Understanding Respiratory Tract Infections and Neoplasms

1. Chapter 36Respiratory Tract Infections,Neoplasms, and Childhood Disorders

2. Areas Involved in Respiratory Tract Infections • Upper respiratory tract • Nose, oropharynx, and larynx • Lower respiratory tract • Lower airways and lungs • Upper and lower airways

3. Common Respiratory Infections • Common cold • Influenza • Pneumonia • Tuberculosis • Fungal infections of the lung

4. Factors Affecting the Signs and Symptoms of Respiratory Tract Infections • The function of the structure involved • The severity of the infectious process • The person’s age and general health status

5. Transmission of Common Cold • Viral infection of the upper respiratory tract • Rhinoviruses, parainfluenza viruses, respiratory syncytial virus, corona viruses, and adenoviruses • Fingers are the greatest source of spread. • Cough, sneeze • The nasal mucosa and conjunctival surface of the eyes are the most common portals of entry of the virus.

6. Question • The most common port of entry for cold viruses is _______. • A. inhalation • B. small cuts • C. food • D. conjunctival surface of the eyes • E. fingers

7. Answer • D. conjunctival surface of the eyes • Rationale: Conjunctival surface of the eyes and the nasal mucosa are the most common ports of entry for cold viruses.

8. Rhinitis and Sinusitis • Rhinitis • Inflammation of the nasal mucosa • Sinusitis • Inflammation of the paranasal sinuses

9. Types of Sinuses • Paranasal sinuses • Air cells connected by narrow openings or ostia with the superior, middle, and inferior nasal turbinates of the nasal cavity • Maxillary sinus • Inferior to the bony orbit and superior to the hard palate • Its opening is located superiorly and medially in the sinus, a location that impedes drainage. • Frontal sinuses • Open into the middle meatus of the nasal cavity

10. Types of Sinuses (cont.) • Sphenoid sinus • Just anterior to the pituitary fossa behind the posterior ethmoid sinuses • Its paired openings drain into the sphenoethmoidal recess at the top of the nasal cavity. • Ethmoid sinuses • Comprise 3 to 15 air cells on each side, with each maintaining a separate path to the nasal chamber

11. Classifications of Rhinosinusitis • Acute rhinosinusitis • May be of viral, bacterial, or mixed viral–bacterial origin • May last from 5 to 7 days up to 4 weeks • Subacute rhinosinusitis • Lasts from 4 weeks to less than 12 weeks • Chronic rhinosinusitis • Lasts beyond 12 weeks

12. Allergic Rhinosinusitis • Occurrence • Occurs in conjunction with allergic rhinitis • Mucosal changes are the same as allergic rhinitis • Symptoms • Nasal stuffiness, itching and burning of the nose, frequent bouts of sneezing, recurrent frontal headache, watery nasal discharge • Treatment • Oral antihistamines, nasal decongestants, and intranasal cromolyn

13. Types of Influenza Viruses • Type A • Most common type • Can infect multiple species • Causes the most severe disease • Further divided into subtypes based on two surface antigens: hemagglutinin (H) and neuraminidase (N) • Type B • Has not been categorized into subtypes

14. Antiviral Drugs • Amantadine • Rimantadine • Zanamivir • Oseltamivir

15. Types of Influenza Vaccinations • Trivalent inactivated influenza vaccine (TIIV) • Developed in the 1940s • Administered by injection • Live, attenuated influenza vaccine (LAIV) • Approved for use in 2003 • Administered intranasally

16. Pneumonia • Definition • Respiratory disorders involving inflammation of the lung structures (alveoli and bronchioles) • Causes • Infectious agents: such as bacteria and viruses • Noninfectious agents: such as gastric secretions aspirated into the lungs

17. Factors Facilitating Development of Pneumonia • An exceedingly virulent organism • A large inoculum • Impaired host defenses

18. Classifications of Pneumonias • According to the source of infection • Community-acquired • Hospital-acquired • According to the immune status of the host • Pneumonia in the immunocompromised person

19. Tuberculosis • Caused by the mycobacterium, M. Tuberculosis • Outer waxy capsule that makes them more resistant to destruction • Infect practically any organ of the body, the lungs are most frequently involved • Macrophage-directed attack, resulting in parenchymal destruction • Cell-mediated immune response • Confers resistance to the organism • Development of tissue hypersensitivity

20. Forms of Tuberculosis • M. tuberculosis hominis (human tuberculosis) • Airborne infection spread by minute droplet nuclei harbored in the respiratory secretions of persons with active tuberculosis • Living under crowded and confined conditions increases the risk for spread of the disease • Bovine tuberculosis • Acquired by drinking milk from infected cows; initially affects the gastrointestinal tract • Has been virtually eradicated in North America and other developed countries

21. Positive Tuberculin Skin Test • Results from a cell-mediated immune response • Implies that a person has been infected with M. tuberculosis and has mounted a cell-mediated immune response • Does not mean the person has active tuberculosis

22. Laboratory Tests to Diagnose Histoplasmosis • Cultures • Fungal stain • Antigen detection • Serologic tests for antibodies

23. Classification and spread of Fungi • Yeasts • Are round and grow by budding • Molds • Form tubular structures called hyphae • Grow by branching and forming spores • Dimorphic Fungi • Grow as yeasts at body temperatures and as molds at room temperatures • Mechanisms of Fungal Spread • Inhalation of spores

24. Causative Factors Smoking Asbestos Familial predisposition Primary lung tumors (95%) versus bronchial, glandular, lymphoma Secondary via metastasis Lung Cancer

25. Categories of Bronchogenic Carcinomas • Squamous cell lung carcinoma (25% to 40%) • Closely related to smoking • Adenocarcinoma (20% to 40%) • Most common in North America • Small cell carcinoma (20% to 25%) • Small round to oval cells, highly malignant • Large cell carcinoma (10% to 15%) • Large polygonal cells, spread early in development

26. Question • The lungs are a common sight for secondary tumor development. Why? • A. Due to the highly vascular nature and small capillaries • B. Due to the fragility of the cells • C. Due to the rapid replication of type I alveolar cells • D. Due to dumb luck

27. Answer • A. Due to the highly vascular nature and small capillaries • Rationale: Due to the highly vascular nature and small capillaries

28. Categories of the Manifestations of Lung Cancer • Those due to involvement of the lung and adjacent structures • The effects of local spread and metastasis • The nonmetastatic paraneoplastic manifestations involving endocrine, neurologic, and connective tissue function • Nonspecific symptoms such as anorexia and weight loss

29. Question • Which of the following involves infection of the entire respiratory track? • A. Common cold • B. Pneumonia • C. Tuberculosis • D. Cancer

30. Answer • B. Pneumonia • Rationale: Pneumonia can involve all respiratory tissues, and due to its virulence, is a major health risk.

31. Stages of Lung Development • Embryonic period • Pseudoglandular period • Canalicular period • Saccular period • Alveolar period

32. Respiratory Disorders in the Neonate • Respiratory distress syndrome • Bronchopulmonary dysplasia

33. Respiratory Disorders in Children • Upper airway infections • Viral croup • Spasmodic croup • Epiglottis • Lower airway infections • Acute bronchiolitis

34. Impending Respiratory Failure in Infants and Children • Rapid breathing • Exaggerated use of the accessory muscles • Retractions • Nasal flaring • Grunting during expiration