URINOGENITAL SYSTEM INJURIES
1) THE KIDNEYS
Causes:
Blunt and sharp trauma, obstruction to urine outflow, poisons, leptospirosis.
Signs:
Pain in the anterior dorsal abdomen. May see haematuria or oliguria or anuria. Azotaemia may develop if neither kidney is functioning. Kidneys are an important regulator of acid / base balance so watch for signs of acidosis ( panting with no other obvious cause, this makes the lungs lose CO2 which is acidic). Watch for signs of blood loss and measure urine output (catheter) and blood urea. Serial measurements are often the most useful.
N.B. Fluids may be appropriate or may be contra-indicated (e.g. in obstruction), depending on whether there is any kidney function.
a/Trauma
Sharp trauma to the kidneys is relatively rare as they are well protected internally and mobile.
Blunt trauma is more common and is usually the result of an RTA, although for the damage to be serious, the trauma has to be very severe. The Right kidney is further forward, and is better sheltered by the ribs, so the Left, which is more mobile and lies further back, is more commonly the damaged one, and usually suffers from crush ijuries or haematomas.
The renal blood supply comes straight off the Aorta, so haemorrhage is usually acute and severe. The kidney capsule may be able to contain it, giving rise to a haematoma, or it may escape behind the peritoneum, and blood may be seen lying under the lumbar muscles, thus there may be severe blood loss without it appearing in the peritoneal cavity, and abdominal swelling is variable. Always keep an eye on the circulatory markers (pulse, colour, refill time.).
Treatment:
If monitoring reveals signs of haemorrhage then fluid or blood transfusions are appropriate., but urinary output must be measured via a catheter to check that there is kidney output.
b/ Outflow obstruction
Urinary output can be obstructed by calculi, incorrectly applied surgical ligatures (e.g. during spaying, particularly through unnecessarily small holes).
If the other kidney is functioning, then it will clear waste products, so pain may be the only sign initially. Eventually hydronephrosis develops and the damaged kidney swells and becomes non-functional.
c/ Poisons
Antifreeze (ethylene glycol), Heavy metals, Chlorate and paraquat weedkillers.
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Treatment:
Usually fast fluid transfusions, sometimes with diuretics are used to dilute and flush the poisons out. It may be appropriate to try to acidify or alkalinise the urine, depending on the poison.
d/ Infection
Leptospirosis- a zoonosis passed via the URINE, see under the liver damage section.
2 THE URETERS
Causes:
Severed or damaged due to trauma (may be torn away from the bladder), Blockage by calculi, or damaged by surgery as above.
Signs:
May not develop for days, depending on the functioning of the other kidney. Blockage causes signs as for renal outflow obstruction, but the ureters are behind the peritoneum, so urine will try to accumulate in the space under the lumbar spine. Giving fluids will initially improve the situation by dilution of the urine, but uraemia will eventually develop and surgical attention will be necessary.