Hi
Have bladder stones and sludge been both excluded by palpitation and an x-ray?
There is a not well known condition called sterile interstitial cystititis (or sterile IC), i.e. a non-bacterial recurring bladder infection in guinea pigs that doesn't react to in more severe cases or can only be temporarily suppressed but not healed in milder cases. I have mentioned it as a possible cause in my first post together with the others.
Sterile IC seems to particularly affect the natural glucosamine coating of the walls in the urinary tract that prevents the corrosive urine from coming into contact with raw tissue. Deep red porphyrine coloured pees are typical for the onset of any acute phase; symptoms in the urinary tract can be very similar so it is usually only diagnosed by default. It has become a lot more common over the last decade due to commercial mass breeding (whether that is pet shop suppliers or for sale breeders) but vets that do not see guinea pigs frequently. They may have perhaps heard of sterile feline cystitis (FSC); treatment of guinea pigs follows similar lines.
Management is with glucosamine and analgesics such as meloxicam (metacam). Glucosamine is classed as a food supplement and not as a medication (hence why it is generally not prescribed by vets) although in severe cases, high glucosamine medication such as a cartrofen, which is a widely used arthritis drug for humans and larger animals has recently shown to work in guinea pigs, too. You can get glucosamine as a food supplement for cats in capsules widely online (easier to dose) or even from a supermarket shelf as a human supplement (although you will have to grind that down and do the mathematics with dosages when mixing it with the correct amount of water. The piggies really don't like the taste but it is a lot cheaper). Glucosamine supplementing is not an instant cure; it takes weeks to build up in the body but it has shown to be the most important part of sterile IC management; especially in bringing the regular flare-ups under control. It is not curable, only manageable until it hopefully goes away on its own some years down the line. An analgesic (anti-inflammatory and painkiller) is also important in order to help with the pain of the inflamed tissue.
Could you discuss this with your local vet? We cannot diagnose sight unseen, just show up further avenues to pursue with your vet. In the UK, both metacam (meloxicam) and cartrofen are prescription-only medication.
Links - Interstitial Cystitis - Guinea Lynx Records
Dietary recommendations for sterile IC can be found in the urinary tract problems special diet recommendations chapter of our diet guide. Here is the link again:
Long Term Balanced General And Special Needs Guinea Pig Diets
. Any one know how much and how often I should give?
