Porth's Essentials of Pathophysiology, 4e

espiratory illnesses represent one of the more common reasons for visits to the physician, admission to the hospital, and forced inactivity among all age groups. The common cold, although not usually serious, results in missed work and school days. Pneumonia and influ- enza are ranked as the eighth leading cause of death in the United States. 1 Tuberculosis remains one of the deadliest diseases in the world. In addition to microbial pathogens, cigarette smoking contributes significantly to disorders of the respiratory tract, including lung cancer. The content in this chapter is divided into three sections: respiratory tract infections, cancer of the lung, and respiratory disorders in children. RespiratoryTract Infections Respiratory tract infections can involve the upper respi- ratory tract (i.e., nose, oropharynx, and larynx), the lower respiratory tract (i.e., lower airways and lungs), or both. The discussion in this section of the chapter focuses on the common cold, rhinosinusitis, influenza, pneumonia, tuberculosis, and fungal infections of the lung. For the most part, the signs and symptoms of respiratory tract infections depend on the function of the structure involved, the severity of the infectious process, and the person’s general health status and age. Acute respiratory infections in children are discussed in the last section of the chapter. Viruses are the most frequent cause of respiratory tract infections. They can cause infections ranging from a self-limited cold to life-threatening pneumonia. Moreover, viral infections can damage the bronchial epithelium, obstruct airways, and lead to secondary bacterial infections. Each viral species has its own pat- tern of respiratory tract involvement. The rhinoviruses grow best at 33°C and remain strictly confined to the Respiratory Tract Infections, Neoplasms, and Childhood Disorders 22 C h a p t e r

Respiratory Tract Infections The Common Cold Rhinosinusitis Clinical Features Influenza Etiology Pathogenesis Manifestations

Diagnosis and Treatment Influenza Immunization

Pneumonias

Classification Acute Bacterial (Typical) Pneumonia Primary Atypical Pneumonia Tuberculosis Etiology Pathogenesis Primary Tuberculosis Secondary Tuberculosis

Diagnosis Treatment Fungal Infections

R

Types of Infections Clinical Features

Cancer of the Lung

Types of Lung Cancer

Non–Small Cell Lung Cancers Small Cell Lung Cancer

Clinical Features Manifestations

Diagnosis and Treatment Respiratory Disorders in Children Lung Development Ventilation in the Neonate Airway Resistance

Lung Volumes and Gas Exchange Control of Ventilation Alterations in Breathing Patterns Respiratory Disorders in the Neonate Respiratory Distress Syndrome Bronchopulmonary Dysplasia Respiratory Infections in Children Upper Airway Infections Lower Airway Infections Signs of Impending Respiratory Failure

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