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Dvm Reinrie Egberink mrcvs
Introductie:
This page covers what urine is and how it is produced, with specific examples of when it can be important to analyse,
and four methods of urine collection from the cat.
Urine is a clear, sterile, amber coloured liquid which is formed in the
kidneys, stored in the bladder and voided through the urethra.
Every twenty minutes all the blood in the body is filtered through the kidneys.
Their function is to keep the blood within homeostatic limits.
Metabolic waste products and toxins are excreted in to the urine, while other substances are resorbed in to the blood.
They regulate the levels of ions and pH in our extra cellular fluid, which is of critical importance.
For instance, red blood cells placed in tap water literally explode due to the osmotic imbalance.
The kidneys play an important role in salt concentrations in the blood.
When is a urine examination necessary?
If there is a problem in the body, this is often reflected in the blood.
Because the blood is filtered by the kidneys, important information can be obtained by analysing the urine.
For example in diabetes hyperglycaemia may mean glucose is filtered out in to the urine - a feature not seen normally.
Urine can also give us an indication of kidney function itself.
The urine can also show abnormalities in the lower urinary tract (the bladder and the urethra).
Metabolic problems:
Diabetic (mellitus)
A major symptom of diabetes mellitis is polydipsia (PD) (excessive drinking) which results in large volumes
of dilute urine production (polyuria (PU). Diagnosis is possible after blood examination, but if cats are
stressed the glucose level in the blood can be temporarily high giving a false result.
If high blood glucose (hyperglycaemia) exceeds a threshold it will be filtered in to the urine through the kidneys,
because the kidneys are unable to resorb all the glucose past a point.
Therefore, examination of the urine collected can be useful. A tip: If your cat is diabetic then when you re-use
the katkor litter flush it through thoroughly with plenty of water to remove all the glucose.
Cushings Disease (hyperadrenocorticism)
An important symptom of cushings disease is also polydipsia and polyuria, which will increase in severity over time.
Other important symptoms are a pendulous abdomen due to muscle wasting, thinning skin and hair loss.
There is a mild hyperglycaemia which does not often cause a glucosuria.
A diagnosis of cushings is sometimes missed because of the many differentials of PU/PD.
A good way to aid a diagnosis is by examination of the urine cortisol:creatinine ratios.
This is in addition to blood tests.
Problems with the kidneys:
Kidney failure
In moderated to advanced cases of kidney failure polydipsia and polyuria are noticable.
Urine analysis is an important aid in this diagnosis.
Sediment of the urine is important to check for haematuria, proteinuria, pyuria, crystalluria, bacteriuria,
funguria, or ova of capillaria.
Feline Lower Urinary Tract Disease (FLUTD):
FLUTD is a syndrome encompassing many problems in the lower regions of the feline urinary system.
One common diagnosis of FLUTD is bacterial infection of the bladder. This occurs in less than ten percent of cases.
The symptoms of this are frequent painful urination with small volumes of urine, sometimes containing blood.
Urolithiasis (stones or crystals in the urine) accounts for more than 30% of FLUTD cases.
Stuvite and calcium oxalate are the most common types of crystal found.
Morphological defects and tumours are very rare.
No discernable cause can be found in over 50% of FLUTD presented cases, and idiopathic (unknown cause) cystitis
becomes an exclusional diagnosis.
Urinary incontinence:
This means unconscious loss of urine. One of the causes for this can be a bladder infection.
Examining urine will also aid in this diagnosis.
To collect a urine sample from the cat:
There are 4 ways to collect a urine sample
- collection of spontaneous urine voiding
- with pressure on the bladder
- catheterization
- cystocentesis (bladder tap)
Bladder pressure, catheterization and cystocentesis are possibly for the vet.
Spontaneous urine losing is only way by cat owners.
Spontaneous urine voiding
Clean the litter tray thoroughly. Sprinkle Katkor onto the middle of the litter tray.
After the cat visits the tray, tilt the litter tray resting on one corner,
place the pipette in the bottom corner of the tray and collect the urine.
With pressure on the bladder
The veterinary surgeon will apply continuous bladder pressure, but not squeezing,
for a few seconds (ten to twenty) until the cat voluntarily urinates.
It only takes a minute to see if this method will be successful.
Cystocentesis
The site where the needle enters the body wall to go in to the bladder is usually shaved and disinfected.
With one hand the bladder can be palpated and held and with the other hand a sterile needle is inserted through
the abdominal wall in to the bladder.
Catheterization
A catheter will be placed in to the urethra and up in to the bladder.
Sedation or anaesthesia of the cat will often be necessary for this procedure.
Conclusion
Urine examination is an important tool for the vet to diagnose some diseases.
You will think it is not easy to collect some urine sample from the cat but that is not true.
Even the cat owner can help the vet to collect urine sample on easy way.
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