Chocolate is a 3 year old Guinea Pig with a glossy brown coat. Mr & Mrs Coomber brought him to us as they had noticed he was often damp around his nether regions and he was leaving blood spots on the floor. Our vet, Duncan, immediately considered the possibility of one or more bladder stones but initially decided to try treatment for cystitis which shows similar signs. This initial treatment with antibiotics and anti-inflammatory and pain relieving drugs did not help and Chocolate continued passing more blood so Duncan advised an X-ray to check for stones.
As you can see the X-ray revealed one large stone and Chocolate was booked in for surgery to remove it. This operation is called a cystotomy and involves making an incision into the bladder to remove the stone, whilst being very careful not to allow any urine to leak into the rest of the abdomen. It is delicate surgery in any species, but even more tricky because of the small size of a guinea-pig's bladder!
A bladder stone is an accumulation of chemicals that deposit out of the urine, gradually developing from sand-grain size to often quite large stones. In Guinea-pigs they are usually composed of Calcium carbonate.
The cause is not well understood but there appear to be genetic and dietary factors. Being overweight is another contributory cause. Unfortunately recurrence is common. To reduce the chances of further stones guinea-pigs should be encouraged to drink more water (try filtered - they may prefer the chemical-free taste and filtered water reduces the level of calcium), and have a relatively low calcium diet - unlimited high quality grass hay along with leafy greens and limited (or no) low-calcium pellets should be the cornerstone of his food.
Chocolate’s surgery was very successful and he was soon back home and went on to make a full recovery back to his squeaky self! Let’s hope he doesn't get another stone!