Week 3 - Large Animal Lower Urinary Tract Disease Flashcards
What is the definition of urinary incontinence?
The involuntary passage of urine
* Primary disorders of lower UT
* Neurologic diseases
How might you investigate urinary incontinence?
- Thorough history
- Neuro exam
- Rectal palpation
- Ultrasonography
- Urethral and bladder endoscopy
- Blood analysis
- Urinanalysis and blood culture
What is the most common type of UTI in horses?
- Primary lower UTI’s are uncommon
- secondary to an underlying pathology or associated urinary stasis
- bladder paralysis, urolithiasis, urethral damage, iatrogenic (bladder catheterisation)
What gram negative bacteria cause Urinary Tract Infections?
- E.Coli
- Klebsiella
*Enterobacteriaceae
What Gram Positive Bacteria cause UTI’s?
Staphylococcus
* Strep faecalis
* Cattle: Corynebacterium
What are the main clinical signs of equine UTI’s?
Can vary and may depend on concurrent / underlying condition
* Dysuria, Stranguria, Pollakiuria, Haematuria
* Dribbling urine
How might you diagnose an equine UTI?
Blood biochemistry and haematology usually unremarkable if lower UTI
* Urine sediment examination
* > 20 micro-organisms and >10 x WBC per high power field
* Culture
* Rectal examination & bladder palpation
* Ultrasound
* Cystoscopy
How might you treat an equine UTI?
Treat the underlying condition…
* Appropriate and targeted use of antimicrobials
* Based on culture and sensitivity where possible
What is the function of Trimethoprim sulphonamides?
= First line choice (broad spectrum, low cost, easy to administer)
for equine UTI
What is the epidemiology of Equiine Urolithiasis?
Geographical predispositions
* Adult horses (mean 10yrs)
* Male horses (75%, mainly geldings)
* No breed disposition.
What is the aetiology of equine urolithiasis?
Invariably calcium based due to high dietary calcium intake and renal
excretion.
* Type 1 Ca2CO3
(spiculated, ovoid, yellow-green usually easily fragmented)
* Type 2 Also Ca2CO3 but contain more phosphate (grey-white smooth, uncommon)
What are nephroliths?
nidus for formation likely to be piece of damaged tissue
What are ureteroliths?
descending nephrolith
What are cystoliths?
nidus often not clear, potentially bacterial involvement?
What are the clinical signs of urolithiasis?
Vary depending on severity and whether unilateral or bilateral
* May be associated with renal failure if hydronephrosis present
* Gross haematuria not common and not often associated with UTI
* Uroperitoneum if rupture of ureter or renal pelvis
How would you diagnose Urolithiasis?
Ultrasonography – transabdominal or transrectal
* Transrectal palpation for some ureteroliths
What are the most common clinical signs of equine urolithiasis?
Most common clinical sign is haematuria after exercise
* Urine dribbling
* Stranguria/Dysuria/pollakiuria
* Signs of concurrent UTI – WBCs & RBCs, bacteria ++
* Stilted HL gait
* Possible low grade colic
How might you diagnose Urolithiasis?
Transrectal palpation (bladder small) and ultrasonography
* Cystoscopy
How might you treat urolithiasis?
Antimicrobial tx for concurrent bacterial infection
Surgical resection where possible;
(Depends on gender, physical condition & size of patient)
What are the three operations for urolithiasis?
- Cystotomy
- Urethrostostomy
- Nephrectomy
What is lithotripsy?
Breaking down solid masses/stones to encourage or facilitate removal using shockwave or laser
What is Extracorporeal Shock Wave Therapy?
Limited success in large animals due to depth of tissue
What is Trans-Endoscopic Lithotripsy?
Electrohydraulic shockwave
* Laser: Holmium:YAG
How might you prevent Equine Urolithiasis?
Low calcium diet
* Remove rich, legume hay – e.g. alfalfa
Urine acidification <pH6.0 ?
* Ammonium salts in diet (Ammonium sulphate/ammonium chloride)
* Very unpalatable, need to be given 2-3 times daily
* No evidence to support their use
Promote diuresis
* 50g-75g of salt in food daily → polydipsia and therefore polyuria
* Control any UTI if recurrent after urolith removal
What is sabulous urolithiasis?
CaCO3 crystals accumulate/sediment within the bladder >
large inspissated mass
* Causes secondary cystitis
* Associated with incomplete voiding of the bladder
* Neurological dysfunction
* Orthopaedic/musculoskeletal Pain
* Idiopathic Bladder Paralysis
What are the clinical signs of sabulous urolithiasis?
Urinary incontinence
* HL weakness and ataxia
How would you diagnose sabulous urolithiasis?
Assist urine evacuation to avoid detrusor
atony from chronic overdistension
Daily lavage of bladder
* Treat underlying condition
* Pharmacological Treatments?
* Promote bladder emptying (eg: Bethanechol)
* Antimicrobials to control cystitis
* Anti-inflammatories
What is the prognosis for sabulous urolithiasis?
poor unless primary problem can be resolved
* Ascending urinary tract infection > renal failure can
occur
* Weight loss, anorexia, apathy, depression
What is the urachus?
structure though which urine passes into allantoic cavity in utero.
What does failure to close the urachus at birth do?
Failure to close at birth, or reestablishment of patency in the neonatal
period > leakage from the umbilical stump
What is congenital patent urachus?
Umbilicus persistently moist after birth from which urine leaks.
What is acquired patent urachus?
Urine leakage within a few hours to days after birth.
* Septic omphalitis/omphalophlebitis.
* Often weak/compromised foals.
What are the clinical signs of patent urachus?
Dysuria or stranguria
* Wet umbilical stump to overt umbilical urine dribbling
What does a transabdominal ultrasound indicate with patent urachus?
Transabdominal ultrasound indicated to
check for evidence of infected internal
umbilical remnants (urachus, umbilical
arteries and umbilical vein).
What is the treatment for patent urachus?
Many resolve with supportive care
* Urachus may close spontaneously
* Umbilical disinfection
* Results in acquired patent urachus as result in premature removal of stump?
* Systemic antimicrobial therapy
* Surgical resection of umbilical remnants if obviously septic structures and/or not
responding to medical treatment
What is uroperitoneum in foals?
Rupture of urachus, renal pelvis/ureter/bladder or proximal
urethra → accumulation of urine in abdomen
Usually due to trauma during parturition:
* Colts > fillies
* Dorsal bladder wall most common
* Clinical signs in 1-3 days
What are the clinical signs of uroperitoneum?
Abdominal distension
* Inappetence, lethargy
* Mild colic
* Tachycardia, tachypnoea
* Straining to urinate, pollakiuria, urine dribbling or anuria.
* May still be able to urinate!
How would you diagnose uroperitoneum?
Ultrasound
* Abdominocentesis
* Peritoneal fluid:serum Creatinine ratio (≥2 is diagnostic for uroperitoneum)
* Biochemistry: Hyperkalaemia, hyponatremia, hypochloraemia
What do foals with uroperitoneum often present with?
Often present with azotaemia and significant electrolyte abnormalities
How might you treat Uroperitoneum?
Initial medical support to address metabolic disturbances;
* Peritoneal drainage
* IV Fluid Therapy
* Treatment to address hyperkalaemia
* IV glucose/dextrose solution
* Sodium bicarbonate solution?
* Broad spectrum antimicrobials
* Can have reactive/chemical peritonitis
How would you do a surgical repair of the bladder?
2 layers, second layer inverting
* Monofilament suture
* Laparoscopy assisted?
Resection of umbilical remnants if indicated
When is pyelonephritis most likely to be established in ruminants?
o Post calving (within 3 months)
o Signs of systemic disease and renal dysfunction
o Inappetance, pyrexia, pyuria, urine staining/scalding
What is Corynebacterium renale?
Infectious cause of UTI’s in ruminants
o Direct vulvar contact
o Urine splashing between cows
o Iatrogenic transmission
o Sexual contact – bull acting as fomite for spread
How does Corynebacterium renale adhere to the urinary tract?
Adheres to urinary tract epithelium via pH-mediated pili
o Adherence enhanced in alkaline conditions
What is the treatment for Ruminants UTI’s?
Prolonged and aggressive antimicrobial therapy
* Penicillin = 1st choice in ruminants due to C. renale
Procaine penicillin; 22-44mg/kg IM BID
Ampicillin; 11mg/kg IM BID
* Be aware meat and milk withdrawal
* Urine acidifiers (e.g. ammonium salts) to reduce adherence of C.renale
* Unilateral nephrectomy may be indicated (where appropriate) in chronic
/ refractory cases
What is the aetiology for ruminant urolithiasis?
Greater influence of dietary and management factors
* Changes in herd diet can result in large no. of animals affected
High phosphate diet (grain-based diets where Ca:P ratio is < 2:1)
High magnesium & potassium may also be involved
* Struvite (magnesium ammonium phosphate hexhydrate)
* Apatite (calcium phosphate)
High Calcium diet – small ruminants on lush legume pastures
→ Calcium carbonate or Calcium oxalate
What is the clinical presentation for ruminant urolithiasis?
- Acute or chronic urethral obstruction
- Urethral rupture
- Bladder rupture
In what gender of ruminant is the urolithiasis prevalence higher?
Restless, tail swishing, grinding teeth, straining (prolapse of rectum)
* Dribbling of urine if partial obstruction
* Penile/preputial/perineal swellings, cellulitis in area of ruptured urethra
What are the common sites for urolithiasis obstruction?
Common sites for obstruction:
Sheep/Goat: Urethral process
Cattle: Distal aspect of sigmoid flexure
How might you examine the penis of the ruminant (urolithiasis)
Common to have to facilitate extrusion of penis for examination and/or
catheterisation in large animals.
Acepromazine induces relaxation of skeletal mm, incl. muscles actively
retracting penis
* Does not provide deep sedation - may require α-2 agonist
* CARE with α-2 agonists = potent diuretics
→may be contraindicated if urethral obstruction
* Can place caudal epidural block in small ruminants to facilitate exam
How might you treat urolithiasis in ruminants?
Some obstructions may be relieved with medical therapy…
Surgical intervention usually indicated
→ clear or bypass obstruction and regain urine output by
– Amputation of urethral process
– Urethrostomy – perineal or pre-pubic
– Cystotomy
– Tube cystotomy
– Bladder marsupilsation
