UREMIA AND CONSEQUENCES OF URINARY DISEASE
Retention of excretory wastes
Abnormal urination
Abnormal urine contents
Systemic lesions
Nephrotic syndrome
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RETENTION OF EXCRETORY WASTES

One of the CONSEQUENCES of URINARY DISEASE is incomplete excretion of waste products. Do you recall the definitions of azotemia and uremia?

AZOTEMIA is defined as the presence of excessive urea or creatinine in the blood. Azotemia may be due to several causes - renal failure is not the only cause!

UREMIA is the presence of urinary constituents in the blood AND the toxic condition produced by those constituents.

Thus uremic animals would be azotemic AND have clinical signs or systemic lesions caused by the retained waste products.

Dogs often have gastro-intestinal or neurologic signs when they are uremic. This dog is nauseous and depressed.

PRE-RENAL AZOTEMIA

This is 1 of 3 forms of azotemia.

Pre-renal azotemia is due to conditions which cause decreased blood flow to the kidney.

Since blood does not perfuse through the kidney, waste products are not removed. Urine that is formed has a high specific gravity (due to attempts to conserve water).

Can you think of an example?
Click to see answer!
ANSWER: Dehydration as seen in this calf with severe scours is a common pre-renal cause. Note the shunken eye which tells you the calf is very dehydrated.

RENAL AZOTEMIA

This is 1 of 3 forms of azotemia.

Renal azotemia is due to disease or lesions in the kidney which interfere with renal function.

Since the kidney does not perform its normal function of waste removal, waste products are retained in the blood. In addition, the kidney can no longer concentrate or dilute urine, resulting in a urine specific gravity similar to that of the serum (isosthenuria).

Can you think of an example?
Click to see answer!
ANSWER: This dog does not have much functional renal parenchyma. There are multiple renal cysts (black arrows)and the cortex and medulla are thin and not distinguishable. The pelvis is also dilated (white arrow).

POST-RENAL AZOTEMIA

This is 1 of 3 forms of azotemia.

Post-renal azotemia is due to disease or lesions in the lower urinary tract (post-renal tract) which prevent excretion of urine.

Since little or no urine is excreted, toxic wastes remain or are reabsorbed from the urine into the blood.

Can you think of an example?
Click to see answer!
ANSWER: This dog has a transitional cell carcinoma of the urethra (all that which tissue in the blue circle). This is obstructing outflow from the bladder which is on the right.

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