Abnormal micturition, prostatic disease Flashcards
Abnormal micturition broadly includes two disorder groups:
Disorders of storage: inadequate urethral tone, normal bladder pressure
Disorders of emptying: inability to completely empty the bladder
Give 4 examples of micturition related Disorders of storage.
= inadequate urethral tone, normal bladder pressure
Ectopic ureters
Urethral sphincter mechanism incompetence
Lower motor neuron bladder
Detrusor hyperreflexia/over-active bladder
Give 3 examples of micturition related Disorders of emptying.
= inability to completely empty the bladder.
Detrusor atony
Functional urethral outflow obstruction
Upper motor neuron bladder
Describe lower motor neuron bladder.
Incontinence disorder can occur secondary to spinal cord injury or disease. Lesions in S1-S2 region lead to weakness of the striated muscular sphincter.
Animals with a LMN bladder are identified by decreased anal tone and a poor perineal reflex as well as their easily expressible bladder.
Most are unable to voluntarily void and require intermittent catheterization or manual expression by the owner.
incomplete emptying of the bladder with manual expression, affected animals are at increased risk of developing UTIs
The muscarinic agonist bethanechol has been used in these patients to increase detrusor contraction; however, the evidence for its efficacy remains controversial.
Describe detrusor hyperreflexia aka over-active bladder.
most common form of urinary incontinence in people, but it has been poorly characterized in companion animals.
characterized by sudden urgency to urinate and involuntary evacuation of urine associated with bursts of detrusor contractions at bladder volumes far below capacity
In dogs it may manifest as loss of bladder compliance and capacity, causing a need to urinate more often without polyuria or inflammation of the lower urinary tracta
Describe detrusor atony.
Loss of adequate detrusor contraction can result from neurogenic or non-neurogenic abnormalities.
Injury to the sacral spinal cord (S1-S3) or pelvic nerves can lead to bladder atony, and is often associated with weakened urethral tone. Affected animals often have decreased perineal reflexes and easily expressed bladders (LMN bladder).
Direct damage to the detrusor muscle can occur from over-distension due to mechanical or functional outflow obstruction of acute or chronic nature.
With over-distension, the muscular tight junctions are interrupted, leading to an absent or ineffective contraction. The over-distension may be acute, as with obstructive feline idiopathic cystitis in a male cat, or chronic, as in a dog with a functional obstruction of the urethra
Describe upper motor neuron bladder.
Neurogenic functional urethral obstruction is generally caused by spinal cord lesions cranial to the sacral segment. This leads to loss of inhibitory signals to the hypogastric and pudendal nerves, and this loss prevents sphincter relaxation upon voiding.
This is the classic “UMN bladder,” in which the patient is unable to urinate normally and where the bladder is difficult to express manually. The most commonly affected dogs are those with intervertebral disc disease and associated paresis or paralysis.
Ectopic ureters - etiopathogenesis
congenital abnormality in which at least 1 ureteral opening is located distal (caudal) to the bladder trigone, either unilaterally or bilaterally.
Can be either:
Intramural (dogs) - ectopic ureter tunnels submucosally through the wall of the bladder/urethra before opening into the urethra.
Extramural (cats) - ectopic ureter inserts directly into the urethra.
Concurrent congenital urogenital tract abnormalities are commonly reported, including renal dysplasia/ hypoplasia/ aplasia, ureterocele, urethral hypoplasia and vestibulovaginal abnormalities.
Secondary consequences may develop in some individuals, including hydronephrosis and hydroureter resulting from increased resistance to outflow of urine, altered peristalsis and/or vesicoureteral reflux, and bladder hypoplasia due to reduced vesicular filling.
Ectopic ureters - signalment
Breed predisposition in dogs
Golden retriever, labrador retriever, newfoundland, siberian husky, poodle, soft coated wheaten terrier, entlebucher mountain dog
Juveniles
Dogs: < 6 m
Cats: mean age 1.4 y
Females
Ectopic ureters - clinical signs
Urinary incontinence: Severity variable - from mild, intermittent to continuous dripping/pooling.
Hematuria, stranguria, pollakiuria with
Concurrent UTI, bladder hypoplasia, ureterocele.
Recurrent UTIs
Or even No clinical signs
Physical examination:
Wet fur around the vulva, perineum, pelvic limbs
Vulvar conformational abnormalities (hooded)
Renomegaly
Rectal examination (urethra)
Ectopic ureters - diagnosis
biochemistry, urinalysis, urine culture:
- Renal compromise possible but rareish
- Secondary renal injury from recurrent pyelonephritis, chronic reflux, chronic hydronephrosis
- Congenital renal disease and/or UTI
Diagnostic imaging:
- Upper + lower urinary tract
- Imaging method of choice: cystoscopy in bitches, CT excretory urography in male dogs and cats.
- Ultrasonography
Ectopic ureters - treatment
Relocate the ureteral orifices cranially to their normal position within the bladder trigone.
Intramural EU:
- Transurethral cystoscopic-guided laser ablation
- Cystoscopic-guided scissor transection
- Surgical correction:
Intravesicular - neoureterostomy
Extravesicular - ureteral re-implantation
Extramural EU:
- Surgical correction Ureteral reimplantation
Severe unilateral hydronephrosis/ pyelonephritis consider: ureteronephrectomy
Ectopic ureters - outcome
Better in male than in female dogs. Persistent incontinence in 35-63% of female dogs. -> Concurrent Urethral Sphincter Mechanism Incompetence.
Persistent incontinence:
1. Repeat cystoscopic evaluation
2. Phenylpropanolamine until the first estrus/lifelong
3. Additional surgery, artificial urethral sphincter - wait until after at least the first estrous cycle.
Describe USMI
Urethral Sphincter Mechanism Incompetence is the Most common storage disorder and cause of urinary incontinence in dogs.
Reduced muscular responsiveness and tone, changes in the periurethral tissues due to decreased Estrogen/testosterone & increased FSH and LH.
Spayed female dogs most commonly,
Less common in castrated males. The earlier a large breed dog is spayed, the more likely she is to develop USMI.
Rare in intact male dogs and cats.
Predisposing factors: pelvic bladder, short urethra, recessed vulva
USMI - clinical signs
Adult onset, within a few years of neutering
Urination normal and complete
Unconscious leaking when recumbent, sleeping, after exertion
Grooming of perivulvar/preputial area
Perivulvar/preputial urine staining, dermatitis
Clinical signs worsen with comorbidities (PU), UTI (& Incontinence = increased risk of UTI)
USMI - diagnosis
Urinary incontinence in an otherwise healthy neutered female dog that was previously continent - presumptive diagnosis, response to therapy.
But in Intact female dog/intact or neutered male dog/cat - diagnostics:
. Urinalysis and urine culture
Check Iso/hyposthenuria - underlying cause?
- CBC, biochemistry not essential but Important with PU.
- Imaging when anatomic abnormalities suspected.
USMI - treatment
Estriol (hormone supplementation)
Phenylpropanolamine
In Severe/refractory incontinence cases: use both estriol + phenylpropanolamine in combo.
Describe Estriol use.
Used for the treatment of USMI.
Increases number and sensitivity of alpha-receptors in the urethral sphincter.
Response rate 89%
Adverse effects (dose-related): mammary gland development, vulvar swelling, attractiveness to males, bone marrow suppression.
CBC before and 1 month after starting treatment.
Not for use in cats or male dogs, only bitches.
Describe Phenylpropanolamine use.
Used for the treatment of USMI.
Stimulates alpha-receptors in the urethral sphincter.
Response rate 75-90%
Dosage and frequency vary, may need to be increased over time.
Adverse effects (dose-related): restlessness, aggression, changes in sleeping patterns, GI signs.
Also used in male dogs and cats.
Response rate in male dogs 43%.
In addition, neutered male dogs may be treated with testosterone cypionate as monthly injections; however, its efficacy is not well documented
Functional urethral outflow obstruction - treatment
Treatment of the hypertonic urethral sphincter with Alpha antagonist like Prazosin/tamsulosin.
+/- skeletal muscle relaxant
Benzodiazepines (diazepam), acepromazine, methocarbamol
Intermittent catheterization if severe/refractory.
Medical therapy of associated bladder atony after relief of functional urethral obstruction.
- Bethanechol, cisapride, metoclopramide
Monitoring:
- Residual urine volume
- UTIs
most dogs will require lifelong therapy for FOO.
Prostatic disease in small animals is typically 1 of 4:
Benign prostatic hyperplasia
Acute or chronic prostatitis
prostatic abscessation
(cysts, neoplasia, squamous metaplasia poss. too… but less common)
BPH - diagnosis made by:
Presumptive: history, signs, PE, routine laboratory results, imaging (Definitive: histology)
Blood and urine analysis
- Hematuria
Imaging
- Radiographs
- U/S
Should you treat BPH?
Based on grade: mild/moderate/severe.
Treat when:
- Life-threatening
- Adversely affecting the function of other organs
- Adversely affecting the dog’s quality of life
No therapy, q3-6m monitoring when:
- Mild signs
- Signs that do not appear to affect quality of life.
How do you grade BPH?
BPH - treatment.
Aim: suppress/prevent androgen synthesis/action.
Castration
- Common, easy, definitive
- Resolution of BPH, prostatic volume decreases within 7-14 days.
Breeding dogs, castration not desired/possible - medical therapy:
- Finasteride 1.25 mg/day PO for 195 days (product used for men’s hairloss)
- Osaterone acetate (Ypozane) 0.2-0.5 mg/kg/day PO for 7 days q5m
- Deslorelin acetate (suprelorin) SC implant q6-12m
Treatment approach for prostatic disease.
