Chapter 115. Approach to the Acutely Ill Infected Febrile Patient (Part 3)

Adjunctive treatments may reduce morbidity and mortality and include dexamethasone for bacterial meningitis; intravenous immunoglobulin (IVIg) for TSS and necrotizing fasciitis caused by group A Streptococcus; low-dose hydrocortisone and fludrocortisone for septic shock; and drotrecogin alfa (activated), also known as recombinant human activated protein C, for meningococcemia and severe sepsis. Adjunctive therapies should usually be initiated within the first hours of treatment; however, dexamethasone for bacterial meningitis must be given before or at the time of the first dose of antibiotic.Specific PresentationsThe infections considered below according to common clinical presentation can have rapidly catastrophic outcomes, and their immediate recognition...
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Chapter 115. Approach to the Acutely Ill Infected Febrile Patient (Part 3) Chapter 115. Approach to the Acutely Ill Infected Febrile Patient (Part 3) Adjunctive treatments may reduce morbidity and mortality and includedexamethasone for bacterial meningitis; intravenous immunoglobulin (IVIg) forTSS and necrotizing fasciitis caused by group A Streptococcus; low-dosehydrocortisone and fludrocortisone for septic shock; and drotrecogin alfa(activated), also known as recombinant human activated protein C, formeningococcemia and severe sepsis. Adjunctive therapies should usually beinitiated within the first hours of treatment; however, dexamethasone for bacterialmeningitis must be given before or at the time of the first dose of antibiotic. Specific Presentations The infections considered below according to common clinical presentationcan have rapidly catastrophic outcomes, and their immediate recognition andtreatment can be life-saving. Recommended empirical therapeutic regimens arepresented in Table 115-1. Sepsis Without an Obvious Focus of Primary Infection These patients initially have a brief prodrome of nonspecific symptoms andsigns that progresses quickly to hemodynamic instability with hypotension,tachycardia, tachypnea, respiratory distress, and altered mental status.Disseminated intravascular coagulation (DIC) with clinical evidence of ahemorrhagic diathesis is a poor prognostic sign. Septic Shock (See also Chap. 265) Patients with bacteremia leading to septic shock mayhave a primary site of infection (e.g., pneumonia, pyelonephritis, or cholangitis)that is not evident initially. Elderly patients with comorbid conditions, hostscompromised by malignancy and neutropenia, and patients who have recentlyundergone a surgical procedure or hospitalization are at increased risk for anadverse outcome. Gram-negative bacteremia with organisms such asPseudomonas aeruginosa or Escherichia coli and gram-positive infection withorganisms such as Staphylococcus aureus or group A streptococci can present asintractable hypotension and multiorgan failure. Treatment can usually be initiatedempirically on the basis of the presentation (Table 265-3). Adjunctive therapy witheither drotrecogin alfa (activated) or glucocorticoids should be considered forpatients with severe sepsis. Overwhelming Infection in Asplenic Patients (See also Chap. 265) Patients without splenic function are at risk foroverwhelming bacterial sepsis. Asplenic adult patients succumb to sepsis at 58times the rate of the general population; 50–70% of cases occur within the first 2years after splenectomy, with a mortality rate of up to 80%, but the increased riskpersists throughout life. In asplenia, encapsulated bacteria cause the majority ofinfections. Adults, who are more likely to have antibody to these organisms, are atlower risk than children. Streptococcus pneumoniae is the most common isolate,causing 50–70% of cases, but the risk of infection with Haemophilus influenzae orNeisseria meningitidis is also high. Severe clinical manifestations of infectionsdue to E. coli, S. aureus, group B streptococci, P. aeruginosa, Capnocytophaga,Babesia, and Plasmodium have been described. Babesiosis (See also Chap. 204) A history of recent travel to endemic areas raises thepossibility of infection with Babesia. Between 1 and 4 weeks after a tick bite, thepatient experiences chills, fatigue, anorexia, myalgia, arthralgia, shortness ofbreath, nausea, and headache; ecchymosis and/or petechiae are occasionally seen.The tick that most commonly transmits Babesia, Ixodes scapularis, also transmitsBorrelia burgdorferi (the agent of Lyme disease) and Ehrlichia; co-infection canoccur, resulting in more severe disease. Infection with the European speciesBabesia divergens is more frequently fulminant than that due to the U.S. speciesBabesia microti. B. divergens causes a febrile syndrome with hemolysis, jaundice,hemoglobinemia, and renal failure and is associated with a mortality rate of >50%.Severe babesiosis is especially common in asplenic hosts but does occur in hostswith normal splenic function, particularly at >60 years of age. Complicationsinclude renal failure, acute respiratory failure, and DIC. Other Sepsis Syndromes Tularemia (Chap. 151) is seen throughout the United States but occursprimarily in Arkansas, Oklahoma, and Missouri. This disease is associated withwild rabbit, tick, and tabanid fly contact. The uncommon typhoidal form can beassociated with gram-negative septic shock and a mortality rate of >30%. In theUnited States, plague (Chap. 152) occurs primarily in New Mexico, Arizona, andColorado after contact with ground squirrels, prairie dogs, or chipmunks. Plaguecan occur with greater frequency outside the United States, especially indeveloping countries in Africa and Asia. The septic form is particularly rare and isassociated with shock, multiorgan failure, and a 30% mortality rate. These rareinfections should be considered in the appropriate epidemiologic setting. TheCenters for Disease Control and Prevention lists tularemia and plague, along withanthrax, as important agents that might be used for bioterrorism (Chap. 214).