Armando Hasudungan
Biology and Medicine videos

Asthma (Adults)

Adults Asthma overview

Summary Clinical features of asthma such as dyspnoea, chest tightness and wheezing can mimic other respiratory conditions. It is important to take a careful history and examination and ideally demonstrate reversible airflow obstruction. Other clinical features of asthma arise during periods of bronchoconstriction (ie. exercise, smoking, stress, cold air). Exacerbation of asthma confounds the breathing difficulty, cough and wheeze in patients.

Video: Adult Asthma

 

Overview

Overview Asthma is one of the most common respiratory diseases. It is generally accepted that asthma is associated with affluent Westernised lifestyle, with the prevalence being higher in more developed countries. The prevalence increasing significantly since 1960. Asthma is more common in children than adults and affects boys more than girls, with most patients being symptomatic by age 3 years. Between 30-80% of children become asymptomatic around the time of puberty.

Asthma is one of the most common causes of presentation to the emergency department. It implies reversible airway constriction (peak flows vary by >20%) +/- wheeze, dyspnoea or cough. Airway obstruction occurs due to a combination of:

  • Inflammatory cell infiltration
  • Mucus hypersecretion with mucus plug formation
  • Smooth muscle contraction

Mast cells and Eosinophils play a major role. This page will mainly focus on adult asthma

Definition
Asthma: Condition of bronchial hyperactivity and smooth muscle hypertrophy leading to a chronic inflammatory condition of the airways associated with widespread bronchospasm that is reversible.
Acute cough: Condition for less than 3 weeks, most commonly caused by acute upper respiratory infection but also may be caused by congestive heart failure, pneumonia, and pulmonary embolism.
Chronic cough: Condition for longer than 3 to 8 weeks (case definitions vary). Smoker – chronic obstructive pulmonary disease. Nonsmoker with a normal chest radiograph and not taking an ACE inhibitor, it may be due to postnasal drip, gastroesophageal reflux disease (GERD), or asthma.
overview

Asthma is a chronic airway inflammation disorder due to complex interactions between inflammatory cells, mediators and airway cells. 

Risk Factors

RF

Risk Factors for asthma include having an atopic history (rhinitus, ezcema), family history and having multiple allergies (ie. dust/pollen). For children developing viral infection is a risk.

Signs and Symptoms

Asthma Triad CDE: Cough, Dyspnea, Expiratory wheeze

Clinical Presentation Patients may present because of an asthma exacerbation due to a recent respiratory infection. This is often the case for children. Asthma is clinically characterised by having a expiratory wheeze. Some patients may have a completely normal examination and a lung spirometry has to be performed +/- exercising to check for exercise induced asthma.

Sands

Differential Diagnosis

Remember The three most common causes of chronic cough in immunocompetent nonsmokers who are not taking ACE inhibitors are postnasal drip, asthma, and gastroesophageal reflux disease.

Investigations

  • Spirometry – shows <80 FEV/FVC ratio. Broncho-reversibility testing FEV >12% (or 200ml).
  • Chest X-Ray – normal or hyperinflation
  • Full blood count – normal or shows eosinophilia (allergy)

Ix

Diagnosis
Clinical triad CDE
Airflow reversibility 12% FEV1/FVC OR 200ml
Day-to-day peak flow variability

 

Pathophysiology

Pathophysiology

Watch Asthma Pathophysiology

Pathology

 

Pathology copy

Pathology Asthma is an inflammatory condition of the airways. Postmortem studies reveal hyperinflated lungs, mucus plugging and small areas of pulmonary atelectasis are also observed. Microscopically, there is mucus hypersecretion, goblet cell hyperplasia, infiltration of mast cells and eosinophils and smooth muscle hypertrophy and proliferation.

Management

Asthma is a chronic lung disease, which can be controlled but not cured. Management of asthma include:

  • Pharmacological – involves administration of a reliever and a preventer, depending on patients severity, co-morbidities, allergies and compliance
  • Non-pharmacological interventions – Education and developing a asthma action plan is critical for preventing emergency admission and for controlling asthma.
Remember Treatment of asthma is a stepwise process based on frequency of symptoms and response to prescribed medications.
Step approach

Pharmacological There are guidelines used for the management of asthma. These guidelines are divided into 6 steps, 6 being the most severe.

Step 1 – mild intermittent and exercise-induced asthma

  • SABA for quick relief

Step 2 – mild persistent

  • SABA + Low dose inhaled Corticosteroids (ICS)

Step 3 – moderate persistent

  • LABA + Low does ICS which can gradually be increased
  • SABA is used for quick relief

Step 4-6 – severe persistent

  • LABA + moderate to high dose ICS
  • SABA is used for quick relief
  • Oral corticosteroids can be used it very severe
  • An imunomodulator is considered in patents with allergies (Montelukast)

Non-Pharmacological

  • Asthma action plan (Aimed to reduce emergency visits following acute exacerbations)
  • Education
    • Altering therapy
    • What to do and how long to do it
    • Allergen avoidance
    • Dietary intervention
    • Complementary medicine
    • Smoking cessation

Asthma Emergency

Sometimes people with asthma can have exacerbations. It can be mild, moderate, severe or life threatening. During an exacerbation if their SABA (ventolin) does not help people present to emergency for help.

Assessment of and management of Asthma in Emergency 

  • Acute Mild/moderate asthma
  • Acute Severe asthma
  • Life-threatening asthma

Complications and Prognosis

Complications

  • Moderate – severe exacerbations
    • treat with oxygen, fluids, SABA and ICS.
  • Airway remodelling
  • Gastrointestinal candidiasis secondary to inhaled corticosteroids
  • Dysphonia secondary to inhaled corticosteroids
  • Acute asthma
  • Life threatening asthma

Prognosis

Side note Smoking:

  • Increases the risk of asthma flare-ups in people with asthma
  • Increases the risk of COPD
  • Reduces the probability of achieving good asthma control
  • Reduces therapeutic response in inhaled corticosteroid
  • Accelerates long-term decline in lung function

References

Australian Asthma handbook 2015