Asthma : Diagnosis & Therapy

Overview

Asthma is a heterogenous disease that is characterized by chronic airway inflammation and the resulting symptoms are mentioned in the Introduction section.

Worldwide, asthma has affected an estimated 300 million people. A more detailed discussion on the prevalence of asthma can be found in the Epidemiology section.

The mechanism of airway hyperresponsiveness and the mediators of inflammation in patients with asthma are discussed in the Pathophysiology section.

The Risk Factors section discusses the factors that can contribute to poor asthma outcomes, including those from asthma exacerbation, development of persistent airflow limitation and medication side effects.

Asthma can be classified by asthma phenotypes or severity. The Classification section enumerates these different types.

Asthma_Disease Summary

History and Physical Examination

The Clinical Presentation section enumerates the usual symptoms associated with airflow obstruction.

The History section identifies the information that needs to be elicited from the patient in diagnosing asthma and its severity.

The physical examination of an asthmatic patient upon presentation may be normal but the Physical Examination section mentions the variable signs that the patient may present with.

Diagnosis

Tests to measure the lung function are in the Laboratory Tests and Ancillaries section.

The Differential Diagnosis section enumerates the diseases that may also present with asthma symptoms, and these should be ruled out especially when the symptoms are not typical for asthma and lung function does not support a finding of asthma. This section also discusses the difficult diagnostic groups that may require specialist referral.

Management

After the diagnosis of asthma is made, it is recommended to initially start treatment with corticosteroids (inhaled, low dose) as soon as possible for better outcomes. This depends on the patient's presenting symptoms, risk factors, comorbidities, and treatment preference.

The goals of treatment and therapeutic strategies are discussed in the Principles of Therapy section.

The Pharmacological Therapy section includes Global Initiative for Asthma (GINA) recommendations on the initial treatment depending on presenting symptoms and management plans for long-term asthma control that includes the controller and reliever medications to be given in each treatment step. This section also further discusses the stepwise therapy based on control and its maintenance.

Other management options like allergen immunotherapy and bronchial thermoplasty are discussed in detail in the Nonpharmacological section.

Detailed evaluation and management procedures of Asthma Exacerbations have a separate section.

Measures that can be taken to prevent the development of asthma and to decrease exacerbation are in the Prevention section.

Patient monitoring is an important part of the management of asthma exacerbation. Frequency of follow-up and monitoring of patients with asthma is discussed in the Monitoring section.

Frequently Asked Questions

What clinical features suggest a diagnosis of asthma?

Patients commonly have more than one respiratory symptom, including wheezing, shortness of breath, chest tightness and cough. Symptoms are usually intermittent and variable, may worsen at night or upon waking, and may be triggered by exercise, allergens, irritants, weather changes, medicines or viral respiratory infections. Associated airflow obstruction is often reversible spontaneously or with treatment. Read more

How is variable airflow limitation confirmed in asthma?

Spirometry is recommended to determine airflow limitation and reversibility by measuring FEV₁ and forced vital capacity. An increase in FEV₁ or forced vital capacity of at least 12% and 200 mL after bronchodilator administration confirms variable airflow limitation. When spirometry is unavailable, an improvement in peak expiratory flow of at least 20% after bronchodilator administration suggests asthma. Read more

What factors should be assessed before adjusting treatment?

Assess daytime symptoms, activity limitation, nocturnal waking or coughing and reliever use during the previous four weeks. Risk factors for exacerbations, decline in lung function and medication adverse effects should also be evaluated. Presenting symptoms, comorbidities, treatment adherence, inhaler technique and patient preference should guide the continuous cycle of assessment, treatment and review. Read more

What is the preferred long-term pharmacological treatment?

Low-dose inhaled corticosteroid-containing treatment should be started as soon as possible after asthma is diagnosed. The initial regimen depends on presenting symptoms, risk factors, comorbidities and treatment preference. For infrequent symptoms or symptoms occurring fewer than five times weekly with normal or mildly reduced lung function, as-needed low-dose inhaled corticosteroid plus formoterol is preferred.
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Which findings indicate a severe asthma exacerbation?

A severe exacerbation may present with a respiratory rate above 30 breaths per minute, pulse rate above 120 beats per minute, oxygen saturation below 90% and peak expiratory flow of 50% or less of predicted or personal best. Patients may use accessory muscles, speak only in words, sit hunched forward and appear agitated. Immediate hospital transfer is required. Read more