Читать книгу Animal Behavior for Shelter Veterinarians and Staff - Группа авторов - Страница 124

One of the most common non‐neurogenic disorders seen in dogs is hormone‐responsive incontinence. Older studies have suggested that this condition may affect more than 20% of gonadectomized female dogs (Arnold 1992; Thrusfield et al. 1998). However, more recent studies have not found incidence rates that high. Specifically, the condition appears to occur secondary to urethral sphincter mechanism incompetence (USMI) and results in incontinence most often when the animal is relaxed or asleep. Neutering appears to increase the risk of urethral incompetence in large dogs (>20 kg), and neutering prior to three months of age may increase the risk of urinary incontinence in female dogs (Spain et al. 2004), but additional studies have not consistently supported this finding (see Section 4.8.4). Other conditions that can lead to USMI and the occasional dribbling of urine are urinary tract infection (UTI), inflammation, prostatic disease, or a history of prostate surgery. Animals with these problems should still have voluntary control of urination some of the time, but at other times the urethral incompetence allows urine to dribble out, and the animal cannot voluntarily stop the flow.

Urinary bladder storage dysfunction can also result in frequent leakage of small amounts of urine. This can occur due to detrusor muscle instability, UTIs, chronic inflammatory disorders, infiltrative neoplastic lesions, external compression, and chronic partial outlet obstruction. These animals, too, will have voluntary control over urination some of the time.

Continuous dribbling of urine with the ability to urinate voluntarily can also occur in cases of ectopic ureters. Ectopic ureters are a congenital anomaly of the urinary system and are most commonly seen in juvenile female dogs. Some dog breeds, including golden retrievers, Labrador retrievers, Siberian huskies, Newfoundlands, miniature and toy poodles, and some terriers appear to be predisposed (Berent 2011). However, there appear to be regional differences in breed prevalence. The condition occurs infrequently in cats. Affected dogs will display urinary incontinence from birth and may have problems with chronic UTIs. Diagnosing the condition will require imaging such as cystoscopy, ultrasonography, contrast urography, or cystourethrovaginoscopy. Surgery is required to correct the condition.

Dogs may also urinate due to excitement, fear, or conflict. This is an involuntary action that can occur due to fear‐inducing or social stimuli. It typically occurs as the dog lowers its pelvic limbs, with the ears held back and tail tucked. The tail may be stiff, and the tip may be wagged rapidly if the dog is more conflicted rather than fearful. The dog may also roll over and then urinate while demonstrating the same ear and tail posture. It is critical that the dog not be punished for this behavior. Even acting upset or frustrated with the dog may increase their fear, anxiety, and conflict and, thus, make the problem worse. The problem is more likely to occur in young dogs and may be exacerbated by the presence of a full bladder during exciting or fear‐inducing events. Young female puppies may be particularly prone to this problem due to poor sphincter control. Ideally, these dogs should be greeted only after first being allowed outside to eliminate to ensure that they have an empty bladder. People should avoid leaning over these dogs when greeting. If all people who interact with the dog greet the dog in a calm, non‐threatening manner, the problem will usually improve with age.

When an animal is experiencing continuous dribbling of urine, without the ability to voluntarily control urination, it is most likely a result of a neurogenic disorder such as lower motor neuron bladder. However, the presence of uroliths often have a similar presentation. These conditions occur as a result of a lesion in the spinal cord and have a guarded to poor prognosis, depending on the cause of the lesion (e.g., trauma, neoplasia, intervertebral disc disease). Lesions of the cerebellum or cerebral micturition center can also result in frequent, involuntary urination or leakage of small amounts of urine.

When faced with a dog that is urinating inappropriately and the urination appears to be conscious rather than unconscious, consider that the dog may have been incompletely house trained or may have a medical condition resulting in polyuria and polydipsia or an inflammatory disease leading to an increased urgency and frequency of urination. Dogs with cognitive decline may begin housesoiling simply due to a loss of previously learned behaviors. Canine cognitive decline is an irreversible, neurodegenerative condition of aging dogs (and cats) and is a diagnosis of exclusion. In addition to housesoiling, pets with cognitive decline may also act disoriented, seem less interested in social interactions, have altered sleep‐wake cycles, and appear anxious or apathetic.

Aged dogs may need a more complete medical workup to rule out the large number of conditions that could be contributing to the behavior. For example, anything leading to musculoskeletal pain or weakness can result in incomplete elimination, where a dog postures to eliminate but cannot maintain the posture until she has completely voided the bladder or bowels. The dog may then return indoors and need to eliminate shortly thereafter, resulting in housesoiling. Good observation skills are necessary to recognize this problem in a case where the cause may not be readily identified with radiographs.

Urine marking is another potential cause for housesoiling in the dog. Urine‐marking behavior is a normal form of communication. Intact male dogs urine mark more than castrated or female dogs but all dogs may urine mark. When neutered animals mark indoors, it is often due to situations involving conflict, frustration, or anxiety. However, this may also simply reflect incomplete house training. Regardless of the posture used for urination, medical conditions will need to be ruled out.