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Chapter 28 Respiratory Tract Infections, Neoplasms, and Childhood Disorders Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Areas Involved in Respiratory Tract Infections • Upper respiratory tract – Nose, oropharynx, and larynx • Lower respiratory tract – Lower airways and lungs • Upper and lower airways Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Common Respiratory Infections • Common cold • Influenza • Pneumonia • Tuberculosis • Fungal infections of the lung Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Transmission of Common Cold • Viral infection of the upper respiratory tract – Rhinoviruses, parainfluenza viruses, respiratory syncytial virus, coronaviruses, and adenoviruses • Fingers are the greatest source of spread • Coughing, sneezing – The nasal mucosa and conjunctival surface of the eyes are the most common portals of entry for the virus. Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins 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 Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Rhinitis and Sinusitis • Rhinitis – Inflammation of the nasal mucosa • Sinusitis – Inflammation of the paranasal sinuses Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins 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 Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins 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 3–15 air cells on each side, with each maintaining a separate path to the nasal chamber Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins 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 Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins 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 Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins 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 Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Answer a. Inhalation b. Small cuts c. Food d. Conjunctival surface of the eyes: The eyes and the nasal mucosa are the most common ports of entry. e. Fingers Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins 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 Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Antiviral Drugs • Amantadine • Rimantadine • Zanamivir • Oseltamivir Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins 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 Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins 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 Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Factors Facilitating Development of Pneumonia • Virulence of organism • Inoculum size • Impaired host defenses Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Classifications of Pneumonias • According to source of infection – Community-acquired – Hospital-acquired • According to immune status of the host – Pneumonia in the immunocompromised person Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Tuberculosis • Caused by a mycobacterium, M. tuberculosis – Outer waxy capsule makes the organism more resistant to destruction • Infects practically any organ of the body; the lungs are most frequently involved • Macrophage-directed attack, resulting parenchymal destruction • Cell-mediated immune response – Confers resistance to the organism – Development of tissue hypersensitivity Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins 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 Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins 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 Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Question • Which of the following involves infection of the entire respiratory tract? a. Common cold b. Pneumonia c. Tuberculosis d. Cancer Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Answer a. Common cold b. Pneumonia: Pneumonia can involve all respiratory tissues and, due to its virulence, is a major health risk. c. Tuberculosis d. Cancer Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins 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 Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Laboratory Tests to Diagnose Histoplasmosis • Cultures • Fungal stain • Antigen detection • Serologic tests for antibodies Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Lung Cancer • Causative factors – Smoking • Primary lung tumors (95%) vs. bronchial, glandular, lymphoma – Asbestos • Secondary via metastasis – Familial predisposition Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Categories of Bronchogenic Carcinomas • Squamous cell lung carcinoma (25–40%) – Closely related to smoking • Adenocarcinoma (20–40%) – Most common in North America • Small cell carcinoma (20–25%) – Small round to oval cells, highly malignant • Large cell carcinoma (10–15%) – Large polygonal cells, spread early in development Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Categories of the Manifestation 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 Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Stages of Lung Development • Embryonic period • Pseudoglandular period • Canicular period • Saccular period • Alveolar period Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Respiratory Disorders in the Neonate • Respiratory distress syndrome • Bronchopulmonary dysplasia Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Respiratory Disorders in Children • Upper airway infections – Viral croup – Spasmodic croup – Epiglottis • Lower airway infections – Acute bronchiolitis Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Impending Respiratory Failure in Infants and Children • Rapid breathing • Exaggerated use of the accessory muscles • Retractions • Nasal flaring • Grunting during expiration Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Question • The lungs are a common site of 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 Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Answer 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 Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins