eMedicine Specialties > Infectious Diseases > Bacterial Infections

Sepsis, Bacterial

Author: Burke A Cunha, MD, Professor of Medicine, State University of New York School of Medicine at Stony Brook; Chief, Infectious Disease Division, Winthrop-University Hospital
Contributor Information and Disclosures

Updated: Oct 19, 2009

Introduction

Background

Sepsis is a clinical term used to describe symptomatic bacteremia, with or without organ dysfunction. Sustained bacteremia, in contrast to transient bacteremia, may result in a sustained febrile response that may be associated with organ dysfunction. Septicemia refers to the active multiplication of bacteria in the bloodstream that results in an overwhelming infection.

Pathophysiology

The pathophysiology of sepsis is complex and results from the effects of circulating bacterial products, mediated by cytokine release, caused by sustained bacteremia. Cytokines, previously termed endotoxins, are responsible for the clinically observable effects of the bacteremia in the host. Impaired pulmonary, hepatic, or renal function may result from excessive cytokine release during the septic process.

Frequency

United States

Sepsis is an overused term often misapplied to patients with fever, leukocytosis, and hypotension due to other causes, including pseudosepsis. True sepsis is a common cause of hospitalization in the United States. Frequent sources of infection are listed in History.

International

Sepsis is a common cause of mortality and morbidity worldwide.

Mortality/Morbidity

The prognosis of sepsis depends on the underlying status and host defenses, prompt and adequate surgical drainage of abscesses, relief of any obstruction of the intestinal or urinary tract, and appropriate and early empiric antimicrobial therapy with the drug spectrum appropriate to the presumed septic source.

Race

Sepsis does not appear to have a racial predisposition.

Sex

Sepsis does not appear to have a sexual predisposition.

Age

Elderly men are more likely to develop urosepsis due to benign urinary tract obstruction caused by prostatic hypertrophy.

Clinical

History

  • The patient’s history is essential in determining the likely source of the septic process. This, in turn, determines the appropriate antimicrobial therapy.
  • Sources of infection
    • Suspect intravenous-line infections when other sources of sepsis are eliminated and the intravenous line has been in place for a prolonged period, usually more than one week. Central intravenous lines are the lines most commonly associated with bacteremia or sepsis. Peripheral venous lines are almost never involved, and arterial lines are rarely associated with bacteremia, although it can still occur.
    • Patients with an intra-abdominal or pelvic source of infection usually have a history of antecedent conditions that predispose to perforation or abscess (eg, chronic or retrocecal subacute appendicitis, diverticulitis, Crohn disease, previous abdominal surgery, cholecystitis).
    • The urinary tract source is suggested by an antecedent history of pyelonephritis, stone disease, congenital abnormal collecting system, prostate enlargement, or previous prostate or renal surgery.
  • Patients with diabetes, systemic lupus erythematosus (SLE), or alcoholism or who are taking steroids are also at an increased risk for bacteremia.
  • Patients with nonspecific symptoms are usually acutely ill with fever, with or without shaking chills. Mental status may be impaired in the setting of fever or hypoperfusion.

Physical

  • Physical examination
    • This may be helpful in suggesting a potential source for sepsis. An infected central intravenous-line site immediately suggests the probable etiology. However, it is important to note that only 50% of patients with central intravenous-line infections have evidence of infection at the insertion site.
    • Right upper abdominal quadrant tenderness may suggest gallbladder etiology (eg, cholecystitis, cholangitis).
  • Diffuse abdominal pain suggests pancreatitis (not sepsis) or generalized peritonitis.
  • Discrete tenderness over the left lower abdominal quadrant suggests diverticulitis, particularly in elderly patients.
  • Tenderness in the right lower abdominal quadrant in a young adult suggests appendicitis or Crohn disease.
  • A rectal examination may reveal exquisite tenderness due to prostatic abscess or, more commonly, an enlarged noninflamed prostate suggestive of benign prostatic hypertrophy (BPH).
  • Costovertebral angle (CVA) tenderness with a temperature of 102°F defines acute pyelonephritis. Subacute or chronic pyelonephritis may manifest as only mild tenderness.
  • Patients with bacteremia from any source often display an increased breathing rate due to respiratory alkalosis.
  • The skin of patients with sepsis may be warm or cold, depending on the adequacy of organ perfusion and dilatation of the superficial vessels of the skin.
  • In many cases, the history is critical for diagnosis, and abdominal findings on physical examination may be unimpressive or absent.

Causes

  • Sepsis or septic shock may be associated with the direct introduction of microbes into the bloodstream via intravenous infusion (eg, intravenous line, other device-associated infections).
  • An intra-abdominal or pelvic structure may be perforated, compromised, or ruptured.
  • Bacteremia due to bacteruria (urosepsis) may complicate cystitis in compromised hosts. Intrarenal infection (pyelonephritis), renal abscess (intrarenal or extrarenal), acute prostatitis, or prostatic abscess may cause urosepsis in immunocompetent hosts.
  • Sepsis is not a random occurrence and is usually associated with the conditions discussed above.
  • Sepsis may be caused by overwhelming pneumococcal infection in patients with impaired or absent splenic function.
  • Meningococcemia from a respiratory source may also result in sepsis, with or without associated meningitis.

More on Sepsis, Bacterial

Overview: Sepsis, Bacterial
Differential Diagnoses & Workup: Sepsis, Bacterial
Treatment & Medication: Sepsis, Bacterial
Follow-up: Sepsis, Bacterial
References
Further Reading
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Further Reading

Additional resources on sepsis are available at Medscape's Sepsis Resource Center.

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Keywords

sepsis, bacterial sepsis, urosepsis, septic shock, bacteremia, symptomatic bacteremia, septicemia, leukocytosis, pseudosepsis, bacteruria

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Contributor Information and Disclosures

Author

Burke A Cunha, MD, Professor of Medicine, State University of New York School of Medicine at Stony Brook; Chief, Infectious Disease Division, Winthrop-University Hospital
Burke A Cunha, MD is a member of the following medical societies: American College of Chest Physicians, American College of Physicians, and Infectious Diseases Society of America
Disclosure: Nothing to disclose.

Medical Editor

Pranatharthi Haran Chandrasekar, MD, Director of Infectious Disease Fellowship, Professor, Department of Internal Medicine, Harper Hospital, Wayne State University School of Medicine
Pranatharthi Haran Chandrasekar, MD is a member of the following medical societies: American College of Physicians and Infectious Diseases Society of America
Disclosure: Nothing to disclose.

Pharmacy Editor

Francisco Talavera, PharmD, PhD, Senior Pharmacy Editor, eMedicine
Disclosure: eMedicine Salary Employment

Managing Editor

Thomas M Kerkering, MD, Chief of Infectious Diseases, Virginia Tech, Carilion School of Medicine, Roanoke, Virginia
Thomas M Kerkering, MD is a member of the following medical societies: Alpha Omega Alpha, American College of Physicians, American Public Health Association, American Society for Microbiology, American Society of Tropical Medicine and Hygiene, Infectious Diseases Society of America, Medical Society of Virginia, and Wilderness Medical Society
Disclosure: Nothing to disclose.

CME Editor

Eleftherios Mylonakis, MD, Clinical and Research Fellow, Department of Internal Medicine, Division of Infectious Diseases, Massachusetts General Hospital
Eleftherios Mylonakis, MD is a member of the following medical societies: American Association for the Advancement of Science, American College of Physicians, American Society for Microbiology, and Infectious Diseases Society of America
Disclosure: Nothing to disclose.

Chief Editor

Michael Stuart Bronze, MD, Professor, Stewart G Wolf Chair in Internal Medicine, Department of Medicine, University of Oklahoma Health Science Center
Michael Stuart Bronze, MD is a member of the following medical societies: Alpha Omega Alpha, American College of Physician Executives, American College of Physicians, American College of Physicians-American Society of Internal Medicine, American Federation for Clinical Research, American Medical Association, American Society for Microbiology, Association of Professors of Medicine, Association of Program Directors in Internal Medicine, Infectious Diseases Society of America, Oklahoma State Medical Association, and Southern Society for Clinical Investigation
Disclosure: Nothing to disclose.

 
 
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