Urinary tract stones (urolithiasis) are stones/crystals that can be found anywhere in the urinary tract and are more common in males. Normally the rat will not show any symptoms until a stone blocks the flow of urine or enough stones have formed to distend the bladder. Symptoms of urinary tract stones include: difficulty or lack of urinating, foul odour, distension, cloudy or bloody urine, dehydration and poor appetite, restlessness, biting itself, and twitching/spasms caused by pain. The stones rub and irritate the linings of the urinary tract and as urine is obstructed there is a very high chance of infection occurring.
It’s usually hard to determine what the exact cause of stones is and if treatment effectively removes stones, there is still a high chance of re-occurrence. The many factors that can contribute to stone formation are: genetic predisposition, diet imbalance, diabetes, high blood calcium, dehydration, bacterial infections, bladder thread worm, or loss of bladder control due to a stroke or hind leg paralysis.
Stones are very difficult to treat in rats and it’s important that it’s done by a qualified, experienced vet. Antimicrobials may be used to help dissolve smaller stones or surgery can be used to remove them. If the bladder is distended a catheter can be used to drain the urine. A sedative or muscle relaxant should be provided to help relieve pain, antibiotics to treat infection, and if bladder thread worm is suspected also treat with ivermectin or fenbendazole. If the rat is dehydrated, an injection of fluids should be given but only in moderation until the urine is able to flow again! The diet should also be modified to include less calcium and protein (and if urine is able to flow) encourage drinking to prevent dehydration. If treatment is ineffective and the rat’s quality of life is poor, you should consult with your vet about euthanasia.