Clinical relevance Flashcards
What is anuria?
Non-passage of urine
What may cause anuria?
- Uretal or bladder stones
- Aka urolithiasis
- Damage to urethra/ureters
What are uretal or bladder stones made up of?
Ammonium, magnesium, phosphate
What are some clinical signs of urolithiasis?
- Kicking at belly
- Straining
- Grinding teeth
- Hunched posture
- Pyrexia
- Tachycardia
- Isolation
- Depressed appearance
What may predispose to urolithiasis in sheep?
- High concentrate feed
- Younger males
- Summer
- Castration (removes hormonal control)
What are the most common sites for urolithiasis in male sheep?
- Vermiform appendage (urethral process)
- Scrotum/sigmoid flexure
- Glans penis
Why is obstructive urolithiasis more common in male sheep than females?
- Mares more flexures in urinary tract
- Thinner ureter
What are some of the consequences of obstructive urolithiasis?
- Urethra and penis may rupture
- Bladder rupture
- Irreversible kidney damage
How can obstructive urolithiasis be diagnosed in the male sheep?
- Rectal palpation
- External palpation
- Extrude penis to examine vermiform appendix for presence of caliculi
- Excision of vermiform penis leading to free flowing urine
- Abdominocentesis to assess state of bladder
- Ballotment
What breed of sheep are predisposed to obstructive urolithasis and why?
- Texels (and Scottish blackface)
- Tend to excrete phosphorous through urinary tract rather than saliva and faeces
Outline some of the treatments for obstructive urolithiasis
- Surgery (not appropriate for breeding animals)
- Catheterisation (cat or dog, not recommended for sheep as sigmoid flexure too narrow)
- Diet (may be able to dissolve them)
- NSAIDs to reduce inflammation allowing passage of urine
What changes may occur in the upper urinary tract in cases of obstructive urolithiasis?
- Destruction of renal tissue architecture
- Thickened ureters due to increased back pressure
