in harmful chemicals including diacetyl (used to create flavours including fruits and candy), ammonia, chlorine, nitrogen oxides and acetaldehyde (found in cigarette and cannabis smoke).

Postinfectious Bronchiolitis

It is an irreversible obstructive lung disease that causes fibrotic narrowing and subepithelial inflammation of bronchioles after lower respiratory tract infection. Children are primarily affected by the disease, especially during early childhood. Airway pathogens such as mycoplasma and adenovirus cause the rare condition.

Other types of bronchiolitis include:

Cryptogenic Bronchiolitis Obliterans: Forms granulation tissue that affects the air sacs and small airways of the lungs
Bronchiolitis Obliterans with Organising Pneumonia: Inflammation of the small airways, alveoli and bronchioles
Hypersensitivity Pneumonitis: Bronchiolocentric inflammation of the lung in response to breathing in allergens
Respiratory Bronchiolitis: Associated Interstitial Lung Disease: Interstitial lung disease and inflammation of small airways in people who smoke

Symptoms of Bronchiolitis

Symptoms initially include runny nose, loss of appetite stuffy nose and cough. As the symptoms worsen after a few days, an infected child may experience wheezing, worsening cough and shortness of breath.

Young children with weak immune systems may have trouble swallowing and breathing. Symptoms may also include dehydration including dry mouth, less urine production, and crying without tears. In adverse scenarios, the affected child may have blue skin or lips, respiratory failure and pauses in breathing.

Causes of Bronchiolitis

A viral infection causes bronchiolitis, which may include the flu and respiratory syncytial virus, or RSV (which is more common in children).

These viruses infect the small breathing tubes in the lungs, called bronchioles. The tubes then clog up with mucus, restricting the air from getting in and out of the lungs. Children younger than 2 years old are usually affected during the RSV season such as winter and early spring.

Risk Factors of Bronchiolitis

Bronchiolitis mostly affects children under the age of 2 as their lungs and immune system are not fully developed to fight infections. Other risk factors may include premature birth, heart and lung conditions at birth, and a family history of viral infections.

Complications of Bronchiolitis

A drop in oxygen levels in the body is one of the complications of severe bronchiolitis. Individuals may also experience respiratory failure, inability to drink enough fluids, and difficulty breathing if it is not treated at the right time.

Diagnosis of Bronchiolitis

A healthcare professional conducts a physical exam of a child who is experiencing the symptoms. The test helps listen to the child’s breathing and count the breaths per minute. A doctor may also recommend blood tests or X-rays in severe cases such as worsening of symptoms or inability to identify the infection cause. Other diagnostic tests include pulse oximetry, nasopharyngeal swab, sputum culture and spirometry.

Treatment for Bronchiolitis

No treatment can help an individual fully recover from the disease. Treatments are only aimed at managing the symptoms till the infection resolves. It can be taken care of through supportive care at home. This includes ensuring the infected child is hydrated and able to breathe properly. A bulb syringe can also be used at home to remove mucus from the nose. Additionally, if the child is over the age of 1 year, their head can be lifted with an extra pillow to help with breathing.

The infected person can be monitored at home for worsening symptoms such as nasal flaring, rapid breathing, cyanosis, decreased urine output, and adverse chest retractions. Consult with a healthcare professional if the symptoms aggravate further.

Bronchiolitis medication may include nirsevimab (efforts), given to infants younger than 8 months or through 19 months old. Hospital care may include oxygen therapy and intravenous (IV) fluids.

Preventive Measures for Bronchiolitis

Make sure to wash your hands to prevent the infection from spreading, especially when coming in contact with a child. Also, avoid being around people who have a fever or cold.

Other preventive measures include covering mouth and nose with a tissue when coughing or sneezing; and cleaning and disinfecting areas that are often touched. All these methods can help prevent the spread of this viral infection.

Myths and Facts Related to Bronchiolitis

Following are the myths and facts related to bronchiolitis:

Myth 1: Bronchiolitis affects only adults

Fact: Bronchiolitis is more common in younger children and infants, especially under the age of 2. They are more vulnerable to inflammation and blockage caused by this viral infection.

Myth 2: Bronchiolitis and bronchitis are the same

Fact: Bronchiolitis affects the smaller airways (bronchioles) in the lungs and is more prevalent in children and infants. On the other hand, bronchitis affects the larger airways (bronchi) and is more common in adults.

Myth 3: Bronchiolitis can be treated with antibiotics

Fact: Antibiotics often help deal with bacterial infections, making it an ineffective solution for bronchiolitis. The treatment plan may include monitoring breathing and hydration.