Idiopathic detrusor-urethral dyssynergia in dogs: a retrospective analysis of 22 cases

ACVIM consensus statement on diagnosis and management of urinary incontinence in dogs

Urinary incontinence (UI) is a disorder of micturition that can occur in dogs of any age, sex, and breed depending on the underlying cause and time of onset. Diagnosis and treatment for various causes of UI in dogs have been described by multiple comprehensive single author review articles, but large prospective clinical trials comparing treatment outcomes in veterinary medicine are lacking. The objectives of this consensus statement therefore are to provide guidelines on both recommended diagnostic testing and treatment for various causes of UI in dogs. Specifically, pathophysiology directly related to the canine urinary system will be reviewed and diagnostic and therapeutic challenges will be addressed. A panel of 12 experts in the field (8 small animal internists [L. Adams, J. Bartges, A. Berent, J. Byron, J. Foster, A. Kendall, S. Vaden, J. Westropp], 2 neurologists [J. Coates, N. Olby], 1 radiologist [G. Oetelaar], and 1 surgeon [C. Adin]) was formed to assess and summarize evidence in the peer-reviewed literature and to complement it with consensus recommendations using the Delphi method. Some statements were not voted on by all panelists. This consensus statement aims to provide guidance for management of both male and female dogs with underlying storage or voiding disorders resulting in UI.

Idiopathic functional urinary outflow tract obstruction in dogs, a retrospective case series (2010-2021): 31 cases

BACKGROUND

Idiopathic functional urinary outflow tract obstruction (iFUOTO) is an uncommon but life-limiting disease whose etiology and clinical course of disease remain poorly understood.

OBJECTIVE

Characterize signalment, clinical signs, clinicopathologic findings, treatments, and propose a standardized response score for dogs with iFUOTO.

ANIMALS

Thirty-one client-owned dogs diagnosed with iFUOTO.

METHODS

Retrospective case series. Medical records from 2010 to 2021 were reviewed and findings recorded. Dogs were categorized based on the presence or absence of overt signs of neurological disease. Response to treatment was scored.

RESULTS

Thirty-one dogs were included. All dogs had stranguria and 14 (45%) had overflow urinary incontinence. Mean age of onset for signs was 6.9 years±8 months. Twenty-four dogs (77%) were castrated males, 5 (16%) intact males, and 2 (6%) spayed females. Eight (26%) of dogs had overt neurological deficits. Follow-up data were available for 29 dogs (median 38 days, range: 2-1277). Final outcome scores were not significantly different among dogs with overt signs of neurological disease (median score 2.5; range: 0-3) and those without (median score 1; range; 0-3; P = .35). Treatments included alpha antagonists, skeletal muscle relaxants, parasympathomimetics, anti-inflammatories, castration, temporary placement of a urethral catheter, or a combination of these.

CONCLUSIONS AND CLINICAL RELEVANCE

Multimodal treatment was frequently prescribed, but a standard outcome score is needed to evaluate the effectiveness of these therapies. Serial neurological examinations and monitoring of the dogs' dysuria are warranted.

NEOURETEROCYSTOSTOMY AND URETHRAL STENT PLACEMENT IN A BLACK-HANDED SPIDER MONKEY (ATELES GEOFFROYI)

A 27-y-old female black-handed spider monkey (Ateles geoffroyi) was evaluated 13 d after an ovariohysterectomy because of abdominal distension, anorexia, and absent urination. The animal was diagnosed with a uroabdomen and urethral obstruction from computed tomographic findings and fluid creatinine levels. During exploratory laparotomy, a defect in the right ureter was confirmed as the source of the uroabdomen. Utilizing intraoperative fluoroscopy, a urethral obstruction with an irregular luminal filling defect was evident. A self-expanding nitinol urethral stent was placed, and a ureteral transposition was performed. Two months after the procedure, the animal developed dysuria, a urinary tract infection, recurrent bladder distension and a partial urethral obstruction. Treatment with prazosin 1 mg/kg PO q12h improved urination. Reobstruction of the urethra occurred 17 mo postsurgery, and the animal was euthanatized. On postmortem examination, the animal had ingrowth into the stent with proliferative granulation tissue, detrusor muscle degeneration, pelvic adhesions, cystitis, pyelonephritis, and hydronephrosis.

Detrusor urethral dyssynergy in dogs: 35 cases (2007-2019)

OBJECTIVES

To evaluate clinical presentation, diagnosis, treatment and outcome of dogs diagnosed with detrusor urethral dyssynergy.

MATERIALS AND METHODS

Multicentre (n = 3 UK referral clinics), retrospective, observational study. Database searches were performed (2007 to 2019) to identify dogs with detrusor urethral dyssynergy. Dogs with structural abnormalities or detectable neurological disorders affecting micturition were excluded. Clinical presentation, diagnostic procedures, treatment and outcome were evaluated.

RESULTS

Thirty-five dogs were included. Middle-aged, large-breed, male neutered dogs were most frequently documented. Four female dogs were included. Fifteen breeds, including Labrador retrievers (8/35; 22.9%), golden retrievers (5/35;14.3%) and cross-breeds (5/35; 14.3%) were identified. Median duration of clinical signs was 152 days (range 0 to 1095). All dogs were dysuric at presentation with 17/35 (48.6%) reported to have an altered stream of urine and 17/35 (48.6%) to be stranguric. Follow-up data were available for 34 dogs (median 136 days, range 4 to 2188). Response was classified as good (20/34; 58.8%), partial (7/34; 20.5%) or poor (7/34; 20.5%). Overall time to response was known for 21 of 34 dogs (partial n = 6, good n = 15) with a median of 11 days (range 1 to 155). Four dogs had surgical intervention (castration n = 4, cystostomy tube n = 2). Three dogs were euthanased due to partial (n = 1) or poor (n = 2) response. Medications were discontinued in 11 of 20 (55.0%) dogs with a good response to therapy, two of these relapsed.

CLINICAL SIGNIFICANCE

Detrusor urethral dyssynergy is an uncommon micturition disorder in dogs, in particular females. Medical therapy with or without surgery resulted in a favourable prognosis in the majority of dogs, although many require long-term medication.

Retrospective evaluation of prazosin and diazepam after thoracolumbar hemilaminectomy in dogs

Management of urinary retention after spinal cord injury in dogs is often needed and can include use of medications to relax the urethral sphincter. This was a retrospective study evaluating two such medications, prazosin and diazepam, and whether dogs treated with these medications had different lengths of hospitalization, urinary continence levels, or development of bacteriuria compared to dogs not receiving these medications after thoracolumbar hemilaminectomy for intervertebral disc herniation (IVDH). Electronic medical records were searched for dogs that underwent CT or MRI followed by a hemilaminectomy between the 3^rd thoracic and 3rd lumbar vertebra for treatment of IVDH. Dogs were grouped based on whether or not they received a medication to aid in urethral sphincter relaxation (either prazosin, diazepam, or both medications). The total length of hospitalization, urinary continence at the time of discharge, and presence of bacteriuria were recorded from the medical file. Medical records from 71 dogs were included in the analysis. There were no significant associations between administration of prazosin and/or diazepam and length of hospitalization or urinary continence scores at the time of discharge from the hospital (P > 0.05).

Disorders of micturition in small animal patients: clinical significance, etiologies, and management strategies

OBJECTIVES

To review the physiology of micturition, the pathophysiology of micturition disorders, and current pharmacological agents used to treat these disorders. To discuss different urinary catheterization techniques, along with the risks of catheter-associated urinary tract infections attributed with these techniques.

ETIOLOGY

Many critically ill veterinary patients are at risk of developing a number of neurological and non neurological micturition-related disorders.

DIAGNOSIS

Micturition disorders can be diagnosed based on physical examination findings, urinary voiding contrast studies, urethral pressure profiles, and diagnostic testing such as urinalysis and urine cultures.

THERAPY

Therapy can be either pharmacological, involvement of urinary catheterization, surgical, or a combination of all the above. The goal of the treatment is to correct the underlying causes resulting in the micturition-related disorder, and if possible, allow the patient to regain their normal physiological micturition behavior.

PROGNOSIS

Depending on the underlying disease process and duration of the micturition disorder, the prognosis can be variable. In many instances, near-normal or normal function can return, but in severe cases, the patient may not regain its normal, appropriate micturition response.

Advances in Urinary Tract Endoscopy

The use of endoscopy in veterinary medicine has become the mainstay of diagnosis and treatment in the subspecialty of small animal urology over the past decade. This subspecialty is termed endourology. With the common incidence of urinary tract obstructions, stones disease, renal disease, and urothelial malignancies, combined with the recognized invasiveness and morbidity associated with traditional surgical techniques, the use of endoscopic-assisted alternatives using interventional endoscopic techniques has become appealing to both owners and clinicians. This article provides a brief overview of some of the most common urologic procedures being performed in veterinary medicine.

Evaluation of urethral stent placement for benign urethral obstructions in dogs

Background

Benign urethral obstructions (BUO) in dogs result in substantial morbidity because of challenges with conventional therapies. Treatment of malignant urethral obstructions with intraluminal urethral stents is reported to successfully relieve obstructions.

Hypothesis/Objectives

To evaluate the efficacy and outcome of urethral stent placement for treatment of BUO in dogs.

Animals

Eleven client‐owned animals with urethral stents placed for treatment of BUO.

Methods

Retrospective study in which medical records were reviewed in dogs diagnosed with BUO and treated with a metallic urethral stent. Data collected included signalment, cause of benign obstruction, procedure time, size and type of stent, complications, and short‐ and long‐term outcome.

Results

Eleven dogs with 15 urethral stents were included. Intraluminal urethral stent(s) relieved the obstructions in all dogs. Four dogs had 2 stents placed in separate procedures because of incomplete patency after treatment (n = 1), inadvertent compression of the stent (n = 1), or tissue ingrowth through the stent (n = 2). The median continence score after stent placement was 10 of 10 (range 3–10) with 6 dogs being continent, 3 mildly incontinent, and 1 each moderately and severely incontinent. All owners considered their dog to have an excellent long‐term clinical outcome with long‐term urethral patency. The median follow‐up time was 24 months (range 4–48).

Conclusions and Clinical Importance

Urethral stents appear to be an effective treatment for benign urinary obstructions. Moderate to severe incontinence developed in a minority (12.5%) of dogs. Stents relieved obstructions in all dogs with an excellent long‐term outcome.

Urodynamic testing in the diagnosis of small animal micturition disorders

Urodynamic testing provides a quantitative assessment of the function of the small animal lower urinary tract. Most commonly these techniques are utilized to assess urethral tone (urethral pressure profile or UPP) and bladder detrusor muscle function (cystometrogram or CMG). A UPP may be indicated in cases of canine and feline micturition disorders. Examples include suspected primary sphincter mechanism incontinence (PSMI), ureteral ectopia, other congenital abnormalities, suspected neurological disorders, and mechanical or functional urethral obstruction. A UPP can be performed effectively utilizing human dedicated equipment. A CMG may be indicated to assess detrusor function in all of the above cases as well as cases of suspected atonic or infiltrated urinary bladder. This procedure can also be performed using the same human equipment. These tests are useful not only in providing an accurate diagnosis, but also in providing a sensitive prognostic indicator for clinical outcome of micturition disorders with and without pharmacological or surgical therapy. A leak pressure point may also be established in dogs with urinary incontinence, and may be even more sensitive than a UPP to predict clinical incontinence in some cases.

Diagnosis and management of urinary retention

Failure to empty the urinary bladder completely can be attributed to failure of detrusor contractile function, inappropriate outlet resistance, or both. For each of these mechanisms, anatomic, neurogenic, and end-organ (myogenic or idiopathic) abnormalities are possible. The approach to urinary retention involves systematic consideration of neurogenic, obstructive, and functional causes and requires understanding of the neurophysiology and pharmacology of micturation.