Blood Poisoning (Sepsis): Causes

Pathogenesis (development of disease)

Sepsis refers to a life-threatening organ dysfunction due to a dysregulated body response to infection. It is triggered by infections with pathogens of all types (bacteria, their toxins, viruses, or fungi), especially Staphyloccocus aureus or E. coli; furthermore with anaerobes, Clostridium difficile, Clostridium perfringens, Enterobacter, Enterococci, Haemophilus influenzae, coagulase-negative Staphylococci, Pneumococci, Pseudomonas, Streptococcus agalacticae, Streptococcus pneumoniae, Streptococcus pyogenes, Streptococcus, Streptococcus group A, Streptococcus group B, or Streptococcus group D. Urosepsis is most commonly caused by enterobacteria: E. coli (52%), Proteus spp, Enterobacter spp, Klebsiella spp, P. aeruginosa, and gram-positive bacteria such as enterococci (5%). Common sites of infection in community-acquired sepsis are:

  • Lower respiratory tract (e.g., pneumonia/pneumonia, pleural empyema/accumulation of pus (empyema) within the pleura, that is, between the two pleural leaves)
  • Gastrointestinal tract (e.g., intra-abdominal abscess, cholangitis/bile duct inflammation, diverticulitis/disease of the large intestine in which inflammation forms in protrusions of the mucosa (diverticula))
  • Genitourinary tract (about 80% of cases obstructive uropathy/disturbed urinary flow due to obstruction of the urinary tract: e.g., pyelonephritis/renal pelvic inflammatory disease with obstruction; note: the most common cause of urosepsis is pyelonephritis). → Urosepsis (9-31% of all septicaemia results from infection of the genitourinary tract and male genital tract).

In the course of infection, sepsis results in the release of pathogen products, so-called PAMPs (“pathogen-associated molecular patterns”, e.g. bacteria) and/or endogenous signaling molecules (so-called DAMPs), which affect effector cells (e.g. vascular and tissue cells, blood and lymphoid cells). This in turn leads to a massive release of mediators (e.g. CRP, PCT, TNF-α, IL-2, IL-6, IL-8), which has an impact on all organ functions (for more information, see secondary diseases). Fulminant courses are:

  • Meningococcal sepsis – sepsis caused by the bacterium Neisseria meningitidis.
  • OPSI-syndrome (overwhelming post splenectomy infection syndrome) – sepsis after splenectomy (splenectomy).
  • Toxic shock syndromes (toxic shock syndrome, TSS; synonym: tampon disease) – severe circulatory and organ failure due to bacterial toxins (usually enterotoxin of the bacterium Staphylococcus aureus, more rarely streptococci, then called streptococcal-induced toxic shock syndrome).
  • Severe cases of sepsis with high lethality (mortality) are caused, among others, by the pathogen Vibrio vulnificus (V. vulnificus). Vibrio vulnificus is a gram-negative bacterium of the Vibrionaceae family, which is obligate halophilic (salt-loving). Gastrointestinal symptoms may occur after oral ingestion of raw infected seafood; in addition, sudden fever and chills associated with multiple skin and soft tissue infections (bullae (fluid-filled cavities), ecchymoses (small area bleeding of skin or mucous membranes), necrotizing fasciitis: oudroyant life-threatening infection of the skin, subcutis (subcutaneous tissue), and fascia with progressive gangrene) that are metastatic-especially to the lower extremity-are observed. In addition to anti-infective therapy, immediate focal sanitation of the skin and tissue infection (e.g., fasciitis) is required.

Gender differences (gender medicine).

  • Triggers of sepsis:
    • Men: mostly upper respiratory tract infections
    • Women: mostly infections of the genitourinary tract.
  • Gram-positive or Gram-negative pathogens:
    • Men: predominantly Gram-positive pathogens
    • Women: predominantly gram-negative pathogens

Etiology (causes)

Biographical causes

  • Age
    • Youngest have the lowest risk of sepsis, oldest the highest
    • Study retrospectively examined how antibiotic prescription or nonprescription affected sepsis risk in patients who saw a primary care physician:
      • Without antibiotic therapy: sepsis rate of 15- to 24-year-olds at 1:9,900 (men, M) or 1:12,500 (women, F); 85 years and older: 1:215 (M) or 1:321 (F).
      • With antibiotic therapy: sepsis rate of 15- to 24-year-olds at 1:24,390 (M) or 1:41,667 (F) ; 1:1200 (M) or 1:1964 (F) from 85 years: 1:1,200 (M) or 1:1,964 (F), respectively.
      • The highest risk of sepsis was for urinary tract infections, followed by skin and lastly respiratory tract infections.

Disease-related causes

Infectious and parasitic diseases (A00-B99).

  • Infection with pathogens (see above ), unspecifiedZ. B. urinary tract infection and concomitant eGFR (estimated GFR, the estimated glomerular filtration rate) < 45 ml/min/1.73 m2; mortality (death rate) was increased by 63% in patients with eGFR < 30 ml/min/1.73 m2 compared with those with normal or only mildly impaired renal function.

Medications

Operations

  • Postoperative (usually the result of an infection acquired during surgery).
  • Zust. n. splenectomy (splenectomy).