Pathology: shock Flashcards
Shock 3 possible mechanisms
Pump failure of heart
Loss of circulating fluid
Loss of peripheral vascular tone
Shock
State of HYPOPERFUSION of tissue with blood
Shock - what would happen?
Collapse of circulation
Disproportion of circulating blood volume and vascular space
Shock results in
Tissue anoxia
Multi- organ failure
Cardiorespiratory failure
Type of shock
- Cardiogenic schock - pump failure of heart
- Hypovolemic shock - “not enough volume” (blood)
- Hypotonic shock - “not enough tone” (peripheral tissue)
Cardiogenic shock
- results from heart pump failure
- most commonly follows infarction and destruction of large portion of functioning myocardium
- loss of contractile elements
- inability to pump
- may also follow myocarditis/valvular disease, conduction block or arrythmia
Hypovolemic shock
- loss of circulatory volume
- can be due to massive hemorrhage or fluid loss (burns, vomiting, diarrhea)
- Hypotonic shock
- Results from the loss of vascular tone
- Blood pool in peripheral vessels
- Can be due to Anaphylatic shock, neurogenic stimuli (trauma/pain/cord injury), bacterial infection
Events of shock
- Series of events, acting synergistically causing vicious cycles that if uninterrupted result in death
- early stages are treatable and reversible
- Once serious organ failure ensures, shock becomes irreversible
- can lead to ARDS (acute respiratory distress syndrome)
ARDS
Acute Respiratory Distress Syndrome
“shock lung”
result of shock whereby lungs cannot unction properly
Pump failure, vasodilation, lead to low blood pressure
Leads to stagnation of blood in pulmonary circulation
Causes pulmonary edema
ARDS - what happens tissue levels
Acute Respiratory distress syndrome
- breaks down alveolar-capillary unit of lungs
- leads to loss of lung function
- contributes to hypoxia/anoxia
- Anoxia of tissues leads to release of cytokines including TNF and IL-1
- Cause increased permeability of blood vessels and vasodilation
what kind of cytokines Anoxia trigger?
TNF (Tumor necrosis factor) and IL-1 trying to increase permeability of blood vessels and vasodilation
Clinical correlations of shock Three stages
- Early or compensated shock
- Decompensated but reversible shock
- Irreversible shock
- Compensated shock
Set of adaptive characteristics to compensate
- Tachycardia (increase heart rate)
- Peripheral artery vasoconstriction (palour)
- Reduced urine production to preserve volume of circulating blood
- Blood pressure is normal
- No serious signs of organ ischemia
- Decompensated shock
Results when early compensatory mechanisms fail
- hypotension (Blood pressure and cardiac output drop progressively)
- tachypnea (shortness of breath (SOB)/increased respiratory rate)
- Oliguria (less peeing renal fluid output decrease)
- Acidosis (Metabolic state: renal excretory failure and retention of metabolites) More acidic. Ph is dropping.