1. Shock

2. Definition
Failure of circulation, that leads to inadequate tissue perfusion.
Despite the compensatory mechanisms tissue hypoxia is developed.
Tissue hypoxia leads to functional and morfological changes in organs.
The result of untreated shock is irreversible organ failure and death.

3. Pathomechanisms different mechanisms all leads to:
decrease in return of blood to the heart
decrease in cardiac minute output
hypotension
hypoperfusion of peripheral tissues

4. Stages of shock 1. stage – reversible, compensated
response of compensatory mechanisms
activation of SAS – peripheral vasoconstriction (skin, kidneys), vasodilatation in „central“ organs (brain, heart)
RAAS activation
increased ADH secretion

5. Stages of shock 2. stage – developed, decompensated
failure of compensatory mechanisms
microcirculation failure
increased blood viscosity, higher platelets agregation, thrombosis
higher concentration of vasoactive mediators (histamine, bradykinin...) – higher permeability
metabolic (lactate) acidosis

6. Stages of shock 3. stage - irreversible cell damage
MODS (multiple organ dysfunction syndrome)
ARDS – „shock“ lungs
acute kidney failure
acute liver failure
loss of consciousness, coma,
DIC
ulcers, bleeding in GIT
...

7. Types of shock hypovolemic shock haemorrhagic - bleeding
nonhaemorrhagic – GIT – diarhea, vomiting; kidneys – treatment with diuretics, DM; skin - burns
cardiogenic shock
inadequate contractility – acute MI, myocarditis, cardiomyopathies
arrhythmias
mechanical obstruction – acute valves dysfunction, rupture of ventricular septum, cardiac tamponade
distributive shock
septic – toxic
anaphylactic
neurogenic – CNS, spinal cord damage

8. Clinical signs low minute cardiac output SAS activation
hypotension
SAS activation
tachycardia
sweating
piloerection
cold, pale skin
inadequate peripheral perfusion
cyanosis
oliguria
unconsciousness
muscle weakness

9. Hypovolemic shock deficiency in volume of extracelular fluid
most frequent – haemorrhagic shock
bleeding
traumatic shock – bleeding + pain
other – nonhaemorhagic shock
GIT – diarhea, vomiting
kidneys – treatment with diuretics, patient with diabetes mellitus
skin – burns (burn shock)

10. Cardiogenic shock heart failure reduced cardiac output
inadequate contractility – acute MI, myocarditis, cardiomyopathies
arrhythmias – ventricular tachycardia, supraventricular tachycardia, atrial fibrilation, AV block - bradycardia, WPW syndrome
mechanical obstruction – acute valves dysfunction, acute rupture of ventricular septum in MI, cardiac tamponade...

11. Anaphylactic shock accelerated allergic reaction
increase of vasoactive mediators – histamine – marked vasodilatation
8 – 10% - lethal
signs
itching, nausea, erythema, dyspnoe
larynx oedema, bronchospasm
circulation failure, unconsciousness, cramps

12. Septic shock Neurogenic shock bakterial, virus infection
release of vasoactive mediators – permeability, vasodilatation
platelets adhesion and agregation
acute damage of brain or spinal cord
inflammation, trauma, bleeding, anaesthesia
loss of vasomotoric regulation  marked vasodilatation
irritation of n. vagus  bradycardia,
damage of respiratory centre  hypoventilation
Neurogenic shock