Urolithiasis In SA Flashcards
What is the difference between uroliths and crystals?
One is macroscopic, one is microscopic
What type of crystals are found in normal young cats with concentrated urine?
STRUVITE
When do crystals form?
When urine is supersaturated
How does increasing concentration affect the stability of urine?
Stable -> meta stable -> unstable
What occurs when urine is unstable?
Nucleation - formation of a new crystal
Compare the concentration of solute required for Nucleation to growth when a nidus is present
Concentration of solute required is higher for nucleation
Is it possible to dissolve crystals?
Yes, for some if the concentration of solute can be reduced sufficiently
What clinical signs may be associated with cystoliths ?
Dysuria, pollakiuria, haematuria
Inappropriate urination
Generally not palpable
What clinical signs may be associated with urethroliths?
Abdominal discomfort Poor to no urine stream Licking of genital area Obstruction and post renal azotaemia Enlarged painful bladder May be palpable per rectum or at base of os penis
What clinical signs may be associated with nephroliths and ureteroliths ?
Asymptomatic if non obstructive
Pyelonephritis - can be nidus for infection
Renal failure - if bilateral obstruction or infection
Renal colic
What can cause kidney abnormalities on palpation?
Hydronephrosis or irregularity
What type of stone are UTIs associated with?
Struvite
What is the only reliable way of assessing uroliths?
Quantitative analysis with lab
X-ray diffraction provides detailed analysis of mineral composition
What type of stone is not usually amenable to dissolution?
Calcium oxalate
What treatments should you consider for renal and ureteral stones?
Surgical removal Urinary bypass Dietary dissolution IF non obstructed Benign neglect Extra-corporal shock wave lithotripsy
Why should surgical removal be carefully considered in renal and ureteral stones ?
Will damage nephrons and decrease GFR
What species should you not perform extra-corporal shock wave lithotripsy on?
What can you? When?
CATS
Dogs - referral procedure, rare
How should you attempt to treat urethroliths?
Retrograde flush into bladder and perform cystotomy if surgery is required
What uroliths are amenable to medical dissolution
Struvite
Urate
Cystine
When would you consider medical management ?
No obstruction
No contraindications to diet therapy
Urolith composition amenable
How do you medically manage uroliths?
Decrease concentration of urine by INCREASING water intake
Decrease quantity of CALCULOGENIC crystalloids with diet or drug therapy
Increase solubility of salts by changing the pH
Treat any predisposing cause
What is urohydropropulsion?
SEDATED - cats + sm dog Fill bladder with saline Position so urethra vertical Agitate Allow stones to settle Initiate voiding Continue pressure to keep brisk flow Peri-procedural antibiotics
