Sepsis

Sepsis is systemic inflammatory response syndrome (SIRS) due to an infectious process. Patients present with fever, tachycardia, and tachypnea. In severe sepsis, there is shock, confusion, and oliguria. The most common antecedent infection is pneumonia. Blood cultures are positive in 1/3 of cases.

CASES/YEAR
1,600,000 (US); 31,000,000 (Global)
CATEGORY
Localized Infections
AGENT TYPE
Bacteria
OTHER NAMES
Systemic inflammatory response syndrome (SIRS) due to infectious process;
ACUITY
Acute-Severe
INCUBATION
Estimated 1 day to several weeks;
INITIAL SYMPTOMS
Sepsis: fever, tachycardia, and tachypnea; Severe sepsis: shock, confusion, and oliguria; [Merck Manual, p. 2300-1]
PRECAUTIONS
COMMENTS
"Sepsis is life threatening organ dysfunction caused by a dysregulated host response to infection." Important sources are pneumonia, empyema, peritonitis, cholangitis, cellulitis, fasciitis, pyelonephritis, meningitis, primary bacteremia, and abscess. [Cecil, p. 651-2] Sepsis is the systemic inflammatory response of microbial etiology. Laboratory abnormalities may include leukocytosis, leukopenia, thrombocytopenia, prolonged thrombin time, decreased fibrinogen level, increased D-dimer level, azotemia, hyperbilirubinemia, transaminitis, and metabolic acidosis. The main complications are hypotension, ARDS, adrenal insufficiency, acute renal failure, coagulopathy, polyneuropathy, and immunosuppression. [Harrisons, 18th Ed, p. 74-6] In severe sepsis, thrombocytopenia is a frequent finding. Diffuse erythema is characteristic in toxic shock syndrome caused by S. aureus or S. pyogenes. [PPID, 8th Ed, p. 926-8] Reactivation of latent herpes simplex, varicella-zoster virus, and cytomegalovirus occurs in about 1/3 of patients with severe sepsis. Critical illness polyneuropathy is seen in patients with chronic septic illness. [Harrison ID, p. 198] Jaundice may occur in cases of severe sepsis, e.g., Listeria monocytogenes, Neisseria spp., and Pneumococcus infections. [Cohen, p. 1135t] Skin lesions include pustules, petechiae, bullae, cellulitis, gangrene, and ecchymotic areas that become necrotic and ulcerated. Blood-borne toxins may cause diffuse eruptions. [PPID, 8th Ed, p. 928] Muscle weakness, due to accelerated catabolism, is common in patients with systemic infections and sepsis. [PPID, p. 1315] Coagulation pathways are activated in sepsis, and DIC may result. Liver transaminases are elevated. Leukopenia signifies a poor prognosis. [Cohen, p. 415-23] Septic shock is severe sepsis plus refractory hypotension. [Merck Manual, p. 569] Sepsis, especially Gram-negative sepsis, may cause intermittent fever. [ID, p. 55]
DIAGNOSTIC
The most common antecedent infection is pneumonia. Blood cultures are positive in about 1/3 of cases. [Harrisons, p. 68]
SCOPE
Global
SIGNS & SYMPTOMS
  • >fatigue, weakness
  • >fever
  • >fever, biphasic or relapsing
  • >myalgia
  • G abdominal mass
  • G abdominal pain
  • G blood in stool
  • G diarrhea
  • G jaundice
  • G liver function test, abnormal
  • G nausea, vomiting
  • H anemia
  • H hemolysis
  • H leukocytosis
  • H leukopenia
  • H thrombocytopenia
  • N confusion, delirium
  • N headache
  • N lethargy
  • N muscle weakness
  • N stiff neck
  • R chest pain
  • R cough
  • R dyspnea
  • R sputum production
  • S papules or plaques
  • S petechiae and ecchymoses
  • S pustule
  • S rash (exanthem)
  • S skin blister or vesicles
  • S ulcer of skin
  • U pyuria
  • X lung infiltrates
  • X pleural effusions
  • *acute renal failure
  • *ARDS
  • *bleeding tendency
  • *endocarditis
  • *glomerulonephritis
  • *meningitis
  • *peripheral neuropathy
  • *pneumonia
  • *pulmonary edema
  • *rhabdomyolysis
  • *sepsis
  • *shock
  • *stupor, coma
ANTIMICROBIC

Yes

VACCINE

No

ENTRY
Inhalation, Ingestion, Needle (Includes Drug Abuse), Scalpel or Transfusion, Skin or Mucous Membranes (Includes Conjunctiva), Animal Bite, Swimming, Sexual Contact
VECTOR
Fleas, Biting Flies, Lice, Mites, Mosquitoes, Ticks
SOURCE
Person-to-Person, Human Fecal-Oral, Fecally Contaminated Soil, Animal Excreta, Animal Tissue, Soil or Dust (Ingesting or Inhaling), Eating Contaminated Food, Eating Contaminated or Infected Meat, Eating Infected or Toxin-Containing Fish, Eating Contaminated Mollusks or Crustacean, Eating Unpasteurized Milk or Cheese, Eating Contaminated Produce, Waterborne (Ingesting, Inhaling, or Swimming)
RESERVOIR
Birds and Poultry, Cattle, Goats and Sheep, Cats, Deer, Elk and Antelope, Dogs, Fish and Shellfish, Horses, Monkeys, Rabbits, Rodents, Swine, Human, Wild Animals
RISK FACTORS
  • AIDS patients
  • Cancer patients
DRUG LINK
Merck Manual: Sepsis and Septic Shock
REFERENCES FOR CASES/YEAR
1. (US) Incidence = global cases 31 million/20 = 1.6 million new cases in US every year; [5MCC-2020]
2. (Global) Global cases/yr = 31 million cases/yr; [5MCC-2020]