Respiratory tract pathology

Premed 2Pathophysiology

Common Upper respiratory tract Disorders

• Acute rhinitis-common cold-adenovirus

• Allergic rhinitis-type I hypersensitivity reaction-mast cells, basophils

• Bacterial infection-superimposed infection-common bacteria: Staphylococcus, Streptococcus, Hemophilus

• Sinusitis-inflammation of the paranasal sinuses

• Laryngitis-edema, inflammation, hoarseness

• Acute epiglotitis-severe, children-Hemophilus influenzae

• Acute laryngotracheobronchitis-croup-inflammation of the larynx, trachea and epiglottis-viral infection

Malignancies of the URT

• Nasopharyngeal carcinoma

-SEA and Africa-Epstein-Barr virus

• Squamous cell carcinoma-most frequently occurring tumor

Chronic Obstructive Pulmonary disease

• Airflow obstruction• Decrease in 1-minute forced expiratory

volume• Increased/normal forced vital capacity• Bronchial asthma• Chronic bronchitis• Pulmonary emphysema• Bronchiectasis

Bronchial asthma

• Episodes of dyspnea• Wheezing on expiration• Smooth muscle hypertrophy• Hyperplasia of the bronchial submucosal

glands and goblet cells• Viscid mucus with Curschmann spirals

and Charcot-Leyden crystals

Chronic bronchitis• Productive cough that occurs for 3 consecutive

months in 2 consecutive years• Hyperplasia of the bronchial submucosal

glandsincreased Reid index• Reid index: ratio of the thickness of the gland

layer to that of the bronchial wall• Cigarette smoking• Air pollution• Infection• Complication: cor pulmonale

Chronic bronchitis

Emphysema

• Dilatation of the air spaces• Destruction of the alveolar walls• Lack of elastic recoil• Increased antero-posterior diameter of the chest

• Hypoxia, cyanosis, respiratory acidosis• Cigarette smoking• Hereditary alpha-antitrypsin deficiency

Bronchiectasis

• Permanent abnormal bronchial dilatation• Chronic infection• Inflammation and necrosis of the bronchial

wall• Copious pururlent sputum• Hemoptysis• Lung abscess

• Predisposing factor:-bronchial tumor-Kartagener syndrome: sinusitis, bronchiectasis, situs inversus

Respiratory Distress Syndrome

• Surfactant– decreases the surface tension of

the alveoli– needed for alveoli to fill with air

and expand (compliance)• Infant respiratory distress syndrome

(hyaline membrane disease)• Adult respiratory distress syndrome

Neonatal respiratory distress syndrome

• Hyaline membrane disease• Most common cause of death in

premature infants• Dyspnea, cyanosis, tachynea after birth• Deficiency of surfactant: dipalmitoyl

lecithin; from type II pneumocytes

HMD

• Predisposing factorsprematuritymaternal diabetescaesarean section

Pneumoconiosis

• Anthracosis: carbon dust• Coal worker’s pneumoconiosis: coal dust• Silicosis: free silica dust• Asbestosis: asbestos fibers ferruginous

bodies-brochogenic carcinoma-malignant mesothelioma

Bronchogenic carcinoma

• Directly proportional to the number of cigarettes smoked daily and the number of years

• Air pollution• Radiation: radium, uranium• Asbestos• Nickel, chromates

Bronchogenic carcinoma

• 5-year survival rate: 10 %• Cough

hempotysisbronchial obstruction

• Local extension: pleura, pericardium, ribs

Bronchogenic carcinoma