SAEVA Congress 2018 Proceedings | 12-15 February 2018 | ATKV Goudini Spa
ACUTE AND CHRONIC RENAL FAILURE
Dr. Warwick Bayly, BVSc, MS, PhD, Dip ACVIM
College of Veterinary Medicine, Washington State University
In horses, primary renal disease most frequently originates from renal ischemia (pre-
renal failure), the deposition of antigen-antibody complexes in the glomeruli, or is
subsequent to the ingestion or administration of a nephrotoxic plant, chemical or
medication, although renal abscessation and neoplasia, and polycystic kidneys have
been reported. Equine renal disease can also be associated with a variety of other
medical problems. Renal failure (RF) requires the loss of function of a majority of
nephrons (assumed to be about 65-70%), and therefore, does not always occur with
renal disease. In each instance, the outcome of the case may ultimately depend on
the degree of renal dysfunction and the ability of the practitioner to recognize,
evaluate and treat it.
Acute failure (ARF) is characterized by a sudden and usually rapid deterioration in
renal function. In horses this is almost invariably manifest by oliguria due to reduced
perfusion of glomeruli or renal tubular obstruction, or both. Anuria is occasionally
observed in particularly severe cases. If the horse does not die or recover
completely from the acute failure, it may progress to the chronic stage which is
characterized by polyuria due to a loss of ability to concentrate the glomerular filtrate.
ACUTE RENAL FAILURE:
History and physical examination –
The clinical signs of ARF are usually nonspecific. The onset is sudden and horses
are usually inappetant, depressed and weak. There is often a history of a pre-
existing or concurrent disease, which may be associated with lowered renal
perfusion. Occasionally the animal has been treated with a potentially nephrotoxic
agent. Renal problems arising from the ingestion of potentially nephrotoxic
substances such as plants (most of which are relatively unpalatable), mycotoxins or
heavy metals are often difficult to establish historically, and are more commonly
associated with CRF although the problem may appear acute in onset.
Generally only the caudal pole of the left kidney can be palpated per rectum and its
evaluation is extremely subjective. With ARF, the kidneys are often enlarged and
may be painful on palpation, although failure to discern such changes does not rule
out the problem. Rectal palpation of the right kidney should be regarded as
abnormal.
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