A kidney disease known as Renal Dysplasia is common in the Shih-Tzu breed. It bears some similarity to kidney disease in the Lhasa Apso. Whether the disease is inherited is not yet known but a good deal of evidence points in that direction.
the occurrence of renal disease in young Shih-Tzu puppies and the fact that usually more than one puppy in a litter and in some instances, the entire litter is affected leads us to suspect it is inherited and that every effort should be made by Shih-Tzu breeders to avoid breeding any stock whose former offspring have been affected. Currently the disease is irreversible and death is inevitable.
There are 3 stages of development. Unfortunately there are no clinical symptoms of early renal disease which may progress over a period of months or years to the second stage,when symptoms first become obvious. The affected dog will develop an excessive thirst and will pass greatly increased amounts of urine. The urine will appear to be very diluted or watery. Some dogs will be listless, poor eaters, and may suffer a weight loss. In the final stage, the symptoms of stage two are more pronounced and may be accompanied by severe depression, diarrhea, vomiting and dehydration -- all evidences of kidney dysfunction which will sooner or later result in coma and death.
Renal disease runs high in all breeds of dogs. After the age of eight years, 85% of all dogs have some kidney degeneration or will have developed chronic nephritis. This is known to be a congenital, hereditary progressive kidney disease in certain breeds, whereby the kidneys do not maintain sufficient function to sustain life.
Kidney and bladder stones
Stones occur more in males than females because of the male anatomy: the urethra in the male is small and can easily become obstructed by a stone. The urethra in the female is larger and less prone to stone development. Phosphate stones are the most common and greater incidence of this type is found in the female than in the male. They are associated with alkaline urine and frequently with a bladder infection.
Urate stones, composed of uric acid are more frequently found in the urinary system of males and in these cases the urine is acid. Cystine uroliths composed of the amino acid cystine makes about five percent of all stones and occur exclusively in males. It is an inherited defect wherein cystine is reabsorbed into the kidneys rather than excreted in the urine and it accumulates in the bladder where stones form. They must be removed by surgery.