Bladder stones in guinea pigs serve to remind us that sometimes life isn't fair. We can do everything right, and still fall victim to calcium carbonate. A guinea pig that pauses and gives a high pitched squeak when going pee or poop or has blood in the urine may be suffering from a bladder stone.
Unfortunately, this is a problem that can't be ignored. There is no medication that can dissolve them once they have formed, and the longer they are left untreated the larger and more painful they may grow. Specific conditions, such as a diet too high in calcium, are known to cause these stones. But, sometimes, there is no explanation. Some guinea pigs just didn't hit the genetic jackpot.
Preventing Bladder Stones Through Diet
The good news is there is plenty that can be done to prevent bladder stones in the first place. Dr. Becky Burk, an exotic veterinarian at VCA Mercedes Place Animal Hospital in Benbrook, Texas, recommends pet parents focus on making the majority of the diet grasses/hays that are low in calcium. "Too much alfalfa hay in the diet contributes to hypercalciuria, a risk factor for calculus formation. Alfalfa has a high calcium:phosphorus ratio, too. All legumes can be associated with urinary calculi, especially if the animals have a high content of legume-only foods in their diet for extended periods," she says. According to Dr. Burk, the ideal ratio of calcium to phosphorus in a guinea pig's diet is 1.2-2:1. While legumes (like alfalfa and clover) have a ratio of greater than 4:1, grass hays are closer to 1.5:1. Pellets should be timothy hay-based for this reason, too.
Fresh green foods contain a lot of water, which is important to flush out the bladder. Roughly a cup of veggies a day is sufficient, but a few extra water-rich treats like cucumbers may benefit the piggy that takes little interest in the water bottle. Some vegetables, like spinach, need to be fed in moderation to adult guinea pigs due to the high calcium content. Try simple swaps, like cilantro instead of parsley, to lower the guinea pig's overall calcium intake. Guinea Lynx takes the guesswork out of balancing calcium and phosphorus with a handy calculator; just enter weight in grams and generate a calcium: phosphorus ratio for a day's worth of foods.
Bladder Stone Treatment
Now for the bad news. Most of the time, once bladder stones have formed they will need to be surgically removed - especially true in male guinea pigs. Guinea pigs can be tricky surgical patients due to their sensitivity to anesthesia and delicate GI tract (not to mention the anatomical disadvantage of weighing two pounds and being the size of a baked potato). Don't be afraid to ask the vet plenty of questions to see if they're familiar with the procedure and won't withhold food from guinea pigs before surgery. And, of course, make sure a simple urinary tract infection is first ruled out. An X-ray should be done to confirm the presence of a bladder stone.
If a stone has moved into the urethra, and the piggy is lucky enough not to have a full blockage, sometimes they can be manipulated out with light sedation, lubrication, and a skilled veterinarian. Lifelong pain medication can be attempted for guinea pigs that aren't good candidates for surgery. Quality of life should always be considered.
How To Avoid Recurrence
Once stones have been removed, Dr. Burk recommends "encouraging diuresis, as it aids in the expulsion of urine sludge and microscopic calculi." A simple way to do so is to provide a second water bottle with flavored water (perhaps with a splash of 100% fruit juice) to encourage extra water intake. " I would ensure that the guinea pig is not drinking hard water; treated tap water or low calcium content water is preferred," she says.
Diuretic drugs can also be used. "Decreased levels of urine calcium are generally associated with the use of thiazide diuretics. Avoid giving loop diuretics like Lasix though, as they cause excretion of inappropriately high levels of calcium and magnesium in the urine," she warns. Alternatively, Dr. Burk suggests supplementing the diet with potassium and magnesium citrate, which both may prevent stones from forming. "Citrate is recommended not because of its urine pH modifying effect, but because of its ability to reduce crystal formation."
Managing Bladder Sludge and Cystitis
Guinea pig urine is slightly opaque, but if it leaves behind white gritty deposits when dry on multiple occasions, it's a sure sign it's time to make adjustments in the diet. Guinea pigs that are prone to bladder sludge are at a higher risk of forming stones. Those that have had a bladder stone removed still may struggle with bladder sludge and cystitis afterward. Putting your guinea pig on a dark-colored towel is a great way to look at how the urine dries. A white towel is helpful to check for blood in the urine (if unsure if blood or just normal oxidation, pour a little hydrogen peroxide on the towel to see if it bubbles).
Because bladder stones can come back in just a few weeks or less, continuing symptoms after surgery warrant another X-ray. If multiple views show no stones (and diet has been adjusted) the vet may recommend increasing fluids via syringe or subcutaneously. An over-the-counter supplement like vegan glucosamine can coat the bladder wall and soothe irritation.
Herbs like Shi Lin Tong and natural supplements like Renavive are alternative treatments used lately with mixed reviews, but be warned there is little scientific research backing their claims. Reportedly, they may help guinea pigs with very small crystals pass them before they turn into true stones. Always discuss adding any new medications with your veterinarian. Bladder problems can be very uncomfortable, and sometimes prescription pain/anti-inflammatory medicine can be given as needed to give the piggy a better quality of life.
Bladder stones are a common problem that guinea pig slaves have come to dread. Careful diet adjustments are key to preventing stones from forming, but some guinea pigs will struggle despite our best efforts. Luckily, there's finally more research on the topic than ever before and plenty of options to help keep stones at bay.