Chapter 21 Respiratory Tract Infections, Neoplasia, and Childhood Disorders

1. Chapter 21Respiratory Tract Infections, Neoplasia, and Childhood Disorders

2. Upper Respiratory Viruses in Adults • Common cold • Rhinosinusitis • Influenza

3. The Common Cold • Rhinoviruses • Occur in early fall and late spring in persons between ages 5 and 40 • Parainfluenza viruses • Occur in children younger than 3 • Respiratory syncytial virus • Occurs in winter and spring in children younger than 3 • Coronaviruses and adenoviruses • Occur in winter and spring

4. Rhinosinusitis (Sinusitis) • Infection or allergy obstructs sinus drainage • Acute: facial pain, headache, purulent nasal discharge, decreased sense of smell, fever • Chronic: nasal obstruction, fullness in the ears, postnasal drip, hoarseness, chronic cough, loss of taste and smell, unpleasant breath, headache

5. Influenza • In the United States, approximately 36,000 persons die each year of influenza-related illness • Transmission is by aerosol (three or more particles) or direct contact • Upper respiratory infection (rhinotracheitis) • Like a common cold with profound malaise • Viral pneumonia • Fever, tachypnea, tachycardia, cyanosis, hypotension • Respiratory viral infection followed by a bacterial infection

6. Question For which viruses is a 2-year-old most at risk? • Rhinoviruses • Parainfluenza viruses • Respiratory syncytial virus (RSV) • All of the above • b and c

7. Answer • b and c Rationale:Slightly older children (> 5 y) are at risk for rhinoviral infections. Children under the age of 3 are at risk of infection from both parainfluenza viruses and RSV.

8. Mechanism of Viral Infection and Treatment amantadine, rimantadine zanamivir, oseltamivir

9. Pneumonia—Inflammation of Alveoli and Bronchioles • Typical: bacteria in the alveoli • Lobar: affect an entire lobe of the lung • Bronchopneumonia: patchy distribution over more than one lobe • Atypical • Viral and mycoplasma infections of alveolar septum or interstitium

10. Onset of Pneumonia Infection • Signs of systemic inflammation • Malaise • Chills and fever Inflammation Congestion, productive Serous exudate cough

11. serous exudate • Blood-tinged sputum • Pleuritic pain fibrous exudate: consolidation RED HEPATINIZATION WBCs denature hemoglobin: GRAY HEPATINIZATION

12. If WBCs Overcome the Infection WBCs denature hemoglobin: GRAY HEPATINIZATION WBCs destroy fibrous proteins and liquefy resolution exudate: it is reabsorbed into the circulation

13. Question Tell whether the following statement is true or false. In the progression of pneumonia, serous exudate develops before fibrous exudate.

14. Answer True Rationale:Serous exudate develops (just after inflammation) before fibrous exudate, and is characterized by a congested, productive cough. If the pneumonia does not resolve at this stage, fibrous exudate develops, and the patient will experience pleuritic pain (worse when taking a deep breath or coughing) and may expectorate blood-tinged sputum.

15. Tuberculosis • World’s foremost cause of death from a single infectious agent • Causes 26% of avoidable deaths in developing countries • Drug-resistant forms • Mycobacterium tuberculosis hominis • Aerobic • Protective waxy capsule • Can stay alive in “suspended animation” for years

16. Initial TB Infection TB bacteria inhaled • Macrophages begin a cell-mediated immune response • Takes 3–6 weeks to develop positive TB test • Results in a granulomatous lesion or Ghon focus containing • Macrophages • T cells • Inactive TB bacteria ingested by macrophages in lungs macrophages present them to T cells activated activated T cells T cells stimulate kill macrophages to bacteria kill bacteria more efficiently

17. Ghon complex • Nodules in lung tissue and lymph nodes • Caseous necrosis inside nodules • Calcium may deposit in the fatty area of necrosis • Visible on x-rays

18. Discussion Someone in your class has a positive TB test. Question: • What does this mean? • Are you at risk of infection?

19. Primary TB primary TB usually if immune response is isolated in inadequate, bacteria Ghon foci multiply in the lungs not bacteria progressive primary TB contagious are inactive

20. Miliary TB progressive primary TB • Miliary TB lesions look like grains of millet in the tissues • Meat inspection was introduced to keep them out of the food supply • Pasteurization of milk was introduced to keep TB out of the milk supply bacteria may signs of bacteria in erode blood pneumonia sputum and vessels and exhaled spread through droplets the body MILIARY TB

21. Secondary TB • Reinfection from inhaled droplet nuclei • Reactivation of a previously healed primary lesion • Immediate cell-mediated response walls off infection in airways • Bacteria damage tissues in the airways, creating cavities • Signs of chronic pneumonia: gradual destruction of lung tissue • “Consumption”: eventually fatal if untreated

22. Question Which type of TB may be reactivated if the patient becomes immunocompromised? • Primary • Latent • Miliary • Secondary

23. Answer • Secondary Rationale:Secondary TB, often referred to as reactivation or reinfection TB, may occur if patients are reexposed to TB bacilli (after a primary infection) or if they become immunocompromised (they are unable to contain the infection).

24. Cavitary Tuberculosis

25. Lung Cancer • Bronchogenic carcinoma • Arises from epithelial cells lining the lungs • Small-cell lung cancer • Non–small-cell lung cancer • Large-cell carcinoma • Squamous cell • Adenocarcinoma

26. Manifestations of Lung Cancer • Changes in organ function (organ damage, inflammation, and failure) • Local effects of tumors (e.g., compression of nerves or veins, gastrointestinal obstruction) • Ectopic hormones secreted by tumor cells (paraneoplastic disorders) • Nonspecific signs of tissue breakdown (e.g., protein wasting, bone breakdown)

27. Respiratory Distress Syndrome • Lack of surfactant; infants are not strong enough to inflate their alveoli • Protein-rich fluid leaks into the alveoli and further blocks oxygen uptake • Treatment with mechanical ventilation may cause bronchopulmonary dysplasia and chronic respiratory insufficiency

28. Question Tell whether the following statement is true or false. Premature infants are at greater risk of developing respiratory distress syndrome (RDS) than term infants.

29. Answer True Rationale:RDS occurs due to a lack of surfactant in the alveoli (the surfactant is produced by alveolar cells, and keeps them inflated). Surfactant is typically produced from week 28 (gestational age) through term (40–42 weeks). The more premature the infant/neonate, the greater the likelihood that there will be insufficient surfactant to sustain ventilation.

30. Respiratory Obstruction in Children • Increased airway resistance • Extrathoracic airways (upper airways) • Prolonged inspiration; inspirational stridor • Inspiratory retractions as ribs are moved outward and body wall does not expand with rib cage • Intrathoracic airways (lower airways) • Prolonged expiration with wheezing • Rib cage retractions as ribs are pulled inward, but air does not leave lungs

31. Obstructive Disorders • Upper airway • Croup • Epiglottitis • Lower airway • Acute bronchiolitis

32. Question Tell whether the following statement is true or false. Epiglottitis causes stridor.

33. Answer True Rationale:Epiglottitis affects the upper airway (inflammation causes the lumen of the upper airway to become more narrow). When the child inspires, it is difficult to pass air through the narrowed airway. This causes noisy inspiration/stridor.