Wiebke's Guide to Pees and Stones

[Wiebke]

Overview
1 The Urinary Tract
2 Pees
- Water intake changes
- Pee discoloration
3 Infections
- Bacterial urine infection (UTI)
- Bacterial cystitis
- Sterile cystitis (interstitial cystitis or IC)
4 Stones, Sludge and Crystals
- Crystals, stones and sludge
- Stone and sludge removal
5 Kidneys and Bladder Cancer
- Kidney infections and failure
- Bladder cancer


Wiebke's Guides are a series of articles I have written for Guinea Pig Magazine in 2023 and 2024.
They are there to help you understand how the urinary tract works, learn to spot what is normal and what not and what are the most common health issues connected with it.


1 The Urinary Tract

The urinary tract starts in the two kidneys located higher up in the body towards the spine where any fluid waste is processed and excreted in the form urine.

A tube called a ureter runs from each kidney into the bladder which acts as a holding tank that is emptied when it is full.

This happens via a single larger tube called the urethra which carries the urine to the exit. The urethra is one of the areas where there is a physical gender difference. It is shorter and straighter in sows whereas boars have a longer urethra with an awkward inglenook widening in it where any debris, like stones or crystals can get caught and stuck. In sows the narrowest point is the muscular ring that controls the exit opening where any stones tend to fetch up.

Pee is a very corrosive substance that stings badly when it comes in contact with raw tissue or a small rip. The walls of urinary tract are coated by a layer of natural glucosamine that acts as insulation and enables the normal smooth operation of urinary tract.

Infections can affect this glucosamine layer and stones, sludge and crystals can scratch it as they are banged painfully around the bladder with every pee. The intense pain from the pee hitting raw tissue is what causing the screaming when peeing.



2 Pees

The urine concentration usually depends on how much your piggy is individually drinking. This can vary from a bottle or more per day to not drinking at all and just getting the fluid from the veg. It is worth noting that this is the normal spectrum and that the concentration of urine doesn’t have any impact on the kidney function.

Water intake changes
It is also worth keeping in mind that the need to drink comes before the need to eat. A guinea pig that is fully eating and holding their weight is also drinking, unless water is not available (run out, blocked nozzle, frozen or too hot water bottle or spoiled water dish or bad taste from additives, green algae overgrowth etc.). Make sure that a guinea pig with mobility issues or old age arthritis (lifting the head) can still reach a bottle or offer regular watering support via syringe.

What you need to keep an eye on are noticeable changes to the fluid intake. First always check whether the water source is OK. Then consider whether there are any major changes in the environment in terms of temperatures or humidity like heat or cold spikes, air conditioning or radiator heat coming on etc. which can also decrease or increase the water intake shortly without any major changes to the weight.

Decreased fluid intake
A decrease of fluid intake very often comes hand in hand with a loss of appetite; when support feeding, you should also always offer water; about 1 ml for every 5 ml of solids. Please never just squirt any water or feed into the mouth at full force. It will go mostly up into the nose (causing temporary congestion noises) but it can end up in the bronchia or lungs (aspiration) if it coincides with an intake of breath. Make sure that you only ever give 0.1-0.3 ml in one go to a piggy that is fighting the syringe, depending on age and weakness. An adult piggy can hold about 0.5 ml in their mouth. Make sure that they have swallowed everything before giving more – slowly and gently.

Causes of a decreased water intake can include dental overgrowth or a fungal mouth infection (oral thrush), which are making swallowing difficult.
Runny diarrhoea, painful belly cramps and bloating but also any obstructions in the mouth, throat or digestive tract.
Any serious respiratory illnesses will firstly kill of the appetite and then the thirst since the need to breathe comes before the need to drink and then the need to eat.
Increasing weakness/apathy and heat stroke will also lead to a decrease or stop in drinking.
Total loss of appetite as a side effect to antibiotic treatment or as a reaction to GA drugs in the wake of an operation also means that you need to make sure that your piggy is offered water with every feeding feeding session.

Signs of acute dehydration:

• A waxy, stiff coat
• Very dry and shrivelled fresh poos or tiny poos with a mucus coating – the latter means that a guinea pig has not eaten or drunk in 24 hours and is a life or death emergency
• Sunken eyes (on both sides)
• A single shrivelled eye is severely dehydrated often as a result of an injury. Please see a vet as soon as you can.
  The eye – unless it has burst – can be rehydrated with artificial tear fluid (ideally a carbomer based tear gel) but the injury will still have to be properly treated for an infection and further damage if at all possible. If you are lucky, sight may return.
  A stroke piggy may no longer be able to clean the eye on the affected side of the body and will require regular rehydration with tear gel.
  

Increased drinking and weight loss
Please see a vet when you notice a sudden or quick persistent increased drinking especially in combination with weight loss.

In the majority of cases this caused by kidney issues or an infection especially in the urinary tract but other infections in the body can also lead to a higher water intake if the appetite is not killed off. Diabetes is after an initial fad of over-diagnosing actually not all that common but needs to be taken into account once the kidneys and any infections have not checked out.


Pee Discoloration
Urine concentration, the natural oxidising process when in contact with air, blood, natural dyes and bacterial overgrowth can all contribute to the coloured patches of pee you find when cage cleaning.

Here is a quick guide to urine and urine puddles:

• Pee concentration
  Pee is the more yellow the more it is concentrated when it leaves the body. This is not something to worry about unless you are dealing with very watery pee and weight loss in a piggy that is not normally drinking a lot.
  
  
• Oxidised Urine
  Clear pee when leaving the body dries normally in increasingly darker shades of orange to rusty tones with the rim of the puddle always darker but in the same colour range. The intensity of the discoloration depends on the concentration of the urine, the amount of bacteria and the drying time – the longer the darker the shade.
  Oxiding fresh pee (was clear when leaving the body)
  
  
  Dried in strongly oxidised pee
  
  
  
• Blood
  Sheer blood appears as a pinkish or sometimes orange shade when fresh but dries off to a small dull brown patch that is quite distinct from the usual rusty colours.
  When mixed with urine is more common to find drops of pink/brown in a pee puddle and/or a distinctly brown and not rusty ring around the puddle when there is a lot of it.
  However, you want to see some other urinary symptoms before you jump to the conclusion of having a bloody pee puddle if you are inclined to panic.
  
  Porphyrin coloured pee puddle
  
  
  Natural dyes in pee
  Porphyrin appears red and also dries to a dull brown.
  Tomato juice can cause bright red drops.
  Died cherry tomato drops filtered through a fleece
  
  Occasionally veg can cause orange pees; not just carrots, but lettuce, cucumber or grass, too. This is perfectly harmless. Beetroot is a strong natural food dye and will always appear as purplish pink pee and dry in shades purple. Beetroot poos are purple coloured.
  Pink beetroot pee in a drip dish
  
  
  
• Bacterial overgrowth
  Intense orange pees drying to a deep, rich rusty tone are rare but they can cause a panic because of the richness of colour. They are caused by a usually suppressed form of bacteria in the bladder that can flourish in the course of repeated bladder stone or antibacterial treatment when the immune system is suppressed. It can be easily treated with antibiotics and an immune boosting 2-3 weeks vitamin C course.
  In the corner you can see the intensely orangey pee (which happened in the wake of several courses of antibiotics
  
  
  
• White calcium pees
  The normal way of the body to excrete any excess calcium is via the kidneys. These white pees dry as powdery white patches. The occasional white patch is not a problem at all; it means just that the process is working. A calcium pee hitting a poo can give it a white crust.
  A cluster of calcium pees in a day or two can in some cases signal the onset of a sterile cystitis flare but you want to review your diet if you see calcium pees on a regular, daily or near daily basis and you want to see a vet if you feel/find sharp solid bits (crystals) in those patches.
  Please also be aware that a diet too low in calcium can also lead to the excretion of calcium and calcium pees. It is unfortunately not quite as straight forward as you may wish.

 

[Wiebke]

3 Infections of the Urinary Tract

Problems in the urinary tract usually come with very similar symptoms and are therefore not necessarily as easy or – these days as cheaply – to diagnose.
Squeaking, arcing or grunting when peeing, red pees and general signs of discomfort can apply to both infections and stones/sludge. While stone damage can cause bloody pees, the intensely red pees that characterise the onset of an infection in the urinary can actually test free or low in blood because they are caused by a natural dye called porphyrin. The red is a tiny shade darker and duller than pure fresh blood but you need some experience with either to spot the difference. These strongly coloured pees are usually intermingled with seemingly clear pees that can test high in blood in the initial stages of an infection but the red pees can really scare unsuspecting owners. Normal is a mix and normal is also that there is a little blood when urine is expressed at the vet’s. My own blood-free red pee bloody clear samples were both collected at home prior to the vet visit. If you urine sample at home by sitting your piggy on in a plastic container and wait very, very patiently, please keep your sample in the fridge until you leave for the vets.

It usually takes several days for symptoms to become consistent. You will also see increased or very frequent peeing. A strong stale smell can indicate an infection but please make sure that it is not just the result of an elderly/ill piggy with decreased mobility sitting in their pee and not being able to clean their genital area themselves anymore. In the latter case you need to take over that job (including checking the underside of the feet) and in either case please spot clean the denning areas at least once daily or change the bedding in that area very regularly.


We distinguish between three different infections in the urinary tract:

Bacterial urinary tract infection (UTI)
This is an opportunistic urine infection caused by faecal bacteria in the urinary tract in combination with a lowered immune system. Most guinea pigs have some faecal bacteria in their urinary tract since the tiny scent gland is located right in front of the genitalia/anal opening but the immune system is generally keeping them under control. UTI happens when this control of the bacterial growth is gone.

UTI commonly happens in outdoors guinea pigs that are not well protected and exposed to major temperature swings. We also see a spike in UTIs every spring when indoors guinea pigs are put out on the lawn on the first sunny Spring days without any previous acclimatisation to the outdoors.

You can avoid this very easily: if the lawn is damp and cold to your naked feet within 5 minutes of you standing on the spot you are putting them, then your piggies will be feeling cold and damp very quickly, too. It is not the sun but the ground temperatures (especially after still cold or even frosty nights) that is relevant, the same as tender plants.
Always make sure that your piggies have a warm, dry space out of the wind chill from a sudden cloud or too intense sunshine to retire to.


Bacterial cystitis
A bacterial infection of the bladder walls is generally the result of mechanical damage to the walls of the bladder from a stone or sludge when bacteria get into the scratched areas. It is mostly seen as complication to a stone. A course of antibiotics and analgesics like metacam should do the trick.


Sterile cystitis (interstitial cystitis or IC)
A sterile cystitis is the new kid on the block and therefore not necessarily much known in vet circles that do not see guinea pigs very regularly. It has however become the most common urinary tract infection in indoors guinea pigs over the last 15 years. The infection seems to be mainly affecting the glucosamine coating of the urinary tract and then secondarily the exposed tissue underneath.

‘Sterile’ means that this infection is not caused by bacteria and can therefore not be healed by an antibiotic although its milder forms can be temporarily suppressed by one. That is the reason why sterile cystitis often starts out as what looks like recurring or chronic UTI when treated by a vet who is not aware of it.

Sterile cystitis can run the whole range from the very mild to the very severe and sadly untreatable form. It seems to mainly affect guinea pigs with a high stress default setting, which happens while still in the womb when the mother’s high stress is accepted as the embryo’s ‘normal’ similar to feline sterile cystitis (FSC) in cats – the other species known for their problems with the urinary tract.

More relaxed companions can fend it off with their immune system; they may have temporarily some pees that stain hay intensely yellow but will never progress to developing any further acute symptoms.

Diagnosis usually still happens mostly by default after all other potential problems with the urinary tract have been excluded but a positive diagnosis can be made by the combination of infection markers (like high protein and often blood in the urine) with a zero or low count of bacteria in the urine. Since most guinea pigs have some faecal bacteria in their urine, it is the lower than expected count that will usually swing the balance towards sterile IC.

Because antibiotics are no use, sterile cystitis cannot be cured; it can only be managed while lasts. Once the initial symptoms are under control, it is characterised by regular flare-ups every few weeks. These flares are the ‘interstitial’ (i.e. recurring) part of its better known name which is a description of its special feature.

In milder to medium forms of the infection, the interim between the acute flares can eventually lengthen and the infection can disappear again, never to return. But we are talking years rather than months. The stronger forms are sadly not yet treatable and the most virulent form is coming as a very fast decline in a matter of days. The stronger forms can lead to the bladder to contract and the walls to thicken but thankfully this will reverse to some degree if the infection can be kept under control or is gone.

Treatment is with anti-inflammatories and painkillers like metacam (meloxicam). In milder to medium cases, a glucosamine cat bladder supplement (like the contents capsules for easy dosage) will help to replenish the beleaguered natural coating but any form of glucosamine will do – glucosamine is classed as a food supplement and not as a medication but you will need to work out the appropriate dosage for your case with your vet. It will however take several weeks to build up in the system, so don’t expect instant miracles. You will also have learn how much you need to up the glucosamine and metacam shortly during acute flares to bring them under control again quickly aside from the general maintenance dose.

For more severe forms there is now cartrophen, which recent research has shown that it also works for guinea pigs. The combination of cartrophen and glucosamine plus analgesics may push the boundary of treatable cases a bit further out yet again; I have very recently come across a successful example. In parallel with cat treatment there seems to be currently also some experimentation with calming medication but we have yet to see whether that can be successfully transferred to guinea pigs with a very different metabolism.

More information on urinary tract inections in these links here:
Guinea Lynx :: UTI
Links - Interstitial Cystitis - Guinea Lynx Records

 

[Wiebke]

4 Stones, Sludge and Crystals

Guinea pigs have very alkaline urine. The lack of acidity means that any calcium is not dissolved and can easily build up.

Crystals, stones and sludge
All stones start as crystals or very small stones in the kidneys and move gradually down via the ureters into the bladder or on into the urethra. They most commonly fetch up in the bladder where they can grow to quite a size and may also pass into the urethra where can get stuck and cause major problems. Smaller stones can be passed out naturally. Stones can be rather rough or smoother when in the bladder for longer, and rather rarely, they can be a composite of smaller crystals.
Some stones can unfortunately grow to quite a large size without ever causing symptoms until a very sudden and fast mystery decline.

Any sharp gritty bits in a powdery white calcium pee that do not dissolve are crystals. When crystals build up in the bladder without being flushed out but without bonding with others or growing layers, then they form bladder sludge. In the extreme sludge can pack the full bladder cavity and will have to be removed operatively.

Contrary to what most people would assume, stones are not made out of calcium; they commonly consist of carbohydrates or rarely of oxalates.

Three very large bladder stones (the one on the right is rabbit-sized)


This is a more unusual stone resulting from a conglomerate of small crystals (it is still carbohydrate-based).
Because it was so very scratchy, the damage to the bladder walls was bad and resulted in a cancerous growth inside the bladder.


Bladder stone and sludge removal
The first step when a guinea pig is presenting with urinary tract symptoms at the vets is often a quick palpation of the bladder. A stone in the bladder can be often felt. If the bladder is large and soft to the feel, a bladder stone can be excluded; a small bladder with hardened thick wall points toward considerable longer term or severe pain or trauma. It can be both the result of a more severe sterile cystitis or a stone/sludge problem – even if the stone has moved on. It does however give your vet a quick hint as to where to direct their inquiry and what further investigations (a scan, x-ray or tests) may be needed.

Unfortunately, there is no reliable medication that will dissolve stones or that will make guinea pig urine turn acidic enough. There are sporadic success stories but in the vast majority of cases they do not work out.

Some vets may additionally use potassium citrate but it is just at the best a supportive measure and not an all heal. I would recommend discussing this with your treating vet.

What is always good to do is supplementing with glucosamine in order to help protect and replenish the beleaguered bladder and urinary tract walls. In the case of stones or sludge, the damage to them is mechanical but it is not fun getting them banged into the walls around the exit with every pee!

In most cases operative removal of bladder or urethral stones and packed sludge is the only option. The success depends on where the stone is located and whether it is a straight forward operation or not. In some cases there can be several stones or crystals embedded in the walls of the bladder or the urethra, making their removal and the operation a lot more difficult. However, especially in view of the exposure of any operation wounds to urine, straight forward bladder operations have actually a good and fast recovery rate. Often the sheer instant absence from the constant pain of the stone acts as an instant perk as soon as the healing process gets underway.

Unfortunately, boars have an awkward inglenook in their longer and narrower urethra where stones and crystals usually fetch up and can get stuck. It is a more risky operation but if a boar with urinary tract symptoms very suddenly starts to goes downhill very quickly, then he needs to be rushed to the vets as a life or death emergency because there is a high likelihood that a stone in the urethra is blocking the flow of urine.

Urethral stones in sows usually fetch up just inside the ring of muscles that control the exit. A small stone may be manipulated out by your vet or come out with just a small incision but with a larger stone, a proper operation may be needed. It is much rarer that stone is blocking the urethra in sows but it does happen.

Large urethral stone in a sow sitting behind the exit


Sadly, operating kidney stones or stone in the ureter seems to be still just beyond the horizon for the time being. It is being attempted but so far pretty much without success. You can hope that a stone will move down into the bladder on its own volition but sometimes it doesn’t happen or more stones form in quick succession or are already forming. Better diagnostics can help with spotting them but it may lead to some tough decisions.

Milder cases of sludge can be treated by flushing the bladder very gently with water. However, you need a good vet with experience with it because when it is done too roughly, urine will be pushed back up into the kidneys with fatal consequences.

Repeated flushing every few months however prolonged my own Cariad’s life for nearly two years when her calcium absorption process went suddenly haywire and she produced a large stone in just a few weeks. Dietary tweaks could slow down that process, keep it to the sludge and gradually extend the interval between treatment but they could not stop the formation altogether until she became too frail for further treatment.

We speak of bladder trauma in the wake of a bladder stone or severe sludge operation when the constant banging and scratching from stones, sludge or crystals can lead damage of the walls of the bladder or urethra. It can result in sometimes heavy bleeding in the wake of an operation and will require high amounts of painkiller and an antibiotic to hopefully make a recovery. It very much depends on how bad the damage is. This can also sometimes happen in the wake of passing a stone naturally. Any sheer bleeding from the anus should be seen by a vet promptly.

More helpful information links:
Guinea Lynx :: Bladder Stones
Emergency and Crisis Care as well as Bridging Care until a Vet Appointment
Tips For Post-operative Care


Dietary considerations
Calcium
What can play into the stone formation is an imbalance between the calcium and the phosphates in the diet. There is a sweet spot where the diet is perfect; however since this sweet spot is not quite the same everywhere, there isn’t the perfect diet that fits everything. Go too low in calcium, and you can also get calcium pees and stones.

Most diet recommendations focus only on the vegetables and fruit whereas in a mainly hard water country like the UK, most of the calcium in a diet comes via the water and also the pellets. The USA is mainly a soft water country so you have to be very careful when following dietary recommendations as to where they come from; they may be just wrong for you.

In many cases, filtering hard water and reducing the amount of pellets will do the trick. It is also not well known that the calcium content even in no added calcium pellets is –weight for weight – still noticeably higher than that of kale. That is the reason why I have switched to just feeding 1 tablespoon of pellets per piggy per day for the UK; it gives you a bit more leeway with the veg.

However, unless you feed a grossly calcium rich diet, it is often more than one factor that plays into the formation of stones since not all of your piggies will ever develop stones. Often there seems to be a genetic disposition in play or sometimes the complex calcium absorption process can suddenly flip and larger stones can suddenly form in a matter of just a few weeks.

Guinea pigs that are not naturally big drinkers or that will not drink at all are also at a greater risk of stones and infections since their bladder is not flushed out as often and as strongly. If you have a water guzzling piggy at the upper end of the spectrum you don’t usually have to worry about stones. However, you cannot make guinea pigs drink more and you should definitely not syringe lots of water to a non-drinker. If you have access to fresh grass or can grow it indoors, then that is a much better way of smuggling water into the diet. A bit more cucumber is also an option when grass is not available.

Diet is just pretty much the only way we have for controlling the potential build- up of stones, so options are limited. This is crucial especially in the first few weeks after a bladder stone operation since dietary changes will take some weeks to come through while the system is still unbalanced and a second stone can form.

Foods high in calcium
Please avoid alfalfa/Lucerne hay or alfalfa pellets unless for neglected pregnant and nursing sows and very young pups with a neglect background where it is very helpful indeed.

Kale and greens can be fed, but more as an occasional treat as part of a mix and not as a daily food. The same goes for most fresh herbs.


Oxalates

Some stones are formed from oxalate (although fairly rarely) but oxalates also play a role in the formation of stones and are best used with caution in a piggy diet. Too many oxalates in a daily guinea pig diet can actually lead to kidney failure.

Foods high in oxalates
Spinach is best avoided or only fed as a rare special treat (a single leaf or two) if you have leftovers from your own cooking. A one-off larger meal will also not do any harm if that is all you have handy. But it is definitely not something you should feed daily or even several times a week. The same also goes for other foods high in oxalates and calcium.

Cabbages can also be rather high oxalates as well as calcium. Many herbs, especially parsley are also high in both oxalates and calcium and should only be fed occasionally in a small quantity; they are however also rich in a wide range of trace elements that are not in pellets so I would not strike them off entirely.
Beet leaves, Swiss chard leaves, purslane and clover are all high in oxalates. Lettuces can also vary with rocket and butter head salad the highest.

Nitrates (as in lettuce or most green foods) seem to be the latest issue thrown into the ring as another potential contributing factor to stone formation. However, please don't panic and ditch everything in your diet straight away. so it becomes totally unbalanced and then really leads to stone formation.
You have to see the whole of fresh veg, fresh and dry forage, 1 tablespoon of pellets per piggy per day (optional) and any treats as basically one food group that replaces the supplementary role that wild forage used to have in the grass/hay based diet guinea pigs have evolved on. Once you filter any hard and/or mineral rich water, you have some leeway in that combined food group. The old rule of 'everything in moderation' still holds - and still works in cutting down majorly on stone formation in our long term members.

Long Term Balanced General And Special Needs Guinea Pig Diets (it is not the leading recommended diet but it is a diet that has stood the practical test of time)


PS: It is probably not quite a surprise that the supply issues at the start of the pandemic have led to a noticeable increase in bladder stones since it was much harder to get hold lower calcium greens and veg in the run up to and during the first lockdown, according to vets I have spoken to.

 

[Wiebke]

5 Kidney problems and bladder cancer

Kidney infections and failure
Pain in the kidney or in surrounding organs often results in a quite distinctive rounded hunchback posture.

If it is combined with weight loss, then a vet trip may be necessary. Kidney infections are treatable with antibiotics.

However, if you are dealing with weight loss, often but not always increased drinking and typically very dilute, watery urine that hardly discolours when oxidising then you may be facing kidney failure. There are some rather expensive medications can extend the life for a few weeks but not much more. Unfortunately, kidney failure in guinea pigs is not something that can be treated well. Their faster metabolism and the way they absorb medication is unfortunately against them. It is one of the more common organ failures in older guinea pigs.


Bladder cancer
Bladder cancer or cancerous growths in the bladder are thankfully rare but unfortunately not all that well treatable, like most cancers in guinea pigs. It is one area where you have to rely on your vet and their advice as any further steps very much depend on the nature of the cancer and where it is located and whether it is already spreading.



I hope that this guided tour around the urinary tract is going to help you in learning what is normal and what not, and when to step in with a trip to the vets and opening a support thread in our specially monitored Health/Illness section for moral and practical support during any treatment.

Please try to make sure that you know the alert signals but that you do not fall into the trap of spending most of your ownership on the lookout for possible symptoms. Most guinea pigs are thankfully perfectly healthy and they are there to brighten up your lives, not feed your mental health issues.
Pet Owners Anxiety - Practical Tips For Sufferers and For Supporters