Complete Guide on Asthma What is Asthma?

Asthma is an inflammatory disease of the airways of the lungs. With asthma, the airways become hypersensitive and narrowed in response to a trigger, emotional upset, or exercise. This reaction makes it difficult to breathe because less air is entering the lungs.

The symptoms of asthma can range from an occasional cough to life-threatening shortness of breath. Although asthma cannot be cured, it can be successfully managed to reduce and prevent asthma attacks. Asthma can develop at any age, but it commonly occurs during childhood or teenage years^.

Asthma takes place in two forms; acute and chronic. Acute asthma, known as an asthma attack is an episodic event that occurs due to an asthma trigger. Chronic asthma develops due to the changes that occur from prolonged inflammation over time. Proper control of asthma can limit the effects of chronic inflammation.

What happens during an Asthma attack?

During an asthma attack, the muscles surrounding the airways tense up, which makes it difficult to breathe. In addition, the mucous membranes lining the airways become inflamed and produce thick mucus. As the airways become narrower and clogged with mucus, you experience symptoms of  cough, wheeze, and shortness of breath.

Causes of Asthma

The exact cause of asthma is unknown. However, genetics and the environment play a large role in the development of asthma. If you have asthma, exposure to an asthma trigger can produce an asthma attack.

Asthma triggers include:

• Viral respiratory infections
• Airborne environmental contaminants such as tobacco smoke and pollutants
• Airborne allergens such as dust mites, pollen, pet dander, mold spores, and cockroach waste particles
• Dietary changes
• Stress
• Gastroesophageal reflux disease
• Breathing in some chemicals
• Exercise
• Some medicines
• Food additives
• Fragrances
• Bad weather
• Cold, dry air

Who is at most risk for developing Asthma?

The following are potential risk factors that can increase the chance of developing asthma^:

• Genetics; having a parent who has asthma increases your chances of developing it
• A low birth weight
• Having other allergy-related conditions such as eczema or hay fever in yourself or your family
• Smokers or being exposed to second-hand smoke
• Maternal tobacco smoking increases the risk of childhood asthma
• Obesity
• Viral respiratory infections
• Chronic lung disease
• Air pollution
• Occupational exposure

Signs and Symptoms of Asthma

In children, asthma mostly begins as episodes of prolonged coughing. These episodes gradually resolve with time, but continue to persist into adulthood in some individuals. The frequency and severity of these episodes increase with exposure to asthmatic triggers or if there is a family history of asthma.

Signs and symptoms of asthma differ for each individual. Some individuals may experience mild symptoms such as a cough, while others may experience severe symptoms such as wheezing and breathing difficulty, known as an asthma attack.

Symptoms can be episodic, meaning they happen only occasionally or can be a continuous daily occurance. Asthma may interfere with everyday activities if they are severe, whereas mild symptoms may only cause some discomfort.

Children mostly experience shortness of breath with wheezing and whistling sounds while breathing. Teenagers and adults experience the following symptoms:

• Shortness of breath
• Wheezing, whistling, rattling while breathing
• Breathlessness during exercise
• Tightness in the chest
• Coughing

Types of Asthma

Depending on the types of trigger and age

Allergic Asthma

Also called extrinsic asthma, is caused when allergens and irritants from the outside air are inhaled. These allergens include pollen, pet dander, tobacco smoke, smoke fumes, dust mites, and mold.

Non-allergic Asthma

Also known as intrinsic asthma, is caused by triggers that are inside the body. These triggers may be caused by bacterial or viral inflammations in the airways. Intrinsic asthma may also be caused by certain medications such as pain-killers or non-steroidal anti-inflammatory drugs. Stress or anxiety that cause breathlessness may also trigger intrinsic asthma.

Childhood Asthma

Predominant in males. It may resolve or continue into adulthood. Childhood asthma may be caused due to genetics or environmental factors. Maternal tobacco smoking during pregnancy increases the chances of developing childhood asthma. Family history also plays a role in the development of childhood asthma.

Adult Asthma

Predominant in females. Asthma is a common condition among adults while half of the middle-aged patients develop it in adulthood. In contrast to childhood asthma, adult asthma is caused more often due to smoking and environmental causes than family history. Other risk factors include lower lung function, habitual snoring, rhinitis, and chronic cough.

Occupational Asthma

Caused by exposure to allergens or irritants in the workplace. These allergens are divided into high molecular weight compounds and low molecular weight compounds.

High molecular weight compounds include dust, enzymes (plant and animal-derived), rubber-derived proteins, animal and insect-derived allergens, seafood-derived allergens, gums, and tobacco.

Low molecular weight compounds include metals, acid anhydrides, western red cedar, and a spectrum of chemical substances. Once a person is diagnosed with occupational asthma, avoidance of further exposure to these allergens is essential to prevent the progression of disease.

Aspirin (acetylsalicylic acid)-induced asthma (AIA)

Consists of the triad of aspirin intolerance, sinusitis with nasal polyposis, and asthma. Asthma symptoms are experienced after the ingestion of aspirin or other non-steroidal anti-inflammatory drugs.

Cough Variant Asthma (CVA)

A type of asthma in which cough is the only symptom the patient presents. CVA is one of the most common causes of chronic cough and should, therefore, be considered in patients who have persistent cough so that proper treatment can be given to prevent the progression of the disease.

Exercise-induced Asthma

Occurs when you exercise, especially in cold, dry environments. Symptoms such as cough, chest pain, and shortness of breath occur 8-15 minutes after exercise.

Classification of Asthma

Asthma is classified into the following categories based on severity.

• Mild intermittent asthma- mild symptoms experienced two days or less in a week.
• Mild persistent asthma- mild symptoms experienced two to six days in a week.
• Moderate persistent asthma- moderate symptoms experienced every day of the week.
• Severe persistent asthma- severe symptoms experienced many times a day, every day of the week.

Diagnosis

Diagnosis is important to determine if the symptoms you are experiencing are caused by asthma or some other medical conditions. Diagnosis also helps your physician to develop the best treatment plan. This is especially important in children since coughing and wheezing are mostly associated with viral infections^. Asthma diagnosis involves medical history, physical exam, and test when needed.

Medical history: The physician has an in-depth talk with the patient and asks questions about the medical and family history of the patient. The physician will also ask about the quality of symptoms, lifestyle, and possible exposures to allergens.

Physical examination: Physical examination will be conducted and the medical provider will listen to the lungs for any sounds indicating a narrowing of the airways. The physician also examines the skin for signs of allergies, heart for quality of blood circulation, and overall health.

Diagnostic tests: Following are the common diagnostic tests available for asthma:

• Spirometry measures how much air you can breathe out after inhaling as much air as possible. This test assesses your lung function and expiratory airway obstruction. Once airway obstruction is confirmed, obtaining variations in obstruction is essential to diagnose asthma.
• Peak Expiratory Flow (PEF) rate using a peak flow meter. This test is done at home over 1 or 2 weeks to assess variations in airway obstruction. It is done once in the morning and once in the evening. This test is only used to diagnose asthma in adults, especially occupational asthma. It is also used to monitor the effect of asthma treatment on the patient.
• Bronchial provocation testing is performed if there is no confirmation in variation in airway obstruction or responsiveness to medication. It measures how sensitive the airways in your lungs are.
• Allergy testing detects the presence of other allergic diseases such as rhinitis and atopic dermatitis that increases the probability of a person experiencing respiratory symptoms to have asthma. Skin testing or serum testing can be performed to identify allergens you are exposed to. Exposure to that allergen will help reveal if you display asthmatic symptoms.
• Fractional exhaled nitric oxide (FeNO) testing is not usually recommended for the diagnosis of asthma. Still, it is used when standard diagnostic tests reveal an intermediate probability of having asthma. This test measures the amount of nitric oxide in your breath. Elevated levels of nitric oxide could be a result of inflammation.

Treatment and Management

The main goal of treatment for asthma is to reduce the frequency and severity of asthma symptoms. Treatment also helps improve the quality of life.

Avoidance Measures

Avoidance of allergens and irritants such as pollen, dander, tobacco smoke, and dust mites can help manage symptoms. Patients who are allergic to dust mites can use allergen-impermeable covers for bedding and keep the relative humidity of their homes below 50%.

In addition, using air-conditioning, limiting the time spent outdoors in peak pollen seasons, and keeping windows closed can help reduce pollen exposures. For patients who are allergic to animal dander, removal of the animal from home greatly reduces symptoms.

Medical treatment

Sometimes, asthma triggers in everyday life are hard to avoid. Therefore, medication is needed to help control and manage symptoms.The medications used to treat asthma are divided into two groups: fast acting and slow acting.

Fast-acting medication: This medication serves as a rescue or reliever medication during asthma attacks and is taken when needed. The most common and preferred fast-acting medication is inhaled rapid-acting beta₂-agonists.

Fast-acting medication includes the following:

• Short-acting beta₂-agonists (SABA) – Short acting bronchodilators are often the first line of treatment for patients who have low severity cases and exhibit asthma symptoms less than  twice a week. They are administered by inhaler in order to open up the airways during an asthma attack. Such as salbutamol and terbutaline
• Long-acting beta₂-agonists (LABA) – such as formoterol and salmeterol, used for maintenance and administered daily via inhaler.
• Short-acting anticholinergic bronchodilators – such as ipratropium bromide. This medication is only used as a second line of therapy since it is not as effective as inhaled rapid-acting beta₂-agonists.

Slow-acting medication: This medication serves to control and prevent symptoms of asthma attacks and is taken regularly.

Slow-acting medication includes the following:

• Inhaled corticosteroids (ICSs) – are the most effective anti-inflammatory medications. Often inhaled, corticosteroids are the first line of treatment for maintenance in patients who exhibit asthma symptoms more than twice a week. They are administered through an inhaler and treat asthma by blocking the inflammation of the bronchial tree, thus preventing wheezing attacks. These are medications that mimic the hormone cortisol, which is produced by the adrenal glands and reduces inflammation. The regular use of ICSs has been shown to improve lung function and the quality of life.
• Combination ICS/LABA inhalers – this combination therapy is highly effective at reducing asthma symptoms because it works both on inflammation and spasms in the lungs.
• Leukotriene receptor antagonist –  are reserved for patients who are unwilling or unable to use ICSs. Leukotriene modifiers help reduce inflammation due to allergic responses and keep the airways open. It includes montelukast and zafirlukast.
• Long-acting muscarinic receptor antagonists – it is an add-on treatment and is delivered by a mist inhaler. For example, tiotropium.
• Theophylline- it is an oral bronchodilator with anti-inflammatory effects.
• Biologic therapy – it is effective in reducing asthma symptoms. An example of biologic therapy is the anti-IgE monoclonal antibody omalizumab.
• Oral Cortiosteroids: Such as prednisone, can be used in severe cases of asthma flare-ups. Oral steroids have several side effects, which is why they are not typically prescribed for long periods of time. Some of these side effects include weight gain, stomach ulcers, abnormal hair growth, sleep disturbance, slow wound healing, dizziness, nausea, etc. If a patient has been taking oral steroids for more than 10 days, he/she will need to wean themselves off the medication gradually by tapering down the dosages.

Mild asthma usually only requires resuce medication to control symptoms. However, severe asthma requires slow-acting medication to help control symptoms since it helps reduce chronic inflammation in the airways.

Breathing exercises can be practiced in combination with medication to help control symptoms as much as possible. In patients who have allergic asthma, allergen-specific immunotherapy may be delivered by physicians who are extensively trained in the treatment of allergies.

After a patient’s asthma symptoms are controlled, ongoing monitoring and follow-up by the patient’s physician are needed to monitor side effects. Monitoring the patient’s symptoms also helps to maintain proper lung functioning, observe possible new allergens and triggers, as well as helps ensure the correct medication dosage administered to the patient.

Asthma Complications

Asthma can successfully be managed with the right treatment plan. It is important to treat asthma at an early stage to prevent complications. It is also important to correctly follow your treatment plan to avoid complications. Asthma complications include:

Sleep deprivation

Asthma attacks often happen at night, which may cause sleep deprivation. Sleep deprivation leads to feeling tired during the day, which impedes proper functioning during work or school.

Physical activity

Asthma may inhibit people from engaging in physical activities such as exercise or sports. Being unable to engage in physical activities can lead to obesity, diabetes, and high blood pressure.

Growth delay

Children with asthma may experience growth delays and are at a higher risk of developing learning abilities.

Mental health issues

Asthma may cause mental health issues such as stress, anxiety, and depression.

Hospital visits

Severe asthma attacks may lead to unplanned hospital visits, which can interfere with everyday life.

Short-term and long-term complications can also be due to side effects from asthma medications. Medical complications include:

• Osteoporosis
• Fractures
• Susceptibility to infections
• Stroke
• Cataract
• Skin thinning
• Symptomatic coronary heart disease
• Glucose metabolism changes
• Permanent narrowing of the bronchial tubes in the lungs
• Pneumonia
• Obesity
• Lung collapse
• Pregnancy issues
• Respiratory failure