Awatif Jamal, MD, MSc, FRCPC, FIAC Consultant & Associate Professor Department of Pathology King...

Awatif Jamal, MD, MSc, FRCPC, FIAC Consultant & Associate Professor

Department of PathologyKing Abdulaziz University Hospital

Hemodynamic Hemodynamic Disorders Disorders

Thrombosis & ShockThrombosis & Shock

ShockShock ShockShock

Shock Shock or cardiovascular or cardiovascular

collapsecollapseShock constitutes systemic hypo perfusionShock constitutes systemic hypo perfusion due todue to

reduction either in : reduction either in : --cardiac output --cardiac output

--or in the effective circulating blood --or in the effective circulating blood volume.volume.

It is the common final pathway for a number It is the common final pathway for a number ofof

potentially lethal events including ;potentially lethal events including ;

severe hemorrhage severe hemorrhage Extensive traumaExtensive trauma

Severe burnsSevere burnsLarge myocardial infarctionLarge myocardial infarction

Massive pulmonary embolismMassive pulmonary embolismMassive microbial sepsis.Massive microbial sepsis.

Shock Shock or or cardiovascular collapsecardiovascular collapse

The The end end resultsresults are: are: 1.Hypotension1.Hypotension, followed by , followed by

2.Impaired Tissue Perfusion2.Impaired Tissue Perfusion

3.Cellular Hypoxia3.Cellular Hypoxia

4. Hypoxic and metabolic effects of 4. Hypoxic and metabolic effects of

hypoperfusion causes initially reversible hypoperfusion causes initially reversible

cell injury.cell injury.

5. Persistence of shock causes irreversible 5. Persistence of shock causes irreversible

cell injury, even to death of patient.cell injury, even to death of patient.

ShockShock Shock or “cardiovascular collapse” Shock or “cardiovascular collapse”

could be grouped into three Main could be grouped into three Main

Categories: Categories: Cardiogenic shock Cardiogenic shock

Hypovolemic shockHypovolemic shock

Septic shockSeptic shock

Others: Others: Neurogenic Shock (spinal cord injury)Neurogenic Shock (spinal cord injury)

Anaphylactic ShockAnaphylactic Shock

Cardiogenic ShockCardiogenic Shock

Results From Severe Myocardial Pump Results From Severe Myocardial Pump

Failure Failure Due toDue to:: Myocardial Infarction Myocardial Infarction

Ventricular ArrhythmiaVentricular Arrhythmia

Extrinsic Compression (Cardiac Extrinsic Compression (Cardiac

Tamponade)Tamponade)

Outflow Obstruction (Pulmonary Embolism)Outflow Obstruction (Pulmonary Embolism)

Hypovolemic ShockHypovolemic Shock

Results From Loss of Blood or Results From Loss of Blood or

Plasma Volume:Plasma Volume: HemorrhageHemorrhage

Fluid loss from severe burns or traumaFluid loss from severe burns or trauma

NEUROGENIC NEUROGENIC SHOCKSHOCK

In case of spinal cord injury or In case of spinal cord injury or anesthetic accident which can lead anesthetic accident which can lead to;to;

Loss of vascular toneLoss of vascular tone And peripheral pooling of bloodAnd peripheral pooling of blood

ANAPHYLACTIC ANAPHYLACTIC SHOCKSHOCK

Initiated by generalized Ig E-Initiated by generalized Ig E-mediated hypersensitivity reaction mediated hypersensitivity reaction associated with systemic associated with systemic vasodilatation and increased vasodilatation and increased vascular permeability.vascular permeability.

Septic ShockSeptic ShockMost common cause of death in ICU’s in the USMost common cause of death in ICU’s in the US

The incidence is increasing due to;The incidence is increasing due to;

Improved life support for high-risk patientsImproved life support for high-risk patients

Increased invasive proceduresIncreased invasive procedures

Increasing number of immunocompromized Increasing number of immunocompromized

cases as HIV infection, secondary to cases as HIV infection, secondary to

chemotherapy, and immunosuppression.chemotherapy, and immunosuppression.

Caused by systemic microbial infection; most Caused by systemic microbial infection; most

often by often by endotoxins-producingendotoxins-producing gram-negative gram-negative

bacilli infection (endotoxic shock) [in 70% of bacilli infection (endotoxic shock) [in 70% of

cases], but can also occur with gram-positive and cases], but can also occur with gram-positive and

fungal infectionsfungal infections

Pathogenesis Of Endotoxic Pathogenesis Of Endotoxic [Septic] Shock[Septic] Shock

EndotoxinsEndotoxins are are bacterial wall bacterial wall

lipopolysaccharides (LPS)lipopolysaccharides (LPS) which which

consists of ;consists of ;

--a toxic fatty acid (lipid A) core and --a toxic fatty acid (lipid A) core and

--a complex polysaccharide coat.--a complex polysaccharide coat.

LPS are released when the cell walls areLPS are released when the cell walls are

degraded in an inflammatory response.degraded in an inflammatory response.

Pathogenesis Of Endotoxic Pathogenesis Of Endotoxic [Septic] Shock[Septic] Shock

Free LPS attaches to circulating LPS- binding Free LPS attaches to circulating LPS- binding proteins,proteins,

It will then bind to a receptor ( CD14) in It will then bind to a receptor ( CD14) in macrophages , monocytes, and neutrophils macrophages , monocytes, and neutrophils leading to their activation and production of leading to their activation and production of TNF, and IL-1.TNF, and IL-1.

Depending on the dose and number of Depending on the dose and number of macrophages that are activated ,the macrophages that are activated ,the secondary effects of LPS release can cause secondary effects of LPS release can cause severe pathologic changes including the fatal severe pathologic changes including the fatal shock.shock.

Pathogenesis Of Septic Pathogenesis Of Septic ShockShock

High quantities of LPSHigh quantities of LPS

systemic vasodilatation (systemic vasodilatation (hypotensionhypotension))

diminished cardiac contractility (diminished cardiac contractility (low cardiac low cardiac

outputoutput))

endothelial injury and activation endothelial injury and activation leukocyte leukocyte

adhesionadhesion

activation of coagulation system ( activation of coagulation system ( Disseminated Disseminated

Intravascular CoagulopathyIntravascular Coagulopathy))

adult respiratory distress syndrome ( adult respiratory distress syndrome ( ARDSARDS))

multiorgan system failure and deathmultiorgan system failure and death

Stages of Shock:Stages of Shock:Shock is a progressive disorder that evolves through Shock is a progressive disorder that evolves through

3 stages, and if uncorrected will lead to death.3 stages, and if uncorrected will lead to death.

Initial “Non-progressive stage”:Initial “Non-progressive stage”: Reflex compensatory mechanism activation Reflex compensatory mechanism activation

maintain perfusion of vital organs through maintain perfusion of vital organs through maintenance of cardiac output and blood maintenance of cardiac output and blood pressure.pressure.

C/P; tachycardia,C/P; tachycardia, peripheral vasoconstriction ,cold skin, pallor peripheral vasoconstriction ,cold skin, pallor

(although septic shock may be associated with (although septic shock may be associated with inflammation and hotness)inflammation and hotness)

ShockShock

Stages of ShockStages of Shock

Irreversible stage:Irreversible stage: Severe cellular and tissue injury Severe cellular and tissue injury thus survival thus survival

is not possibleis not possible Acute renal tubular necrosisAcute renal tubular necrosis Adult respiratory distress syndrome ( ARDS )Adult respiratory distress syndrome ( ARDS ) Bowel ischemia and release of its flora.Bowel ischemia and release of its flora. Disseminated Intravascular CoagulopathyDisseminated Intravascular Coagulopathy

““Progressive stage:Progressive stage: tissue hypo perfusion with widespread hypoxia tissue hypo perfusion with widespread hypoxia

circulatory & metabolic imbalance.circulatory & metabolic imbalance. C/P: patient is confusedC/P: patient is confused Reduced urine output.Reduced urine output.

Disseminated Intravascular Disseminated Intravascular Coagulation (DIC)Coagulation (DIC)

Sudden widespread fibrin deposition in Sudden widespread fibrin deposition in

microcirculationmicrocirculation

Rapid consumption of platelets and coagulation Rapid consumption of platelets and coagulation

proteins proteins (consumption coagulopathy)(consumption coagulopathy)

Secondary massive fibrinolysisSecondary massive fibrinolysis, all the little , all the little

thrombi dissolvethrombi dissolve

Clotting disorder turns into a Clotting disorder turns into a Bleeding Bleeding

DisasterDisaster