South African Equine Veterinary Association Congress 2015 Protea Hotel Stellenbosch
(grain) intake, and adding fat to the diet are recommendations to increase caloric intake. Over the
past couple of decades restricting dietary protein intake by human and veterinary patients with
CKD was thought to have beneficial effects; however, the current recommendation is to provide
adequate amounts of dietary protein and energy to meet or slightly exceed predicted requirements
while maintaining a neutral nitrogen balance. Adequacy of dietary protein intake can be assessed
by the BUN to Cr ratio: values >15 (mg/dL units) suggest excessive protein intake while values
<10 may indicate protein-calorie malnutrition.
Progressive loss of nephron function with CKD precludes successful long-term treatment.
However, many horses with early CKD may be able to continue in performance or live as pets for
quite some time (months to a few years). In general, as long as Cr remains <5 mg/dl (440 µmol/L)
and the BUN:Cr ratio is <15 (mg/dL units), horses seem to maintain a fair attitude, appetite, and
body condition. However, once Cr exceeds 5 mg/dl (440 µmol/L), the rate of progression of CKD
appears to accelerate and signs of uraemia (anorexia, poor hair coat, and loss of body condition)
become more apparent. Due to the variable nature of progression, each case should be handled on
an individual basis with the emphasis on maintenance of body condition until humane euthanasia
becomes necessary.
Hematuria: Haematuria can be presenting complaint for a variety of disorders of the urinary
tract. The problems causing haematuria can range from relatively minor disorders to more severe
disease processes that may result in life-threatening haemorrhage. Urolithiasis, urinary tract
infection, drug toxicity, and neoplasia are some of the more common causes of haematuria. For
this presentation, three less commonly recognized causes of haematuria are described: i) exerciseassociated hematuria, ii) proximal urethral tears in stock type horses, and iii) idiopathic renal
hematuria.
Exercise-associated haematuria: Exercise is accompanied by increased filtration of red blood
cells across the glomerular barrier. Typically, haematuria is microscopic but occasionally gross
discoloration of urine may be observed. Gross haematuria is likely a consequence of bladder
mucosal erosions that are traumatically induced by abdominal contents pounding the bladder
against the pelvis during exercise. Detection of focal bladder erosions or ulcers with a contrecoup
distribution and a history of emptying the bladder immediately prior to the exercise bout would be
characteristic for this problem. A diagnosis of exercise-associated haematuria should be one of
exclusion after diagnostic evaluation has ruled out other causes of haematuria such as presence of
a cystolith.
Urethral tears: Although a recognized cause of hemospermia in stallions, tears of the proximal
urethra at the level of the ischial arch are a more recently described cause of haematuria in
geldings. Since the defects are difficult to detect without use of high-resolution videoendoscopic
equipment, it is likely that condition was misdiagnosed previously. Consequently, haematuria has
also been attributed to urethritis or haemorrhage from "varicosities" of the urethral vasculature.
Urethral tears typically result in haematuria at the end of urination, in association with urethral
contraction. Affected horses generally void a normal volume of urine that is not discoloured. At
the end of urination, affected geldings have a series of urethral contractions resulting in squirts of
bright red blood. In most instances, the condition does not appear painful or result in pollakiuria.
Interestingly, the majority of affected geldings have been Quarter Horses or Quarter Horse crosses
which have been free of other complaints. Treatment with antibiotics for a suspected cystitis or
urethritis has routinely been unsuccessful, although haematuria has resolved spontaneously in
some cases.
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