cme: sepsis pathogenesis - host factors

By:

Dr JAMI SWATHI

Under the guidance of Prof Dr CHENTHIL

SEPSIS

PATHOGENESIS-

HOST DERIVED MECHANISMS

WHAT IS SEPSIS???.....

Sepsis is the systemic maladaptive response of the host organism to the invasion of normally sterile tissue, fluid or body cavity by pathogenic or potentially pathogenic microorganisms

HOST RESPONSE

Recruitment of inflammatory cells

Cytokine release

Activation of coagulation system

Neutrophil- endothelial cell interactions

Role of Nitric Oxide

RECRUITMENT OF INFLAMMATORY CELLS

CYTOKINES

Pro inflammatory cytokines: predominate in the early phases of sepsis

Anti inflammatory cytokines: prevail in the later phase

ROLE OF LYMPHOCYTES

Participate mainly in the late phase of sepsis

Play a role in the production of both pro inflammatory & anti- inflammatory cytokines

CD4 lymphocytes play a major role

Outcome of sepsis depends nature of the lymphocyte response (expression of Th1 or Th2)

COAGULATION SYSTEM Extrinsic pathway is predominantly activated

activation of intravascular coagulation results in microthrombi formation

multi organ failure

NEUTROPHIL- ENDOTHELIAL CELL INTERACTIONS

• Neutrophil activation & degranulation exposes the endothelium to reactive O2

species, NO & proteases

• leads both to microbial clearance & diffuse endothelial injury

NITRIC OXIDESynthesized in the presence of TNF-α, IL-1,

LPS

Initiates vasodilatation

Responsible for increased neutrophil and platelet adherence

Intracellular killing

Lipid peroxidation

Enzyme inhibition

THANK YOU