Porth's Essentials of Pathophysiology, 4e

69

Inflammation, the Inflammatory Response, and Fever

C h a p t e r 3

4. A 3-year-old child is seen in a pediatric clinic with a temperature of 39°C (103°F). Her skin is warm and flushed, her pulse is 120 beats per minute, and her respirations are shallow and rapid at 32 breaths per minute. Her mother states that she has complained of a sore throat and has refused to drink or take medications to bring her fever down. A. Explain the physiologic mechanisms of fever generation. B. Are the warm and flushed skin, rapid heart rate, and respirations consistent with this level of fever? C. After receiving an appropriate dose of acetaminophen, the child begins to sweat, and the temperature drops to 37.2°C. Explain the physiologic mechanisms responsible for the drop in temperature. R E F E R E N C E S 1. Murphy HS. Inflammation. In: Rubin E, Strayer D, eds. Rubin’s Pathology: Clinicopathologic Foundations of Medicine . 5th ed. Philadelphia, PA: Wolters Kluwer Health/ Lippincott Williams & Wilkins; 2012:47–82. 2. Kumar V, Abbas AK, Fausto N, et al. Robbins and Cotran Basic Pathology . 8th ed. Philadelphia, PA: Saunders Elsevier; 2010:43–77. 3. Schmid-Schonbein GW. Analysis of inflammation. Annu Rev Biomed Eng. 2006;8:93–131. 4. Medzhitov R. Origin and physiological roles of inflammation. Nature. 2008;454(24):428–435. 5. Szekanecz Z, Koch AE. Vascular endothelium and immune responses: implications for inflammation and angiogenesis. Rheum Dis Clin North Am. 2004;30:97–114. 6. Steinhubl SR. Platelets as mediators of inflammation. Hematol Oncol Clin North Am. 2007;21:115–121. 7. Gawaz M, Langer H, May AE. Platelets in inflammation and atherogenesis. J Clin Invest. 2005;115(12):3378–3384. 8. Ricciotti E, Fitzgerald GA. Prostaglandins and inflammation. Arterioscler Thromb Vasc Biol. 2011;31(5):986–1000. 9. Ormenetti A, Gattorno M. Principles of inflammation for the pediatrician. Pediatr Clin North Am. 2012;59:225–243. 10. Bachelet I, Levi-Schaffer F, Mekori YA. Mast cells: not only in allergy. Immunol Allergy Clin North Am. 2006;26:407–425. 11. Frenette PS, Wagner DD. Adhesion molecules—parts I and II. N Engl J Med. 1996;334(23):1526–1529. 12. Bochner BS. Adhesion molecules as therapeutic targets. Immunol Allergy Clin North Am. 2004;24:615–630. 13. Stein DM, Nombela-Arrieta C. Chemokine control of lymphocyte trafficking: a general review. Immunology. 2005;116:1–12. 14. Underhill DM, Ozinsky A. Phagocytosis of microbes. Annu Rev Immunol. 2002;20:825–852. 15. Simmons DL, Botting RM, Hla T. Cyclooxygenase isoenzymes: the biology of prostaglandin synthesis and inhibition. Pharmacol Rev. 2004;56(3):387–437. 16. Barnes PJ. How corticosteroids control inflammation: Quintiles Prize Lecture 2005. Br J Pharmacol. 2006;14B:245–254. 17. Covington MB. Omega-3 fatty acids. Am Fam Physician. 2004;70(1):133–140.

■■ Fever, an elevation in body temperature, is one of the most prominent manifestations of the acute-phase response, especially if inflammation is caused by infection. It is produced in response to pyrogens that act by prompting the release of prostaglandin E 2 or fever-producing cytokines, which in turn resets the hypothalamic thermoregulatory center. ■■ The reactions that occur during fever consist of four stages: a prodromal period with nonspecific complaints, such as mild headache and fatigue; a chill, during which the temperature rises; a flush, during which the skin becomes warm and flushed; and a defervescence stage, which is marked by the initiation of sweating. ■■ The approach to fever in children varies depending on the age of the child. Infants and young children have decreased immunologic function and are more commonly infected with virulent organisms. ■■ The elderly tend to have a lower baseline temperature, so that serious infections may go unrecognized because of the perceived lack of a significant fever. R E V I EW E X E R C I S E S 1. A 15-year-old boy presents with abdominal pain, a temperature of 38°C (100.5°F), and an elevated white blood cell count of 13,000/ μ L, with an increase in neutrophils. A tentative diagnosis of appendicitis is made. A. Explain the significance of pain as it relates to the inflammatory response. B. What is the cause of the fever and elevated white blood cell count? C. What would be the preferred treatment for this boy? 2. Aspirin and other nonsteroidal anti-inflammatory drugs are often used to control the manifestations of chronic inflammatory disorders such as arthritis. A. Explain their mechanism of action in terms of controlling the inflammatory response. 3. Persons with long-standing ulcerative colitis, an inflammatory bowel disease, have a higher risk of colorectal cancer than the general population. A. Hypothesize on cancer-producing mechanisms of this chronic inflammatory disease.