LA Urolithiasis: Medical/Surgical Management and Complications Flashcards

1
Q

what are the goals of medical versus surgical therapy? what do they include?

A

medical:
-stabilize patient
-dissolve existing calculi
-prevent formation of additional stones
-include: analgesics, antimicrobials, urine acidifers (tetanus prophylaxis!!)

surgical:
-urine drainage
-remove excess calculi
-re-establish urethral patency
-include: cystoscopy, urethrotomy/perineal urethrotomy (PU) in males, lithotripsy (mechanical, laser, shock wave)

management changes long term!

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2
Q

describe cystoliths in horses

A
  1. presenting complaint:
    -typically hematuria mid or end stream, especially after exercise
  2. clinical signs: hematuria, stranguria, oliguria, incontinence, urine scald, weight loss
  3. typically calcium carbonate, calcite (mineralized form)
    -TI: soft, yellow, spiculated stones of CaCO3 crystals
    -TII: <10% of calculi, smooth, rounded white (Ca, carbonate, P, Mg)
  4. calculi most commonly in the bladder of the horse!!
  5. majority cases: males >8 years of age
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3
Q

describe considerations for surgery for uroliths in horses

A
  1. gen anesthesia or standing sedation
  2. perioperative analgesia: systemic and local (epidural)
  3. antimicrobials
  4. complications
  5. recurrence (especially if leave nidus behind (lithotripsy-punch until it shatters))
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4
Q

describe surgical approaches for removing bladder stones in horses

A
  1. mare lithotripsy, endoscopic bag removal
  2. gelding progressive urethral dilation via perineal urethotomy
  3. laparascopic removal: in standing horse; size limitations
  4. modified parainguinal approach: for larger stones, require general anesthesia
  5. pararectal cystotomy
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5
Q

describe what the bladder needs re: surgery

A

bladder requires water tight seal!

single layer closure recommended:
-achieves anatomic reconstruction
-accelerates healing
-obviates reduction in luminal diameter
-achieves water tight seal

potential complications:
1. incisional infection
2. dehiscence
3. difficult access
4. incision: mucosal defects heal in 5 days and full thickness defects heal in 14-21 days
5. cystolith removal tends to be incomplete :( lots of dust and debris can act as nidus for infection or future stone formation

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6
Q

describe potential surgical complications

A
  1. difficult exteriorization of bladder
  2. prolonged manipulation/bladder fatigue
  3. loss of stone architecture: incomplete removal
  4. tension in closure - can dehiss
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7
Q

describe follow-up care from cystotomy

A
  1. indwelling urinary catheter and abdominal drain
  2. broad spectrum antimicrobials (penicillin, gentamicin)
  3. anti-inflammatories: flunixin, IV lidocaine CRI
  4. IV fluid therapy
  5. serial metabolic panels
  6. serial abdominal ultrasounds
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8
Q

describe ultrasound for bladder stones in horses

A

a beneficial diagnostic!

renal and ureters: check them both

10% calculi at more than one location

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9
Q

how are larger calculi best removed?

A

through a parainguinal, caudal midline, or pararectal approach

-incisional infection or dehiscence and difficult accessa re known complications

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10
Q

what type of inflammation does urine cause?

A

nonseptic/sterile neutrophilic inflammation: because chemical irritant
-cell count: >5000 NC per ml
-specific gravity: >1.025 (hypersthenuric)
-total solids: >3.0 g/dL

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11
Q

describe urolithiasis in ruminants

A
  1. formation of stones within urinary tract
    -leading cause of obstruction!!
  2. very common due to dietary imbalances
  3. all species affected
  4. males predisposed: long urethra, small diameter urethra
  5. castrated males predisposed:
    -urethral diameter is influence by testosterone, so if a pet goat, delay castration (the longer the better)!
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12
Q

compare and contract partial and complete obstruction in ruminants

A

partial:
-dribbling when urinating
-small, frequent urinations
-medial or surgical management

complete:
-no urine produced
-surgical EMERGENCY

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13
Q

describe early and late signs of urolithiasis in ruminants

A

early signs:
1. hematuria
2. dysuria
3. crystals on prepuce
4. dribbling
5. tail flagging
6. colic

late signs:
1. anorexia
2. depression
3. prepucial swelling
4. abdominal distension
5. recumbency
6. seizure activity
7. death

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14
Q

describe diagnostics for urolithiasis in ruminants

A

plain view radiographs helpful for radiopaque:
-calcium carbonate
-calcium oxalate
-silica

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15
Q

describe options for surgical management of obstruction in ruminants

A
  1. urethral process amputation:
    -#1 place for obstruction in small ruminants
    -no effect on future fertility in breeding males
    -exteriorization is the hardest part!
  2. bonnano-pre-pubic catheter
  3. perineal/ventral urethrostomy
  4. tube cystotomy +/- urethrotomy
  5. bladder marsupialization
  6. lithiotripsy
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16
Q

describe the goals of surgical management of urolithiasis in ruminants and complications

A

immediate/short term:
-relieve obstruction: pain relief, stop spasm, allow other urethral stones to pass
-temporary or permanent rerouting of urine

longterm: maintain normal urinary and breeding function

complications: make worse prognosis (duh)
-bladder rupture
-urethral rupture
-hydronephrosis

17
Q

describe urethral rupture

A
  1. trauma from stones: ischemic necrosis (leads to sloughing) from sharp stones
  2. usually due to chronic obstruction
  3. swollen prepuce: pitting edema
  4. poor prognosis: urethral stricture
18
Q

describe emergency workup for urolothiasis

A

signalment: age, male, castrated or intact

history: onset, duration, clinical signs, waxing and waning, prior treatment

exam: TPR, attitude/mentation
-abdominal palpation: bladder, free fluid, ballottement
-rectal palpation: urethral dilation, pulsation
-prepucial evaluation: swelling?

imaging:
-radiographs: stones and location
-ultrasound: free abdominal fluid? eval bladder (size and stones), eval kidneys (hydronephrosis?)
-abdominocentesis: creatinine
-EKG: arrhythmias due to potassium

19
Q

describe urethral process amputation

A

-#1 place for obstruction in small ruminants
-no effect on future fertility in breeding males
-exteriorization is the hardest part!

advatanges:
-quick, cheap, easy
-GA not required, sedation with local block
-abdominal cavity not opened

disadvantages:
-short term fix: most stricture within 6 months
-hemorhage
-urine scalding

20
Q

describe perineal urethrostomy

A
  1. salvage procedure: not an option for breeding animal
  2. incise skin, dissect down to penis, suture urethra to skin
  3. stricture common
  4. modified proximal for goats: transection of ischiocavernosis muscles; low rate of stricture formation
  5. these are pretty expensive surgeries
21
Q

describe tube cystotomy

A

advantages:
-goal: functional urethra/penis
-necessary for breeding males
-permits bladder repair
-best/gold standard option!
-only 75% success rate though :(

disadvantages:
-abdominal surgery
-general anesthesia
-more difficult and time consuming (expensive!)
-longer recovery
-cystitis

goals:
-provide urine egress: urethral relaxation, stone dissolution with ammonium chloride and renacidin
-challenge the animals: close tube, let them try to urinate and see if they can and repeat until they can
-tube can stop functioning during procedure = annoying

success:
-mean time to normal urination: 11 days
-76% successfully treated
-re-obstruction in <20% of animals within 12 months

-concurrent medical management!
-dietary modifications
-ammonium chloride
-IV fluid therapy if needed

22
Q

describe percutaneous tube cystotomy

A
  1. percutaneous suprapubic balloon catheter
    -trocar tip
    -inflatable ballon
    -cheaper than tube cystotomy!
  2. can be introduced with sedation
    -ultrasound guidance helpful
    -the bigger the bladder the easier (complete obstruction easier than partial)
  3. disadvantage: unable to manually remove cystoliths
23
Q

describe bladder marsupialization

A
  1. stoma created between bladder and body wall
  2. provide urine egress permanently

advantages: quick fix

disadvantages:
-chronic cystitis
-urine scald
-abdominal surgery

last resort!
not viable for breeding males!!

24
Q

describe urethral catheterization

A

diverticulum interferes with retrograde catheterization in ruminants!

bern catheter: bent tip facilitates passage of diverticulum

more likely to traumatize urethra though