Equis ISSN 2398-2977

Kidney: renal failure

Synonym(s): Kidney failure

Contributor(s): Annalisa Barrelet, Prof Jonathon Naylor, Prof Susan Rhind


  • Cause: toxic, obstructive, hemodynamic (ischemic injury).
  • Signs: variable systemic signs depending on cause and duration; localizing signs include abdominal pain, dysuria.
  • Diagnosis: rectal palpation, ultrasonography, hematology, urinalysis.
  • Treatment: remove inciting cause; fluid therapy.
  • Prognosis: guarded to grave.



  • Inadequate blood pressure/flow to the kidney including shock and endotoxemia.



  • Blockage to the urine drainage system caused by calculi   Bladder: calculi  , developmental abnormality, prolapse, etc.


  • Renal disease is rare in horses, and initial diagnosis may be difficult due to the large functional reserve of the excretory system.
  • The kidney depends on adequate blood pressure in the bloodstream (pre-renal), functional filtration apparatus (intra-renal), and free flow of urine away from the kidney (post-renal).
  • Problems can be divided into pre-renal, renal and post-renal.
  • The kidney is particularly susceptible to ischemic injury because of its unique anatomic/physiologic features.
  • The kidneys receive about 20% of the cardiac output but only about 10-20% of the total renal blood flow reaches the renal medulla via the vasa recta.
  • This is necessary for the functioning of the counter-current mechanism, but creates a large corticomedullary oxygen gradient and renders the renal medulla relatively hypoxic and susceptible to ischemic injury.
  • Conversely the renal cortex receives 80-90% of the renal blood flow and is particularly susceptible to nephrotoxin exposure.

Acute renal failure

Chronic renal failure

  • Infrequently diagnosed condition in the horse.
  • It occurs most frequently in older horses as a result of glomerular, tubulointerstitial disease or obstructive urolithiasis of the kidneys or ureter.
  • The most common cause of chronic renal failure is proliferative glomerulonephritis, which is thought to be a result of immune complex deposition within the glomeruli   Kidney: glomerulonephritis 01 - histopathology    Kidney: glomerulonephritis 02 - histopathology  .
  • Thickening of the filtration barrier leads to a progressive decline in glomerular filtration rate and development of azotemia.
  • EIA antigen   Equine infectious anemia virus  has been identified in connection with glomerulonephritis and renal amyloidosis is a condition peculiar to hyperimmunized horses.
  • Hypercalcemia is a feature of equine chronic renal failure, perhaps due to a decrease in glomerular filtration rate. Secondary hypoparathyroidism, with decreased levels of parathyroid hormone may be associated.
  • At least 50% of the renal tubules must be functional to elaborate concentrated urine, isosthenuria occurs when two-thirds of the nephrons are non-functional.


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Further Reading


Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Han J H & McKenzie III C (2008) Intermittent peritoneal dialysis for the treatment of acute renal failure in two horses. Equine Vet Educ 20 (5), 256-264 VetMedResource.
  • Peek S F (2008) Peritoneal dialysis and acute renal failure: A new treatment for an old disease? Equine Vet Educ 20 (5), 265-266 Wiley Online Library.
  • Gallatin L L, Couetil L L & Ash S R (2005) Use of continuous-flow peritoneal dialysis for the treatment of acute renal failure in an adult horse. JAVMA 226 (5), 756-759 PubMed.
  • Bartol J M et al (2000) Nephrotoxicant-induced acute renal failure in five horses. Comp Cont Educ Pract Vet 22 (9), 870-876 VetMedResource.
  • Aguilera-Tejero E et al (2000) Polycystic kidneys as a cause of chronic renal failure and secondary hypoparathyroidism in a horse. Equine Vet J 32 (2), 167-169 PubMed.
  • Holdstock N B, Ousey J C & Rossdale P D (1998) Glomerular filtration rate, effective renal plasma flow, blood pressure and pulse rate in the equine neonate during the first 10 days post partum. Equine Vet J 30 (4), 335-343 PubMed.
  • McKeever K H (1998) Effect of exercise on fluid balance and renal function in horses. Vet Clin North Am Equine Pract 14 (1), 23-44 PubMed.
  • Hogan P M et al (1996) Acute renal disease due to Leptospira interrogans in a weanling. Equine Vet J 28 (4), 331-333 PubMed.
  • Johnson P J (1995) Electrolyte and acid-base disturbances in the horse. Vet Clin North Am Equine Pract 11 (3), 491-514 PubMed.
  • Divers J G, Timoney J F, Lewis R M & Smith C A (1992) Equine glomerulonephritis and renal failure associated with complexes of group-C streptococcal antigen and IgG antibody. Vet Immunol Immunopathol 32 (1-2), 93-102 PubMed.
  • Rantanen N W (1990) Renal ultrasound in the horse. Equine Vet J (3), 135-136 VetMedResource.
  • Kerr M G (1990) Renal disease in the horse. Equine Vet J (3), 123-126 VetMedResource.
  • Hillyer M H, Mair T S & Lucke V M (1990) Bilateral renal calculi in an adult horse. Equine Vet J (3), 117-120 VetMedResource.
  • Young A (1990) Laboratory investigation of equine kidney disease. Equine Vet J (3), 130-134 VetMedResource.
  • West H J & Kelly D F (1987) Renal carcinomatosis in a horse. Equine Vet J 19 (6), 548-551 PubMed.
  • Bayly W M, Brobst D F, Elfers R S & Reed S M (1986) Serum and urinary biochemistry and enzyme changes in ponies with acute renal failure. Cornell Vet 76 (3), 306-316 PubMed.
  • Bayly W M et al (1986) A reproducible means of studying acute renal failure in the horse. Cornell Vet 76 (3), 287-298 PubMed.
  • Read W K (1983) Renal medullary crest necrosis associated with phenylbutazome therapy in horses. Vet Pathol 20 (6), 662-669 PubMed.
  • Tennant B, Bettleheim P & Kaneko J J (1982) Paradoxic hypercalcemia and hypophosphatemia associated with chronic renal failure in horses. JAVMA 180 (6), 630-634 PubMed.