Sepsis - Under The MicroscopeA closer look at the causes, symptoms and risks.

Sepsis is a serious medical condition caused by the body's systemic response to either a local or systemic infection.1,2 Sepsis is a leading cause of death worldwide.3-5

Pathogens associated with sepsis include:4

  • Bacteria (typically the most common agent)
  • Fungi
  • Parasites
  • Viruses 

An early diagnosis of sepsis can significantly improve outcomes through clinical interventions such as antibiotic administration and hemodynamic and organ support.6-8 Early identification of at-risk patients, early diagnosis, and appropriate therapy are daily challenges for clinicians based in the emergency department and other hospital departments because the signs and symptoms of sepsis are nonspecific, and thus it may be missed or confused with other medical conditions. The often rapid onset of sepsis can impede early diagnosis, reducing the critical window for implementation of effective therapeutic measures.6

Infection site



  • Viral or bacterial pneumonia


  • Acute appendicitis (rupture risk)
  • Gastrointestinal disorders (can allow leakage of intestinal bacteria into the abdomen)
  • Peritonitis (infection of the abdominal cavity),
  • Pancreatitis
  • Gallbladder or liver infections
  • Postsurgical infections
  • Trauma

Urinary tractc

  • Bladder infection
  • Kidney infection
  • Temporary or indwelling catheter (for bladder drainage)


  • Skin wounds
  • Skin inflammation
  • Cellulitis (inflammation of the skin's connective tissue)
  • Intravenous (IV) catheters (tubes inserted into the body to administer or drain fluids)

Central nervous system

  • Viral or bacterial meningitis
  • Viral or bacterial encephalitis

Cardiovascular system

  • Infectious endocarditis
  • Ischemia (inadequate blood supply) resulting in infection, leading to gangrene
  • Septicemia (blood infection)

NICE Clinical Definition of Sepsis18

Sepsis is defined as life-threatening organ dysfunction caused by a dysregulated host response to infection.

Early detection and specific clinical intervention have been shown to be crucial for the improved outcome of patients with sepsis.8 However, sepsis can be difficult to distinguish from other, non-infectious conditions in patients with clinical signs of inflammation, delaying therapeutic decision making.

Once a patient is in septic shock, survival rates can drop 7.6% for every hour that antibiotic therapy is delayed6. Up to 72 hours may elapse before microbiological culture results are available, and false negatives are common. In addition, an infectious agent may never be identified in a large percentage of patients.10,11

Sepsis exacts a high toll in the UK:

  • At least 245,000 cases each year19
  • Up to 48,000 deaths each year19
  • Nearly 80,000 people each year suffer life-changing after-effects that could include one or more of cognitive, psychological or physical sequelae19

Patients may suffer significant morbidities including:

  • amputation (single or multiple)
  • irreversible organ damage
  • reduced quality of life
  • reduced life expectancy13

Sepsis biomarker testing has been shown to significantly improve clinical decision making.14,15

Sepsis can occur at any age:

  • The greatest risk occurs among the elderly and the newborn3,4
  • Sepsis is more likely to occur if the patient already has an underlying disease
  • Sepsis can develop rapidly in previously healthy people15
  • The incidence of sepsis is increasing by approximately 1.5% per year, and is expected to continue growing as the population ages3.

Neonatal Sepsis17

Sepsis in newborns can be particularly difficult to recognize and diagnose. Signs and symptoms are less specific than in adults, and interpretation may be highly subjective. Symptoms can include:

  • Diminished activity
  • Less vigorous sucking
  • Apnea
  • Bradycardia
  • Temperature instability

Unlike older children and adults, only 10–50% of newborns may be consistently febrile for over 1 hour.

  • Early-onset sepsis occurs within 7 days of birth, but onset most commonly occurs within 6 hours of birth
  • Early-onset sepsis can occur in infants infected by pathogenic organisms infecting the mother’s birth canal or genitalia
  • Pneumonia is a danger for infants who aspirate meconium as a complication of labor
  • Late-onset sepsis (developing between 7 and 28 days after birth) is usually acquired from the environment
  • Preterm infants, especially very low birth-weight babies, are at particular risk from infections acquired through invasive procedures and devices (e.g., venous or urinary catheters, ventilators, etc.)
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