• Asthma: A disorder characterized by chronic inflammatory reversible airways

obstruction and increased airways hyperresponsiveness to a variety of stimuli that causes

recurrent episodes of wheezing, breathlessness, chest tightness, and coughing.

• It is a chronic condition involving the respiratory system in which the airways

occasionally constrict, become inflamed, and are lined with excessive amounts of mucus,

often in response to one or more triggers.


• Bronchial asthma may be either episodic or chronic.

• There is a tendency for atopic individuals to develop episodic asthma and non-atopic

individuals to develop chronic asthma.

Classification

• Bronchial asthma may be classified into two types

Extrinsic asthma (early-onset or childhood asthma).

 Intrinsic asthma (late-onset or adulthood asthma)

Figure 1: The Differences Between Extrinsic and Intrinsic Bronchial Asthma


*Atopic individuals are people having a familial hereditary tendency of asthma or other allergic

disorders while non-atopic individuals are the ones who become asthmatic after exposure to

high doses of allergens e.g. at work as in carpenters (sawdust) and farmers (pollens).

Episodic Asthma

• In episodic asthma the patient has no respiratory symptoms between episodes, or signs of

asthma.

• Paroxysm of wheeze and dyspnoea may occur at any time and can be of sudden onset.

Chronic Asthma

• Symptoms of chest tightness wheeze and breathlessness on exertion together with

spontaneous cough and wheeze during the night and early in the morning may be chronic

unless controlled by appropriate drugs.

• Severe asthma persisting from childhood may form a pigeon chest deformity.

Etiology & Epidemiology of Bronchial Asthma

Race

• According to cause Bronchial asthma occurs in persons of all races worldwide.

Sex

• Bronchial asthma predominantly occurs in boys in childhood with a male to female ratio

of 2:1 till puberty.

• Asthma prevalence is greater in females after puberty and the majority of adult-onset cases

diagnosed in persons older than 40 years occurs in females.

• Boys are more likely than girls to experience a decrease in symptoms by late adolescence.

Age

• Bronchial asthma prevalence is high in very young persons and very old persons because

of airways hyperresponsiveness and lower levels of lung function

Occupation

• High risk jobs are

o Farming

o Painting

o Janitorial work

o Plastic manufacturing

Causes

• Asthma is caused by a complex interaction of environmental and genetic factors that

researchers do not yet fully understand.

• These factors can also influence how severe a person’s asthma is and how well they

respond to medication.

• Environmental tobacco smoke, especially maternal cigarette smoking, is associated with

high risk of asthma prevalence and asthma morbidity, wheeze, and respiratory infections.

• Poor air quality, from traffic pollution or high ozone levels, has been repeatedly

associated with increased asthma morbidity

 

Genetic

• Over 100 genes have been associated with asthma in at least one genetic association

study.

Gene-environment Interactions

• Research suggests that some genetic variants may only cause asthma when they are

combined with specific environmental exposures, and otherwise may not be risk factors

for asthma.

Factors Contribute to Bronchial Asthma or Airways Hyper Responsiveness

• Environmental allergens

House dust mites

 Wood dust

Cockroach allergens

Fungal spores

Plants

Animal allergens especially from cats and dogs

Feathers in pillow and mattresses

• Food e.g. fish, eggs, milk, yeast, and wheat which reaches the bronchi via blood stream

• Environmental pollutants e.g. smoke from tobacco, industries, cars, firewood

• Irritants e.g. household sprays, paints, and perfumes

• Industrial chemicals

Isocyanates

Anhydrides

Epoxy resin

• Drugs

Aspirin or NSAIDs

Non-selective beta-blockers including ophthalmic preparations e.g. Propranolol

• Exercise or hyperventilation

• Emotion

• Stress e.g. infections or trauma

• Gastroesophageal reflux disease (GERD)

• Infection: Viral or bacterial infections of the respiratory system

Factors Contribute to Exercise-Induced Asthma

• Exposure to cold or dry air

• Environmental pollutants e.g. sulfur, ozone

• Levels of bronchial hyperactivity

• Chronicity of asthma and symptomatic control

• Duration and intensity of exercise

• Allergen exposure in Atopic individuals

• Co-existing respiratory infection

Pathology, Symptoms and Signs of Bronchial Asthma

Pathology

Airways obstruction is caused by

• Bronchoconstriction

During an asthma episode, inflamed airways react to environmental triggers such as

smoke, dust, or pollen.

The airways narrow and produce excess mucus, making it difficult to breathe.

In essence, asthma is the result of an immune response in the bronchial airways.

The airways of asthmatics are "hypersensitive" to certain triggers, also known as

stimuli. In response to exposure to these triggers, the bronchi (large airways) contract

into spasms (an asthma attack).

Inflammation soon follows, leading to a further narrowing of the airways and

excessive mucus production, which leads to coughing and other breathing difficulties.

• Airways edema

• Chronic mucous plug formation. It consists of exudate of serum proteins and cell

debris that may take weeks to resolve.

• Airways remodeling: It is associated with structural changes due to long-standing

inflammation and may profoundly affect the extent of reversibility of the airways

obstruction.

 

Symptoms of Asthma

• Productive cough

• Wheezing

• Shortness of breath

• Chest tightness

• Decrease exercise tolerance

• Symptoms such as cough and wheeze are commonly occurring at night and disturb sleep

Signs of Asthma

• General evidence of respiratory distress

Increased respiratory rate

Increased heart rate

Diaphoresis

Use of accessory muscles of respiration

Marked weight loss may indicate severe emphysema

Chest Examination

• Barrel chest

• End-respiratory rhonchi or prolonged expiratory phase

• Diminished breath sounds and chest hyperinflation may be observed during acute

exacerbations

• Severe asthma persisting from childhood may cause a ‘pigeon chest’ deformity (pectus

carinatum)

Features of Acute Severe Asthma in Adult

• Patient cannot complete a sentence

• Pulse rate >110bpm

• Respiratory rate >25bpm

Features of Life Threatening Asthma in Adult

• Silent chest

• Cannot speak

• Confusion or reduced level of consciousness

• Cyanosis

• Bradycardia or arrhythmias

• Hypotension

• Exhaustion

• Confusion

• Coma

• Near fatal asthma: Patients have raised PaCO2

Complications of Asthma

• Pneumonia

• Pneumothorax

• Respiratory failure

• Complications from corticosteroids

Osteoporosis

Immunosuppression

Cataract

Myopathy

Weight gain

Addisonian crisis

Thinning of the skin

Differential Diagnosis, Investigations & Treatment of Bronchial Asthma

Differential Diagnosis of Asthma

• Bronchiectasis

• Pulmonary edema

• Emphysema

• Congestive Cardiac Failure

• Allergic rhinitis

• Pneumonia

• Tuberculosis

Investigations

• Full Blood Picture

• Eosinophilia of greater than 4% or 300-400 cells/ml supports the diagnosis of asthma

• Radiography

Normal

Show signs of hyperinflation, indistinguishable from that of emphysema

Show ‘pigeon chest’ deformity in the lateral view

Show opacity caused by lobar or segmental collapse when a large bronchus is

obstructed by tenacious mucus

• Sputum

Gram stain

Ziehl-Nelsen stain

Note: In this case, only sputum examination may be examined in the dispensary or health

center. For the rest of the investigations, patients need to be referred to the hospital.

Treatment

• Acute severe asthma and life-threatening asthma in adult

Perform pre-referral treatment : give

Nebulized salbutamol or inhaled salbutamol (if available)

Hydrocortisone 200mg i.v slowly (if available)

Aminophylline 250mg i.v slowly or tabs

Monitor vital signs

Treatment (at Higher Centre)

• Oxygen 40-60% via nasal prongs or face mask if available

• Nebulized salbutamol or inhaled salbutamol delivered by a spacer

• Hydrocortisone 200mg i.v slowly than oral prednisolone 30-60mg for 5-7 days

• Aminophylline 250mg i.v slowly or tabs when therapy above fails

Goals of Therapy in the Treatment of Chronic Asthma

• Achieve and maintain control of symptoms

• Prevent asthma exacerbations

• Maintain pulmonary functions as close to normal levels as possible

• Maintain normal activity levels, including exercise

• Avoid adverse effects from asthma medications

• Prevent the development of irreversible airflow limitation

• Prevent asthma mortality

Management of Chronic Persistent Asthma

Step-I:

• Occasional Use of Inhaled Short-Acting Beta2-Receptor Agonist

• Indications

Intermittent symptoms occurring less than once a week

No daily medication needed

• Treatment

Long term control (controller medication): Not required

Quick-relief (reliever medication) : A short-acting beta2-receptor agonist inhaler

• Dose

Metered doses inhaler (MDI): 1-2 puff when required (PRN)

Nebulizer: Dilute 0.5 mL (2.5 mg) of 0.5% inhalation solution in 1-2.5 MLS of normal

saline or water for injection, administer 2.5-5 mg when required (PRN).

Step-II:

• Regular Use of Inhaled Anti-Inflammatory Agents

• Indications

Symptoms occurring more than once a week but less than once a day

Patient using beta2-adrenoceptor agonist more than once daily

• Treatment

Reliever medication (bronchodilator): A short-acting beta2-adrenoreceptor agonist

inhaler

Metered doses inhaler (MDI): 1-2 puff every 4-6 hrs, not to exceed 12 puffs/day

Nebulizer: Dilute 0.5 mL (2.5 mg) 0.5% inhalation solution in 1-2.5 mls of normal

saline or water for injection; administer 2.5-5 mg every 4-6 hrs. Plus

Controller medication: (anti-inflammatory)

Inhaled corticosteroids: Beclometasone (up to 800 ugs daily)

Step-III:

• High Dose Inhaled Corticosteroids or Low Dose Inhaled Corticosteroids Plus a Long-

Acting Inhaled Beta2-Adrenoceptor Agonist

• Indication: Daily symptoms

• Treatment

Reliever medication: A short-acting beta2-adrenoreceptor agonist inhaler given as

required (PRN)

Controller medication: Inhaled corticosteroids e.g. Beclometasone, Plus

Long-acting bronchodilator such as beta2-adrenoreceptor agonist e.g. Formoterol

fumarate 6 ug 12 hourly or Salmeterol 50 ug 12 hourly or aminophylline maybe

added

In patients whose asthma is poorly controlled by inhaled corticosteroids, the addition

of a long-acting beta2-receptor agonist improves symptoms and lung function and

reduces exacerbations

Step-IV:

• High Dose Inhaled Corticosteroids and Regular Bronchodilators

• Indications: Failure of step-III medications

• Treatment

Reliever medication: A short-acting beta2-adrenoreceptor agonist inhaler given as

required (PRN)

Controller medication: Inhaled corticosteroids e.g. Beclometasone in a dose range

800-2000 ug daily, plus.

Step-V:

• Addition of Regular Oral Corticosteroid Therapy

• Indications: Failure of step-IV medications

• Treatment

Step-IV medications. Plus

Regular Prednisolone tablets prescribed in the lowest amount necessary to control

symptoms as a single daily dose in the mornings

Patient’s Education

• It should begin at the time of diagnosis and be revisited in every subsequent

consultation.

• Education involves the patient understanding the nature of asthma, the practical skills

necessary to manage asthma successfully e.g. using inhaler devices and monitor the effect

of treatment and the severity of exacerbations with a spirometer and the adoption of

appropriate actions in responses to deteriorating asthma.

• Patients should appreciate the differences between the reliever medication

(bronchodilator) and the controller medication (anti-inflammatory).

Antibiotics

• They should be reserved for patients with fever and purulent sputum or other evidence of

pneumonia or sinusitis.

Hydration

• Aggressive hydration is not recommended for adults,

• Chest physiotherapy, mucolytics, and sedation are not recommended.

Diet

• No special diet is generally indicated.

Prevention of Asthmatic Attack

• Avoidance of exposure to an allergen to which patients are sensitive to:

Animal dander: Avoid contact with dogs, cats, horses, or other animals.

Feathers in pillows or quilts: Substitute latex foam pillows and terylene quilts.

Avoid all preparations of relevant drugs e.g.beta-blockers, aspirin, and other nonsteroidal

anti-inflammatory drugs if the patient is sensitive.

Food: Identify and eliminate from the diet.

Industrial chemicals e.g. isocyanates, epoxy resins, perfumes: Avoid exposure to

chemical or change occupation.

Do not smoke and avoid environmental smoke.

o Pollens: Try to avoid exposure to flowering vegetation and keep the bedroom

windows closed.

Avoid exertion during high levels of pollution.

Exercise-Induced Asthma

• A warm-up period of 15 minutes is recommended before the scheduled exercise event.

This approach is not helpful for unscheduled events, prolonged exercise, or elite athletes

• Use of Inhaled medications

Drug Used

• Inhaled short-acting beta2 agonist: e.g. Salbutamol is given 15-30 before exercise.

• Inhaled mast cell stabilizers: e.g. sodium cromolyn is given 15-30 before exercise.

Others

• Long acting beta2agonist (given 90 minutes before exercise) for repetitive exercise

• Leukotriene antagonist

• Inhaled heparin

• Inhaled Frusemide

Prognosis

• The prognosis of individual asthma attacks is generally good.

• Seasonal fluctuations can occur in both types of asthma, atopic subjects with episodic

asthma is usually worse in the summer when they are more heavily exposed to antigens

while chronic asthmatic patients are usually worse in winter months because of the

increased frequency of viral infections.

REFERENCES;

•      Braunwald & Fauci (2001). Harrison’s principles of internal medicine 15th Ed.  Oxford: McGraw Hill

•      Davidson, S (2006). Principles and practice of medicine 20th Ed.  Churchill: Livingstone.

Kumar & Clark (2003) Textbook of clinical medicine. Churchill: Livingstone.

•      Douglas Model (2006): Making sense of Clinical Examination of the Adult patient. 1st Ed. Hodder Arnold

•      Longmore, M., Wilkinson, I., Baldwin, A., & Wallin, E. (2014). Oxford handbook of clinical medicine. Oxford

•      Macleod, J. (2009). Macleod's clinical examination. G. Douglas, E. F. Nicol, & C. E. Robertson (Eds.). Elsevier Health Sciences.

•      Nicholson N., (1999), Medicine of Non-communicable diseases in adults. AMREF

•      Stuart and Saunders (2004): Mental health Nursing principles and practice. 1st Ed. Mosby

•      Swash, M., & Glynn, M. (2011). Hutchison's clinical methods: An integrated approach to clinical practice.