Asthma

Asthma......An introduction

1. Case summary 20 yrs old male ,nonsmoker, normotensive, euglycemic presented with Chief c/o : Acute onset of dyspnea and cough with scanty sputum production X 2 d No H/o fever but however h/o wheezing and chest tightness is present. No H/o PND, chest pain, hemoptysis

2. Case summary Symptoms appeared after he went to visit his friend ,while playing with his dog. Similar episodes was present 1 year back. Running nose , sneezing and rashes were accompanied features. Family history present . Patient became asymptomatic after use of some inhalers.

3. Pratap Sagar Tiwari MD, Lecturer, NMC An introduction to Asthma

4. Definition Asthma is a syndrome characterized by airflow limitation/obstruction that varies markedly , both spontaneously and with treatment . There is a hyperresponsiveness to a wide range of triggers leading to excessive narrowing with consequent decrease in airflow and symptomatic wheezing and dyspnea . Note: Airway hyper-reactivity (AHR)-the tendency for airways to contract too easily and too much in response to triggers that have little or no effect in normal individuals. Reference: Davidson

5. The "classic" signs and symptoms of asthma are intermittent dyspnea, cough, and wheezing.

6. Etiology/triggers/risk factors Atopy Hygiene hypothesis Infections Genetics: ADAM33, GPRA Occupational: bakers and chemical factory Diet: vit a/c/d def , Mg/Se def , obesity Hormonal: premenstrual period, thyroidal illness

7. Atopy It is the genetic predisposition to develop specific IgE antibodies directed against environmental allergies. It is the strongest identifiable risk factor for asthma. Trigger includes pollen, fungal spores, food containing nuts, air pollution, cold air, laughter, perfumes etc.

8. Hygiene Hypothesis Lower level of infection in childhood may be a factor related to increase risk of asthma. The HH proposes that lack of infection in early childhood preserves the TH2 bias. Exposure to infection result in shift towards predominant protective Th1 immune response.

9. Infections Viral: rhinovirus, corona virus, RSV Bacterial: mycoplasma, chlamydia etc

10. Etiology/triggers/risk factors Other risk factor includes, Low birth weight, prematurity, low maternal age Other trigger includes b blockers, ACE inhibitors Others: Exercise, Acid reflux, Stress Note: ACE inhibitors inhibits degradation of Bradykinin  Increase bradykinin  Vasodilation, bronchoconstriction and increase vascular permeability. B blockers  bronchospasms

11. Pathophysiology Airway inflammation Airway obstruction Bronchial hyperresponsiveness

12. Making a diagnosis Compatible clinical features Precipitating factors Family history Reversibility of symptoms/response to bronchodilators

13. Asthma vs copd Asthma -- Not always productive cough -- Usually reversible -- Often associated with allergies -- Cough at night and early mornings -Family history --Variability COPD -- Cough is usually productive -- Symptoms not reversible -- Common history of smoking -- Cough in morning and throughout the day. -- Age

14. Note: The diagnosis of asthma is predominantly clinical and based on a characteristic history. A trial of corticosteroids: e.g . 30 mg daily for 2 weeks Ref: GINA guideline Pic taken from: http ://upload.wikimedia.org/wikipedia/commons/f/f7/Peak_flow_meter_horiz.jpg

15. Assessment of Severity

16. Drugs used in asthma Controller Reliever ICS : Glucocorticosteroids Beclomethasone / budesonide/ fluticasone SAB2A : Salbutamol / Levalbuterol / Terbutaline / Pirbuterol LAB2A : Salmeterol / formeterol Anticholinergics : Ipratropium / Oxitropium B Antileukotrienes : montelukast / zafirlukast Short acting Theophylline : Aminophylline Cromones : Cromolyn / nedocromil sodium Epineprine /Adrenaline Anti- IgE : Omalizumab Controlle r medication: taken daily to prevent symptoms, improve lung function and prevent attacks. Reliever : Occasionally required to treat acute symptoms such as wheezing, chest tightness and cough.

17. Treatment strategy 1 2 3 4 5 Leukotriene modifier Anti IgE Theophylline SR

18. Level of Asthma COntrol

19. Notes: COPD affects both the airways and the parenchyma, whilst asthma affects only the airways. The nature of inflammation in Asthma is primarily eosinophilic and CD4-driven .In COPD it is neutrophilic and CD8-driven . For asthma, severity is based on symptom frequency and severity, lung function but for COPD, the stages of severity are defined by lung function.

20. Homework : Management of Acute severe Asthma References: Harrison 18 th ed . Davidsons. Uptodate 19.2 GINA guidelines