VET’S DIARY: Tackling the kidney conundrum

ONE of the best things about being a vet is that there is nearly always something that makes you have to think. Of course, the flip side to that is that not everything is straightforward and this inevitable can introduce a certain element of frustration, writes Dominic Plumley.

One particular organ (and its associated diseases) is especially good at throwing up conundrums, often presenting with a jumble of pieces to put together, knowing that the completed puzzle can end with very different pictures. This organ – or more precisely organs as there are two of them – is the kidney.

The kidneys have quite a tough time of it. Effectively the sewage treatment plant of the body, they are responsible for sorting out the good bits to keep from the bad bits to get rid of, the latter filtered off into the bladder to be excreted in the form of urine. All of this is done under the pressure of trying to conserve body fluids without losing too much water.

In response to this arduous and often toxic task, nature has developed a pretty good safety mechanism to protect the individual from the catastrophic effect of failure of its waste treatment system; namely to set everything off in life with a huge functional reserve capacity to cope with the gradual damage caused by a lifetime of filtering wee.

In fact, though most animals – including us – have two kidneys, they could cope perfectly well with only one or even just a small part of one.

This is how we can get away with the wonderfully altruistic act of donating a kidney to a genetically-matched friend in need.

The moral dilemma of performing organ transplants in animals where the donor patient has no way of providing active consent to the procedure is not one to be tackled here – though there is no doubt that the operation is perfectly possible and actually frequently performed in the United States.

There are a whole heap of diseases that can affect the kidneys, many of which present in pretty much the same way.

If the kidneys stop functioning, renal failure, the patient suffers from a build-up of toxic wastes circulating in the blood causing signs ranging from nausea and in-appetence resulting in weight loss right through to coma and death.

Similarly they are unable to retain water, producing volumes of dilute urine resulting ironically in severe thirst with concurrent dehydration.

To make matters even more complicated, because of the large functional reserve of kidney tissue a particular disease process may have been going on for quite a while before the patient starts to display symptoms, such that a chronic disease may present very acutely.

Thanks to in-house biochemistry analyzers, we have been able to identify kidney disease relatively easily for a number of years, though these tests only give limited information about the cause of the problem. Ultrasound and CT scans can shine some light and certainly have moved things forward in identifying the different causes of renal failure.

However, here’s the real frustration. Even when you know what the cause is, it is often incredibly difficult to predict how they will respond to treatment, if at all.

Usually involving the administration of intravenous fluids, treatment revolves around flushing toxins out of the body and rehydrating patients while simultaneously addressing the underlying cause (if known).

Unfortunately, it is unable to regenerate like the liver, so once the kidney tissue is gone, it will never return, hence the need for transplants.

Using special diets, we can reduce the workload of the kidneys which can work very well in many patients,though it has to be said real failure on the whole is pretty bad news.

Over the last few months we have been treating a young rottie called Kerry who, for all the world, looked like she had complete renal failure.

Presenting with hugely elevated blood levels, she initially lost large amounts of weight and though she did start to eat again, the treatment seemed to have little effect on her lab results.

Her owners have persevered with a special prescription diet and miraculously she seems to have turned a corner, to the extent that this weeks blood tests showed that her kidney enzymes had returned to normal.

Frustrating though it can be, the wonders of life never cease to amaze.