ASTHMA

ASTHMA

It is a human respiratory system disease in which the airways constrict and become narrow, often in response to a "trigger" such as exposure to a cold air, or emotional stress, allergen, exercise. Asthma is a chronic inflammatory disease that may occurs in the smaller airways of the lungs.

Etiology:

• Family history of asthma
• Exposure to infections in early life
• Occupational exposure to pollutants
• Cigarette smoking
• Viral respiratory infections
• Swimming
• Exercise
• Emotion
• Stress
• Drugs (Aspirin,NSAIDS,β blockers)

Pathophysiology of asthma:

The pathology of asthma is characterized by various changes in the airways, including mucus plugging, shedding of epithelial cells, thickening of the basement membrane, angiogenesis, inflammatory cells infiltration, smooth muscle hypertrophy and hyperplasia. The pathogenesis of asthma can be broadly subdivided into inflammatory and remodeling components.

Stages of asthma:

•  Immediate phase
•  Late phase

 Immediate phase:

            Exposure to allergen leads to sensitization and the formation of antibodies through differentiation of b- lymphocytes. It is initiated after activation of cells bearing allergen-specific IgE.

 Late phase:

          The other mediators of the inflammatory process, in late phase are adenosine ,neuropeptides  and Bradykinin .Growth factors released from the  inflammatory cell, as it secretes mediators Eosinophilic Cationic Protein (ECP), Eosinophils Derived Neurotoxin (EDNT), GM-CSF, TNF, PG and cytokines which results in epithelial shedding, bronchoconstriction and promotion of inflammation in the respiratory tract.

Types of asthma:

Allergic asthma: It is due to allergens, antibodies, or antigen reaction in the mast cells of the respiratory tract. It is associated with Atopic / Eczema.

Idiosyncratic: It is occurring due to the neurological imbalances in autonomic nervous system in which the parasympathetic and sympathetic systems are not coordinated properly.

Clinical features:

• Shortness of breath
• Wheezing, a hissing sound at exhalation (breathe out).
• Chest tightness and pain.
• Distended abdomen
• Suffered with severe anxiety
• Itchiness to throat and chin
• Frequent cough at night
• Increase in palpitation and Uneasy in body.
• Cold
• Mucus production
• Moodiness, running nose, Headache, etc.
• Sweating is also common.

Diagnosis of asthma:

• History
• Physical examination; Weight, Height, Blood pressure, respiratory rate, breathing pattern.
• Chest wall excursion and  Abdominal  examination
• Spirometry
• Muscle length and strength test
• History
• Physical examination; Weight, Height, Blood pressure, respiratory rate, breathing pattern.
• Chest wall excursion and  Abdominal  examination
• Spirometry
• Muscle length and strength test

Dietary Treatments for Asthma

1. Avoid food such as rice, curds, buttermilk, sugar, lentils, heavy milk products like cheese, pannier etc...Which has natural tendency to produce the phlegm or to accumulate the mucus
2. Avoid fried and processed foods
3. Avoid over eating. Take light dinner one hour before going to bed
4. Drink boiled water in plenty
5. Avoid fruits such as guava, papaya, watermelon and banana

Pharmacotherapy of asthma:

• The pharmacological management of asthma depends upon frequency and severity of
• patient`s symptoms. Infrequent attacks can be managed by treating each attack when it occurs, but with more frequent attacks preventive therapy needs to be used. The following categories of drugs are used in asthma:

1. Bronchodilators:

a. Sympathomimetics:

Eg: Adrenaline, Ephedrine, Isoprenaline, and Salbutamol

b. Methyl xanthenes:

Eg: Theophyline

c.Anticholinergics:

Eg: Atropine, Ipratropium bromide

2. Mast cell stabilizers:

Eg: Disodium chromoglycate, Ketotifen

3. Corticosteriods:

Eg: Beclomethasone Dipropionate, Prednisolone

4. Leukotriene antagonists:

Eg: Montelukast, Zafirlukast

5. Anti-IgE antibody:

Eg: Omalizumab

Adrenaline: It is a potent drug which acts by stimulating beta receptors in the bronchial smooth muscles and it relieves an acute attack and pulmonary congestion by constricting pulmonary arteries.

Adverse effects: Ventricular tachycardia and ventricular fibrillation

Contraindications: It is contraindicated in patients with cardiac asthma, hypertension and hyperthyroidism.

Ephedrine: It acts on both alpha and beta adrenergic receptors.

Isoprenaline: Its acts on beta receptors of bronchi. The risk of Isoprenaline is cardiac stimulation.

Salbutamol: Its acts by stimulating beta receptors. It has potent bronchodilator effect by acting on beta 2 receptors.

Theophylline: It acts synergistically with beta adrenergic agonists. It produces a direct relaxant effect on bronchial smooth muscle. 

Atropine: It causes bronchodilation by blocking cholinergic constrictor tone. It acts primarily in the larger airways.

Ipratropium: may be effective in some patients as an adjunct anti-asthmatic, but has greater utility in preventing bronchospastic episodes in chronic bronchitis.

Disodium chromoglycate (Cromolyn): It is a synthetic compound which acts by preventing mast cell degranulation. This prevents the release of spasmogenic substances (Histamine, Seratonin).

Uses: Allergic bronchial asthma, allergic rhinitis, Allergic conjunctivitis.

Ketotifen: It acts by inhibiting airway inflammation induced by platelet activating factor. It also has anti histaminic action.

Adverse effects: Nausea, dizziness, weight gain, dry mouth, sedation.

Beclomethasone Dipropionate: It is a corticosteroid which is effective in chronic asthma.

Zafirlukast: It is a long-acting, selective, and potent Leukotriene receptor (LTD4, LTE4) antagonist with antiallergic activity /anti-inflammatory and efficacy in the maintenance therapy of chronic asthma. It is given both orally and by inhalation. The onset of action (3 to 14 d) is slow. Protective effects against inhaled LTD4 last up to 12 to 24 h.

Omalizumab: It is a monoclonal antibody against IgE. On antigen challenge, little IgE is available bound to the mast cell surface receptors to trigger mediator release.

 First treatment of choice for the acute attack is short-acting, aerosolized β2-sympathomimetics, e.g., Albuterol, salbutamol, fenoterol, terbutaline, and others. Their action occurs within minutes and lasts for 4 to 6 h.

If β2-mimetics have to be used more frequently than three times a week, more severe disease is present. At this stage, management includes anti-inflammatory drugs, such as “mast-cell stabilizers” (in children or juvenile patients) or else glucocorticoids. Inhalational treatment must be administered regularly, improvement being evident only after several weeks. With proper use of glucocorticoids undergoing high presystemic elimination, concern about systemic adverse effects is unwarranted.

Adverse effects are: oropharyngeal candidiasis and dysphonia.

To minimize the risk of candidiasis, drug administration should occur before morning or evening meals, or be followed by rinsing of the oropharynx.

Asthma, bronchodilators, diagnosis