Description

• Systemic inflammatory response syndrome (SIRS): nonspecific inflammatory response, defined as at least two of the following four criteria (one of which must be either abnormal temperature OR leukocyte count):
  • Temperature >38.5 or <36°C
  • Tachycardia (mean HR >2 SDs above normal for age)
  • Tachypnea (mean RR >2 SDs above normal for age), or requiring mechanical ventilation for acute respiratory failure
  • Leukocytosis, leukopenia, or >10% bands
• Sepsis: SIRS in the presence of infection
  • Infection: suspected or proven infection or clinical syndrome associated with high probability of infection
• Severe sepsis: sepsis accompanied by evidence of altered end organ perfusion (cardiovascular dysfunction OR acute respiratory distress syndrome [ARDS] OR two or more other organ dysfunctions)
• Septic shock: sepsis with cardiovascular dysfunction (hypotension, need for vasoactive drug to maintain normal BP, or any combination of altered mental status, unexplained metabolic acidosis, increased arterial lactate, oliguria, prolonged capillary refill, and core-to-peripheral temperature gap)

Epidemiology

Risk Factors

Sepsis may occur in previously healthy children, but children with chronic underlying conditions that render them immunosuppressed or vulnerable to invasive infections are at increased risk, including:

• Neutropenia (neutrophils <1,000/mm³, especially <500/mm³)
• Primary or acquired immunodeficiency (e.g., AIDS, severe combined immunodeficiency)
• Malignancy
• Organ transplant recipients
• Chronic use of high-dose systemic steroids
• Indwelling central venous catheters or other invasive devices (e.g., urinary catheter)
• Hyposplenism, either surgical or functional (e.g., sickle cell anemia)
• Neuromuscular disease (e.g., static encephalopathy)
• Extensive burns
• Multiple trauma injuries
• Prematurity
• Unimmunized/underimmunized children
• Severe malnutrition

General Prevention

• Routine vaccination for Haemophilus influenzae type b (Hib), Streptococcus pneumoniae, and Neisseria meningitidis particularly in high-risk patients (e.g., asplenia)
• Antibiotic prophylaxis for household or day care exposure to confirmed cases of Hib or N. meningitidis
• Antibiotic prophylaxis for children with asplenia
• Prompt evaluation of fever in immunosuppressed patients
• Aseptic technique for insertion and care of vascular catheters, minimizing duration of use

Etiology

• Microbial invasion of the bloodstream or release of microbial products/toxins into the bloodstream; stimulates host defense, resulting in activation of proinflammatory mediators and systemic inflammation
• Pathogens vary with age, host immune status, and setting (community or hospital).
• Neonates
  • Group B Streptococcus
  • Escherichia coli
  • Staphylococcus aureus
  • Listeria monocytogenes
  • Enterococcus spp.
  • Herpes simplex virus
  • Enterovirus
• In neonates with a history of hospitalization, instrumentation, or mechanical ventilation, also consider
  • Coagulase-negative staphylococci
  • Gram-negative bacilli
  • Candida spp.
• Otherwise healthy older infants and children
  • S. pneumoniae
  • N. meningitidis
  • S. aureus
  • Group A Streptococcus
  • Salmonella spp.
  • Rickettsiae
  • Influenza
• Patients with underlying immune defects are also susceptible to a broad range of additional organisms.