What is Asthma ? Pathophysiology, Clinical Manifestation, Diagnosis, Management

By March 12, 2017 No Comments
What is Asthma ? Pathophysiology, Clinical Manifestation, Diagnosis, Management

What is Asthma? What would be your answer if someone asks you this question? Asthma is a chronic inflammatory disease of the airways that causes airway hyperresponsiveness, mucosal oedema, and mucus production. This inflammation ultimately leads to recurrent episodes of asthma symptom: a cough, chest tightness, wheezing, and dyspnoea. The predisposing factors are atopy and female gender. The causal factors include exposure to indoor and outdoor allergens and occupational sensitizers. The contributing factors for asthma are respiratory infections, air pollution, active and passive smoking, congested and crowd environment. Asthma affects more than 22 million people (panel report 3, 2007). Asthma accounts for more than 497,000 hospitalizations annually  (Agency for Healthcare research and quality  [AHRQ, 2007).

The most common chronic disease of childhood, asthma can occur at any age. For most of the patients, asthma is a disruptive disease affecting daily lifestyle, school and work attendance, occupational activity, physical activity and general quality of life. Risk factors for asthma include family history, allergens  (strongest factor), and chronic exposure to airway irritants ( e.g. grass, weed pollens, mold, dust, smoke or animals). Some of the common triggers for asthma symptoms and exacerbation includes pollutants, stress or emotional stress, cold, heat, strong odors, smokes, rhinosinusitis, medications, viral respiratory tract infection and gastroesophageal reflux. Most of the people have asthma are sensitive to a variety of triggers.

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Asthma: Status Asthmaticus

Status Asthmaticus is severe and persistent asthma that does not respond to conventional therapy; attacks can occur with little or no warning and can progress rapidly to asphyxiation. Infection, anxiety, abuse of nebulizer, increased adrenergic blockage, and unspecified irritants may contribute to these episodes. Hypersensitivity may precipitate an acute episode of aspirin. Two predominant pathologic problems occur a decrease in bronchial diameter and a ventilation-perfusion abnormality.


The underlying pathology in asthma is reversible and diffuse airway inflammation that leads to airway narrowing or stenosis. This narrowing, which is exacerbated by a variety of changes in the airway, includes bronchoconstriction, airway hypertrophy, and airway hyperresponsiveness.

Antibodies such as mast cells, neutrophils, eosinophils, and lymphocytes play a vital role in the inflammation of asthma. When activated, mast cells release several chemicals called mediators. These mediators, which include histamine, bradykinin, prostaglandins, and leukotrienes, perpetuate the inflammatory response, causing increased blood flow, vasoconstriction, a fluid leak from the vasculature, an attraction of white blood cells to the area and bronchoconstriction (Expert panel report 3, 2007).

As asthma becomes more persistent, airflow limitation may involve the inflammation develops and other factors. These airway oedemata, mucus hypersecretion, and the formation of mucus plugs. Also, airway “remodeling” may occur in response to chronic inflammation causing further airway narrowing.

Clinical manifestation

  • Most common symptoms of asthma are a cough (with or without mucus production), dyspnoea and wheezing (first on expiration, then possibly during inspiration as well).
  • Asthma attacks frequently occur at night or in the morning.
  • An asthma exacerbation is usually preceded by increasing symptoms over days, but it may begin abruptly.
  • Expiration requires effort and becomes prolonged.
  • As exacerbation progresses, central cyanosis secondary to severe hypoxia may occur.
  • Additional symptoms such as diaphoresis, tachycardia, and widened pulse pressure may occur.
  • Activity or exercise-induced asthma: maximal symptoms during exercise, an absence of nocturnal symptoms, and sometimes only a description of a “choking” sensation during exercise or physical activity.

Diagnostic assessment

  • Medical history, family environment, and occupational history are essential with complete physical examination most importantly auscultation and palpation for wheezing and crepitus sound. Observation for cyanosis.
  • During acute episodes, sputum and blood test, pulse oximetry, ABGs analysis, hypocapnia and respiratory alkalosis and pulmonary function test and forced vital capacity are performed.

  • Chest X-ray

Preventive approach

Patient with recurrent asthma should undergo regular tests to identify the substances that trigger or precipitate the symptoms. Possible causes are dust, dust mites, smoke, pets, woolen clothes, detergent, soaps, strong perfumes, and pollens etc. If the attacks are seasonal, pollens can be strongly suspected. Instructor instructs patients to avoid such causative agents whenever possible. Proper knowledge and education should be given to the patient for caring asthma and avoiding possible complications. Emphasise the quality of living and environment.

Complications of asthma

It may include status Asthmaticus, respiratory failure, pneumonia, and atelectasis. Airway obstruction, particularly during acute asthmatic episodes, often results in hypoxemia requiring the administration of oxygen and close monitoring of saturation and arterial blood gases. Fluids are administered to prevent dehydration due to diaphoresis and insensible fluid loss with hyperventilation.


The medical management of asthma includes two general classes of asthma medications: quick-relief medications for immediate treatment of asthma symptoms and exacerbation whereas long-acting medications to achieve and maintain control of persistent asthma. These medications have systemic side effects when used over a longer period.

Quick-relief medications

Short-acting beta2-adrenergic agonists are the medications of the choice for relief of acute symptoms and prevention of exercise-induced asthma. They relax smooth muscle.

Anticholinergics inhibit muscarinic cholinergic receptors and reduce the intrinsic vagal tone of the airway. Doctors use these in patients who do not tolerate short-acting beta2-adrenergic agonists.

Long-Acting medications

Corticosteroids are usually the most potent and effective anti-inflammatory medications currently available all over. They are widely effective in alleviating symptoms and improving airway function. Initially, Patients should use an inhaled form of corticosteroids along with spacer and patient should clean their mouth to prevent thrush. These corticosteroid stabilize mast cells, are effective on a prophylactic basis to prevent exercise-induced asthma. An acute asthma exacerbation contraindicates these medications.

Long-Acting beta2-adrenergic agonists are used along with anti-inflammatory medications to control asthma symptoms usually (nocturnal) that occurs at night. The immediate relief of symptoms doesn’t indicate long-acting medications. In addition to inhaling corticosteroids uses mild to moderate bronchodilator.

Home-based care

  • Provide full information about the condition of patient and education about asthma to the patient and family.
  • Management about the administration of oxygen at home.
  • Instruct patient about the use and side effects of medications.
  • Emphasise adherence to prescribed therapy, preventive measures and need for follow up an appointment.
  • Home visit or refer home care nurse as indicated.
  • Remind patients and families about the importance of health promotion strategies and recommended health screening.

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