L21: Hypertension, Hypotension, Shock Flashcards Preview

Cardiovascular System > L21: Hypertension, Hypotension, Shock > Flashcards

Flashcards in L21: Hypertension, Hypotension, Shock Deck (36):
1

When does venous hypertension develop

Impaired outflow of venous blood a.k.a passive congestion

2

Give examples of conditions that may lead to venous hypertension pls

Congenital/ acquired arteriovenous anastomosis e.g. congenital hepatic arterioportal fistula

3

What is a consequence of venous hypertension

INC plasma hydrostatic pressure in tributary veins, venues, capillary beds upstream --> oedema and diapedesis of erythrocytes

4

What is pulmonary hypertension

sustained increase in systolic BP in pulmonary artery
(>30mm Hg dog/cat)

5

What is cor pulmonale

R heart disease caused by pulmonary hypertension

6

Why does cor pulmonale develop

pressure overload on right ventricle during systole --> R sided congestive heart failure or chronic compensatory concentric hypertrophy of right ventricle

7

In which circumstances does pulmonary hypertension develop

Congenital anomalies --> L to R shunting blood E.g.
Patent ductus arteriosus
Atrial septal defect
Ventricular septal defect

Inc resistance in pulmonary blood flow E.g.
heart worm
pulmonary neoplasia
Severe chronic diffuse interstitial fibrosis

8

Whats systemic hypertension

sustained increased in systemic arterial BP

9

Which diseases can predispose animals to the development of systemic hypertension

Diabetes
liver disease
glomerular disease
renal disease
endocrinopathies
NSAIDS

10

Describe how some endocrinopathies can lead to systemic hypertension in animals

middle aged cats can develop nodular hyperplasia of their thyroid gland, generating too much T3, T4

Low thyroid function & obesity in older dogs

Cushing's (high adrenocortical cortisol)

11

Why can systemic hypertension be self-perpetuating if not adequately treated

related to underlying disease process --> must treat this to reduce hypertension

12

Which organs are most susceptible to systemic hypertension

eyes
brian
kiddys

13

What are some clinical signs that can develop subsequent of systemic hypertension

PU/PD --> reflects both diuresis and underlying primary disease process (E.g. renal failure, diabetes mellitus, hyperthoiridism, hyperadrenocorticism)

Cardiac murmur +/- galloping heart

epistaxis

strokes

14

What is systemic hypotension

sustained decrease in systemic arterial blood pressure (<60mm cats, dogs or <80mm Hg systolic pressure)

15

What overall cardiovascular changes can cause systemic hypotension

dec in CO and TPR

16

What does persistent systemic hypotension lead to

shock

17

Define shock

generalised phenomenon peripheral circulatory failure, characterised by systemic hypo perfusion and systemic hypotension

18

What are the types of shock

Cardiogenic shock
Hypovolaemic shock
Distributive
Neurogenic
Anaphylactic
Septic

19

What is cardiogenic shock

rapid decrease in systolic CO despite adequate blood volume

20

what causes cariogenic shock

Severe dilated cardiomyopathy*
Myocardial infarction
Cardiomyopathy
Atrial fibrillation
Tachyarrhythmias
Rupture chordae tendinae
Rapid pericardial effusion
Pulmonary hypertension/ severe systemic hypertension
Heart worm

21

What is hypovolaemic chock

significant reduction in circulating blood volume (>20-25%)

22

what are some causes of hypovolaemic shock

haemorrhage
severe fluid loss (vomiting/ diarrhoea)
or fluid loss through increased vascular permeability
sequestration fluid (e.g. grain overload)

23

What is distributive shock

inappropriate vasodilation arterioles, pooling of blood in capillary beds & venous channels
(total reduced peripheral vascular resistance, decreased effective circulating blood volume)

24

What are the 4x types of distributive shock

neurogenic shock
anaphylaxis
sepsis
heat stroke

25

Describe neurogenic shock

fear/ pain --> brain signals affect vasomotor centre of medulla --> inappropriate peripheral vasodilation/ bradycardia

26

Describe anaphylactic shock

mass mast & basophil degranulation= mass release vasoactive amines e.g. histamine

27

What is septic shock

e.g. endotoxin release --> endothelial release vasodilators -> systemic arteriolar vasodilation --> hypotension & decreased effective circulating blood volume

High LPS doses cause also activate platelets, activate cascade, cause widespread vascular injury & thus widespread DIC

28

What are the 3 stages of shock

1. Initial non-progressive stage
2. Progressive stage of tissue hypo perfusion
3. Irreversible stage

29

Describe the initial, non progressive stage of shock

COMPENSATED HYPOTENSION

baroreceptors detect hypotension
chemoreceptors detect hypercapnia

Stimulation sympathetic NS

Activation RAAS

30

What is the outcome of initial non progressive/ compensated shock?

Vasoconstriction of arterioles and venules
Maintenance of blood pressure
Conservation of fluid

31

In which case is the bodies attempt to compensate for initial non-progressive shock essentially useless?

In cases of distributive shock, where peripheral vasoconstriction is a characteristic, therefore value of compensatory response is diminished

32

Describe the progressive stage of tissue hypoperfusion as part of shock

sustained vasoconstriction in nonessential organs= hypoxia --> lactic acid --> reversal of vasoconstriction --> pooling of blood in microcirculation

Hypoxic injury can trigger DIC

Oliguria

33

Describe the irreversible stage of shock

shock will eventually lead to widespread hypoxic ell necrosis, multiple organ failure +/- DIC

Death can't be prevented in this stage, only in 2nd stage with correction of underlying haemodynamic abnormalities

34

What are the clinical signs of hypovolaemic and cardiogenic shock

hypotension
tachycardia
thready pulse
tachypnoea
MM pallor
inc CRT
decreased mentation

35

What are the clinical signs of cardiogenic shock

arrhythmia,
murmur
muffled heart sounds

36

What are the clinical sings of distributive shock

dark red (injected) MM, rapid CRT