Overview

Do you know someone who struggles with a respiratory condition? Have you ever thought that it might be asthma or something else? Are you worried your child has something more than just asthma? In this article, we will shed light on both asthma and bronchiolitis.

So, what are they? Asthma is a common chronic lung disease that causes difficulty breathing , while bronchiolitis is a common chest infection in children (below the age of 2) and babies.^1,2 It is important to differentiate between the two to give the proper treatment to the affected individual and improve their quality of life. This article will provide the differences between these two conditions and help people navigate them.

Bronchiolitis

Overview and origin

Bronchiolitis is considered a common lung infection affecting one the lower respiratory tract in kids.³ It is of viral origin and affects the bronchioles, which are small airways with a diameter of ≤ 2 mm, which results in inflammation and some cases fibrosis.^3,4 There are two forms of bronchiolitis: acute and chronic; acute bronchiolitis from viral infections is the most common type of bronchiolitis in infants and children, meanwhile adults mostly experience a wide spectrum of bronchiolar diseases and are mostly chronic forms.⁴ Additionally, respiratory bronchiolitis is the most common form that is found in adults and is typically associated with smoking cigarettes.⁴

Almost all children are exposed to respiratory syncytial virus (RSV) and other viral agents, such as rhinovirus, during the 1^st 2 years of their life, and around 40% of these children would develop clinical bronchiolitis, where up to 3% of them are hospitalised.⁵ What starts as an upper respiratory tract infection can become a lower respiratory tract infection over 2-5 days, with infants being more susceptible as they have small bronchi that are more likely to be blocked by secretions and oedema, as well as they have a less developed ability to respond and clear infections.³

Hence, we need to make sure our kids have a safe recovery and healthy life.

Symptoms and risk factors

Common symptoms of bronchiolitis include:^2,3

• Rhinorrhoea that develops into a harsh moist cough (over 2-4 days) and a fever below 39˚C
• Fever (above 38.5˚C) can be observed
• Rapid breathing
• Difficulty eating
• Wheezing/noisy breathing
• Irritability

Some risk factors can contribute to children developing severe bronchiolitis such as:²

• Babies are born very prematurely
• Heart or lung conditions
• Weakened immune system

Diagnosis and treatment

Diagnosis for bronchiolitis can be done through different aspects, these will be summarised below:³

• Physical findings:
  • Increased respiratory rate: ≥60/min is considered severe and ≥70/min is critical
  • Chest recession
  • Hyperinflation
  • Wheezing/crackles
• Imaging/lab findings:
  • Chest radiography is not required for diagnosis but increases diagnostic uncertainty in cases of other underlying conditions (e.g. pneumonia)

The recommended therapy for bronchiolitis is usually symptomatic and does not require hospitalisation as it gets better on its own, however, severe cases might require a hospital visit.² Some of the things that can help the child include:²

• Painkillers
• Saltwater drops for blocked nose
• Sit upright when awake to help them breathe better
• Drink lots of fluids

Prevention

Several things can be done to lower the chances of children getting bronchiolitis or spreading the virus that causes it:²

• Washing your and your child’s hands often
• Wash/wipe down toys and clean surfaces on the regular
• Use disposable tissues and throw them away as soon as they are used
• Keep newborns away from anyone with a cold or flu (especially if they are ˂ 2 months old or were born prematurely)

It is also important to avoid smoking around children, as children who breathe in cigarette smoke have a higher risk of getting bronchiolitis.²

Asthma

Overview and origin

Asthma is a chronic disease that affects the lower respiratory tract and is characterised by chronic inflammation and airway hyper-reactivity that causes mucus production and remodelling of the airway wall which leads to coughing, wheezing, breathing difficulties, chest tightness and hyperresponsiveness to non-specific stimuli such as cold air.^6,7 It is also worth noting that genetic factors have a strong impact on the risk of developing asthma.⁶ Also, there was a suggestion that breastfeeding has a protective effect on asthma inception which is related to the early-life respiratory infections in babies carrying the risk alleles.⁶

Asthma usually has a childhood onset, however, it can develop later in life in some patients (late-onset asthma) and has differences from childhood-onset asthma.⁷ Late-onset asthma is generally more severe and is less likely to be linked with allergy compared to childhood-onset asthma.⁷ Currently, asthma is considered to be an umbrella term/diagnosis that engulfs several variable clinical presentations (known as phenotypes) and distinct pathophysiological mechanisms (endotypes) and can be historically referred to as allergic asthma and non-allergic asthma.^7,8 Allergic asthma is the most common asthma phenotype with an early onset, sensitisation to an allergen such as grass, tree pollen, animal dander and many others, but it can also be acquired later in life from a new allergen such as occupational allergens.^7,8 It is also associated with T helper 2 (Th2) cell responses which are seen in other allergic reactions such as atopic dermatitis or allergic rhinitis.⁷

The other form of asthma (although overly simplified) would be non-allergic asthma, it usually presents itself as late-onset asthma and is more common in obese and female (assigned at birth) patients and can be difficult to treat at times.⁷ This form of asthma is usually linked to obesity, age and smoking.⁷

Symptoms and risk factors

The main symptoms of asthma include:¹

• Coughing
• Chest tightness
• Breathlessness
• Whistling sound when breathing/wheezing

Usually, asthma can be kept under control, however, it can cause numerous other problems, for example:¹

• Stress, anxiety and depression
• Delays in growth/puberty in children
• Lung infections (e.g. pneumonia)
• Work/life disruptions due to GP or hospital visits
• Absence from work/school
• Exhaustion and feeling tired all the time

Sometimes, these symptoms can become aggravated temporarily which is known as an asthma attack.¹

Additionally, there are some triggers for asthma including:¹

• Allergies (e.g. dust mites, animals)
• Smoke, cold air and pollution
• Exercise
• Infections like colds and cases of flu

As mentioned earlier, genetics can play a role in increasing the risk of asthma. In kids, atopy, lower-lung function, and respiratory tract infections, particularly ones with rhinovirus, are associated with being major risk factors for the persistence of asthma.⁷

It is still not clearly understood whether the underlying inflammation present in asthmatic children causes the pathogenicity of respiratory viruses or if the frequent viral infections that occur at a young age make it easier for asthma to develop.⁷ Since inflammation is very central in asthma pathogenesis, the main objective of asthma treatment was to control the symptoms and underlying inflammation which then can help avoid future disease exacerbations.⁷

Diagnosis and treatment

Diagnosis of asthma can be performed through:⁹

• FeNO test: nitric oxide levels in the patient’s breath are measured when they breathe into the designated machine for analysis. This is used to check for signs of inflammation in the lungs.
• Spirometry: the patient blows into a machine that measures how fast they can breathe out and how much air is being held in the lungs.
• Peak flow test: the patient blows into a handheld device that measures how fast they can breathe out, and this may be done several times over a few weeks to see if there are any changes over time.

Asthma is usually treated with inhalers equipped with medications and the main types include:¹

• Reliever inhalers: they are used when needed to quickly relieve asthma symptoms for a short period.
• Preventer inhalers: these types of inhalers are used every day to prevent asthma symptoms from happening.

It is worth noting that some people might be required to take tablets on top of their current treatment which should be discussed with their healthcare provider.

Summary

Asthma and bronchiolitis are both conditions that affect the lungs and would require attention to avoid future complications. While bronchiolitis is majorly due to infections, asthma is an inflammation in response to an allergen and usually occurs at a young age, however, it can also be due to non-allergic origins such as weight and age and is mostly seen in adults. It is important to diagnose the patient properly to provide the appropriate treatment and provide a better quality of life for our loved ones.