Bronchial Asthma new ppt04 including causes , risk factors , pathophysiology, diagnostic tests and treatment

Bronchial asthma definition, sign and symptoms pathophysiology, management

1. Bronchial Asthma

2. Introduction Asthma is a heterogenous disease characterized by bronchial hyperreactivity with reversible expiratory airflow limitation . Signs and symptoms can be variable.

3. DEFINITION It is chronic inflammatory disorder of airway which causes airway hyperresponsiveness that leads to recurrent episode of wheezing, breathlessness, chest tightness & cough particularly at night/early morning. Episodes are reversible but not curable Usually triggered by allergy

4. Risk Factors for Asthma and Triggers of Asthma Attacks Nose and Sinus Problems : Most patients with asthma have a history of allergic rhinitis. Respiratory tract infections are often a major trigger of an acute asthma attack. Acute infection can decrease the diameter of the airways and induce airway hyperresponsiveness

5. Continued.. Allergens: cause varying degrees of allergic reactions in susceptible persons. Indoor and outdoor allergens, such as cockroaches, furry animals, fungi, pollen, and molds , can trigger asthma attacks. Cigarette Smoke : The Centers for Disease Control and Prevention (CDC) estimates that 21% of asthma patients smoke Various air pollutants: wood smoke or vehicle exhaust, can trigger asthma attacks. In heavily industrialized or densely populated areas, climate conditions often lead to concentrated pollution in the atmosphere, especially with thermal inversions and stagnant air masses

6. Continued.. Occupational asthma is the most common job-related respiratory disorder. These agents are diverse and include wood dusts, laundry detergents, metal salts, chemicals, paints, solvents, and plastics Physical Exertion : Asthma that is induced or worse during physical exertion is called exercise-induced asthma (EIA) or exercise-induced bronchospasm (EIB). Typically, symptoms of EIA are pronounced during activities in which there is exposure to cold, dry air

7. Continued.. Drugs and Food Additives: Some people with asthma have what we call the asthma triad: nasal polyps, asthma, and sensitivity to aspirin and nonsteroidal anti inflammatory drugs (NSAIDs). Persons with asthma who use salicylic acid (e.g., aspirin) or NSAIDs develop wheezing within 2 hours β- Adrenergic blockers in oral form (e.g., metoprolol [ Toprol -XL]) or topical eye drops (e.g., timolol [ Timoptic ]) may trigger an asthma attack Angiotensin-converting enzyme (ACE) inhibitors (e.g., lisinopril) may cause a dry, hacking cough in susceptible persons, making asthma symptoms worse.

8. Continued.. Gastroesophageal reflux disease (GERD) is more common in people with asthma than in the general population. GERD can worsen asthma symptoms because reflux may trigger bronchoconstriction and cause aspiration

9. Pathophysiology

10. Phases Early-phase response: As a result, inflammatory mediators, such as leukotrienes, histamine, cytokines, prostaglandins, and nitric oxide, are released. 30 to 60 minutes after exposure to an allergen or irritant. Late Phase Response : Symptoms can recur 4 to 6 hours after the early response because of the influx of many inflammatory cells, which are set in motion by the initial response. At this later time, the patient may develop symptoms again or worsening of symptoms. This is called the late-phase response

11. Contiued .. Remodeling : A progressive loss of lung function occurs that therapy cannot fully reverse. The changes in structure may include fibrosis of the sub epithelium, hypertrophy of the smooth muscle of the airways, mucus hypersecretion, continued inflammation Angiogenesis (proliferation of new blood vessels).

12. Clinical Manifestations The characteristic manifestations are wheezing, cough, dyspnea, and chest tightness after exposure to a risk factor or trigger. Normally the bronchioles constrict during expiration. Wheezing usually occurs first on exhalation. As asthma progresses, the patient may wheeze during inspiration and expiration Decreased or absent breath sounds. Severely decreased breath sounds, often referred to as the “silent chest,” are an ominous sign.

13. Hyperventilation occurs during an asthma attack as lung receptors respond to increased lung volume from trapped air and airflow limitation. Decreased perfusion and ventilation of the alveoli and increased alveolar gas pressure leads to ventilation-perfusion abnormalities in the lungs.

14. Diagnostic evaluation The peak expiratory flow rate (PEFR) measured by the peak flow meter is a test of lung function PEFR measurements can help predict an asthma attack or monitor the severity of disease. Test results depend on the patient’s age, gender, and height. Peak expiratory flow measurement (peak flow) is a simple measure of the maximal flow rate that can be achieved during forceful expiration following full inspiration.

15. The Peak Flow Zone System

16. Spirometry Spirometry is usually normal between asthma attacks if the patient has no other underlying pulmonary disease. The patient with asthma may show an obstructive pattern including a decrease in forced vital capacity (FVC), FEV1 , PEFR, and FEV1 to FVC ratio (FEV1 /FVC) Increased serum eosinophil counts and IgE levels are highly suggestive of atopy. Allergy skin testing may be used to determine sensitivity to specific allergens.

17. Continued.. Fractional exhaled nitric oxide (FENO). FENO levels are increased in people with asthma associated with eosinophilic-induced airway inflammation. FENO may be used to gauge loss of asthma control and attacks.

18. A chest x-ray in an asymptomatic patient with asthma is usually normal. A routine chest x-ray is usually not done unless other manifestations, such as fever, chills, or upper airway stridor, are present. It can show if something else is causing symptoms similar to those of asthma (e.g., pneumonia, foreign body in the airway.) A sputum specimen for culture and sensitivity may be done to rule out bacterial infection, especially if the patient has purulent sputum, a history of upper respiratory tract infection (URI), a fever, or an increased white blood cell (WBC) count

19. Drug therapy Anti-inflammatory drugs (basic) Bronchodilators H ormone-containing ( C orticosteroids) N onhormone-containing ( Mast cell stabilizer , leukotriene Modifiers, IgE antagonist) A nticholinergic drugs B 2-agonists M ethylxanthines

20. Exposure to allergens and irritants stress cold air exercise other factors IgE stimulation Mast cell degranulation Histamine Prostaglandins SRS-A Bradykinins Leukotrienes Airway hyperresponsiveness Mucus secretion Bronchospasm Inflammation Steroids Antihistamine Mast cell stabiliser Leukotriene modifiers Non productive cough Shortness of breath Chest tightness wheezing Steroids Bronchodilators B2-agonist Methylxanthines Anticholenergics

21. Complications Pneumothorax Pneumomediastinum Atelectasis Pneumonia Status asthmaticus

22. Status asthmaticus Status asthmaticus is the most extreme form of an acute asthma attack. It is characterized by hypoxia, hypercapnia, and acute respiratory failure. The patient is unresponsive to treatment with bronchodilators and corticosteroids.

23. Causes Viral illness Aspirin, NSAIDS, aspiration Emotional stress Allergens & Pollutants Beta blockers Discontinuation of therapy

24. Clinical Features Chest tightness Severely marked increase in shortness of breath Suddenly be unable to speak Hypotension, bradycardia Respiratory and/or cardiac arrest may occur if we do not recognize that the patient’s condition is getting worse. Increased airway resistance Hypoxemia Acidosis Diaphoresis PEFR (less than 150 ml)

25. Conti…. Silent chest Mediastinal shift Pulsus paradoxus Cardiac or respiratory distress

26. Management Hemodynamic monitoring of the patient is critical. Analgesia and sedation are essential. Continuous analgesic infusions (e.g., ketamine, morphine) and sedation with drugs such as propofol ( Diprivan ) help decrease work of breathing (WOB) and facilitate patient synchrony with the ventilator. Oxygen therapy ( mask ,prongs) ABG monitoring IV fluids Na bicarbonate Mechanical ventilation ( co2 >45 mm of Hg)

27. CONTINUED.. IV magnesium sulfate, which has a bronchodilator effect, may be given to patients with a very low FEV1 (forced expiratory volume in 1 second) or peak flow (less than 40% of predicted or personal best) or those who do not respond to initial treatment.

28. Management

29. NURSING MANAGEMENT

30. Nursing Diagnosis Ineffective breathing pattern related to impaired exhalation and anxiety Ineffective airway clearance related to increased production of secretions and bronchospasm Impaired gas exchange related to air trapping Knowledge deficit related to use of inhaled and nebulised medications