Presenter: Alison Moores BVSc (Hons) CertSAS DipECVS MRCVS, RCVS Specialist in Small Animal Surgery, European Veterinary Specialist in Small Animal Surgery, Anderson Moores Veterinary Specialists
RCVS and European Specialist in Small Animal Surgery, Alison Moores, led last week’s Platinum Members webinar discussing all aspects of diagnosing and managing urinary incontinence in our small animal patients. Dogs did however feature predominantly as this is a condition rarely seen in our feline friends. Differentiating between true incontinence and other conditions such as UTI or partial urinary tract obstructions can be the biggest challenge, and Alison delivered a logical and practice relevant approach on how to achieve this and then go on to manage these conditions as effectively as possible.
The use of a patient’s signalment and history can play a really important role in differentiating between true incontinence and other forms of incontinence, as well as differentiating between the actual causes of true incontinence. For example a dog with true incontinence is likely to produce puddles of urine in sleeping areas whereas a dog with overflow incontinence caused by a partial obstruction is likely to continually drip urine. Also a young Golden retriever presenting with true incontinence is much more likely to have ectopic ureters whereas an older Doberman is more likely to be suffering from urethral sphincter mechanism incontinence (USMI).
Physical examinations can also prove useful in differentiating between true incontinence and other causes of urine leakage. For example, if a patient has been found to have a large bladder which is difficult to express, then overflow incontinence is a more likely reason for urine leakage and is possibly secondary to a partial obstruction or an underlying neurological condition. Alison did however remind us that if we suspect a urethral obstruction but find we can still pass a urinary catheter, this by no means excludes urinary tract obstruction from our list of differentials, as catheters can sometimes by pass the offending obstacle.
Finding a small or normal bladder on physical examination points towards a true incontinence which is most commonly caused by one of two conditions, USMI or ectopic ureters. In fact studies have shown that 50% of young urinary incontinent dogs will be suffering from ectopic ureters and a third will be suffering from USMI, whereas 80% of adult dogs suffering from true urinary incontinence will be suffering from USMI. Physical examination is of no benefit in differentiating between ectopic ureters and USMI and further diagnostics need to be performed in order to diagnose each condition. Historically radiography and contrast studies using intravenous contrast agents were the best ways to diagnose ectopic ureters but it can be easy to miss ectopic ureters using these methods. Ultrasound is another diagnostic tool which could be used but obtaining and interpreting the necessary diagnostic images usually needs a highly experienced ultrasound operator.
Cystoscopy is now judged the diagnostic tool of choice as ectopic ureters can usually be visualised using this method. USMI is diagnosed once other potential underlying causes have been ruled out such as ectopic ureters, uroliths and neoplasia, which could be invading the urethral wall thereby impeding its normal function.
Alison went on to discuss the treatment for both ectopic ureters and USMI. Medical treatment is the natural first choice for USMI and involves the use of the alpha adrenergic agonist, phenylpropanolamine to increase urethral resistance. Its use offers a cure rate of 85% at one month. However, studies have shown a drop off in its efficacy over time with a 50% cure rate, a 40% improvement rate and a 10% failure rate at up to one year on medication. Alison advises, for failing cases, estriol (Incurin) should be given alongside phenylpropanolamine as it increases the number of receptors responding to phenylpropanolamine. If medical treatment is unsuccessful, surgery becomes necessary and techniques including colposuspension and the placement of an artificial urethral sphincter (useful in male incontinence) were discussed in depth within the webinar. The treatment for ectopic ureters is always surgical and various techniques were discussed for normalising the position of the ectopic ureters but currently there is only a cure rate in about 50% of cases using these techniques.
Alison delivered a comprehensive webinar discussing all aspect of urinary incontinence in the dog (although there was a nod to the cat at the end of this webinar). It is always nice to know that the approach you take with these cases is logical and appropriate and I believe Alison has helped to reassure me of this. However, advice on the effects of neutering on continence in bitches still remains unclear, as Alison explained there is no strong evidence demonstrating that spaying can cause urinary incontinence in the bitch. The only real evidence currently available demonstrates that neutering before three months of age is likely to lead to incontinence and should be avoided if possible.
As always ‘The Webinar Vet’ has organised a compelling and information packed webinar and from the final discussions between Alison and the facilitator, it sounds as though she might well be back to deliver more – I can’t wait!