STAGES OF SHOCK

Shock is progressive disorder that if uncorrected leads to death
Shock evolves through 3 phases

Initial non-progressive phase
Progressive phase
Irreversible stage

Initial non-progressive phase

Compensatory mechanism to maintain the homeostasis so that blood supply to vital organs is maintained
By neuro humoral mechanism which maintains blood pressure and cardiac output
Widespread vasoconstriction of vessels except coronary and cerebral vessels
Fluid conservation by kidney
Tachycardia

Progressive phase

As the stage advances there is failure of compensatory mechanism, dilatation of arterioles, veinules and capillary bed
Because of this fluid leaks out of capillaries into interstitium and there is sludging of blood
This reduces the tissue perfusion leading to hypoxia
Initially body tissue except brain and heart suffers from hypoxia

IRREVERSIBLE PHASE (DECOMPENSATED STAGE)

Cellular injury and tissue injury is so severe that condition does not revert back to normal even after correcting hemodynamic defects
Hypoxic and ischemic cell injury – causes leakage of lysosomal enzymes which further aggravates condition
Myocardial infarction and synthesis of NO further worsens condition
Intestinal ischemia causes microbes from intestinal flora to enter the circulation which produces superimposed bacteremic shock
Acute tubular necrosis occurs in kidney

Signs and symptoms in different phases

Compensated phase

15 to 25% of fluid loss from vessels and there are subtle signs of shock
Mean arterial pressure will be less than 10-15mm Hg from the baseline
Increased Renin and Anti-diuretic hormone secretion
Vasoconstriction
Increased heart rate
Decreased pH

Intermediate phase

25 to 35% of fluid loss from vessels and classical signs of shock appears
Mean arterial pressure is less than 20mmHg from Base line
Tissue hypoxia develops
Decreased urine output (oliguria)
Weak rapid pulse
Decreased pH

Irreversible phase

>35% of fluid loss from vessels, body cells die to hypoxia and vital signs come to bottom
Anuria
Excessive organ or tissue damage
Multi organ failure
Decreased pH

STAGES OF SHOCK

Shock is progressive disorder that if uncorrected leads to death

Shock evolves through 3 phases

Progressive phase

Irreversible stage

Initial non-progressive phase

Compensatory mechanism to maintain the homeostasis so that blood supply to vital organs is maintained

By neuro humoral mechanism which maintains blood pressure and cardiac output

Widespread vasoconstriction of vessels except coronary and cerebral vessels

Fluid conservation by kidney

Tachycardia

Progressive phase

As the stage advances there is failure of compensatory mechanism, dilatation of arterioles, veinules and capillary bed

Because of this fluid leaks out of capillaries into interstitium and there is sludging of blood

This reduces the tissue perfusion leading to hypoxia

Initially body tissue except brain and heart suffers from hypoxia

IRREVERSIBLE PHASE (DECOMPENSATED STAGE)

Cellular injury and tissue injury is so severe that condition does not revert back to normal even after correcting hemodynamic defects

Hypoxic and ischemic cell injury – causes leakage of lysosomal enzymes which further aggravates condition

Myocardial infarction and synthesis of NO further worsens condition

Intestinal ischemia causes microbes from intestinal flora to enter the circulation which produces superimposed bacteremic shock

Acute tubular necrosis occurs in kidney

Signs and symptoms in different phases

Compensated phase

15 to 25% of fluid loss from vessels and there are subtle signs of shock

Mean arterial pressure will be less than 10-15mm Hg from the baseline

Increased Renin and Anti-diuretic hormone secretion

Vasoconstriction

Increased heart rate

Decreased pH

Intermediate phase

25 to 35% of fluid loss from vessels and classical signs of shock appears

Mean arterial pressure is less than 20mmHg from Base line

Tissue hypoxia develops

Decreased urine output (oliguria)

Weak rapid pulse

Decreased pH

Irreversible phase

>35% of fluid loss from vessels, body cells die to hypoxia and vital signs come to bottom

Anuria

Excessive organ or tissue damage

Multi organ failure

Decreased pH

References

Vinay kumar, Abul K.Abbas, Nelson Fausto, Jon C. Aster. Robbins and Cotran Pathologic basis of disease. 8th edition