URINARY INCONTINENCE IN DOGS : TREATMENT , CARE & MANAGEMENT
Urinary incontinence is the involuntary leakage of urine. It can sometimes involve just a few drops of urine, but for many dogs, it may be a larger volume of urine where puddles appear on the floor or their bedding is wet where your pet has been sitting or lying. Urinary incontinence is not under your dog’s control, and therefore, dogs cannot be ‘trained’ out of it.
Canine urinary incontinence is not harmful by itself, but potential side effects include scalding of the skin and skin infections, urinary tract infections and in some cases, serious kidney infections.
Urinary incontinence is defined simply as the involuntary passing of urine. But for pet owners whose cat or dog suffers from the condition, understanding and treating urinary incontinence is anything but simple. The most common indicator that an animal might be suffering from incontinence is urination inside the home or outside the litter box that is persistent and seemingly unrelated to a behavioral issue. In most instances, incontinent pets may not even recognize that they’re urinating.
A pet owner might notice small or large puddles of urine when the animal is standing, sitting, or even sleeping. Pets with urinary incontinence may also have wet hindquarters and irritated skin and smell of urine. It’s important for pet owners to obtain a diagnosis from a veterinarian because incontinence can easily be confused with frequent urination, but the 2 are very different. Your veterinarian will also want to rule out behavioral disorders. In these instances, a pet would likely urinate because of a particular event, such as a loud noise, and not a true medical condition. Similarly, urinary incontinence should not be confused with submissive urination, which occurs when a pet (usually a dog) is acting submissively to a person or other animal. In instances like these, if behavior is believed to be the cause, your veterinarian can still provide some techniques to reverse the action or refer you to a veterinary behaviorist for further treatment.
Micturition refers to both storage and voiding of urine, whereas urination refers only to voiding. Urinary incontinence is the involuntary passage of urine. Micturition disorders may cause both urinary incontinence and urine retention.
Non-Neurologic Causes of Incontinence
Urinary incontinence in young animals may be congenital, whereas the condition usually is acquired in older animals. Congenital abnormalities resulting in urinary incontinence include ectopic ureters, patent urachus, female pseudohermaphroditism, rectovaginal fistula, and vestibulovaginal stenosis.
Neurologic Causes of Incontinence
Urinary incontinence often is associated with neurologic disease. Neurologic abnormalities may disrupt function of the detrusor muscle, urethral sphincters, or both.
The location of a lesion in the nervous system dictates the nature of a micturition disorder. Additional concurrent neurologic abnormalities may be present. Neurologic incontinence may result from trauma, tumors, or herniated intervertebral discs.
Patients with UMN lesions (those affecting the spinal cord cranial to sacral spinal cord segments) lack voluntary control of micturition. Urination may be initiated by segmental (spinal) reflexes, but an absence of sensory perception and central control, and the sphincters’ failure to relax, lead to interrupted, involuntary, and incomplete voiding. Manual bladder expression is difficult if sphincter tone is increased, but the urethra may be catheterized normally. Overflow of urine occurs when the bladder pressure exceeds sphincter resistance. The perineal reflex is intact.
Detrusor areflexia with decreased sphincter tone is a result of disease of the sacral spinal cord or bilateral lesions of the sacral spinal nerve roots (called LMN lesions). Voluntary control of urination is absent. Tail paresis/paralysis and fecal incontinence may be present. The perineal reflex and bulbcavernosus reflexes are absent. The bladder is easily expressed, and dribbling of urine occurs when intravesicular pressure exceeds urethral pressure.
Detrusor areflexia also can occur secondary to prolonged overdistention of the bladder. Tight junctions between detrusor muscle cells are disrupted, preventing spread of nerve impulses. The animal will attempt to void because sensory pathways are intact, but the atonic, flaccid bladder is unable to contract. Residual urine volume is large.
Reflex dyssynergia occurs with incomplete spinal cord lesions cranial to the sacral spinal cord segments. The detrusor reflex is normal to hyperactive, and the urethral sphincters are hyperactive. The patient voluntarily initiates urination, but the urine stream is abruptly stopped because there is lack of synchronization between bladder contraction and urethral relaxation, leading to incomplete voiding. Urethral obstruction can result in a similar abnormal pattern of micturition.
Cerebral lesions may result in the loss of voluntary control of micturition. Detrusor hyperreflexia rarely results from cerebellar disease. Urinary incontinence due to bladder atony may occur in cats with autonomic polygangliopathy (feline dysautonomia). Concurrent reduced tear production, pupillary dilation, and regurgitation are present.
Diagnostic Approach to Disorders of Micturition
Important historical information that should be obtained includes the following:
The animal’s age when incontinence first appeared
The chronologic course of events
When the incontinence is typically observed (at rest or with activity)
Whether the animal can urinate normally
Previous surgeries (such as neutering) and illness
Use of medications that might stimulate polyuria (glucocorticoids, diuretics, anticonvulsants) or affect bladder and urethral tone
Previous or current urinary tract disease or abnormalities
A physical examination should include observation of urination to assess voluntary initiation, volume of urine voided, and the diameter and continuity of the urine stream. Bladder size and tone should be assessed before and after urination.
Large Bladder
UMN disorders
LMN disorders
Reflex dyssynergia
Outflow tract obstruction
Small or Normal Size Bladder
Urethral sphincter incompetence
Detrusor hyperrelexia
Congenital abnormalities
Manual expression of the urinary bladder may aid in assessing urethral tone, although bladder expression in normal dogs of either gender may be difficult. The urethra may be palpated percutaneously in males and rectally in both sexes to identify urethral mass lesions. Passage of a urinary catheter will detect urethral obstruction. The volume of residual urine following voiding should be determined by catheterization. Normal residual volume following complete voiding is less than 0.2 to 0.4 ml/kg body weight. Territorial marking of male dogs makes it difficult to assess residual volume.
Following urination, the bladder should be palpated to assess bladder wall thickness or detect calculi or soft tissue masses. In male dogs, the prostate gland should be palpated rectally, abdominally, or by both methods. Urethral discharges should be compared with urine through gross examination, dipstick testing, and sediment examination. A complete neurologic examination should be performed if the incontinence is suspected to be neurogenic. The perineal reflex and bulbocavernosus reflex can be used to evaluate the sacral spinal cord segments and pudendal nerves. The perineal reflex is initiated by stimulating the perineum with a needle. The bulbocavernosus reflex is obtained by squeezing the penis or vulva. Both of these reflexes depend upon an intact pudendal nerve (sensory & motor) and intact sacral spinal cord segments. The response to both reflexes should be constriction of the anal sphincter muscle and flexion of the tail.
Laboratory evaluation should include a urinalysis and a CBC, which might reflect an infection that involves the kidneys. A serum chemistry analysis will assess the presence and magnitude of postrenal azotemia and hyperkalemia in patients with mechanical or functional urethral obstruction. If urinalysis results are consistent with urinary tract infection, urine culture and sensitivity testing are indicated. Survey and contrast radiography may be necessary to evaluate anatomic urinary tract abnormalities.
Additional diagnostic tests that can be performed at many referral institutions include cystometrography, measurement of urethral pressures, and urethral or anal sphincter electromyography and evoked responses. A cystometrogram evaluates bladder capacity, detrusor muscle tone, and the detrusor muscle reflex. Urethral pressure profiles record resting urethral pressures along the length of the urethra and will identify areas of reduced or excessive urethral tone. Electromyography of the urethra and anus aids in evaluation of partial denervation that can be difficult to assess during a neurologic exam. Spinal evoked responses evaluate sensory and motor pathways that mediate the detrusor reflex. Neurogenic abnormalities of micturition may be further evaluated using vertebral column radiography, myelography, computed tomography, magnetic resonance imaging, and cerebrospinal fluid analysis. Direct visualization of the urethra, bladder and vagina can be performed using a rigid cystoscope in female dogs and some cats.
Signs of urinary incontinence in dogs:
- Dribbling of urine or wet patches on the hair around legs
- Wet bedding or puddles on the floor after lying down
- Signs of discomfort or behavioural changes
- Unexplained urinary tract infections
- Scalding of the skin around the vulva
- Excessive licking of the wet genital area
- Unpleasant odour
What causes urinary incontinence in female dogs?
The condition known as urethral sphincter mechanism incompetence (USMI) is the most common cause of urinary incontinence in adult female dogs.
USMI is a medical term used to describe a weakness in control of the muscles of the lower urinary tract.
Female dogs that have been desexed (speyed) may be more susceptible to the condition due to a lack of circulating oestrogen. The reduced oestrogen levels result in reduced stimulation of the sphincter muscle that surrounds the urethra (the structure that takes urine from the bladder to outside the body).
Female dogs with USMI may respond to treatment with hormone supplementation. Hormone responsive urinary incontinence can occur months to years after surgery.
It is essential to understand that the risk of USMI is not a valid reason to avoid desexing your dog. Female dogs that have not speyed are at a much higher risk of other more life-threatening conditions such as pyometra and mammary cancer.
Other potential causes of urinary incontinence might include neurological disease, dementia, ectopic ureters, bladder stones, tumours or other conditions that cause an increase in the consumption of water such as diabetes or kidney disease.
Diagnosis of USMI is usually made based the history and by the elimination of these other possible diagnoses via blood and urine testing and further imaging (this might include contrast radiology and ultrasonography).
Treatment of Urinary Incontinence
Specific treatment of an underlying disease may resolve incontinence; for example, surgery can be used to correct anatomic defects or remove obstructive calculi. Inappropriate urination due to behavioral problems may be corrected with training that modifies the pet’s behavior.
Patients With Neuromuscular Dysfunction
These patients may benefit from temporary drug therapy that assists micturition until neuromuscular function is restored. Rational drug therapy depends on defining the micturition disorder since drugs are selected to produce a specific response (increase or decrease detrusor activity; increase or decrease the tone of the internal or external urethral sphincters). Patients with small bladder capacity due to detrusor hyperactivity may benefit from anticholinergic drugs or smooth muscle relaxants. Atropine is generally ineffective for this purpose and has a substantial risk of adverse effects. Detrusor atony is treated with cholinergic agents. Care must be taken to ensure urethral patency when using cholinergic agents. If the bladder were to contract against a urethral obstruction or in the presence of sphincter hypertonia, the result might be a ruptured bladder or urine reflux into the renal pelves that may result in pyelonephritis.
Patients with Decreased Urethral Tone
These patients are treated with drugs that stimulate sympathetic alpha receptors in the smooth muscle of the urethra. Patients with increased urethral tone are treated with sympathetic alpha-blocking agents or direct-acting smooth muscle relaxants to reduce activity of the internal urethral sphincter. These patients can also be given skeletal muscle relaxants to reduce activity of the external urethral sphincter. A combination of drugs may be required to alter the function of both the detrusor muscle and urethral sphincters. One example is the use of a cholinergic drug to increase detrusor activity and a sympathetic alpha-blocking agent to reduce urethral tone in patients with UMN lesions and sphincter hypertonia. Hormone-responsive incontinence in females or males often responds to administration of estrogen or testosterone, respectively. These patients may also respond to sympathetic alpha-stimulating drugs, and females may respond to a combination of estrogens and alpha-agonist drugs.
Drug doses often are “empirical”, established by clinical observation or extrapolation from human medical data. Several dose ranges for the same drug from different references. Pharmacological manipulation of urination is often through trial and error. Drug doses on the lower end of the range should be used initially, and the doses should be raised in small increments until the response is adequate. Clinical response to some drugs such as phenoxybenzamine may be slow, taking a week or longer. As long as there are no undesirable side effects, a drug trial should continue for several weeks before the drug is considered ineffective.
The duration of drug therapy is determined by the reversibility or irreversibility of the disease causing the micturition disorder. When long-term pharmacologic manipulation is necessary, the lowest dose and the least frequent dosing interval needed to achieve the desired response should be used. Patients should be monitored closely for adverse side effects, some of which may be life-threatening if not recognized early (profound hypotension subsequent to the administration of sympathetic alpha-blocking agents).
Patients with distended bladders often require expression of the bladder or catheterization in addition to drug therapy. Urinary tract infections occur frequently in patients that cannot completely empty their bladders. Infections should be identified and treated appropriately based on the results of culture and sensitivity tests.
Drugs Affecting the Urinary System
Drugs used to treat neurologically caused urinary incontinence:
Cholinergic agonists treat animals with damage to the nerves that control relaxation of the urinary bladder
Promote voiding of urine from the urinary bladder
An example is bethanechol
Anticholinergics treat urinary incontinence by promoting urine retention in the urinary bladder
Block binding of ACh to its receptor site, causing muscle relaxation
Examples include propantheline, dicyclomine, and butylhyoscine
Alpha-adrenergic antagonists decrease the tone of internal urethral sphincters and are used to treat urinary incontinence due to decreased urinary tone as a result of over-distention of the urinary bladder
Examples include phenoxybenzamine, prazosin, and nicergoline
Drugs used to treat non-neurologically caused urinary incontinence:
Estrogen treats hormone-responsive urinary incontinence seen mainly in F/S dogs. An example is diethylstilbestrol (DES)
Testosterone treats hormone-responsive urinary incontinence seen mainly in M/C dogs. Examples include testosterone cypionate and testosterone propionate
Alpha- and beta-adrenergic agonists stimulate these receptors, which increases urethral tone; examples include phenylpropanolamine and ephedrine
Skeletal muscle relaxants treat urge incontinence or urethral obstructions due to increased external urethral sphincter tone; examples include dantrolene, aminopropazine, and diazepam
| Desired effect | Drug | Mechanism of action |
| Stimulate detrusor activity | Bethanechol (Urecholine) | Cholinergic stimulation |
| Reduce detrusor activity | Propantheline (Pro- Banthine) | Anticholinergic, antispasmodic effect on smooth muscle |
| Oxbutynin | Direct antispasmodic effect on smooth muscle, anticholinergic | |
| Increase urethral tone | Pseudophedrine | Alpha-adrenergic stimulation |
| Phenylpropanolamine | Alpha-adrenergic stimulation | |
| Imipramine | Alpha- and beta- adrenergic stimulation | |
| Reduce urethral tone | Phenoxybenzamine | Alpha-adrenergic antagonism |
| Diazepam (Valium) | Central-acting skeletal muscle relaxation | |
| Baclofen | Skeletal muscle relaxation | |
| Dantrolene | Direct-acting skeletal muscle relaxation |
You can also take steps to help your dog manage their incontinence at home. These solutions include:
- Pee padsthat can help limit the scope of your four-legged friend’s accidents and promote easy cleanup
- Doggy diapersthat catch leaks before they reach the floor
- Frequent, safe walksthat allow your dog the opportunity to relieve themselves outdoors
- Proper groomingto remove any urinary or fecal debris and restore your dog’s coat
These at-home solutions help limit messes, promote easy cleanup, and keep your dog comfortable. Consider one or more of the above incontinence management methods, which work well in tandem with your veterinarian’s recommended treatment plan.
Urinary Incontinence in Male Dogs
Urinary incontinence is involuntary loss of urine during the filling phase of the bladder. Male dogs are less often affected by this problem than female dogs. Causes of urinary incontinence in dogs can be divided in congenital and acquired causes. Congenital causes can be ectopic ureters, congenital urethral sphincter mechanism incompetence, persistent urachus, bladder diverticula, hypoplasia of the bladder, prostate, or urethra, and hypospadia. Acquired causes can be hyperreflexia of the detrusor muscle, acquired urethral sphincter mechanism incompetence, detrusor atony because of bladder over distention, prostatic disease, neoplastic disease of the bladder, prostate or urethra, or neurologic disease (lower motor neuron disease).
While congenital urinary incontinence often starts in early life, acquired urinary incontinence can occur at any time. However, congenital diseases can become clinical later in life. For instance, ectopic ureters can appear later in life because of the urethral closure pressure decreasing with age. Also neutering can decrease the urethral sphincter pressure and uncover an ectopic ureter.
Incontinence can be continuous and the dog loses urine all the time. In this case, the urethral closure is constantly overwhelmed. This might occur with ectopic ureters. Oftentimes the dogs only lose urine while sleeping. In this case the urethral pressure is overcome by the bladder pressure only after a certain filling volume in the bladder. This might be the case in urethral sphincter mechanism incompetence. Incontinence only when the dog is excited might indicate detrusor hyperreflexia. Urinary tract infection can occur together with other causes of urinary incontinence or can be the cause of the incontinence. With diseases like ectopic ureters or urethral sphincter mechanism incompetence the dogs urinate normally, while with diseases like urinary tract infection or neoplasia pollakiuria or stranguria can be seen.
The size of the bladder before and after urination can help to differentiate causes of urinary incontinence. A bladder that is always small indicates continuous loss of urine, a bladder that is not empty after urination indicates an obstructive lesion or detrusor atony. A bladder that is atonic and easy to express indicates lower motor neuron disease or overflow incontinence.
Urinalysis is indicated to identify urinary tract infections and to determine urine concentration ability. Blood work might help to identify underlying diseases.
Radiography, ultrasound, computer tomography, or cystoscopy might help to identify the cause of the incontinence.
Congenital urethral sphincter mechanism incompetence can occur in combination with other malformations or alone.
Urethral sphincter mechanism incompetence in adult dogs can be associated with neutering and is more common in large breed dogs than small breed dogs. In one study Boxer dogs were the most common breed with adult onset of incontinence.
Therapy depends on the underlying disease. For urethral sphincter mechanism incompetence the alpha-adrenergic agonist phenylpropanolamine has been proposed. In 44% of the dogs response was considered good to excellent (Aaron et al. 1996). Testosterone cypionate was used in a recent study for urethral sphincter mechanism incompetence in 11 male dogs. Based on owners’ assessments, a good to excellent response was reported in three of eight dogs (38%) (Palme et al. 2017). Adjustable urethral hydraulic occluders have been successfully used in male dogs.
Compiled & Shared by- Team, LITD (Livestock Institute of Training & Development)
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