Vrodené poruchy metabolizmu
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Transcript Vrodené poruchy metabolizmu
Shock
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.
Pathomechanisms
different mechanisms
leading to:
Decrease in return of blood to the heart (!)
Decrease in cardiac output
Hypotension
Hypoperfusion of peripheral tissues
General activation of different neural, humoral
response at systemic, organ, tissue and cellular
level
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
And pro- and antiinflammatory cytokines as
procalcitonin and many others
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, the cytokines as a
double-edged sword
Metabolic (lactate) acidosis
Stages of shock
3. stage - irreversible
Cell damage, necrosis or apoptosis
MODS (multiple organ dysfunction syndrome)
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ARDS – „shock“ lungs
acute kidney failure
acute liver failure
loss of consciousness, coma,
DIC
ulcers, bleeding in GIT
...
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
(obstructive shock)
distributive shock
– septic – toxic
– anaphylactic
– neurogenic – CNS, spinal cord damage
Clinical signs
low minute cardiac output
– hypotension
SAS activation
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tachycardia
sweating
piloerection
cold, pale skin
inadequate peripheral perfusion
– cyanosis
– oliguria
– unconsciousness
– muscle weakness
Hypovolemic shock
Deficiency in volume of extracelular fluid
Most frequent form – haemorrhagic shock
– bleeding
– traumatic shock – bleeding + pain
other – nonhaemorhagic shock
– GIT – diarhea, vomiting
– kidneys – treatment with diuretics, patient with
diabetes mellitus
– burns (burn shock)
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...
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
Septic shock
bacterial, viral infection
release of vasoactive mediators – permeability,
vasodilatation
platelets adhesion and agregation
Neurogenic shock
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