Message Number: YG103 | New FHL Archives Search
From: Dr. Bruce Williams
Date: 2001-02-23 20:36:00 UTC
Subject: Re: Renal Failure

Dear Katharine:

While I'm afraid that I don't have any useful suggestions regarding
the treatment of chronic renal failure in ferrets save for the
protein restricted diet which you are currently pursuing, perhaps I
may be able to shed some light on chronic renal failure that may
explain why treatment is so difficult.

The kidney, like several other tissues in the body (such as heart and
brain) does not have a good ability to regenerate following injury.
Once kidney tissue wears out following aging or injury, it is
replaced by scar tissue, not by new kidney tissue. So it is
essentially a non-renewable resorce. There are some exceptions,
which are lumped together in a syndrome called acute renal failure -
this is usually the result of one-time antibiotic administration or
short term hypoxia, as might be seen in shock.

Chronic renal failure occurs when the functional kidney mass falls
below 25%. Recent investigations suggests that the kidneys may be
able to work adequately and not fail in some conditions when up to
90% of the kidney is lost. When kidneys fail, two things occur -
they lose the ability to concentrate urine, so urine is generally
dilute (and the animal tends to urinate frequently and in large
amounts) and it cannot excrete the normal substances which the kidney
is responsible for removing from the body.

Diagnosis of chronic renal failure is based on the combination of
measuring the concentration of the urine and measuring the
concentration of several compounds in the blood (in most cases, BUN,
creatinine, and occasionally phosphorus.) Failing kidneys don't
excrete them properly, so they build up in higher than normal levels.
So we look at bloodwork and a urinalysis. If the urine is dilute and
remains dilute even in the face of dehydration, and the leve of the
BUN and creatinine is significantly elevated (mild BUN elevations may
be seen in dehydration in animals with normal kidneys), a diagnosis
of chronic renal failure is given. Some practitioners may diagnose
chornic renal failure based on bloodwork alone, which may lead to a
small number of errant diagnoses, as other conditions may cause
elevations of the compounds mentioned above.

As you haven't mentioned the tests that were done or the levels that
indicated chronic renal failure, I can't comment specifically on this

Unfortunately, as the kidney has limited regenerative capability,
when chronic renal failure occurs, a cure is not possible - there is
nothing left but scar tissue. The kidneys become small, contracted,
and hard. As another function of the kidney is to elaborate a
hormone called erythropoetin, which stimulates bone marrow production
of red blood cells, another potentially life-threatening complication
of chronic renal failure.

It has been shown that naimals on protein-restricted diets tend to
have better renal function over their lifetime than those with higher
levels of protein. While the benefits of a restricted protein diet
have not truly been established in animals with chronic renal
failure, the theory that protein restriction may prolong remaining
function in failing kidneys, coupled with the fact that there is
little else that we can truly do to treat this condition, has made
protein-restricted diet a primary mode of therapy in the treatment of
CRF in domestic animals.

With kindest regards,

Bruce Williams, DVM

--- In Ferret-Health-list@y..., katharine <shurcool@t...> wrote:
> Am taking a chance that someone can offer advice. Champ (will be 4
> in May) recently had right adrenal surgery, had a UT infection
> 3-4 days, and is now in renal failure.
> ...Any suggestions, assistance, clues? I really don't understand
> renal failure stuff. Apparently the type he has is not the common
> that ferrets normally have (of course). I guess I'm trying to find
> if anyone has any other suggestions for him.