SASH : Veterinary urinary tract diseases by Dr Bing Yun Zhu

URINARY TRACT DISEASES
A Medical Perspective
Bing Yun Zhu BVSc (Hons I) DACVIM

www.sashvets.comwww.sashvets.com
Overview
• Urinary Incontinence
• Urinary tract infections
(including recurrent)
• Uroliths
• Ureteral obstructions

Sally - 1.5yo FS Chihuahua X
Urinary incontinence

Urinary Incontinence
1) Anatomical
2) Decreased urethral sphincter pressure
3) Increased urethral sphincter pressure
(overflow)
4) Overactive bladder
(urge incontinence)

1) Anatomical
• Ectopic ureter(s)
• Ureterocoele(s)
• Urethral hypoplasia
• Pelvic bladder
• Other:
– Hymenal remnant/paramesonephric septal
remnant/double vagina
– Vestibulovaginal stenosis

2) Decreased Urethral Sphincter
Pressure
• USMI (Urethral Sphincter Mechanism Incompetence)
• LMN Bladder
– Myelopathy
– Neuropathy

3) Increased Urethral Sphincter
Pressure
• Mechanical
- Urethrolith
- Neoplasia
- Urethritis
- Stricture
- Foreign body
- Prostate
- Extra-luminal
• Functional
- UMN bladder
- FUOTO / “dyssynergy”
- Spasms

4) Overactive Bladder
• Infection
• Urolith
• Mass (poly vs neoplasia)
• Foreign body
• Drugs (cyclophosphamide)
• Idiopathic /“urge incontinence

History
• PU/PD
• Stranguria/pollakiuria/haematuria
• Conscious/subconscious
• Stream quality
• Ability to posture
• Gait change

Physical Exam
• Bladder size
• Urine leakage/staining
• Rectal
– Anal sphincter tone
– Urethral mass/stone
– Prostate
• Proprioceptive placement
• Vertebral column pain
• Prepuce/penis/vulva

Sally
• Adopted 1 month ago
• Constant urine leakage
• Never urinated consciously
• Physical examination unremarkable

Diagnostics (before referral)
• Urine culture!
• USG (ideally with urinalysis)
• Abdominal radiographs (stones)
– Include entire urinary tract
• Renal panel
– BUN/Creat, Phos/Ca, Lytes
• +/- CBC (for oestrogen)

Treatment (before referral)
• Phenylpropanolamine
– α1 agonist (noradrenaline release)
– 1 – 1.5mg/kg PO q 12 -24h
– Effect in 2-3 days
– Adverse effects: anxiety, ↑BP
• DES / estriol
– Sensitise α1 receptors
– Loading dose daily then taper

Madison - 6yo FS Brussels Griffon

RECURRENT UTIs
• More than 3 per year
• Re-infection or relapsed infection?
– Negative culture after Rx?
– Same or different bug?
• Re-infection: predisposing cause
• Relapsed infection:
ineffective treatment

CAUSES
1) Owner/veterinary problems
2) Systemic disease
3) Urogenital tract problems

1) Owner/vet problems
• Owner compliance
• Wrong antibiotic choice (culture!)
• Inappropriate antibiotic dose
– Amoxicillin 20mg/kg PO q 8h
– Amoxi-clav 15-20mg/kg PO q 12h
– Enrofloxacin 10mg/kg PO q 24h
• Changed resistance pattern
• Other meds (pred/chemo)
• Inadequate duration

2) Systemic Disease
• Cushings (exogenous/endogenous)
• Diabetes mellitus
• Renal disease
• Hyperthyroidism
• Neoplasia
• Diarrhoea
• Medication – e.g. chemo,
other immunosuppressives

3) Urogenital problems
• Deep seated infection
• Bladder diverticulum
• Urinary incontinence (any cause)
• Bladder mass/neoplasia
• Urinary retention
• Foreign body
• Recessed vulva/dermatitis
• Pyelonephritis/prostatitis

Madison - History
• 2yo – Stump pyo; left ureteral dilation
• 6 months later – hydronephrosis and hydroureter on
ultrasound/IVP
• Between ages 3-4yo: multiple recurrent UTIs with
clinical signs
– Staph and Enterococcus
• Urinary incontinence
despite negative culture

Enterococcus
• Gram positive aerobic cocci
• Intrinsically resistant to:
– Fluoroquinolones
– Cephalosporins, carbapenems
– Clindamycin
– TMS (exogenous folate source)
– Low conc. aminoglycosides
• Treat other bacteria first!

To Treat or Not
• Clinical signs? / Cytological evidence?
• Resistant bacteria cultured previously?
• Underlying cause treatable?
• Immunosuppression?
• Likely cause of disease?
– Colony count, pure growth
– Coag negative Staph, Bacillus, propionibacteria,
Corynebacterium, Mycoplasma

Empiric Therapy
• Uncomplicated UTIs (waiting culture)
• Amoxicillin 15 (-20) mg/kg PO q 8h
– Clavulanate: no evidence for need
– Prefer narrow spectrum
• TMS 15mg (-30) mg/kg PO q 12h
– Schirmer’s before & q 2 weeks
• 7-14 days (probably less)

Madison - History
• Left nephrectomy by local vet to treat incontinence:
– Histopath: severe pyelonephritis, severe hyperplastic
ureteritis
• Cultured MDR Corynebacterium
– Susceptible to chloramphenicol only
• Physical examination
– Unremarkable

Ultrasound
• Remnant left ectopic ureter (dilated)
• Dilated right ureter
• Right nephroliths
• Crystalline material in bladder

Lessons:
1) Don’t remove kidneys without good reason (only
remaining kidney now diseased)
2) Remove ureters with kidneys
3) Is the kidney the PROBLEM?

Madison - Treatment
• Chloramphenicol 30mg/kg PO q 8h
– Aplastic anaemia (humans)
– Bone marrow suppression (all spp.)
• Remove remnant left ureter
• Cystoscopy
– Right ureteral ectopia?
– Crystalline material in bladder?

Courtesy of JL Westorpp, UC Davis

Courtesy of WTN Culp, UC Davis

Madison
• Recheck: picky eater, pollakiuric
• Repeat culture: only vancomycin
• Developed AKI
• Repeat culture: doxy,
amikacin or gentamicin

Struvite urolithiasis
• Dogs: INFECTION CONTROL!
• MEDICAL condition!
• Dissolution possible (Hill’s S/D, RC S/O)
– Concurrent antibiotics
• Urease producing bacteria:
– Staphylococcus
– Proteus
– Klebsiella
– Corynebacterium
– Some Mycoplasma

Ruby Scott Radiographs

Libby
8yo FS Schnauzer
Vomiting, diarrhoea, lethargy

Libby- History
• 4 weeks ago – pollakiuria
• Local vet diagnostics:
– USG 1.025, pH 8, struvite crystals
– Abdominal radiographs: cystic uroliths
– Urine culture: E. coli
• Rx: Clavulox & dissolution diet

Radiolucency vs opacity
Stone Appearance
Calcium Oxalate Radiopaque
Struvite Radiopaque
Silica Radiopaque (faint)
Cystine Radiopaque (faint)
Purine
(urate/xanthine)
Radiolucent

Alex
5yo MC Havanese
Persistent stranguria

Stone Management
• WATER WATER WATER (USG <1.020)
• Repeat radiographs in 4 weeks
– Voiding urohydropulsion (VUH)
• Balanced diet pH (6.5-7)
• Thiazide diuretic (HCT 2mg/kg q 12h)
– Hypercalcaemia, hypokalaemia
• Potassium citrate
– Increased Ca solubility
– Alkalinizing

Urate Stones
• Hill’s U/D
• RC Vegetarian
• RC U/C

Haematuria
• Haematuria vs pigmenturia?
– Centrifuge urine
– Check PCV/TP, CK
• Systemic (coagulopathy) vs local?
– Primary (platelets) coagulopathy
• Where in stream?
• Any LUTD signs?

Key Learning Points
• Urine culture!!
• Urinary incontinence – work up and treatment trial
• Recurrent UTI work up
– To treat or not, empiric therapy
– Enterococcus infections
• Assessing likely stone types
• Struvite – medical condition; dissolution diets
• Calcium oxalate management
• Value of well positioned radiographs

Pierre 14yo MC DSH
• R. ureteral obstruction
• Mycobacterium infx
• 3rd degree AV block
• Chronic chylous effusion
• Pancreatitis

References
• Davidson & Westropp (2014) Diagnosis and Management of Urinary Ectopia in Vet Clin
Small Anim 44:343-353
• International Society for Companion Animal Infectious Diseases (2011) – Antimicrobial
Use Guidelines for the Treatment of Urinary Tract Disease in Dogs and Cats:
Antimicrobial Guidelines
• Berent, Weisse, Mayhew et al. (2012) Evaluation of cystoscopic-guided laser ablation
of intramural ectopic ureters in female dogs in JAVMA 240 (6):716-725
• Sykes (2014) Canine and Feline Infectious Diseases
• Lulich et al. (2013) Efficacy of two commercially available, low-magnesium, urine-
acidifying dry foods for the dissolution of struvite uroliths in cats in JAVMA
243(8):1147-1153
• Nelson & Couto (2014) Small Animal Internal Medicine – 5th Edition
• Berent, Weisse et al. (2014) Technical and clinical outcomes of ureteral stenting
in cats with benign ureteral obstruction: 69 cases (2006-2010) in JAVMA 244(5):559-
576
• Steinhaus, Berent et al. (2015) Clinical presentation and outcome of cats with
circumcaval ureters associated with a ureteral obstruction in JVIM 29(1):63-70

www.sashvets.com.au twitter: @SASHvets
Phone - (02) 9889 0289 Fax - (02) 9889 0431
Level 1, 1 Richardson Place, North Ryde 2113, Sydney, NSW

SASH : Veterinary urinary tract diseases by Dr Bing Yun Zhu

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