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Urolithiasis

Urolithiasis. Katie Simpson, DVM, MS, DACVIM Cross Timbers Large Animal Clinic April 30, 2016. Urolithiasis. Definition Formation of stones (calculi) in the kidneys, ureter , bladder, or urethra Most commonly lodge in urethra Can be anywhere in the urinary tract!

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Urolithiasis

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  1. Urolithiasis Katie Simpson, DVM, MS, DACVIM Cross Timbers Large Animal Clinic April 30, 2016

  2. Urolithiasis • Definition • Formation of stones (calculi) in the kidneys, ureter, bladder, or urethra • Most commonly lodge in urethra • Can be anywhere in the urinary tract! • ‘Stones’ aka ‘calculi’ aka ‘uroliths’ • Concretions of solid mineral and organic compounds • Cause disease through • Direct trauma to urinary tract • Obstruction of urinary outflow

  3. Urolithiasis: The Basics • Males most affected • Long, narrow, non-distensible urethra • Often a herd problem • If one has it….assume they all might! • Significant losses • Monetary • Morbidity (sickness) • Mortality (deaths)

  4. Etiology: Types of Calculi • Struvite • Magnesium, ammonium, phosphate • Most common one in SR…C? • Apatite • Calcium & phosphate • Calcium carbonate • Legumes: clover, alfalfa

  5. Etiology: Types of Calculi • Silicate • Native grasses Western US • Diets high in corn gluten or soybean hulls? • Oxalate • Halogeton, sugar beet tops

  6. Causes & Risk Factors • Presence of a nidus • High concentrations of soluble minerals/salts • Diet (low calcium/high phosphorus, high magnesium) • Decreased water intake • Pelleted rations → less saliva → P excreted in urine • Concreting agents • Mucoproteins in grain • Basic urine pH • NORMAL in sheep, goats, camelids • Leads to certain common types of stones

  7. Risk Factors • Urethral diameter • Gender • Age at castration • Influenced by testosterone • Season • Winter: decreased water intake • Illness • Decreased water intake • Breed? • Texel, Scottish Blackface • Pygmy???

  8. Site of Obstruction • Sheep & goats • Urethral process & sigmoid flexure • Llamas & alpacas • DSF, distal penis, ischial arch

  9. Urolithiasis • Consequences • Urethral obstruction • Ruptured urethra • Urethral stricture (scarring) • Ruptured bladder* • Ruptured ureter • Hydroureter • Hydronephrosis • Rarely—ruptured kidney • Acute renal failure

  10. Clinical Signs, AKA What to look for… • Off feed • Depression • Weakness • +/- Ammonia smell to breath

  11. Clinical Signs… • Crystals on hairs around prepuce • Holding tail up/swishing tail • Pulsations of urethra below tail w/ no urine produced • Bloody appearance to urine* • Straining to urinate (can mistake for straining to defecate) • May lead to rectal prolapse • No urine production, or just dribbling • If not sure, put in a small dry area w/ no bedding

  12. Clinical Signs… • Colic signs • Vocalizing • Grinding teeth • Stretching abdomen • Stamping/shifting back feet • Kicking/looking at abdomen • ‘Standing at the pile’….

  13. Clinical Signs… • Ruptured urethra • Cool, non-painful swelling • Base of scrotum to prepuce • Ruptured bladder • Distention of abdomen—down low

  14. Physical Examination • Evidence of dehydration • Also toxin buildup in blood • Examination of penis • Integrity of urinary tract • Bloodwork • Electrolyte levels, acid-base status, toxin buildup • Evidence of infection

  15. Diagnosis • Species, gender, history, clinical signs • Physical examination • Analysis of urine • IF possible….incomplete obstruction or cystocentesis • Type of crystals/stones • Ultrasound • Urethra, bladder, kidneys, abdomen • Radiographs (x-rays) • Endoscopy

  16. Considerations • Location of obstruction • Concurrent inflammation/infection of bladder • Urethral diverticulum • Frenulum in young

  17. Management • Stage of disease • Urethral obstruction • Ruptured urethra • Ruptured bladder • ‘Water belly’

  18. Management • Class of animal • Commercial/salvage • Breeding • Pet

  19. Obstructed Urethra • Urethral process amputation • Sheep & goats • Catheter & flushing

  20. Catheterize Bladder • IF possible • Lavage w/ acidic solution • Most effective w/ phosphate stones

  21. Decision time! • Urethrostomy • Urethrotomy • Cystotomy/Cystostomy tube • Bladder marsupialization?

  22. Obstructed Urethra • Commercial/salvage animal • Urethrostomy • AKA ‘PU’ • AKA ‘Rerouting’ • They will urinate like a female

  23. Small Ruminants: ‘Rerouting’ • Also camelids? • PU’s stricture/reobstruct • Most w/in 1 year, some w/in 6 wks-months • Good for urethral ruptures • Time to clear bloodstream of toxins • If valuable as a breeding animal or pet…. DON’T DO THIS

  24. Small Ruminants • Most have multiple stones • Urethral process amputation alone cures < 25% long term • Many reobstruct w/in 3 days

  25. Abdominal Surgery: Urinary Bladder • Cystotomy • Remove all the stones • Flush the urethra • ± Leave in tube after surgery

  26. Breeding or Pet Animal: Gold Standard • Cystostomy tube • Also…for ruptured bladder

  27. Cystostomy Tube, or C-Tube • ~75% prognosis if non-ruptured • $1500-2000 • Aftercare is KEY!! • Stall confinement • Goats can chew out tubes • Ascending kidney infection possible…must keep sterile

  28. Ruptured Urethra • Salvage animal • Urethrostomy • Pet • Cystostomy/other • Breeding animal • Now salvage animal • Try C-tube?

  29. Ruptured Bladder • Majority are dorsal • May happen w/ restraint of camelids in chute • Also reported during palpation for pregnancy • Drain abdomen • Gradually

  30. Ruptured Bladder • Valuable breeding animal/pet/show • Drain abdomen/stabilize • Repair bladder – celiotomy • Achieve urinary patency • Or else use C-tube

  31. Bladder Marsupialization • NOT for breeding animals or indoor pets • Prognosis variable • Complications • Urine scald • Cystitis • Ascending UTI • Stricture • Reobstruction • Bladder prolapse

  32. Pain Management • Banamine, NSAIDs???? • USE WITH CAUTION • Butorphanol - $$$

  33. Prevention • Identify risk factors • Diet • Management • Water • Castration • Environment

  34. Prevention… • Diet • Ration analysis • Extension agents, nutritionists • DO NOT feed horse feeds to SR/C unless specifically instructed by a veterinarian • Mineral analysis of stone!! • Increase salt (water) intake • Salt licks/blocks/loose salt • Add 2-4% salt to diet if high grain

  35. Prevention: Diet • Phosphatic stones (MOST COMMON) • Dietary calcium:phosphorus ratio of 2:1 (or greater) • Magnesium content maintained at recommended levels • Decreased amount of pelleted feed • Increased amount of forages fed • Ammonium chloride

  36. Prevention: Diet • Calcium carbonate stones • Reduce alfalfa/legume consumption • Decrease calcium in diet • Ammonium chloride?????

  37. Prevention: Diet • Urinary acidification • Ammonium chloride • In feed up to 1% • Drenching • Bio-Chlor

  38. Prevention: Management • Water • Maximize water intake • CLEAN WATERERS • Summer: shade on waterers • Winter: dark liners or heaters on waterers* • Check automatic waterers frequently to ensure fxn • Shallow water containers = high turnover, less stagnant • Large pastures/many animals • Lots of waterers • Esp sheep

  39. Prevention: Management • Castration • Sheep & goats: castrate at 6-12 months old • Llamas & alpacas: castrate at 2-3 years

  40. Questions?

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