Take my breath away: An Asthma explainer

(Second of two parts)

PREVENTION and TREATMENT of ASTHMA

One of the best ways to prevent asthma is to remove triggers, like staying away from smoke, pollution, allergens etc. but this isn’t always easy. So a myriad of treatment options and medications are given to asthmatics.

Before managing an asthma, it is imperative to know the severity of asthma first as this will determine the medication given.  A physician may perform a complete physical examination to help determine the classification of asthma a patient currently has.

A physician may then ask about the frequency of symptoms, where a patient is questioned the time in which asthma attacks happen (night time or early morning), the amount of obstruction measured through a device known as a spirometer and the frequency that a patient uses asthma medications (if he or she already has one). This will determine if a patient has to maintain a medication or there need to be changes. That is why in any consult, it pays to be honest. A patient has the biggest role in saving his or her own life.

ASTHMA is DIFFERENTIATED BY SEVERITY

listed here are the classes/types from least to most severe and the steps it take to treat them.

Intermittent Asthma – Follow Step 1

• Two or less than two days per week of symptoms
• Two or less than two days per week of (short acting beta agonist) SABA use
• Two or less than two times a month of nighttime awakening from an attack
• Spirometry resulting in a Forced Expiratory Volume in one second (FEV1) or Peak Expiratory Flow (PEF) of 80% or more
• No impairment or limitation in day to day activities

Mildly Persistent Asthma – Follow Step 2

• More than two days per week of symptoms but not daily
• More than two days per week of SABA use but not daily
• Three to four times a month of nighttime awakening
• Spirometry resulting in an FEV1 and PEF of 80% or more
• No impairment or limitation in day to day activities

Moderately Persistent Asthma – Follow Step 3

• Every day one may experience symptoms
• More than once per week of (short acting beta agonist) SABA use but not every night
• More than once per week of nighttime awakening but not every night
• Spirometry resulting in FEV1 and PEF between 60% to 80%
• Some impairment or limitation in day to day activities

Severely Persistent Asthma – Follow Step 4 or 5

• Symptoms often happen throughout the day
• Use of SABA may be every day, seven days a week
• Nighttime awakening may be every day, seven days a week
• Spirometry resulting in an FEV1 and PEF of 60% or lesser
• Extremely limited movements / activities are impaired.

TREATMENT STEPS after Identifying the SEVERITY

1. STEP 1 is to use a short acting beta agonist (SABA) only as needed.
2. STEP 2 is to use or add a low dose Inhaled corticosteroid (ICS) together with the SABA from step 1. Alternatives may be: Theophyline or Leukotriene inhibitors (i.e Montelukast).
3. STEP 3 is to use a low dose ICS with a long acting beta agonist (LABA) or a single medium dose ICS. Alternatives may be a low dose ICS with any of the following: Theophyline, Montelukast or a LOX inhibitor ( i.e Zileuton).
4. STEP 4 is to use a medium dose ICS with a LABA. Alternatives may be to use a medium dose ICS and any of the following: Theophyline, Montelukast or Zileuton.
5. STEP 5 is to use a high dose ICS with a LABA, and one may add Omalizumab, which is an IgE inhibitor – greatly helps if asthma is proven to be allergy associated.
6. STEP 6 is to use a high dose ICS with LABA and an additional Oral Corticosteroid, again one may add Omalizumab.

(DISCLAIMER: Identification of Asthma and treatment STEPS are more complex, this is merely a simplified version, and also a reminder to trust healthcare professionals. Source: GINA Guidelines 2019)

As seen in the treatment options, it’s mostly composed of corticosteroids.

HOW DOES CORTICOSTEROIDS WORK in ASTHMA?

Corticosteroids inhibit phospholipase A2, a key enzyme in the arachidonic acid pathway which is subsequently responsible for two more pathways, the Cycloxygenase (COX) pathway which produces the prostaglandins, and the Lipoxygenase (LOX) pathway which produces the leukotrienes. Leukotrienes are potent activators for asthma that is why asthma medications mostly inhibit the leukotriene pathway – meanwhile corticosteroids inhibit both. The medication Aspirin inhibits the COX pathway only, that’s why one does not give Aspirin in asthma as it only leads to all the arachidonic acid going into the LOX pathway which leads to increased formation of leukotrienes, exacerbating asthma even more – Aspirin and some Non-steroidal anti-inflammatory drugs actually induces asthma.

Meanwhile the relatively common drug, montelukast, is a leukotriene receptor antagonist, which inhibits formed luekotrienes from binding to their receptors, thereby stopping them from inducing asthma.

Acute Asthma exacerbations may happen in any severity, which are severe attacks of bronchospasm possibly incited by a trigger. The patient is usually awake, alert and can still speak fully. Oxygen saturation is usually decreased but not too much and it’s treated by O2 supplementation and SABA. Status Asthmaticus is when a patient is now unable to breathe and the oxygen saturation is severely decreased and is usually treated with Epinephrine. 

ASTHMA and COVID-19

According to an article by Medscape studies have linked respiratory allergic diseases such as allergic rhinitis and asthma with increased risk for contracting COVID-19 and / or have worse clinical outcomes i.e. longer hospital stay and increased risk for turning into severe cases. Meanwhile, those with Non-allergic (intrinsic/non atopic) asthma are four times at risk of developing severe COVID-19 than the usual asthma.

Experts said the reason for non-allergic asthma being more severe may be COVID-19’s polarization to the T helper cell type 1 (Th1) response. While both Th1 and Th2 responses may occur in asthma, it usually has a more prevalent th2 response.  This may mean that non allergic asthma and COVID-19 aggravates th1 responses thus the more severe clinical outcomes. But this is currently being debated.