Urinary Incontinence and Urinary Tract Infections.

Urinary incontinence results from disorders of the lower urinary tract or neurologic diseases either of the nerve supply to the bladder/urethra or within the central nervous system. Congenital causes include patent urachus and ectopic ureter. Coordination of lower urinary tract function involves the interaction of both the sympathetic and parasympathetic system as well as somatic branches of the central nervous system. Well-recognized causes of incontinence include equine herpes virus 1 myeloencephalopathy, polyneuritis equi (neuritis of the cauda equina), and sacral/coccygeal trauma. Idiopathic bladder paralysis is characterized by bladder paralysis and sabulous cystitis in the absence of overt neurologic deficits.

Prevalence of bacteriuria in cats with neurogenic bladder.

Urinary tract infections are defined as the adherence, multiplication, and persistence of an infectious agent within the urogenital system, causing an associated inflammatory response and clinical signs; instead, the presence of bacteria in urine as determined by positive bacterial culture (PUC) from a properly collected urine specimen, in the absence of clinical signs, is defined subclinical bacteriuria. Limited information on the prevalence of PUC in spinal cord injury cats affected by neurogenic bladder (NB) is available. On contrary, in NB dogs and humans the prevalence of bacteriuria is well documented. Moreover, while in humans information about bacteriemia associated with NB is already available, this aspect has never been studied in NB cats. The aim of this prospective study was to determine the prevalence of PUC in cats with NB, compared to animals affected by chronic kidney disease (CKD) and healthy cats. Furthermore, the prevalence of bacteriemia in cats with NB was evaluated. Fifty-one cats met the inclusion criteria: 12 cats were affected by NB, 22 had CKD and 17 were healthy. The prevalence of PUC was 58.33% and 18% in NB and CKD cat populations, respectively. All blood cultures were negative. The incomplete bladder emptying and the decreased resistance in the bladder wall could be considered predisposing elements to PUC in the NB feline population. The results of this study highlight, for the first time, an high prevalence of PUC in cats affected by NB, which was not found to be associated with bacteriemia.

Urological Sequelae to Acute Spinal Cord Injury in Pet Dogs: A Natural Disease Model of Neuropathic Bladder Dysfunction.

The authors review urologic dysfunction, including urine retention, incontinence, and recurrent and resistant urinary tract infection, in dogs as a sequela to acute spinal cord injury. Urologic sequelae to acute spinal cord injury (SCI) pose significant complications in human and canine patients impacting quality of life and long-term cost of treatment. Dogs with intervertebral disc extrusion may serve as a natural disease model of acute SCI for investigating translational interventions, both prophylactic and therapeutic, for urologic dysfunction in human SCI patients.

Detection of the bladder volume from the neural afferent activities in dogs: experimental results.

OBJECTIVE: We evaluate the bladder volume and pressure through recording the bladder afferent activity in the sacral nerve roots in acute experiments of paraplegic dogs. These measurements are intended to report the status of the bladder and to adjust the stimulation parameters of an implantable electric stimulator. METHODS: The extraction of neural information for feedback in functional electrical stimulation is limited by the poor signal to noise ratio (SNR) in the sacral nerve recordings. We propose to inject a very low amplitude sinusoidal current with high SNR to the bladder through the nerve using a tripolar cuff electrode wrapped around the S2 nerve root. The application of this current (0.4 microA peak to peak, 30 Hz) allows detecting bladder afferent activity in its amplitude and the tissues impedance of the nerve. Acute experiments in dogs were performed to evaluate the proposed method. In each dog, the bladder infusion with saline was carried out at both slow and high filling rates. At the same time, the changes in the amplitude of the sinusoidal output voltage V(OUT) were recorded through the cuff nerve electrode. RESULTS: The data obtained from 26 acute experiments using eight dogs demonstrate that the amplitude of the recorded sinusoidal voltage V(OUT) varies proportionally with the bladder pressure during the bladder filling with saline solution. It also demonstrates that the bladder volume can be estimated from the increasing amplitude of the recorded V(OUT). CONCLUSION: This study shows that the increase in the V(OUT) is proportionally related to the increase in bladder pressure. The difference between the recorded V(OUT) during the bladder filling and the baseline V(OUT) can be a useful indicator of the changes in the bladder volume.

Epidural spinal myelolipoma in a dog.

Epidural spinal myelolipoma was diagnosed in a 13-year-old, male Siberian husky that was referred for evaluation of progressive pelvic limb paresis and urinary incontinence. An epidural mass was detected by magnetic resonance imaging and computed tomography. The mass was removed and identified histopathologically as an epidural myelolipoma. Pelvic limb paresis improved after surgery, but urinary retention associated with neurological bladder dysfunction persisted.

Pathophysiology, Clinical Importance, and Management of Neurogenic Lower Urinary Tract Dysfunction Caused by Suprasacral Spinal Cord Injury.

Management of persistent lower urinary tract dysfunction resulting from severe thoracolumbar spinal cord injury can be challenging. Severe suprasacral spinal cord injury releases the spinal cord segmental micturition reflex from supraspinal modulation and increases nerve growth factor concentration in the bladder wall, lumbosacral spinal cord, and dorsal root ganglion, which subsequently activates hypermechanosensitive C-fiber bladder wall afferents. Hyperexcitability of bladder afferents and detrusor overactivity can cause urine leaking during the storage phase. During urine voiding, the loss of supraspinal control that normally coordinates detrusor contraction with sphincter relaxation can lead to spinal cord segmental reflex-mediated simultaneous detrusor and sphincter contractions or detrusor-sphincter dyssynergia, resulting in inefficient urine voiding and high residual volume. These disease-associated changes can impact on the quality of life and life expectancy of spinal-injured animals. Here, we discuss the pathophysiology and management considerations of lower urinary tract dysfunction as the result of severe, acute, suprasacral spinal cord injury. In addition, drawing from experimental, preclinical, and clinical medicine, we introduce some treatment options for neurogenic lower urinary tract dysfunction that are designed to: (1) prevent urine leakage arising because of detrusor overactivity during bladder filling, (2) preserve upper urinary tract integrity and function by reducing intravesical pressure and subsequent vesicoureteral reflux, and (3) prevent urinary tract and systemic complications by treating and preventing urinary tract infections.

Frequency of urination and ultrasonographic estimation of residual urine in normal and dysuric dogs.

The aim of this study was to determine residual urine and frequency of urination in normal male and female dogs and to compare these with dogs with neurogenic and obstructive dysuria. The bladder volume before urination was estimated ultrasonographically in 99 dogs (48 normal and 51 abnormal dogs). Each animal was then taken outdoors and walked on grass for 10 minutes. The number of attempts to urinate (successful or not) was recorded. Bladder urine volume after urination was then calculated. Normal females made only one or two (100 per cent successful) attempts to urinate while males a mean of 6.9 attempts (mean 75.4 per cent successful) within 10 minutes. The residual urine per kg body weight of normal dogs varied from 0.1 to 3.4 ml kg(-1)(median 0.2 ml kg(-1)). The residual urine volumes of normal dogs were significantly less (P<0.0001) than those of dogs with neurological disorders or obstructive disease. Ultrasonographic estimation of residual urine volumes could be valuable in diagnosing suspected neurological or obstructive bladder disease and in monitoring the response to treatment.

Neurogenic disorders of micturition.

Anatomic considerations of micturition are reviewed as well as the effects of lesions at various levels on the urinary system as a whole. Proper diagnostic approach, interpretation of results, and recommendations for therapy are outlined to aid the practitioner in handling neurogenic disorders of micturition.

Equine herpesvirus myeloencephalopathy in a 14-year-old quarter horse stallion.

A 14-year-old, quarter horse stallion was presented in lateral recumbency, unable to rise. Equine herpesvirus myeloencephalopathy was diagnosed, based on presentation, clinical signs, and the ruling out of other possibilities. After initial rapid improvements, ataxia remained, as did chronic cystitis secondary to bladder paralysis. He was euthanized after 2 months.

Use of an implanted sacral nerve stimulator to restore urine voiding in chronically paraplegic dogs.

BACKGROUND: Loss of urinary control after spinal cord injury increases risk of urinary tract disease and is problematical for owners of affected dogs. OBJECTIVES: To design, implant, and test a sacral nerve stimulating device for controlling urine voiding in paraplegic dogs. ANIMALS: Nine pet dogs with severe thoracolumbar spinal cord injury causing paraplegia, loss of hindquarter sensation, and incontinence for more than 3 months. The procedure was offered prospectively to owners of suitable candidates after the irreversibility of the incontinence had been ascertained. METHODS: Open label clinical study. Surgically implantable electrode "books" were designed for insertion and retention of mixed sacral nerves. Sacral nerves were accessed via laminectomy and stimulated to test their ability to elicit detrusor contraction and then inserted into the electrode book, which was attached to a subcutaneously implanted, externally activated receiver. RESULTS: In 8/9 dogs, S2 nerves elicited the largest increases in intravesicular pressure with minimum stimulation and were placed in electrode books. Voiding efficiency was >90% in 8 of the 9 implanted dogs. No important detrimental effects of the procedure were observed. CONCLUSIONS AND CLINICAL IMPORTANCE: This sacral nerve stimulating implant is a simple and apparently effective neuroprosthetic device that restores urine voiding in paraplegic dogs.

Suprapubic bladder catheterization of male spinal-cord-injured Sprague-Dawley rats.

The rat spinal-cord-injury (SCI) model is widely used to study the pathologic mechanisms that contribute to sensory and motor dysfunction in humans. This model is thought to mimic many of the negative outcomes experienced by humans after spinal contusion injury. We theorized that manual bladder expression contributed to the kidney and bladder lesions reported in previous studies using the rat SCI model. In the present study, rats were surgically implanted with bladder catheters after spinal contusion injury to provide continuous drainage of urine. After 72 h, the rats were euthanized and their kidneys and bladders examined histologically. BUN, serum creatinine, and urine protein were compared at 0 and 72 h after surgery. Kidney and bladder lesions were similar in SCI rats with and without implanted bladder catheters. BUN at 72 h was higher than baseline values in both groups, whereas serum creatinine was higher at 72 h compared with baseline values only in the catheterized rats. These findings indicate that suprapubic bladder catheterization does not reduce hydronephrosis in SCI rats and that the standard of care for bladder evacuation should continue to be manual expression of urine.