Respiratory Pathophysiology

Physiology of Breathing, Infectious/Obstructive/Restrictive Pulmonary Disorders, Differential Diagnosis

1. Respiratory Pathophysiology

2. Anatomy of the Respiratory S ystem Upper Respiratory Tract Nose, nasal cavity Pharynx Lower Respiratory Tract Larynx Trachea Bronchial Tree Lungs

3. Anatomy of the Respiratory System Bronchial Tree Primary Bronchi Secondary Bronchi Tertiary Bronchi Bronchioles Terminal Bronchioles Respiratory Bronchioles Alveolar Sacs Alveoli

4. Bronchial Tree

5. Anatomy of the Respiratory System Lungs Right Lung 3 lobes Left Lung 2 lobes

6. Physiology of Breathing Diaphragm contracts and the thoracic cage expands, creating negative pressure in the lungs Negative pressure in the lungs allows air to flow in as the elastic fibers around the alveoli passively contract Air goes out through sympathetic activation, producing smooth muscle relaxation and bronchodilation

7. Pressures Associated with Breathing Atmospheric Pressure Pressure in the outside air Only changes with altitude changes Alveolar Pressure Pressure in the alveoli Intrapleural Pressure Pressure in the pleural cavity Always negative because of opposing forces Outward force of chest wall MINUS the inward force of surfactant and elastic tissue

8. Inspiration Active process requiring energy Contraction of muscles Volume of thoracic cavity increases Pressure in thoracic cavity decreases Atmospheric Pressure > Alveolar Pressure

9. Expiration Passive process Relaxation of muscles Elastic tissue of lung recoils Inward pull of surface tension because of alveolar fluid Volume of thoracic cavity decreases Pressure in thoracic cavity increases Alveolar Pressure > Atmospheric Pressure

10. Alveolar and Systemic Gas Exchange Alveolar Level Oxygen diffuses from alveolar air and into blood in pulmonary capillaries Carbon dioxide diffuses from blood in pulmonary capillaries into alveoli Tissue Level Oxygen diffuses from the blood into systemic capillaries and into the tissues Carbon dioxide diffuses from tissues and into the blood in systemic capillaries to be carries back to the lungs

11. Infectious Pulmonary Disorders Pneumonia Viral, bacterial, or fungal 1 lobe or 2 lobes Tuberculosis Spread by oral droplets; can survive in dry sputum Can go dormant for long periods of time Disease resurfaces when the immune system is compromised Diagnosis: skin test, chest x-Ray, or sputum culture Treatment: long multi-drug treatment for 1 year; disease has grown more resistant to treatment

12. Obstructive Pulmonary Disorders Cystic Fibrosis Results from a single gene mutation Increases mucus in the lungs and risk of infections

13. Obstructive Pulmonary Disorders Asthma Type 1 Hypersensitivity Reaction Forms IgE in response to an allergen Inflammation of mucosa causes bronchoconstriction and obstructive mucus Can cause atelectasis Presents with: hypoxia, alkalosis, cyanosis, cough, chest tightness, thick mucus, and tachycardia Treatment: inhalers and glucocorticoids

14. Obstructive Pulmonary Disorders Chronic Obstructive Pulmonary Disease Emphysema Pink Puffers – red face, over-inflation Destruction of alveolar walls results in permanent inflation Smoking eliminates anti-trypsin that inhibits the enzyme that destroys elastin, so elastin is destroyed Loss of septae b/w alveolar sacs results in decreased surface area for gas exchange

15. Obstructive Pulmonary Disorders Chronic Obstructive Pulmonary Disease Chronic Bronchitis Blue Bloater Inflammatory obstruction results in repeated infections and progressive, irreversible damage of the bronchioles Hypertrophy, hyperplasia of mucous glands, and fibrosis Present with constant cough, shortness of breath, and cyanosis Treatment: smoking cessation, oxygen supplementation, and vaccinations

16. Obstructive Pulmonary Disorders Lung Tumor Inflammation and bleeding in the lungs leads to coughing up blood Pleural Effusion, Pneumothorax Lung Cancer 90% of cases are smoking related Third most common cancer Can be the result of metastasis

17. Restrictive Pulmonary Disorders Pneumoconiosis Exposure to irritants produces inflammation leading to fibrosis, or stiff lung Insidious onset Vascular Disorders Fluid collects in alveoli and interstitial Lung expansion and blood oxygen levels decrease Cause pulmonary hypertension and edema Pulmonary Embolism Blood clot from the veins that’s pumped to the lungs

18. Restrictive Pulmonary Disorders Atelectasis Collapse of the lung, has various causes Obstructed airway, compression, or increased surface tension prevent expansion

19. Restrictive Pulmonary Disorders Pleural Effusion Fluid in the pleural cavity increases proteins and white blood cells to respond to inflammation Pressure is increased in the pleural cavity, the lung layers separate, and lung expansion is prevented Present with increased respiratory or heart rate

20. Restrictive Pulmonary Disorders Pneumothorax Air in the chest cavity causes the lungs to collapse Open: air enters through the hole in the chest cavity Closed: air enters through a rupture on the inside of the chest cavity Tension: air is allowed to enter the cavity and there’s no natural way to remove it

21. Restrictive Pulmonary Disorders Adult Respiratory Distress Syndrome Rapid, shallow respirations increased heart rate and confusion Caused by shock, sepsis, burns, or multi-organ failure

22. Differential Diagnosis: Sputum Yellow/Green indicates an infection Rusty/Dark indicates pneumonia Purulent/Foul Odor indicates bronchiectasis

23. Differential Diagnosis: Breathing Labored indicates an obstruction Wheezing/Whistling indicates an obstruction of small airways Stridor indicates an obstruction of small airways