Incontinence describes uncontrolled urination or defecation, which can be triggered by several diseases. In contrast, continence is the ability to retain urine or faeces. In most cases, we assume incontinence to be of the urinary form. Urination is made possible by numerous anatomical and functional characteristics of the system. It helps to take a look at the anatomy in order to understand this in more detail.
Incontinence in dogs
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The bladder is divided into the corpus and neck. From the kidney, there are ureters on each side, which end in the neck of the bladder and transport urine into the bladder. For excretion, the urine flows out through the urethra.
During the processes of retention and excretion, different muscles contribute to tension and relaxation. This includes the inner and outer bladder sphincter, as well as the bladder muscles. These muscles are controlled by different nerves (sympathetic and parasympathetic nervous system), which conduct stimuli to the brain and from the brain back to the muscles. This brings about two different phases:
1. Filling phase
What is known as a sympathetic nervous system comes about from the spinal cord of the lumbar region and measures the bladder extension. If the bladder is empty, the sympathetic nervous system contracts the urethral sphincter, which causes urine to be retained in the bladder. If the disruption is found in the lumbar area, the dog will wet itself.
- Excretion phase
In contrast to the sympathetic nervous system, the parasympathetic nervous system originating from the sacral region causes the contraction of the bladder muscles when it is full and the expansion of the sphincter muscles to allow urine to flow. If there are disruptions in the sacral region, this can lead to the bladder overflowing.
Urinary incontinence isn't just a big problem for dogs, but mostly for the owners too. In order to more precisely narrow down causes, the causes of incontinence are split into primary and secondary categories:
Primary urinary incontinence
Especially with old female dogs, neutering often results in disruptions in closing the urethra. This presumably occurs due to increased loosening of the connective tissue and a reduced oestrogen level, which is maintained by the ovaries in intact females. Hence, other hormonal diseases that influence oestrogen can lead to incontinence. Another common example is an ectopic ureter, which occurs particularly often with Labrador Retrievers, Golden Retrievers and Boxers. This is a deformed ureter, which doesn't join the bladder as usual but instead ends in the urethra.
Secondary urinary incontinence
These include numerous diseases that can lead to incontinence during their course, such as the following examples:
- Tumours, which constrict the bladder or damage the nerves
- Inflammation of the bladder (cystitis)
- Bladder stones (urolithiasis)
- Kidney diseases (nephropathy)
- Diabetes mellitus
- Injuries to the nerves caused by a slipped disc or accidents
- Side effects of medication (diuretics, cortisone preparations)
Urinary incontinence can be recognised by uninterrupted urine flow or also urine being released drop by drop. This often happens when sleeping with incontinence caused by old age or castration/neutering. If the cause is of inflammatory origin, the dog can show severe pain symptoms, a worsened general condition as well as loss of appetite and fever. Increasingly painful urination (strangury) is typical of this. In contrast, young dogs with a malformation show mostly uninterrupted and painless urination.
Incontinence in dogs: diagnosis
A thorough aetiology is helpful in order to be able to find suitable treatment for the problem. In addition, a complete owner interview by the vet is necessary to be able to interpret duration, frequency and other important indications. A general clinical examination and a special examination of the urinary system then follows to search for the cause in a targeted manner. For urine examinations, the vet takes a sterile urine sample using a cannula and ultrasound device. At the same time, attention is paid to structural changes in the bladder and surrounding organs.
Bacteria and urinary stones can often be recognised under the microscope and in sediment. The specific gravity of the urine gives an indication of the concentration capacity of the kidneys by determining the number of particles dissolved in the urine using a refractometer. A reduced specific gravity occurs with diabetes insipidus, for instance. In contrast, there is typically an increased specific gravity with increased fluid loss (dehydration) and different liver diseases. X-rays are a helpful imaging procedure in order to rule out tumours or dislocations.
Since there are very different causes for urinary incontinence, treatment depends on the underlying disease. Malformations and tumours can mostly be treated through surgery, whilst chemotherapy or radiotherapy can be helpful with the latter. Urinary stones (mostly struvite stones) can likewise be removed surgically or conservatively with a low-protein diet to dissolve the stones.
Administering anti-inflammatory medication and antibiotics is indicated with inflammatory causes, as well as with bacterial contribution after a resistance test has been carried out. With hormonal diseases, the missing hormone can be supplemented depending on the hormone level, whilst attention must be paid to the many side-effects with oestrogen. For this reason, all treatment should be monitored by a vet. Complications of urinary incontinence caused by castration/neutering can be alleviated or even prevented with acupuncture, neural therapy, medication like sympathomimetics and surgery. The choice of treatment always depends on the dog's age and general condition.
Whether and to what extent incontinence can be remedied depends on the cause, severity and success of treatment. If the nervous tissue is completely destroyed by a serious accident, the prognosis is mostly unfavourable. However, a bladder infection or bladder stones are mostly curable.
Since urinary incontinence caused by castration/neutering is one of the most common causes and has a strong predisposition to breed, it should be closely considered whether castration/neutering should be carried out particularly with affected breeds. In order to prevent urinary stones and inflammatory ailments, attention should be paid to sufficient water consumption as well as a balanced diet.
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