Urinary System Flashcards
Define: nephrotomy
cut into the kidney
Define: partial nephrectomy
remove part of the kidney
Define: nephroureterectomy
remove the kidney and ureter
Define: pyelolithotomy
remove stones from the renal pelvis
Define: nephrostomy tube
placing a tube into the kidney
Define: lithotripsy
a treatment using US shock waves to break stones/calculi into small particles
What is the arterial and venous supply of the kidney?
Renal artery comes from aorta
Renal vein drains to CdVC
At renal hilus –> split into dorsal and ventral branches –> interlobular branches which DO NOT cross midline
What are the most common nephroliths?
41% Ca oxalate
What clinical signs are associated with nephroliths?
Nonspecific: depression, anorexia, hematuria, pain
Possible uremia and hydronephrosis
How do you diagnose nephroliths?
Survey radiographs / US
What parameters do you use to determine the best management for nephroliths?
- Type of calculi
- Anatomical location
- Clinical effects
o If asymptomatic may just monitor renal function and imaging
o Removal damages kidney (20-50% reduction in function), but improper medical management can make condition worse
When is surgery for nephroliths indicated?
Obstruction
Infection associated with the calculi
What are the four main treatment options for nephroliths?
Medical management
Lithotripsy
Nephrolithotomy
Pyelolithotomy
How do you perform a nephrolithotomy? (10 steps)
- Ventral midline celiotomy
- Retract mesocolon or mesoduodenum
- Dissect retroperitoneal fat to isolate vessels
- Temporarily (20 minutes) occlude blood supply to kidney using rumel tourniquet or bulldog vascular clamp
- Mobilize kidney
- Make a sagittal incision and identify stone
- Remove stone manually
- Submit for analysis and culture renal pelvis
- Flush renal pelvis and ureter with heparinized saline
- Catheterize ureter to ensure patency
What instruments can you use to occlude renal vessels?
Rumel tourniquet (careful not to damage endothelium, high risk of thromboembolism) Bulldog vascular clamp
How long can you occlude the renal vessels for?
20 minutes
How do you close the surgical site in a nephrolithotomy?
Sutureless closure: hold for 5 minutes to form fibrin seal, then suture capsule only
Replace kidney in renal fossa and nephropexy to prevent renal torsion
What are the advantages of a pyelolithotomy over a nephrolithotmy and when would this be indicated?
Preferred if stone is located in renal pelvis and/or there is dilation of the pelvis
Does not require occlusion of blood supply, does not damage nephrons
How is a pyelolithotomy performed?
Longitudinal incision at renal pelvis
Removal of stone
Closure of pelvis
What is the post-operative management of a nephrolithotomy?
- Post-op radiogrpahs – look for additional calculi
- Monitor PCV, central venous pressure (hydration), urine output, and renal enzymes/electrolytes
- Provide diuresis – helps maintain renal perfusion and minimize clot formation
How can you diagnose renal trauma?
o Contrast excretory urography
o Exploratory celiotomy
o Ultrasound
How do you manage renal trauma?
- Minor trauma – conservative treatment
o Bruising or subcapsular hematoma
2. Moderate trauma – surgical intervention o Capsular/parenchymal tears o Extravasated urine/blood o Hemostatic agents/partial nephrectomy o Omental patching
- Major trauma
o Extensive parenchymal or vascular damage can lead to hemorrhagic shock and death
o If parenchyma is shattered consider partial nephrectomy or nephroureterectomy (evaluate contralateral kidney function first)
How is a nephroureterectomy performed?
- Mobilize kidney
- Identify vessels and ligate separately
- Separate and ligate ureter and vesicoureteral junction
What are the (4) indications for performing a nephroureterectomy?
- Severe infection or trauma
- Obstructive calculi with persistent hydronephrosis
- Neoplasia
- Transplant
Why would you perform a partial nephrectomy and what are the disadvantages over a nephroureterectomy?
- Indications: Compromised GFR in contralateral kidney in the face of trauma, focal hemorrhage, neoplasia
- Advantages – preserves renal function
- Disadvantages – higher incidence of post-operative hemorrhage, technically more difficult
How do you perform a partial nephrectomy?
- Occlude blood supply
- Incise and peel back capsule
- Pass suture with straight needle, dividing kidney in thirds
- Tighten sutures to occlude and remove diseased tissue
- Loosen tourniquet
- Close capsule
What is hydronephrosis?
Progressive dilatation of the renal pelvis and atrophy of the renal parenchyma
What are the clinical signs of hydronephrosis?
Unilateral: abdominal distension with palpable mass
Bilateral: severe azotemia and death
How is hydronephrosis diagnosed?
Abdominal rads / excretory urogram / US
How is hydronephrosis treated?
- Eliminate cause
- Evaluate function
5 week obstruction = may regain 25% - Nephroureterectomy for non-functional or severe parenchymal damage
What is the surgical treatment for severe/advanced pyelonephritis?
Nephroureterectomy
How are animals infected with the giant kidney worm?
Fish or frog consumption
What are the clinical signs of giant kidney worm infection, and how is it diagnosed?
Destruction of renal parenchyma –> kidney failure
Often diagnosed on necropsy, may be visualized on US/rads
How is the giant kidney worm treated surgically?
Nephrectomy or nephrotomy depending on severity of infection
What are the most common benign and malignant renal tumors in the dog and cat?
Benign: renal adenoma (both)
Malignant: renal carcinoma (canine), renal lymphoma (feline)
How are renal carcinomas managed?
Nephroureterectomy and chemo
How is renal lymphoma managed?
Medically or surgically (nephroureterectomy) depending on staging
Describe the development, signalment, and prognosis of nephroblastomas
Congenital neoplasia that occurs as part of the developing kidney.
Affects young dogs and cats.
MST 6 months
What are 4 indications for renal biopsy?
Suspected neoplasia
Nephrotic syndrome
Renal cortex disease
Non-diagnosed ARF (*not indicated in CRF b/c will not change prognosis)
What are the techniques available for renal biopsy?
o Percutaneous (small dogs and cats): secure kidney against abdominal wall – blind technique o US guided (preferred method): advance needle into prepared area penetrate capsule can identify target lesions o Keyhole: modified surgical flank approach secure kidney to incision introduce biopsy needle o Laparoscopic-assisted: forceps hold kidney skin incision needle placement through incision o Wedge or incisional: ventral midline celiotomy occlude renal vessels crescent shaped sample (5-10mm long, 5mm deep in cortex) close with mattress suture
What are the risks and contraindications to renal biopsy?
o Severe hemorrhage (d/t hypertension, NSAID within 5 days, coagulopathy, poor technique), hematuria (usually resolves 2-3 days), hydronephrosis (ureteral obstruction from clot)
o Contraindicated in coagulopathies (obtain clotting profiles), hypertension (risk of hemorrhage), severe chronic hydronephrosis (just do nephroureterectomy)
What are the indications of a renal transplant?
• irreversible acute renal failure, decompensated chronic renal failure, polycystic disease
What are the screening parameters for renal transplant?
CBC, chemistry (renal function – may require diuresis to get to acceptable level), U/A and culture, abdominal radiographs / US / echo, FeLV/FIV/Toxo screens
What are the considerations when selecting renal transplant?
• cost, frequent visits, immunosuppression (lifelong drug suppression)
What is the prognosis for renal transplant patients?
MST ~2 years, but 23% do not survive to discharge
Define: neoureterocystotomy
making a new ureteral opening into the bladder
Define: neoureterostomy
transplantation of ureter into another place
Define: nephroureterectomy
removal of ureter and kidney
Define: ureterotomy
incision into ureter (and subsequent closure)
Defin: ureteroureterostomy
transplantation of one ureter into another ureter/into itself
What is an ectopic ureter?
Failure of one or both ureters to terminate in the normal location (level of trigone)
What is the breed, sex, age and clinical signs of ectopic ureter?
- Breeds: Siberian Husky, Lab/Golden, West Highland Terrier
- Sex: female canines (rare in cats)
- Age: young
- CS: incontinence, failure to house train, UTI, urine scalding
How do you diagnose and classify ectopic ureter and what is the most common type?
• Dx: Primarily excretory urography +/- pneumocystography and fluoroscopy
o Alternatively: image enhanced CT, ultrasound, and cystoscopy (visualization of abnormal uretal orifice)
• Extramural classification (less common) – enters and exists in abnormal location (into neck, urethra, or vagina)
• Intramural classification (most common) – enters normally but exits abnormally
How do you treat ectopic ureter?
- Neouretrocystostomy
♣ End to side – reimplantation of ureter for extramural EU (not as common)
• Cystostomy incision ligation and transection of ureter where it enters urethra stab incision into bladder transplantation into normal location spatulate (open up ureteral entrance) and suture
♣ Side to side – intravesicular diversion for intramural EU
• Cystostomy incision identify ureter slit incision at normal location suture mucosa to mucosa catheterize and ligate remove catheter and tighten sutures dissect out ureteral remnant - Laser transection of wall between EU and bladder or urethra
♣ Scope placed into urethra/bladder identify abnormality obliterate wall underlying ureter until urine allowed to flow normally
♣ Cannot remove remnant ureter that may contribute to incontinence
What is the prognosis after treatment of ectopic ureters?
Incontinence improves in 60%, 90% improvement when phenylpropanolamine (PPA) added