Introduction
Asthma is a chronic inflammatory disorder of the airways, characterized by a reversible narrowing of the airways. Reversibility differentiates it from COPD. Reversibility is an improvement in FEV1 by 15% or more after bronchodilator or steroid therapy,
Cough-variant Asthma
Asthma patients may present with any one or combination of these symptoms: wheezing, cough, or shortness of breath. Wheeze is the most common symptoms/signs in patient of asthma. However, few patients may present with chronic cough only. The diagnosis of asthma is made by spirometry or a bronchial provocation test. These patients are said to have “cough variant asthma.”
Time of asthma symptoms
Symptoms of asthma are especially more pronounced at night and early morning. Symptoms improve over course of the day.
Peak Flow in morning
Peak flow (PEF) readings will show morning dips in asthma.
Suspect asthma triggers at work-place if...
Suspect asthma triggers at patient’s workplace if symptoms improve on weekends or during holidays. Ask the patient to measure their peak flow at intervals at work and at home, at the same time of day, to confirm the presence of workplace triggers.
Diagnosing asthma
Asthma is mainly a clinical diagnosis based on typical history, supported by evidence of obstructive airway obstruction pattern on spirometry with reversibility.
Provocation test & when to do it?
The histamine or methacholine challenge test is a bronchial provocation test to check for airway hyperresponsiveness (AHR). It is done rarely in those patients, who have normal spirometry but are strongly suspected to have asthma.
Look for these in resistant asthma!
In resistant asthma, evaluate for associated conditions such as GERD, Allergic bronchopulmonary aspergillosis (ABPA), Polyarteritis nodosa (PAN) and Churg-Strauss syndrome (CSS).
Asthma differentials!
All that wheezes is not asthma (a golden quote from 1865). Remember this quote & look for other conditions that can also be present with wheeze. These conditions include pulmonary oedema, COPD, large airway obstruction, SVC obstruction, bronchiectasis, and bronchiolitis obliterans.
Asthma & Smokers!
Higher doses of inhaled corticosteroids may be required in smokers on step-1 management. Quitting smoking will benefit the individual in terms of better asthma control. Educate such patients and help them quit smoking.
Step upon which asthma management step?
Start treatment at the step most appropriate to the disease severity. Move up if needed, or down if control is good for > 3 months.
Rescue courses of oral steroids may be used at any time when needed.
Precaution with use of LABA!
Use a combination of long-acting beta-agonists (LABA) with steroids, to avoid paradoxical bronchospasm with the use of LABA alone.
What is MART?
Formoterol has rapid action, and it can be used as reliever therapy in addition to maintenance therapy. This is known as MART, which is an acronym that stands for ‘maintenance and reliever therapy.‘
Things to do in steroid-dependent asthma!
Patients who are on long-term glucocorticoid tablets, e.g., >3 months, or who are receiving more than three or four courses per year, are at risk of systemic side effects. The risk of osteoporosis is reduced by giving bisphosphonates.
These patients should be considered for biological therapy, to minimize long-term harm from oral glucocorticoids.
Treatment for Exercise-induced asthma
In exercise-induced asthma, adequate warm-up exercise or pre-treatment with beta-2 agonist, nedocromil or LTRA can protect against exercise-induced symptoms.
Treatment for Resistant asthma with High IgE
Omalizumab is an anti-IgE monoclonal antibody, preferred in resistant asthma patients with high serum IgE levels.
Treatment for Resistant asthma with High Eosinophils
Anti-IL5 antibodies, like mepolizumab and reslizumab, are used in resistant asthma patients with high eosinophil counts.
PaCO2 levels in 'life-threatening' & 'near fatal' asthma
During an acute attack, paCO2 levels in ABGs should be lower than 34 mmHg. It is because of tachypnea and hyperventilation. If it is in the normal range (34-45 mmHg), it indicates life-threatening asthma. And, if it is high or rising, it is near-fatal asthma. Manage such patients in ICU with mechanical ventilation.