Monday, February 6, 2012

861. Review of recurrent urolithiasis in an 8-year-old lMini Schnauzer

History
Miniature Schnauzer, Male, 8 years
9.3 kg 39.3C

15.9.12 Dysuria >7 days. Eats dry food.
Urethral obstruction. Catheter relieved obstruction.

15.9.12 URINE ANALYSIS
pH=7 (5-8), SG 1.030 (1.005 - 1.030)
Protein +, Blood 4+, WBC 504, RBC 1440, Bacteria +, Crystals Nil

X-ray

BLOOD TEST
Urea = 7 (4.2 - 6.3)
Creatinine = 61 (89-177)
WBC = 13.6 (6-17) with neutrophils 93% absolute 12.6, lymphocytes 6.5%, absolute 0.88
No hypercalcaemia

STONE ANALYSIS - multiple fragmented uroliths. CANINE CALCIUM OXLATE
Calcium oxalaate monohydrate 100% stone 5% shell
Calcium oxalate dihydrate 95% shell

16.9.12 Cystotomy. Urinary stones removed by Vet 1


RECURRENT UROLITHIASIS
3.2.12
8.2 KG 38.4c
Dysuria. Fed home-cooked food.


3.2.12 URINE ANALYSIS
pH=9 (5-8), SG 1.025 (1.005 - 1.030)
Protein 2+, Blood 4+, WBC 0, RBC >2250, Bacteria +, Crystals Triple phosphate +, Amorphous phosphate 3+

STONE ANALYSIS - Sent stones to the lab

Owner did not want blood test
X-rays - 15 stones seen. bladder and behind os penis. see image.

CONCLUSION
This is not a recurrent case of calcium oxalate urinary stones as the 2nd episode showed struvite stone formation.

MANAGING Calcium Oxalate Urolith prevention - do urinalysis and X-rays.
If urine SG >1.020 give canned food or add water to food
If urine pH <6.5, consider diets that produce less acidic urine eg. u/d or use urinary alkalinizers eg. K citrate If urine pH>6.5, USG <1.020, no crystals, repeat urinalysis monthly, then every 3-6 montyhs.
Repeat X-ray every 6-12 months to detect urolith recurrence early.
Repeat urine test and X-rays if signs - haematuria, pollakiuria, dysuria recur.

STRUVITE stones are clinically insignificantg if no urinary tract infection as bacteria forming urease are rquired for struvite urolith formation in dogs.

UROLITHS
1. Voiding urohydropropulsio9n if small uroliths
2. No clinical signs of blood in urine etc, leave stones alone.
3. With persistent signs, remove uroliths
4. Send for stone analysis.

For calcium oxalate prevention,
1. Diets promoting urine pH <6.59 were at highest risk
2. Avoid risk factors like hypercalciuria due to hypercalcemia, metabolic acidosis, high sodium consumption and Vit D excess.
3. Feed canned foods and/or add more water to food so that urine pH is consistently <6.5
4. Consider hydrocholorothiazide (2mg/kg q 12 hr) with highly recurrent urolithaisais in dogs without hypercalcemia.
5. Consider potassium citrate (75mg/kg q 12-24 hr) if urine pH is consistently <6.5

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