Respiratory Pathophysiology PDF

Pathophysiology Respiratory system Dr. Amir El-gendy Clinical Pharmacy Department College of Pharmacy Almaaqal University  Respiratory system The respiratory system consists of two lungs, conducting airways, and...

Pathophysiology Respiratory system Dr. Amir El-gendy Clinical Pharmacy Department College of Pharmacy Almaaqal University  Respiratory system The respiratory system consists of two lungs, conducting airways, and associated blood vessels. The major function of the respiratory system is gas exchange. Pathophysiology – Dr. Amir Elgendy 1   During ventilation, air is taken into the body on inhalation (inspiration) and travels through respiratory passages to the lungs.  Oxygen (O2) in the lungs replaces carbon dioxide (CO2) in the blood (at the alveoli) during perfusion, and then CO2 is expelled from the body on exhalation (expiration). Pathophysiology – Dr. Amir Elgendy 2  General Symptoms of Respiratory Disease 1) Hypoxia 2) Hypoxemia  Decreased levels of oxygen in the tissues.  Decreased levels of oxygen in arterial blood. 3) Hypercapnia 4) Hypocapnia  Increased levels of C02 in the blood   Decreased levels of C02 in the blood. leading to acidosis. 5) Dyspnea 6) Tachypnea  Difficulty breathing.  Rapid rate of breathing. 7) Hemoptysis 8) Cyanosis  Coughing up of blood or blood-stained  Bluish discoloration of skin and mucous mucus from the bronchi, larynx, trachea, or membranes due to poor oxygenation of the lungs. blood. Pathophysiology – Dr. Amir Elgendy 3  1) Bronchial Asthma Chronic inflammatory disease of the airways characterized by episodes of acute Definition reversible bronchoconstriction  shortness of breath, cough, chest tightness, wheezing, and rapid respiration.  A definite genetic predisposition leads to the development of asthma  Exposure to certain "triggers" can induce marked bronchospasm and airway inflammation in susceptible patients  Individuals with asthma appear to produce large amounts of the antibody IgE Causes that attach to the mast cells.  Exposure to a trigger such as pollen will result in the allergen-binding mast cell- bound IgE  release of inflammatory mediators such as histamine, leukotrienes and eosinophilic chemotactic factor. Pathophysiology – Dr. Amir Elgendy 4 Pathophysiology – Dr. Amir Elgendy 5  Early phase of asthma Late phase of asthma (Bronchoconstriction phase) (Inflammatory phase)  Marked constriction of bronchial airways  Occur several hours after the initial (bronchospasm). onset of symptoms.  Accompanied by edema of the airways  Manifests mainly as an inflammatory and the production of excess mucus. response. Phases  Results from increased release of certain  Mast cells release LTB4 (a inflammatory mediators such as chemoattractant)  attraction of histamine, prostaglandins, cysteinyl inflammatory cells (e.g., eosinophils & leukotrienes (LTC4, LTD4, LTE4) and neutrophiles)  inflammation + bradykinin  (they promote hyperreactivity. bronchoconstriction rather than inflammation). Pathophysiology – Dr. Amir Elgendy 6   Coughing, wheezing, difficulty breathing, rapid, shallow breathing.  Excess mucus production and barrel chest due to trapping of air in the Manifestations lungs.  Significant anxiety. o A life-threatening condition of prolonged bronchospasm that is often Status Asthmaticus not responsive to drug therapy. Pathophysiology – Dr. Amir Elgendy 7  2- Chronic obstructive Pulmonary disease (COPD) Chronic obstructive pulmonary disease (COPD) refers to long-term pulmonary disorders characterized by airflow resistance. Two such disorders are chronic bronchitis and emphysema. Chronic bronchitis and emphysema are closely related in cause, pathogenesis, and treatment and may occur together. Pathophysiology – Dr. Amir Elgendy 8  Bronchitis Acute bronchitis Chronic bronchitis  Chronic productive cough last for 3 months of the year and occur for  Most commonly caused by at least 2 consecutive years. infection with bacteria or  Most frequently associated with cigarette smoking & prolonged viruses. exposure to inhaled particulates.  It is a self-limiting condition in  It is characterized by excess mucus production in the lower respiratory healthy individuals but can have tract  obstruction of airflow. This mucus accumulation can also much more severe consequences impair function of ciliated epithelium and lining of respiratory tract and in individuals who are weakened prevent clearing of debris & organisms. with other illness or who are  Manifestations: Productive chronic cough, production of purulent immunocompromised. sputum, frequent respiratory infections, dyspnea, hypoxia, cyanosis  Symptoms: productive cough, and fluid accumulation in later stages. dyspnea and possible fever.  Chronic bronchitis sufferers are often referred to as "blue bloaters" as a result of the cyanosis and peripheral edema that is often present. Pathophysiology – Dr. Amir Elgendy 9 Pathophysiology – Dr. Amir Elgendy 10  Emphysema  Destruction & permanent enlargement of terminal bronchioles and alveolar air sacs. Characters  Obstruction results from tissue changes rather than mucus production Airflow limitation caused by a lack of elastic recoil in the lungs (losing elasticity).  Chronic exposure to cigarette smoke causing:  Chronic inflammation of the alveolar airways.  Infiltration by lymphocytes and macrophages.  Excess release of protease enzymes such as trypsin from lung tissues and Causes leukocytes (digest and destroy the elastic walls of the alveoli).   Levels of a protective enzyme α-1-antitrypsin. This enzyme inactivates destructive protease enzymes in lung tissue.  Patients with emphysema are often referred to as "pink puffers" because of their high respiratory rates and lack of obvious cyanosis. Tachypnea (increased respiratory rate), dyspnea, barrel chest - Lack of purulent Manifestations sputum. Pathophysiology – Dr. Amir Elgendy 11  Emphysema Dyspnea on exertion (initial symptom), Tachypnea (increased respiratory rate), Manifestations barrel chest (from lung overdistention) - Lack of purulent sputum. Pathophysiology – Dr. Amir Elgendy 12  Blue Bloaters Pink Puffers Pathophysiology – Dr. Amir Elgendy 13 Pathophysiology – Dr. Amir Elgendy 14  3- Pulmonary Edema Pulmonary edema is a common complication of cardiac disorders. It is marked by accumulated fluid in the extravascular spaces of the lung. It may occur as a chronic condition or develop quickly and rapidly become fatal. Pulmonary edema may result from left-sided heart failure caused by arteriosclerotic, cardiomyopathic, hypertensive, or valvular heart disease Pathophysiology – Dr. Amir Elgendy 15  3- Pulmonary Edema (cont.) Normally, pulmonary capillary hydrostatic pressure, capillary oncotic pressure (a form of colloid osmotic pressure induced by protein, notably albumin), and capillary permeability are in balance  This prevents fluid infiltration into the lungs. When this balance is disrupted  Pulmonary edema results. If colloid osmotic pressure decreases, the hydrostatic force that regulates intravascular fluids is lost because nothing opposes it, fluid flows freely into the interstitium and alveoli, impairing gas exchange and leading to pulmonary edema. In pulmonary edema, diminished function of the left ventricle causes blood to pool there and in the left atrium  Eventually, blood backs up into the pulmonary veins and capillaries. Increasing capillary hydrostatic pressure pushes fluid into the interstitial spaces and alveoli. Pathophysiology – Dr. Amir Elgendy 16  4) Adult respiratory distress syndrome  A syndrome associated with destruction of alveolar membranes and their related capillaries.  It may occur as a result of direct injury to the lungs or as a result of dramatic decreases in blood flow to the lung "shock lung" 5) Respiratory distress in the premature newborn Causes Manifestations o Caused by a lack of surfactant in the lungs. Rapid, shallow breathing, Lung o Clinical manifestations become evident collapse, lung inflammation and immediately at birth and can be rapidly fatal damage-Hypoxemia, Nasal flaring and if not treated. grunting upon inspiration. Pathophysiology – Dr. Amir Elgendy 17  6) Respiratory failure Definition Manifestations 1. Hypoxemia – Hypercapnia. 2.Cyanosis  possible but not always present. o A condition in which the 3.CNS symptoms: Slurred speech, confusion, lungs are no longer able impaired motor function. to oxygenate the blood 4.Altered blood pH. sufficiently or remove 5.Initial tachycardia and increased cardiac output C02 from it. followed by bradycardia and decreased cardiac output. Pathophysiology – Dr. Amir Elgendy 18 Pathophysiology – Dr. Amir Elgendy 19