Azotemia
Key concepts ·Also called: azotaemia, uraemia, high kidney values, raised urea and creatinine
What it is
Azotaemia is divided by where the problem sits. Pre-renal means not enough blood is reaching the kidneys. Renal means the kidneys themselves are damaged. Post-renal means urine cannot get out. The blood values look similar in all three; the urine concentration is what separates them.
Why it matters
The distinction dictates the treatment entirely. Pre-renal azotaemia resolves with fluids. Post-renal azotaemia needs the blockage relieved urgently. Renal azotaemia means kidney disease, with a completely different long-term plan. Reading the blood without the urine specific gravity leaves the question unanswered.
What it can point to
- Pre-renal: dehydration, blood loss, shock, or heart failure — the urine will be concentrated because the kidneys are working correctly
- Renal: chronic kidney disease, or acute injury from a toxin or infection — the urine is typically dilute despite the body needing to conserve water
- Post-renal: a urinary obstruction or a ruptured bladder — an emergency, particularly in male cats
- A high-protein meal or bleeding into the gut can raise urea alone without creatinine following
Dogs and cats differ
Post-renal azotaemia in a straining male cat is the version that cannot wait — potassium rises alongside it and the heart is at risk within hours. In older cats and dogs, the far more common story is chronic renal azotaemia found on a routine senior panel.
Questions worth asking your vet
- Was the urine concentrated or dilute — which type of azotaemia is this?
- Would this improve with fluids?
- Is my pet passing urine normally?
Related terms
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