Whilst the festive season is more traditionally associated with rejoicing and reflection it is sadly also a time of the year which sees a big increase in disease, pain and misery!

A large number of these ailments are associated with big population movements (family visits) and the consequent spread of contagious disease (flu,gastroenteritis). However, there is also a significant degree of discomfort which is self inflicted through overindulgence. Whilst I myself have thus far remained immune to the barrage of micro-organisms which greet me each day in the consulting room I must confess to subscribing to the latter!

"Doris" too has to "put her paw up" and concede that the considerable discomfort she experienced in trying to pass the stone lodged in her urinary tract was to some extent self inflicted.

Guinea pigs normally digest wild plants which contain calcium in the form of calcium oxalate. This is then passed through the digestive tract unabsorbed or filtered by the kidneys and excreted in the urine.

Some pelleted proprietary foods, as well as dandelion leaves, alfalfa hay and thistles are high in calcium carbonate which is more readily absorbed in the bowel leading to overload of the urine and the formation of calcium carbonate stones. These stones can then accumulate further calcium minerals until they reach quite an alarming size.

Fortunately, for Doris my colleague Aga was able to determine the cause of her distress and was able to remove the stone through a small surgical incision. As you can see from the photo, "Doris" is finding it hard to believe that she was capable of passing something that large!"Doris" and I have both agreed that if she resolves to lay off dandelion leaves and thistles in 2009 I will cut down on the "Scottish mist".