Distinguishing Among Types of Pneumonia

1. Distinguishing Among Types of Pneumonia Adapted from Porth, C.M. 2011. Essentials of Pathophysiology, 3rd edn.

2. Distinguishing Among Types of Pneumonia Adapted from Porth, C.M. 2011. Essentials of Pathophysiology, 3rd edn.

3. Tuberculosis An infectious disease that primarily affects the lungs but can invade other body systems as well. In tuberculosis, pulmonary infiltrates accumulate, cavities develop, and masses of granulated tissue form within the lungs. Tuberculosis may occur as an acute or a chronic infection. Pathophysiology: Tuberculosis results from exposure to Mycobacterium tuberculosis and, sometimes, other strains of mycobacterium. Transmission: an infected person coughs or sneezes, spreading infected droplets. Immune response: sends leukocytes, and inflammation results. After a few days the leukocytes are replaced by macrophages. Tubercle formation: macrophages that ingest the bacilli fuse to form epithelioid cell tubercles, tiny nodules surrounded by lymphocytes. Within the lesion, caseous necrosis develops and scar tissue encapsulates the tubercle. Dissemination: If the tubercles and inflamed nodules rupture, the infection contaminates the surrounding tissue and may spread through the blood and lymphatic circulation to distant sites.

4. Understanding Tuberculosis Invasion Hendler, C.B. 2002. Pathophysiology Made Incredibly Easy, 3rd edn.

5. Tuberculosis: Pathophysiologic Changes Inflammatory and Immune Process: Fever and night sweats; malaise; weight loss; adenopathy; productive cough (lasting longer than 3 weeks); haemoptysis; pleuritic chest pain.

6. Lung Cancer Development of neoplasm, usually within wall or epithelium of bronchial tree. Most common types: squamous cell carcinoma; small cell carcinoma; adenocarcinoma, and large cell (anaplastic) carcinoma. Pathophysiology: lung cancer most commonly results from repeated tissue trauma from inhalation of irritants or carcinogens. These substances include tobacco smoke, air pollution, arsenic, asbestos, nickel and radon. Almost all lung cancers start in the epithelium. In normal lungs, the epithelium lines protects the tissue below it. However, when exposed to irritants or carcinogens, the epithelium continually replaces itself until the cell develop chromosomal changes and become dysplastic. Eventually, the dysplastic cells turn into neoplastic carcinoma and start invading deeper tissues.

7. How Lung Cancer Develops Robinson, J.M. 2005. Pathophysiology: Just the facts.

8. Common Lung Cancers Hendler, C.B. 2002. Pathophysiology Made Incredibly Easy, 3rd edn.

9. Respiratory Infections in Children In children respiratory tract infections are common, an d although they are troublesome, they usually are not serious. Frequent infections occur because the immune system of infants and small children has not been exposed to many common pathogens. Croup: is characterised by inspiratory stridor, hoarseness and a barking cough. Although the respiratory manifestations of croup often appear suddenly, they usually are preceded by upper respiratory infections that cause rhinorrhoea, coryza, hoarseness, and low grade fever. In most children, the manifestations of croup advances only to stridor and slight dyspnoea before they begin to recover.

10. Assessing Your Understanding Tuberculosis is transmitted through _____________ of _______________ droplets. ______________ are the most frequent cause of respiratory infection. The common cold is a viral infection of the _______________ respiratory tract. The term ___________________ describes inflammation of parenchymal structures of the lung, such as the alveoli and the bronchioles. The _____________ include squamous cell carcinomas, adenocarcinoma, and large cell carcinoma. How is lung cancer characterised?

11. Disorders of Ventilation and Gas Exchange

12. Pathophysiologic Concepts Hypoxemia: Reduced oxygenation of arterial blood, evidenced by reduced Pao2 of arterial blood gases. Can be caused by decreased oxygen content of inspired gas, hypoventilation, diffusion abnormalities, abnormal V/Q ratios, and pulmonary right to left shunts. Can lead to tissue hypoxia. Can occur anywhere in the body.

13. Pathophysiologic Concepts Cyanosis: Bluish discolouration of skin and mucous membranes; may be central or peripheral. Central cyanosis: decreased oxygen saturation of haemoglobin in arterial blood; best observed in buccal mucous membranes and lips. Peripheral cyanosis: slowed blood circulation of fingers and toes; best visualised by examining nail bed area. Caused by desaturation with oxygen or reduced haemoglobin amounts (develops when 5 grams of haemoglobin is desaturated, even if haemoglobin counts are adequate or reduced).

14. Disorders of Lung Inflation Air entering through the airways inflates the lung, and the negative pressure in the pleural cavity keeps the lung from collapsing. Disorders of lung inflation are caused by conditions that obstruct airways, cause lung compression, or produce lung collapse.

15. Pneumothorax An accumulation of air in the pleural cavity that leads to partial or complete lung collapse. Classified as either traumatic or spontaneous. Pathophysiology: Traumatic pneumothorax: a penetrating injury, such as a stab wound, or impaled object, may cause traumatic pneumothorax. Open pneumothorax: results when atmospheric air flows directly into the pleural cavity. As the lung pressure becomes positive, the lungs collapses on the affected side, eventually resulting in hypoxia. Closed pneumothorax: occurs when air enters the pleural space from within the lungs. This causes increased pleural pressure and prevents expansion during inspiration. Spontaneous pneumothorax: is a type of closed pneumothorax. It is more common in men and older patients with chronic pulmonary disease.

16. Tension Pneumothorax Hendler, C.B. 2002. Pathophysiology Made Incredibly Easy, 3rd edn

17. Atelectasis Refers to an incomplete expansion of a lung or portion of a lung. Pathophysiology: Occurs when alveolar sacs or entire lung segments expand incompletely, producing partial or complete lung collapse. Removes certain lung regions from gas exchange, allowing unoxygenated blood to pass unchanged through these regions, resulting in hypoxia. May be chronic or acute; commonly occurs in patients undergoing upper abdominal or thoracic surgery.

18. Obstructive Airway Disorders Caused by conditions that limit expiratory airflow. Bronchial asthma represents an acute and reversible form of airway disease caused by narrowing of airway disease caused by narrowing of airways due to bronchospasm, inflammation, and increased airway secretions. Airway disorders affect airway patency and movement of atmospheric air into and out of the gas exchange portion of the lung.

19. Asthma A chronic reactive airway disorder that can present as an acute attack. It causes episodic airway obstruction resulting from bronchospasm, increased mucous secretion, and mucosal oedema. Asthma is one type of Chronic obstructive pulmonary disease (COPD), a long term pulmonary disease characterised by airflow resistance. Pathophysiology: In asthma, bronchial linings overreact to various stimuli, causing episodic smooth-muscle spasms that severely constrict the airways. Asthma can be described in two ways: extrinsic and intrinsic: Extrinsic, or atopic, asthma is sensitive to specific external allergens , which include pollen, animal dander, house dust or mould, and food additives containing sulphites. Extrinsic asthma begins in childhood and is commonly accompanied by other hereditary allergies, such as eczema and allergic rhinitis. Intrinsic, or nonatopic, asthma is a reaction to internal, nonallergenic factors. Most episodes occur after a severe respiratory infection.

20. Understanding Asthma Hendler, C.M. 2002. Pathophysiology Made Incredibly Easy, 3rd edn.

21. Mechanisms of Early and Late Phase IgE Mediated Bronchospasm Porth, C.M. 2011. Essentials of Pathophysiology, 3rd edn.

22. Emphysema A form of COPD, emphysema is the abnormal, permanent enlargement of the acini accompanied by destruction of the alveolar walls. Obstruction results from tissue changes, rather than mucous production, which is the case in asthma and chronic bronchitis. Pathophysiology: Emphysema may be caused by a deficiency of alpha1-protease inhibitor or by cigarette smoking. In emphysema, recurrent inflammation is associated with the release of proteolytic enzymes from lung cells. This causes irreversible enlargement of the air spaces distal to the terminal bronchioles. Enlargement of air spaces destroys the alveolar walls, which results in a breakdown of elasticity and loss of fibrous and muscle tissues, making the lungs less compliant.