Renal failure

Question 1

Describe incidence acute kidney injury

Answer 1

• Rare
• All species
• Poor prognosis
• 3 levels

Question 2

What are the 3 levels at which acute kidney injury can occur?

Answer 2

• Pre-renal
• Renal/intrinsic (worst prognosis)
• Post-renal

Question 3

What may cause pre-renal acute kidney injury?

Answer 3

• Loss of blood, fall in perfusion
• e.g. haemorrhage
• Need to support underlying cause (hypovolaemia)

Question 4

What causes intrinsic AKI?

Answer 4

• Many nephrotoxins

- Lillies, anti-freeze, NSAIDs

Question 5

What can cause post-renal AKI?

Answer 5

• Blockage leading to back flow
• Slows GFR and build up urea
• e.g. renal stones

Question 6

What are the physiological effects of AKI?

Answer 6

• Loss of efficient excretion and homeostasis

- Uraemia, hyperkalaemia and acidosis

Question 7

What are the clinical findings in AKI?

Answer 7

• Rapid and progressive
• Very sick (high uraemia)
• Large painful bladder/kidneys
• Lethargy
• Depression
• Anorexia
• Vomiting
• Dehydration
• No urine (anuria) as no GFR

Question 8

Describe chronic kidney disease

Answer 8

• Common
• Cats > dogs > horses
• Prolonged (>2 months) loss of renal tissue
• Progress - chronic interstitial nephritis
• Irreversible
• Prognosis variable

Question 9

When are clinical signs apparent in chronic kidney disease?

Answer 9

• Loss of 70% of renal tissue

- USG can decrease early on

Question 10

What are the clinical signs of chronic kidney disease?

Answer 10

• Weight loss
• Poor body condition
• Loss of muscle mass
• Increased water intake
• Decreased appetite
• Ventroflexion (cats)
• PU/PD
• GI signs
• Small knobbly kidneys
• Non-regenerative anaemia
• Blindness
• Uraemia, azoaemia, dehydration

Question 11

Why does polydipsia occur in chronic kidney disease?

Answer 11

• Hyperfiltration in remaining nephrons
• Higher GFR, reduced reabsorption, increased loss of water
• More urine produced
• Need to replace loss by drinking more

Question 12

Why does ventroflexion occur in chronic kidney disease?

Answer 12

• Fall in potassium
• Cats due to lack of nuchal ligament
• Fatigue as need potassium for muscle contraction

Question 13

Why do gastrointestinal signs occur with chronic kidney disease?

Answer 13

• High urea in blood irritates stomach lining

- Vomiting and nausea occur

Question 14

Why does non-regenerative anaemia occur with chronic kidney disease?

Answer 14

• EPO produced in kidneys, loss of kidney leads to loss of EPo
• EPO trigger maturation of RBCs so will get anaemia with kidney disease

Question 15

Why can blindness occur with chronic kidney disease?

Answer 15

Increased blood pressure can lead to burst blood vessels in back of retina

Question 16

What is the difference between acute and chronic kidney disease?

Answer 16

• Acute very quick, chronic gradual
• In both signs shown renal insufficiency occurs (33% of kidney left)
• In chronic likely to be skinny due to loss of protein, rise in blood pressure can lead to blood clots in eye

Question 17

What are the features of a renal diet?

Answer 17

• Reduced phosphate
• High quality protein
• Fat soluble vitamins
• Low sodium
• Potassium

Question 18

What treatment options are available for kidney disease?

Answer 18

• Calcium channel blockers, vasodilation of efferent arterioles, reduces filtration pressure
• Decrease GFR (fortekor), in order to retain protein
• Potassium supplementation
• Correct acidosis potentially (bicarbonate solution)
• Synthetic EPO to correct anaemia

Question 19

List some clinical pathological features of renal dysfunction

Answer 19

• PU/PD
• Weight loss
• Hypertension
• Vomiting, loss of appetite
• Blindness
• Anaemia

Question 20

Why does hypertension occur with chronic kidney disease?

Answer 20

• Released renin due to perceived poor perfusion in kidney (damaged areas not perfused)
• Release of renin, activation of RAAS
• Increase in blood pressure
• Further damage to remaining nephrons