Hedgehog kidney disease: the older hedgehog that drinks more

Quick answer

Kidney disease in a hedgehog is found on a scale and in a blood tube, not by looking at the animal. By the time it looks unwell, most of the kidney is already gone.

An older hedgehog that is drinking more, weeing more, and slowly losing weight while still eating is describing kidney disease more often than anything else. It is one of the commonest causes of decline in hedgehogs past middle age, and it is nearly always found late.

Kidneys do not warn you. An animal can lose a large proportion of functioning kidney tissue before a single blood value moves, so the useful signals are all indirect: a rising water intake, a weight trend heading down, and urine that has become pale and abundant.

• Weigh every week on a kitchen scale and write the number down. A downward trend over a month is the earliest thing you can actually measure.
• Measure water rather than judging it. Weigh the bowl at the same time each day, and keep a second bowl elsewhere as an evaporation control.
• Never restrict water in a hedgehog that is drinking more. The extra drinking is compensation, and taking it away causes a crisis.
• Ask for blood and urine tests rather than a visual check at a senior appointment. This diagnosis is not visible from the outside.
• Defend the appetite above everything. A hedgehog that stops eating for even a day risks a serious liver problem on top of the kidney one.

Decide in 60 seconds

Why kidney disease is invisible until it is not

The kidney is built with an enormous reserve. Its filtering units work in parallel, and when some are lost the survivors increase their individual workload to compensate.

That compensation is why nothing shows early. Blood values stay normal because the remaining nephrons are covering the work, and the animal behaves normally because it feels well.

What gives out first is not filtration but concentration. Producing concentrated urine is metabolically demanding and requires an intact architecture through the depth of the kidney. As that architecture is lost, urine becomes progressively more dilute.

The consequence is mechanical. To excrete the same amount of waste in more dilute urine, the animal must produce more urine, and to produce more urine it must drink more. Increased drinking is not a symptom of feeling ill. It is a successful compensation, and it is the earliest thing an owner can detect.

Once compensation fails, everything arrives at once.

Waste products accumulate, which causes nausea and appetite loss. Phosphate is retained, which drives changes in calcium handling and contributes to feeling unwell. The hormone that stimulates red blood cell production is made in the kidney, so anaemia develops and the animal becomes weaker and colder. Protein can be lost into the urine, so muscle wastes.

By that stage the animal looks obviously ill, and the window in which management makes the biggest difference has already passed.

What "drinking more" actually looks like in a hedgehog

Scale, notebook, same time each week. A weight trend and a water measurement are the only two home tests that reliably find this disease early, and both take under a minute.

This is harder to spot than in a dog, for three reasons that are worth working around deliberately.

The animal is awake when you are not.

Almost all of the drinking happens overnight. Watching the bowl in the evening tells you nothing. Measuring what has gone by morning tells you everything.

Bowls lie.

Water evaporates in a warm, heated enclosure, wheels splash, hedgehogs walk through bowls and tip them.

The workaround is simple. Weigh the bowl with a kitchen scale at the same time each day, top it up to the same starting weight, and note the difference. Keep an identical bowl with the same amount of water in the same room but outside the enclosure. Whatever that control bowl loses is evaporation, and the difference between the two is what the hedgehog actually drank.

Fleece hides urine.

If the enclosure is lined with fleece, look at the underside as well as the top, and look at how many wet areas there are rather than only how big they are. A hedgehog producing dilute urine leaves larger, paler, less strongly smelling patches, and more of them.

If the hedgehog wees on the wheel while running, which most do, the volume on the wheel and the surrounding area is a rough guide that is worth noticing over time.

Changes that mean act today

Weight that has fallen across consecutive weekly weigh-ins.

This is the strongest single home signal for almost every illness in this species, and it moves before behaviour does. A single low reading is noise. Three readings in a row heading the same direction is data.

Appetite that has become selective.

Nausea from retained waste products often shows first as a hedgehog that eats its insects and leaves the kibble, or that approaches food, sniffs, and turns away. Turning away from food after showing interest is a much more specific sign than simply eating less.

Rough, dull quills and flaky skin.

Chronic illness shows in the coat because grooming and skin turnover are among the first things a sick animal economises on.

A hedgehog that feels colder and seeks its bed constantly.

Anaemia and chronic illness both reduce heat production. This is easily mistaken for the enclosure being too cool, and both should be checked.

A sore looking mouth, drooling, or an unpleasant breath smell.

Advanced uraemia irritates the lining of the mouth. This is a late sign and warrants an urgent appointment.

Vomiting.

Uncommon in hedgehogs and always significant.

The look-alikes, and what separates them

The distinction that matters most in practice is between large volumes of dilute urine and frequent small volumes. The first points at the kidneys or at diabetes. The second points at the bladder. Owners describe both as "weeing more", so be specific with your vet about volume.

What the vet will do

An open bowl, refilled and weighed daily. Bottles restrict how much a hedgehog can physically drink, which is exactly the wrong constraint for an animal that needs to compensate for water losses.

The examination usually needs sedation.

A conscious hedgehog balls up, and a balled hedgehog cannot have its abdomen palpated, its mouth examined or a blood sample taken from a usable vein. This is normal for the species rather than a sign of a difficult animal, and it is the reason a hedgehog work-up costs more than a similar work-up in a cat.

Blood chemistry and a blood count.

The vet is looking at kidney values, phosphate, protein and albumin, and at the red cell count for anaemia. Only a small volume can be taken safely from an animal this size, so expect a discussion about which tests matter most.

Be aware that published reference intervals for pet hedgehogs are less well established than for dogs and cats, and vary between laboratories. This is one reason a vet may want to repeat the tests in a few weeks rather than act decisively on a single borderline result. A value that has moved between two samples means more than a value sitting just outside a range once.

A urine sample.

This is where the diagnosis often becomes clear, because urine concentration is the function that fails first. The vet may also look for protein in the urine, and at the sediment under a microscope for crystals, cells and casts.

Collecting urine from a hedgehog is opportunistic. A clean, empty enclosure base or a clean tray during the visit is often how it is done, and if you can bring a fresh sample from home in a clean container, take it.

Imaging.

Radiographs and ultrasound show kidney size and shape, look for stones, and rule out the masses that are so common in this species. A small, irregular kidney and a large, distorted kidney mean different things.

Blood pressure, where it is possible.

Measuring blood pressure in an animal this size is difficult and is not available everywhere. Where it is measured, treating high blood pressure protects the remaining kidney.

What management looks like

There is no cure. The aim is to slow progression, keep the animal comfortable and keep it eating.

Water and hydration come first.

An open, shallow, heavy bowl rather than a bottle. Bottles physically limit how fast an animal can drink, and an animal compensating for water loss needs to be able to drink freely.

Where losses are outpacing intake, vets often teach owners to give fluids under the skin at home. This is a genuinely transformative treatment for a hedgehog in this situation and most owners learn it quickly. Whether it can be prescribed for home use varies by country, so ask.

Diet is a negotiation, not a formula.

Reducing dietary phosphate is a cornerstone of managing kidney disease in other species, and phosphate binders may be prescribed. But hedgehogs are insectivores with high protein requirements, and the renal diets formulated for cats and dogs are not straightforwardly transferable.

The practical priority order in this species is: keep it eating, then adjust the composition. A hedgehog that stops eating because it dislikes a prescribed food has been made worse, not better, because a hedgehog that stops eating mobilises fat into a liver that cannot cope with it.

Nausea and appetite.

Anti-nausea medication makes a substantial difference and is easy to underestimate. If a hedgehog on treatment is still turning away from food, ask about it specifically.

Avoid anything that damages the kidney further.

Non steroidal anti inflammatory drugs, some antibiotic classes, and dehydration during any anaesthetic all place extra load on a compromised kidney. Make sure every vet who treats the animal, including out of hours, knows the diagnosis.

Warmth.

An animal with chronic illness and possible anaemia has less capacity to keep itself warm, and a cold hedgehog stops eating and may attempt to hibernate. Keep the enclosure temperature stable and at the upper end of the appropriate range for the species.

What never to do

Do not restrict water. Ever, in this disease.

Do not switch abruptly to a prescription renal diet without a plan for what to do if the hedgehog refuses it. Refusal is common and the consequence in this species is severe.

Do not give any anti inflammatory painkiller, human or veterinary, without the prescribing vet knowing about the kidney disease.

Do not add supplements, tonics or "kidney support" products bought online. Several contain minerals that a failing kidney cannot excrete, and none of them have been studied in this species.

Do not accept a senior check that consists only of a look and a weigh. Ask for bloods and urine, because the disease is invisible on examination until it is advanced.

Do not assume a good day means improvement. Chronic kidney disease fluctuates, particularly with hydration, and a single good day within a downward trend is not a change of direction.

Do not delay because the hedgehog is old. Age is a risk factor for the disease, not a reason to withhold the diagnosis, and knowing what you are dealing with changes what you do about pain, warmth, food and anaesthesia.

When to get help

Warm, settled, and still eating. Comfort is a legitimate treatment goal in a disease that cannot be cured, and most of the work is keeping this picture stable for as long as possible.

Same day:

• Not eating for a day, or a hedgehog that approaches food and turns away repeatedly
• Vomiting, drooling, or an unpleasant smell to the breath
• Collapse, wobbliness, cold to the touch, or unresponsiveness
• Sudden increase in drinking on top of an already raised level
• Any straining to urinate, or blood in the bedding

Within the week:

• A weight trend heading down across consecutive weekly weigh-ins
• Water intake that has risen measurably
• Dull quills, flaky skin, or a hedgehog that has stopped using the wheel

Ask the practice directly whether they anaesthetise hedgehogs and run bloods on them, because a hedgehog work-up needs both. Access to exotic species medicine varies enormously by region, and the practice that gives injections is not always the practice that can stage a kidney disease.

If you are far from an exotics vet, ask whether your local practice will take the samples and consult an exotics specialist remotely. Sample collection is the part that needs to happen locally. Interpretation does not.