Hyperaemia

Question 1

What is colloid osmotic pressure the same as?

Answer 1

Oncotic pressure

Question 2

What is hyperaemia?

Answer 2

Accumulation of RBCs inside blood vessels

Can be physiological or pathological

Question 3

Hyperaemia can be active or passive. What are these also known as? Do they take place in arteries or veins?

Answer 3

Active hyperaemia = inflammation. Accumulation of arterial blood in arteries, arterioles and arteriolar capillary bed
Passive hyperaemia = congestion. Accumulation of blood in veins and venular capillary bed

Question 4

Is active hyperaemia local or generalised? Is it acute or chronic? What about passive hyperaemia?

Answer 4

Active - local, acute

Passive - local or generalised, acute or chronic

Question 5

What colour are the tissues affected by active hyperaemia and passive hyperaemia

Answer 5

Active - bright red

Passive - dark red/blue and swollen

Question 6

What is ischaemia? What are the different types?

Answer 6

Inadequate blood supply to a tissue or organ
Can be complete or partial
Can be local or general

Question 7

What causes ischaemia? (3 ways)

Answer 7

Heart failure (general ischaemia)
Obstruction of an artery (local)
Venous obstruction (local)

Question 8

What is obstruction of artery/arteriole related ischaemia associated with?

Answer 8

Idiopathic cardiac hypertrophy

Question 9

Venous obstruction causes stagnation, hypoxia and ischaemia. What is stagnation?

Answer 9

No blood flow/movement

Question 10

Local passive hyperaemia is an increase in RBCs due to obstruction of venous return from an organ. What can cause this?

Answer 10

Organ misalignment
Venous thrombosis or embolism
Compression of vessel

Question 11

What are the different types of organ misalignment?

Answer 11

Intussusception (invagination)
Volvulus 
Torsion 
Twist
Herniation with strangulation

Question 12

How does organ misalignment cause necrosis and haemorrhagic infarction?

Answer 12

Veins occluded
Persistence of arterial blood supply
Increased blood pressure and congestion
Blood extravasation

Question 13

What is infarction?

Answer 13

Tissue death to inadequate blood supply (ischaemia leads to infarction)

Question 14

What is intussusception or invagination? Where is this most likely to occur?

Answer 14

Trapping of mesentery and vessels causes intestine to fold into the section ahead of it
Small intestine

Question 15

What is volvulus?

Answer 15

Loop of intestine twists 180 degrees around its axis

or 360 degrees if gastric volvulus

Question 16

What is gastric dilation?

Answer 16

Stomach rotates from its long axis to one paralleling the abdomen

Question 17

What does gastric volvulus cause in terms of other GI organs?

Answer 17

Oesophagus completely occluded

Spleen, pylorus and duodenum moved

Question 18

What type of dogs are associated with gastric volvulus? What behaviour is it associated with?

Answer 18

Deep chested breeds

Aerophagia and fast eating

Question 19

What are predisposing factors to gastric volvulus?

Answer 19

Increased laxity of hepatogastric ligament
Small particle diet
Recent kennelling
Raised food bowl

Question 20

What is the difference between gastric volvulus, torsion and dilation?

Answer 20

Volvulus - 360 degrees around itself
Torsion - rotates from long axis to axis parallel to abdomen
Dilation - rotates around its long axis

Question 21

What is torsion? What organs can experience this?

Answer 21

Twisting around its long axis

Lung lobe, stomach, uterus

Question 22

What organs can undergo twist?

Answer 22

Spermatic cord

Question 23

What is herniation with strangulation? Give examples of where this can occur

Answer 23

Displacement of organ through tear or aperture of membrane

E.g. inguinal ring, diaphragm

Question 24

What is a thrombosis?

Answer 24

Thrombus (blood clot) reduces blood flow through a vessel

Question 25

What is an embolism?

Answer 25

A thrombus or other substance becomes stuck in a vessel and obstructs blood flow

Question 26

Give examples of how compression can lead to local passive hyperaemia

Answer 26

Fibrosis - fibrous tissue obstructs blood vessels Tumours Abcesses

Question 27

What can cause generalised passive hyperaemia?

Answer 27

Heart failure Impeded venous return Increased pulmonary resistance

Question 28

What does heart failure cause?

Answer 28

Oedema, tissue hypoxia, RAAS activation, chronic congestion of lungs and liver, ascites and hydrothorax, cardiac hypertrophy

Question 29

What are the 2 types of cardiac hypertrophy? What are these due to?

Answer 29

Concentric - due to pressure overload | Eccentric - due to volume overload

Question 30

What is forward and backwards heart failure?

Answer 30

Forwards - systolic failure (reduced CO and perfusion) | Backwards - inability to cope with preload, due to increased venous pressure

Question 31

What organs does left sided heart failure impact? What does this cause?

Answer 31

Lungs - pulmonary congestion and oedema | Kidneys - hypo perfusion (decreased GFR and urine)

Question 32

What organs does right sided heart failure impact?

Answer 32

Liver, body cavities and subcutaneous tissues Results in LSHF Increased resistance in pulmonary circulation due to right ventricle pressure overload

Question 33

How are arterial pressure and perfusion of vital organs maintained during heart failure?

Answer 33

Increased preload - increasing contractility Myocardial hypertrophy and chamber dilation Activation of RAAS, release of noradrenaline, ANPs

Question 34

Impeded venous return is a cause of generalised active hyperaemia. What can cause impeded venous return?

Answer 34

Caval thrombosis Hydropericardium Exudative pericarditis

Question 35

Increased pulmonary resistance causes generalised active hyperaemia. What causes increased pulmonary resistance?

Answer 35

Thoracic fluids Pulmonary fibrosis Pulmonary emphysema (don't confuse with empyema!)

Question 36

What is pulmonary emphysema?

Answer 36

Damage to lung bronchioles and alveoli A type of chronic obstructive pulmonary disease (COPD)