Rabbits and guinea pigs commonly suffer from problems with urinary stone formation. As vets we call this problem urolithiasis. It relates to the formation of urinary calculi in the kidneys, ureters, bladder, or urethra. Calculi is composed of minerals that join together forming solid objects. These can be in the form of large ‘stones’ or smaller ‘sand’ and actually do resemble rocks and beach sand. The smallest calculi are just visible with the naked eye whereas the largest can be the size of a tennis ball in a rabbit.

What are some of the causes of urolithiasis?

  • High calcium diets in adult rabbits or guinea pigs. Calcium is important within the body for healthy bone and teeth formation as well as several other important physiological functions. However, if too much calcium is consumed, urinary stones can form. Lucerne hay is high in calcium and should only be given sparingly to adult animals, if at all.  Mineral supplements can sometimes increase the risk of urolithiasis.
  • Not enough water intake. Hay is very important for your rabbit or guinea pig for several reasons including dental wear and gastrointestinal function. Another reason is to help encourage your rabbit or guinea pig to drink adequate amounts of water. Hay is quite a dry food item so your pet will drink more when they are eating lots of hay.
  • Infection. Urinary infections can lead to bladder stone formation in some cases.

What are some of the symptoms of urolithiasis?

The most common symptoms are pain or vocalisation when urinating, blood in the urine, straining, lethargy or urinating small amounts frequently.

How do you diagnose the problem?

Luckily for vets, urinary stones often show up well on radiographs (x-rays). We take a few different views to allow us to evaluate the whole urinary tract and see where the stones have formed. In some rare cases, the urinary stones are not visible on radiographs, however ultrasound usually shows them up well.

What treatment options are available?

The treatment options depend on where the urinary calculi have formed as well as the size of the stone or stones. Unfortunately in many cases medical therapies to disintegrate the calculi are often not effective on their own. If stones are too large to pass, surgery will be needed. If there is a lot of small bladder ‘sand’ or ‘sludge’ present then your pet’s bladder may need to be catheterised and gently flushed out.

Is it a serious problem and does it recur?

Urolithiasis can be very serious as the calculi can damage the insides of the urinary tract as well as become stuck and cause a blockage. If a blockage does occur then this can quickly develop into a life-threatening problem. Unfortunately, in some cases urinary calculi can reform however once the stones have been removed there are a number of medical and dietary treatments available to minimise the chance of recurrence.

Article written by Dr James Haberfield of The Unusual Pet Vets