Porth's Essentials of Pathophysiology, 4e

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Respiratory Function

U N I T 6

3. A 4-month-old infant is admitted to the pediatric intensive care unit with a diagnosis of bronchiolitis. The infant is tachypneic, with wheezing, nasal flaring, and retractions of the lower sternum and intercostal spaces during inspiration. A. What is the usual pathogen in bronchiolitis? Would this infection be treated with an antibiotic? B. Explain the physiologic mechanism involved in the retraction of the lower sternum and intercostal spaces during inspiration. C. What would be the signs of impending respiratory failure in this infant? R E F E R E N C E S 1. American Lung Association. 2013. Pneumonia fact sheet . [Online]. Available at: http://www.lung.org/lung–disease/ influenza/in–depth–resources/pneumonia–fact–sheet.html. Accessed October 11, 2013. 2. McAdams AJ, Sharpe AH. Infectious diseases. In: Kumar V, Abbas AK, Fausto N, et al., eds. Robbins and Cotran Pathologic Basis of Disease . 8th ed. Philadelphia, PA: Elsevier Saunders; 2010:366–372. 3. Covington TR, Henkin R, Miller S, et al. Treating the common cold. Am J Nurse Pract. 2004;811:77–88. 4. Heikkinen T, Järvinsen A. The common cold. Lancet. 2003;361: 51–59. 5. Goldman DA. Transmission of viral respiratory tract infections in the home. Pediatr Infect Dis J . 2000;19:S97–S107. 6. Fashner J, Erickson K, Werner S. Treatment of the common cold in children and adults. Am Fam Physician . 2012;862:153–159. 7. Aring AM, Chan MM. Acute rhinosinusitis in adults. Am Fam Physician . 2011;839:1057–1063. 8. Meltzer EO, Hamilos DL. Rhinosinusitis diagnosis and management for the clinician: a synopsis of recent consensus guidelines. Mayo Clin Proc . 2011;865:427–443. 9. Brook I. Acute and chronic bacterial sinusitis. Infect Dis Clin North Am . 2007;21:427–446. 10. Leung RS, Katial R. The diagnosis and management of acute and chronic sinusitis. Prim Care . 2007;35:11–24. 11. Piccirillo JF. Acute bacterial sinusitis. N Engl J Med . 2004;351: 902–910. 12. Slavin RG, Spector SL, Bernstein IL, et al, chief editors; American Academy of Allergy, Asthma and Immunology; American College of Allergy, Asthma and Immunology; Joint Council of Allergy, Asthma and Immunology. The diagnosis and management of sinusitis: a practice parameter update. J Allergy Clinical Immunol. 2005;116(Suppl 6):S13–S17. 13. Beasley MB, Travis WD, Rubin E. The respiratory system. In: Rubin R, Strayer D, eds. Rubin’s Pathology: Clinicopathologic Foundations of Medicine . 6th ed. Philadelphia, PA: Wolters Kluwer Health/Lippincott Williams & Wilkins; 2012:537–604. 14. Husain AN. The lung. In Kumar V, Abbas AK, Fausto N, et al., eds. 2010. Robbins and Cotran Pathologic Basis of Disease . 8th ed. Philadelphia, PA: Elsevier Saunders; 2010:710–731. 15. Labella AM, Merel SE. Influenza. Med Clin North Am . 2013;97: 621–645. 16. Chestnut MS, Prendergast J, Tavan ET. Pulmonary disorders. In: McPhee SJ, Papadakis MA, eds. Current Medical Diagnosis and Treatment . 52nd ed. New York, NY: McGraw–Hill Medical; 2013:270–292.

SUMMARY CONCEPTS (continued)

R E V I EW E X E R C I S E S 1. It is flu season, and although you had a flu shot last year, you have not had one this year. Imagine yourself experiencing an abrupt onset of fever, chills, malaise, muscle aching, and nasal stuffiness. A. Which of these symptoms would lead you to believe you are coming down with the flu? B. Because you hate to miss classes, you decide to go to the student health center to get an antibiotic. After being seen by a health professional, you are told that antibiotics are ineffective against the flu virus, and you are instructed not to attend classes but instead to go home, take acetaminophen for your fever, go to bed and stay warm, and drink a lot of fluids. Explain the rationale for each of these recommendations. C. Explain why last year’s flu shot did not protect you during this year’s flu season. D. There is concern about the possibility of an influenza pandemic such as the one that occurred during the 1917–1918 season. What is the rationale for this concern? ■■ Because of the small size of the airway of infants and children, respiratory tract infections in these groups often are more serious. Infections that may cause only a sore throat and hoarseness in the adult may produce serious obstruction in the child. Among the respiratory tract infections that affect small children are croup, bronchiolitis, and epiglottitis, a life-threatening supraglottic infection that may cause airway obstruction and asphyxia. 2. Bacterial (e.g., S. pneumoniae ) pneumonia is commonly manifested by a cough productive of sputum, whereas with atypical (e.g., M. pneumoniae ) pneumonia, the cough is usually nonproductive or absent. A. Explain. ■■ Children with restrictive lung disorders, such as pulmonary edema or respiratory distress syndrome, breathe at faster rates, and their respiratory excursions are shallow. Grunting is an audible noise emitted during expiration. An expiratory grunt is common as the child tries to raise the end-expiratory pressure to maintain airway patency and prolong the period of oxygen and carbon dioxide exchange across the alveolar–capillary membrane.