Asthma RESY 311 2023 PDF

Asthma By: Dr. Fahad Alhadian RESY 311 2023 Learning objectives State definition of Asthma State the typical clinical presentation of a patient with asthma Identify the treatment currently available for a patient with acute asthma What is asthma? Chronic disease of the ai...

Asthma By: Dr. Fahad Alhadian RESY 311 2023 Learning objectives State definition of Asthma State the typical clinical presentation of a patient with asthma Identify the treatment currently available for a patient with acute asthma What is asthma? Chronic disease of the airways which characterised by: 1. Inflammation 2. Reversible expiratory airflow obstruction 3. Airway hyper-responsiveness 4. Airway remodelling Inflammation Persistent inflammation is the source of every element of asthma Heterogeneous disease o Different endotype o Different phenotypes o Different response to treatment Asthma endotypes Endotypes refer to the inflammatory process behind the pathophysiological observation seen in certain group of patients Its been proposed that asthma has five endotypes: 1. Allergic eosinophilic asthma 2. Non-allergic eosinophilic asthma 3. Neutrophilic asthma 4. paucigranulocytic asthma 5. Mixed granulocytic asthma Asthma phenotypes Phenotypes refer to the clinical manifestation seen on certain group of patients In asthma, five phenotypes has been proposed: Response to treatment Corticosteroid insensitivity Failure to improve FEV1 by at least 15% from baseline following 10-14 days treatment with oral prednisolone 40 mg daily Irresponsiveness to beta-2 agonist Patients don’t respond to inhalers for unknown reason Hot research area! What is asthma? Chronic disease of the airways which characterised by: 1. Inflammation 2. Reversible expiratory airflow obstruction 3. Airway hyper-responsiveness 4. Airway remodelling Expiratory airflow obstruction Refers to inability to exhale normally Ongoing inflammation → mediator release → bronchoconstriction and increase in airway smooth muscle mass → insufficient exhalation ! Assessed by spirometry Reduced FEV1/FVC ratio (0.70) TLC is low Mixed disorders When both FEV1/FVC and TLC low If FEV1/FVC ratio is low and FVC is less than 80% of predicted, but TLC is normal, the patient has an obstructive pattern (FVC is low due to hyperinflation) References 1. Ponce MC, Sankari A, Sharma S. Pulmonary Function Tests. [Updated 2023 Aug 28]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2023 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK482339/