CLINICAL PATHOLOGY - Urinary System

Question 1

List three examples of substances commonly used to estimate the glomerular filtration rate (GFR)

Answer 1

Inulin
Creatinine
Urea

Question 2

Why might an animal have low creatinine levels?

Answer 2

Low muscle mass
Cachexia (muscle wasting)
Young animals

Question 3

Why might an animal have high creatinine levels?

Answer 3

Dehydration
Renal dysfunction
Urinary outflow obstruction
High muscle mass

Question 4

Which breed of dog often has high creatinine levels due to having a high muscle mass?

Answer 4

Greyhounds

Question 5

Why is using urea to estimate the glomerular filtration rate (GFR) unreliable in ruminants?

Answer 5

Urea can enter the rumen and be used by the bacteria in the rumen to synthesise amino acids leading to an unreliable glomerular filtration rate (GFR) value

Question 6

What are some of the renal causes of high urea levels?

Answer 6

Dehydration
Hypovolaemia
Renal dysfunction
Urinary outflow obstruction

Question 7

What are some of the non-renal causes of high urea levels?

Answer 7

High protein diet
Gastrointestinal bleeding
Cochexia

Question 8

What is azotaemia?

Answer 8

Azotaemia is increased levels of non-protein nitrogenous waste in the blood (i.e urea and creatinine)

Question 9

What is uraemia?

Answer 9

Uraemia is the clinical syndrome resulting from several renal dysfunction

Question 10

What are the three main symptoms of uraemia?

Answer 10

Gastritis
Stomatitis
Pneumonopathy

Question 11

What are the three classifications of azotaemia?

Answer 11

Pre-renal azotaemia
Renal azotaemia
Post-renal azotaemia

Question 12

List three possible causes of pre-renal azotaemia

Answer 12

Dehydration
Hypovolaemia
Decreased cardiac output

Question 13

Why do animals with pre-renal azotaemia typically present with hypersthenuria?

Answer 13

Animals with pre-renal azotaemia typically present with hypersthenuria (very concentrated urine) due to the kidneys trying to conserve water

Question 14

What are the typical urine specific gravity (USG) values for an animal with pre-renal azotaemia?

Answer 14

Dog > 1.030
Cat > 1.035
Horses/cattle > 1.025

Question 15

What is the cause of renal azotaemia?

Answer 15

Renal azotaemia is caused by any renal disease which causes enough glomerular damage to lower the glomerular filtration rate (GFR)

Question 16

What percentage of nephron functional tissue needs to be lost before the clinical symptoms of renal azotaemia are presented?

Answer 16

65-75%

Question 17

Why does renal azotaemia typically present with isosthenuria?

Answer 17

Renal azotaemia typically presents with isosthenuria as the kidneys can no longer concentrate the urine so the urine specific gravity value (USG) will be the same as plasma

Question 18

List two possible causes of post-renal azotaemia

Answer 18

Urinary tract obstruction
Urine leakage into the abdomen

Question 19

(T/F) Post-renal azotaemia can commonly present as anuria

Answer 19

TRUE

Question 20

What is the function of symmetric dimethylarginine (SOMA)?

Answer 20

Symmetric dimethylarginine (SOMA) is a molecule produced by the methylation of arginine that can be used for the early identification and monitoring of kidney disease

Question 21

List four examples of substances that can be used to identify and monitor the progression of renal disease?

Answer 21

Inorganic phosphate
Calcium
Potassium
Albumin

Question 22

How can chronic renal failure lead to hypokalaemia?

Answer 22

Hypokalaemia is seen with chronic renal failure as the kidneys cannot concentrate urine and are thus unable to reabsorb K+

Question 23

How can glomerular disease lead to hypoalbuminaemia?

Answer 23

If there is damage to the glomerular basement membrane, albumin can pass through and be excreted in the urine leading to hypoalbuminaemia and even progress to nephrotic syndrome

Question 24

What are the four main symptoms of nephrotic syndrome?

Answer 24

Hypoproteinaemia
Proteinuria
Oedema
Hypercholesterolaemia

Question 25

Which disease is commonly caused secondary to chronic renal disease?

Answer 25

Secondary renal hyperparathyroidism