Page 955 - Equine Clinical Medicine, Surgery and Reproduction, 2nd Edition

930 CHAPTER 7

VetBooks.ir Quantification of GFR the bladder from ureteral openings at least every
60 seconds. Urine can be collected from each ureter.
Measuring GFR as an indicator of functional renal
mass assesses the excretion of endogenous or exog-
fort and excessive straining. Venous air embolism
enous substances (inulin, creatinine, sodium sul- Overinflation of the bladder causes patient discom-
phanilate) that are neither secreted nor resorbed has been reported after room air insufflation and can
after filtration into the tubular lumen. The use of be avoided if CO is used to inflate the bladder.
2
radiopharmaceuticals is a very sensitive tool for GFR
and effective renal blood flow measurement. These Renal biopsy
tests are time- and labour-consuming, require spe- Renal biopsy only occasionally offers information
cialised laboratory assays or equipment and are usu- more specific than that gathered by conservative
ally only used in referral centres. diagnostic approaches. Its use in horses with CKD
should be carefully considered because of the risks
Endoscopy associated with this diagnostic technique. If per-
Endoscopy of the urinary tract is a useful diagnostic formed with ultrasonographic guidance, the risk for
tool. A flexible endoscope with an outside diameter subcapsular haemorrhage and haematuria, or even
of 12 mm or less should be used. An endoscope of bowel penetration, is small. The biopsy can also be
less than 1 metre in length may not be adequate to taken without any direct ultrasonographic guidance;
reach the bladder in males. The procedure is identi- however, ultrasonographic evaluation is needed
cal to that of bladder catheterisation. The urethra, before the procedure to evaluate the site and depth
especially its ampullar portion, colliculus seminalis, of the kidney. The horse should be sedated and prop-
bladder and ureteral openings should be examined. erly restrained. Samples should be placed in forma-
Inflammation, masses and calculi can be visualised lin for histopathological examination or in Michel’s
(Fig. 7.12), as can abnormal discharges from ureters medium for immunofluorescence testing. Bacterial
(Fig. 7.13). A small amount of urine should enter culture can be performed on all samples.

7.12 7.13

Fig. 7.12 Cystolith. Note also the bladder mucosal Fig. 7.13 Ureteral opening. Note the bloody
ulceration. discharge (arrow).