Vet Path

Question 0

What are the three types of shock?

Answer 0

cardiogenic, hypovolaemic, blood maldistribution

Question 1

What happens in cardiovascular collapse as a result of shock?

Answer 1

decreased circulating blood volume, decreased cardiac output, systemic hypotension and hypoperfusion, tissue hypoxia, cell death

Question 2

What is cardiogenic shock and what could cause it?

Answer 2

death of the cardiac muscle due to infarct. It results in an arrhythmia as something e.g. pulmonary thromboembolism stops blood from leaving the heart= lowered SV and CO= stagnant blood flow and tissue hypoxia.

Question 3

What is hypovolaemic shock and what does it lead to?

Answer 3

shock due to reduced circulating volume- by blood loss (haemorrhage) or fluid loss (vomiting, diarrhoea, burns).
Hypotension and hypopefusion.

Question 4

If a 5kg cat lost 150mls blood in an RTA, is this enough to kill it?

Answer 4

Yes. Blood volume is 7% body weight, this cat has 350mls of blood (7% of 5kg) and so has lost 42% of its blood volume.

Question 5

What is blood maldistribution and how does it create hypoxia?

Answer 5

Blood pools in peripheral tissues due to decreased peripheral resistance in the blood vessels. Hypoxia is due to the increase in vascular space which decreases the effective circulating volume.

Question 6

What are the three types of blood maldistribution?

Answer 6

Neurogenic shock, Anaphylactic shock, Septic shock.

Question 7

What happens in neurogenic shock?

Answer 7

There is trauma to the CNS (spinal chord), loss of ANS to smooth muscle in vessel wall=vasodilation=blood pooling in veins.

Question 8

What happens in anaphylactic shock?

Answer 8

The blood vessels are leaky and dilated which causes a drop in blood pressure and reduced perfusion occurs. This is due to histamine which increases vessel permeability to WBCs.

Question 9

What is septic shock?

Answer 9

it is triggered by endotoxin- LPS in g-ve bacteria, mediated by inflammatory mediators in response to bacterial and fungal infections.

Question 10

How does the endotoxin in septic shock affect the body?

Answer 10

The LPS bind to TLR4 and CD14= release of cytokines and interleukins. It also releases Factor XII= coagulation of blood.

Question 11

How dose the dose of LPS relate to the response?

Answer 11

Low dose- macrophages, endothelial cells and complement active.
Med dose- Raised TNF and IL-1 (fever)
High dose- Vasodilation, hypotension, reduced myocardial contractility and hypoperfusion. BV injury and thrombosis-DIC

Question 12

What are the 3 stages of shock?

Answer 12

compensated, progressive and irreversible.

Question 13

What is compensated shock?

Answer 13

The body will raise CO and VC to maintain BP and tissue oxygen supply.
Via sympathetic n system-adrenaline

Question 14

How does the control water balance to compensate for shock?

Answer 14

GFR drops, RAAS, ADH and adrenaline

Question 15

What is progressive shock?

Answer 15

the compensatory mechanisms cannot cope, Hypoperfusion and cell injury occurs, low oxygen= anaerobic resp, production of lactic acid and reduced ATP= cell membrane damage, lysozyme release and necrosis.

Question 16

What is irreversible shock?

Answer 16

VC mechanisms are overwhelmed, there is widespread vasodilation and organ failure.

Question 17

What are the clinical features of shock?

Answer 17

Hypotension, weak pulse and tachycardia, hyperventilation, dcreased urine output, peripheral vasoconstriction. (cold and clammy due to VC and symp system activity= sweat)

Question 18

What lesions would be expected in a case of shock?

Answer 18

Congestion and pooling of blood, Oedema and haemorrage (petechial/ecchymotic), microscopic thrombosis, cellular necrosis (microscopic) e.g. myocardial cells, neurons.