Page 965 - Equine Clinical Medicine, Surgery and Reproduction, 2nd Edition

940 CHAPTER 7

VetBooks.ir culture and sensitivity. Beta-lactam antibiotics (pro- 7.23
caine penicillin 20,000 IU/kg i/m q12 h or ceftiofur
sodium 2.2 mg/kg i/m or i/v q12 h) should be used
initially while awaiting bacterial culture and sensi-
tivity results. A minimum of 14 days of therapy is
required. Repeated urinalyses should be performed
to assess response to treatment. Urine culture should
be repeated 1 week after antimicrobial therapy is
discontinued.
The addition of table salt (2 tablespoons q12–24 h)
to the diet will encourage drinking and increase
urine production. Free access to water should be Fig. 7.23 Distended right ureter (upper) in a
provided. Nephrectomy may be considered if the horse with pyelonephritis and nephroliths. Note the
disease is unilateral, severe and poorly responsive to purulent debris in the ureteral lumen. The left ureter
medical therapy. Complications such as nephrolithi- (lower) is normal.
asis and urinary tract obstruction must be addressed
if they develop.
Dilation of the renal pelvis may be evident ultra-
Prognosis sonographically. Ureteral distension (Fig. 7.23)
The long-term prognosis for survival of cases in an may be palpable p/r or evident ultrasonographi-
early stage of disease is fair. However, because pyelo- cally depending on the location of the obstruc-
nephritis is often diagnosed when the disease is in an tion. Nephrolithiasis is the most common cause of
advanced stage, the prognosis is often poor. hydronephrosis, followed by renal and bladder neo-
plasia, cystitis, acquired strictures of the urethra
Renal tumours or any inflammatory condition that surrounds the
Disseminated tumours of any type, most often lym- urinary tract. Treatment should be directed at cor-
phoma and haemangiosarcoma, may localise to the recting the primary cause of the disease. Prolonged
kidney. Primary renal neoplasia is rare in horses. or repeated periods of obstruction cause irreversible
Renal cell carcinoma (adenocarcinoma) is the most renal damage and CKD.
frequently diagnosed renal neoplasia, followed by
nephroblastoma. Renal cell carcinoma is usually Amyloidosis
diagnosed in older horses. In contrast, nephroblas- Amyloidosis has been reported in horses used for
toma mostly affects young animals. The treatment antiserum production or, rarely, following chronic
of choice for unilateral renal neoplasia is nephrec- infection. The kidney is one of the most frequent
tomy. By the time renal neoplasia is diagnosed the sites of amyloid deposition. Disruption of tissue
prognosis for recovery can already be grave. architecture by amyloid deposits and direct toxic-
ity of amyloidogenic precursor proteins cause renal
Hydronephrosis disease. Proteinaceous complexes are deposited in
Obstruction of urine flow from the proximal urinary glomeruli just below the endothelium; these disturb
tract results in a progressive interstitial fibrosis and normal renal function and lead to end-stage renal
atrophy of the kidney. If unilateral, it may remain disease. No effective treatments have been reported
clinically inapparent for a long period of time. in horses.