CLINICAL PATHOLOGY - Urinary System Flashcards
List three examples of substances commonly used to estimate the glomerular filtration rate (GFR)
Inulin
Creatinine
Urea
Why might an animal have low creatinine levels?
Low muscle mass
Cachexia (muscle wasting)
Young animals
Why might an animal have high creatinine levels?
Dehydration
Renal dysfunction
Urinary outflow obstruction
High muscle mass
Which breed of dog often has high creatinine levels due to having a high muscle mass?
Greyhounds
Why is using urea to estimate the glomerular filtration rate (GFR) unreliable in ruminants?
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
What are some of the renal causes of high urea levels?
Dehydration
Hypovolaemia
Renal dysfunction
Urinary outflow obstruction
What are some of the non-renal causes of high urea levels?
High protein diet
Gastrointestinal bleeding
Cochexia
What is azotaemia?
Azotaemia is increased levels of non-protein nitrogenous waste in the blood (i.e urea and creatinine)
What is uraemia?
Uraemia is the clinical syndrome resulting from several renal dysfunction
What are the three main symptoms of uraemia?
Gastritis
Stomatitis
Pneumonopathy
What are the three classifications of azotaemia?
Pre-renal azotaemia
Renal azotaemia
Post-renal azotaemia
List three possible causes of pre-renal azotaemia
Dehydration
Hypovolaemia
Decreased cardiac output
Why do animals with pre-renal azotaemia typically present with hypersthenuria?
Animals with pre-renal azotaemia typically present with hypersthenuria (very concentrated urine) due to the kidneys trying to conserve water
What are the typical urine specific gravity (USG) values for an animal with pre-renal azotaemia?
Dog > 1.030
Cat > 1.035
Horses/cattle > 1.025
What is the cause of renal azotaemia?
Renal azotaemia is caused by any renal disease which causes enough glomerular damage to lower the glomerular filtration rate (GFR)
What percentage of nephron functional tissue needs to be lost before the clinical symptoms of renal azotaemia are presented?
65-75%
Why does renal azotaemia typically present with isosthenuria?
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
List two possible causes of post-renal azotaemia
Urinary tract obstruction
Urine leakage into the abdomen
(T/F) Post-renal azotaemia can commonly present as anuria
TRUE
What is the function of symmetric dimethylarginine (SOMA)?
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
List four examples of substances that can be used to identify and monitor the progression of renal disease?
Inorganic phosphate
Calcium
Potassium
Albumin
How can chronic renal failure lead to hypokalaemia?
Hypokalaemia is seen with chronic renal failure as the kidneys cannot concentrate urine and are thus unable to reabsorb K+
How can glomerular disease lead to hypoalbuminaemia?
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
What are the four main symptoms of nephrotic syndrome?
Hypoproteinaemia
Proteinuria
Oedema
Hypercholesterolaemia
Which disease is commonly caused secondary to chronic renal disease?
Secondary renal hyperparathyroidism
