Renal health in horses encompasses the study of kidney function, disorders, and their management in equine species. The kidneys are vital organs responsible for filtering waste products from the blood, regulating fluid balance, and maintaining electrolyte levels. Renal disorders in horses can arise from various causes, including dehydration, toxins, infections, and congenital abnormalities. Common conditions affecting equine renal health include acute kidney injury and chronic kidney disease. Diagnostic methods often involve blood tests, urinalysis, and imaging techniques to assess kidney function and structure. This page gathers peer-reviewed research studies and scholarly articles that explore the physiology, pathology, and therapeutic approaches related to renal health in horses.
McLeland S.Uncommon diseases of the equine urinary system span a variety of etiologies and frequently have nonspecific clinical presentations. Because of the infrequency of equine urinary disease and inconsistencies in clinical symptoms, diagnosis and subsequent treatment of urinary disease in this species may be challenging. This article reviews various diseases of the equine urinary system, morphologies, and potential discriminating clinical and clinicopathologic presentations to aid the clinician in determining a definitive diagnosis in practice.
Gilday RA, Wojnarowicz C, Tryon KA, Lohmann KL.A Canadian warmblood foal treated for septic polyarthritis was diagnosed with bilateral congenital renal dysplasia, hydronephrosis, and hydroureter at 2 weeks of age based on abdominal ultrasound and postmortem examination. Intermittent abdominal pain throughout the course of treatment was attributed to hydronephrosis and hydroureter. Un poulain Warmblood canadien traité pour une polyarthrite septique a été diagnostiqué avec de la dysplasie rénale congénitale bilatérale, de l’hydronéphrose et de l’urétérohydrose à l’âge de 2 semaines en se fondant sur une échographie abdomi...
Hardefeldt LY.Four neonatal foals were presented, over a 2-year period, (2011-2012) with aimlessly walking, head pressing, 'chewing gum' seizures and ataxia. The neurological lesion was consistent with increased intracranial pressure in all cases. All foals had severe hyponatraemia and azotaemia identified on biochemistry. Hyponatraemia was transient in 3/4 cases, with the foal in the final case requiring long-term sodium supplementation. Three foals survived to hospital discharge; one was euthanased because of anuric renal failure and one of the surviving foals was euthanased with septic osteomyelitis 2 we...
Smith S, Naylor RJ, Knowles EJ, Mair TS, Cahalan SD, Fews D, Dunkel B.Acorn toxicity has been anecdotally reported to cause fatal colitis and colic in horses but reports in the scientific literature are sparse. Objective: This study reports the diagnosis, treatment, prognosis and outcome of 9 cases with suspected acorn toxicity admitted to 2 referral hospitals. Methods: Retrospective case series. Methods: Case records from 2004 to 2013 were reviewed. Horses were included in the study if they met 3 of 4 criteria: exposure to acorns; clinical and laboratory data suggesting alimentary or renal dysfunction; acorn husks in the faeces or gastrointestinal tract; and ne...
Burton AJ, Giguère S, Arnold RD.Although gentamicin is highly active against Rhodococcus equi in vitro, its clinical efficacy has been limited presumably due to poor cellular uptake. Encapsulation of drugs in liposomes enhances their cellular uptake. Objective: To compare the disposition of liposomal gentamicin (LG) and free gentamicin (FG) in the plasma, pulmonary epithelial lining fluid and bronchoalveolar cells of healthy foals after i.v. administration or by nebulisation, and to assess the tolerability of the drug after repeated i.v. dosing. Methods: Experimental study. Methods: Eight healthy foals received a single i.v....
Paßlack N, Mainzer B, Lahrssen-Wiederholt M, Schafft H, Palavinskas R, Breithaupt A, Neumann K, Zentek J.The concentrations of specific elements in the equine liver and kidneys are of practical relevance since horses are not only food-producing animals, but also partially serve as an indicator for the environmental pollution, as the basic feed includes plants like grass, grain and fruits. In this study, the concentrations of strontium (Sr), barium (Ba), cadmium (Cd), copper (Cu), zinc (Zn), manganese (Mn), chromium (Cr), antimony (Sb), selenium (Se) and lead (Pb) were measured in the liver, renal cortex and renal medulla of 21 horses (8 male; 13 female; aged between 5 months-28 years), using indu...
Raidal SL, Hughes KJ, Charman AL, Nielsen SG, Phillips JK, Noble GK.To compare the effects of 2 NSAIDs (phenylbutazone and meloxicam) on renal function in horses. Methods: 9 Thoroughbred or Standardbred mares (mean ± SD age, 5.22 ± 1.09 years [range, 2 to 12 years]; mean body weight, 470 ± 25 kg [range, 442 to 510 kg]). Methods: A randomized blinded placebo-controlled crossover study was conducted to examine the effects of treatment with phenylbutazone, meloxicam, or a placebo (control solution) on renal responses to the administration of furosemide, dobutamine, and exercise (15 minutes at 60% of maximum heart rate). Renal function was assessed by use of bi...
Lewis N, Racklyeft DJ.The clinical course of toxic envenomation of a mare and her foal after an attack by a swarm of bees in the Upper Hunter Valley of New South Wales is described. Early agitation and urticaria were followed by more severe systemic clinical signs within 18 h. There was severe, generalised angioedema, rhabdomyolysis, hypovolaemia, gastrointestinal stasis and renal injury. A particular feature in the mare was almost maniacal behaviour during the first 48 h. Clinical pathological examination showed evidence of haemoconcentration, intravascular haemolysis, thrombocytopenia, azotaemia, rhabdomyolysis a...
Ohmes CM, Davis EG, Beard LA, Vander Werf KA, Bianco AW, Giger U.Two Quarter horses with weight loss had glucosuria, euglycemia, and a mild metabolic acidosis suggesting a proximal renal tubular defect. Further testing revealed transient generalized aminoaciduria, lactic aciduria, and glucosuria, indicating Fanconi syndrome. Both horses recovered with supportive therapy. This is the first report of acquired Fanconi syndrome in horses. Deux chevaux Quarter horse ayant subi une perte de poids étaient atteints de glucosurie, d’euglycémie et d’une acidose métabolique légère suggérant un défaut tubulaire rénal proximal. De nouveaux tests ont révél...
Medina-Torres CE, Hewson J, Stämpfli S, Stalker MJ.A 9-day-old Thoroughbred filly was presented for diarrhea and lethargy. Diagnostic test results were compatible with severe renal dysfunction. Diffuse cystic lesions of both kidneys were identified on ultrasonographic examination. Postmortem examination confirmed the presence of multiple renal cysts. Congenital nephropathy compatible with bilateral diffuse cystic renal dysplasia was diagnosed. Une pouliche Thoroughbred âgée de 9 jours a été présentée pour de la diarrhée et de la léthargie. Les résultats des tests diagnostiques étaient compatibles avec une dysfonction rénale grave. ...
Davis JL, Kruger K, LaFevers DH, Barlow BM, Schirmer JM, Breuhaus BA.Angiotensin converting enzyme (ACE) inhibitors improve survival and quality of life in human patients and small animals with cardiovascular and renal disease. There is limited information regarding their effects in horses. Objective: The purpose of this study was to determine the pharmacokinetics of quinapril and its effects on ACE and renin in horses. Methods: Experimental study using healthy mature horses. Methods: Six healthy horses were administered quinapril at 120 mg i.v., 120 mg per os and 240 mg per os in a 3-way crossover design. Blood was collected for measurement of quinapril ...
Kivett L, Taintor J, Wright J.Simultaneous administration of a nonselective COX inhibitor and a COX-2 specific NSAID has not been previously reported in horses. The goal of this study was to determine the safety of a 10-day dosage regimen of phenylbutazone and firocoxib, both at their standard dosages, in horses. Six horses were administered 2.2 mg/kg of phenylbutazone and 0.1 mg/kg of firocoxib by mouth, daily for 10 days. Horses were assessed daily for changes in behavior, appetite, fecal consistency, signs of abdominal pain, and oral mucous membrane ulceration. Horses were assessed prior to and on the last day of treatm...
Rumpler MJ, Colahan P, Sams RA.The disposition of plasma glycopyrrolate (GLY) is characterized by a three-compartment pharmacokinetic model after a 1-mg bolus intravenous dose to Standardbred horses. The median (range) plasma clearance (Clp), volume of distribution of the central compartment (V1 ), volume of distribution at steady-state (Vss), and area under the plasma concentration-time curve (AUC0-inf ) were 16.7 (13.6-21.7) mL/min/kg, 0.167 (0.103-0.215) L/kg, 3.69 (0.640-38.73) L/kg, and 2.58 (2.28-2.88) ng*h/mL, respectively. Renal clearance of GLY was characterized by a median (range) of 2.65 (1.92-3.59) mL/min/k...
Pasquel SG, Agnew D, Nelson N, Kruger JM, Sonea I, Schott HC.Although the equine renal pelvis and terminal recesses have been described post mortem, little information exists about the endoscopic appearance of these structures in the living horse for guiding ureteropyeloscopy. Objective: To further document the anatomy of the upper urinary collecting system, specifically the renal pelvis and terminal recesses, of the horse. Methods: Descriptive study of cadaver material. Methods: Kidneys were harvested from 10 horses. Magnetic resonance imaging was performed after distension of the renal pelvis with an elastomer casting material, followed by visual insp...
Habershon-Butcher J, Bowen M, Hallowell G.A reliable method for obtaining renal ultrasonographic measurements in the horse is important for diagnosis and monitoring of clinical renal disease. The aims of this prospective study were to develop and validate a novel translumbar ultrasound technique for measuring renal dimensions in horses. Six Thoroughbred or Thoroughbred part bred horses were recruited. All horses were scheduled for euthanasia due to reasons unrelated to the kidneys. Two observers recorded renal length, width, and depth; and dimensions of the cortex, medulla, pyramids, and pelvis for both kidneys in each horse using nov...
Navas de Solis C, Slack J, Boston RC, Reef VB.To describe the prognosis and clinical, echocardiographic, and pathological features of hypertensive cardiomyopathy in horses. Methods: Retrospective case series. Methods: 5 horses with cardiac hypertrophy and systemic hypertension. Methods: Demographics, history, physical and cardiological examination findings, diagnosis, clinical progression, prognosis, and pathological findings were obtained from medical records. Results: The primary diagnosis was chronic laminitis in 3 horses and chronic renal failure in 2. Persistent tachycardia, hypertension, chronic laminitis, or a combination of these ...
Lester GD, Merritt AM, Kuck HV, Burrow JA.Intravenous (IV) and intragastric (IG) administration of fluid therapy are commonly used in equine practice, but there are limited data on the systemic, renal, and enteric effects. Objective: IV fluid administration will increase intestinal and fecal hydration in a rate-dependent manner after hypertonic dehydration, but will be associated with significant urinary water and electrolyte loss. Equivalent volumes of IG plain water will result in comparatively greater intestinal hydration with less renal loss. Methods: Six Thoroughbred geldings. Methods: Experimental study. 6 by 6 Latin square desi...
Wong DM, Witty D, Alcott CJ, Sponseller BA, Wang C, Hepworth K.Renal replacement therapy (RRT) has been implemented extensively in people to facilitate recovery from acute renal failure (ARF). RRT has not been explored in horses, but might provide a further treatment option in horses with ARF. Objective: To investigate efficacy and safety of RRT in horses. Methods: Five healthy adult horses. Methods: A prospective study was performed on horses restrained in stocks and intravenously connected to a commercial RRT machine to allow continuous venovenous hemodiafiltration to be performed for 6 hours. The RRT machine was set at the following flow rates: blood ...
Arnold CE, Taylor T, Chaffin MK, Schott HC, Caron JP.To report technique for, and outcome after, nephrectomy through a ventral median celiotomy in equids. Methods: Case series. Methods: Equids with unilateral renal disease (n = 6), aged 2 months to 18 years, weighing 90-434 kg. Methods: A ventral median celiotomy was used to access the left or right kidney. To facilitate surgical exposure, the small intestine was reflected towards the diaphragm using laparotomy sponges and the ascending colon was exteriorized and in some cases evacuated. The peritoneum over the affected kidney was incised and blunt dissection used to free the kidney from the ret...
Bolat D, Bahar S, Tipirdamaz S, Selcuk ML.The aims of this study were to determine the total volume of the horse kidney and volume fractions of its functional subcomponents (cortex, medulla, renal pelvis) using stereological methods and investigate any possible difference in the functional subcomponents of the right and left kidneys that may arise from differences in shape. The study was carried out on the kidneys of 5 horses of different breed and sex. The weight of the kidneys was measured by a digital scale, and kidney volume was calculated by Archimedes' principle. Total kidney volume and volume fractions of subcomponents of the r...
Dembek KA, Onasch K, Hurcombe SD, MacGillivray KC, Slovis NM, Barr BS, Reed SM, Toribio RE.The renin-angiotensin-aldosterone system (RAAS) and hypothalamic-pituitary-adrenal axis (HPAA) and their interactions during illness and hypoperfusion are important to maintain organ function. HPAA dysfunction and relative adrenal insufficiency (RAI) are common in septic foals. Information is lacking on the RAAS and mineralocorticoid response in the context of RAI in newborn sick foals. Objective: To investigate the RAAS, as well as HPAA factors that interact with the RAAS, in hospitalized foals, and to determine their association with clinical findings. We hypothesized that critical illness i...
Jennings SH, Wise AG, Nickeleit V, Maes RK, Cianciolo RE, Del Piero F, Law JM, Kim Y, McCalla AC, Breuhaus BA, Roberts MC, Linder KE.Polyomaviruses produce latent and asymptomatic infections in many species, but productive and lytic infections are rare. In immunocompromised humans, polyomaviruses can cause tubulointerstitial nephritis, demyelination, or meningoencephalitis in the central nervous system and interstitial pneumonia. This report describes 2 Standardbred horses with tubular necrosis and tubulointerstitial nephritis associated with productive equine polyomavirus infection that resembles BK polyomavirus nephropathy in immunocompromised humans.
Johnstone LK, Mayhew IG.To investigate the effects of lolitrem B intoxication on renal K(+) secretion in response to increased tubular flow rates. Methods: Results are derived from a repeated measure pilot study of seven horses fed non-perennial ryegrass feed for a week prior to exposing them to perennial ryegrass seed and hay that contained an average of 2 ppm lolitrem B. At the end of the control and treatment period frusemide (1 mg/kg I/V) was administered and serial fractional excretion of K(+)(FEK(+)) and fractional excretion of Na(+)(FENa(+)) calculated. Baseline concentration of aldosterone in plasma, serum K(...
Frederick J, Freeman DE, MacKay RJ, Matyjaszek S, Lewis J, Sanchez LC, Meyer S.Two geldings, aged 11 and 17 years, were examined for treatment of ureteroliths located approximately 10 cm proximal to the bladder. Results: Ureteral obstruction was an incidental finding in 1 horse that was referred because of urinary tract obstruction and a cystic calculus. This horse did not have clinical or laboratory evidence of renal failure, although severe hydronephrosis was evident on transabdominal ultrasonography. The second patient had a serum creatinine concentration of 6.3 mg/dL (reference range, 0.8 to 2.2 mg/dL) and mild hydronephrosis of the affected left kidney. Results: In ...
Noble G, Edwards S, Lievaart J, Pippia J, Boston R, Raidal SL.Safety of meloxicam, a potent NSAID with selective COX-2 inhibition, has not been evaluated in horses. Objective: To evaluate pharmacokinetics and safety of single and repeated oral doses of meloxicam in adult horses. Methods: Forty-nine healthy, university-owned adult lightbreed horses. Methods: Study conducted in 2 parts. Part I addressed pharmacokinetics of single oral dose meloxicam (0.6 mg/kg) in 16 horses. Part II, 33 horses were randomly assigned to 5 treatment groups to assess prolonged administration (0.6 mg/kg PO q24h for 6 weeks, n = 7) or higher doses (1.8 mg/kg, n = 7, or 3.0 mg/k...
Morgan RA, Malalana F, McGowan CM.A 14-year-old Cleveland Bay cross gelding was presented with severe urinary incontinence that had been present for 1 year, and chronic polydipsia and polyuria over 4 years. Water intake had been recorded as 240 L over a 24-hour period. Results: The horse had marked urinary incontinence and polyuria and polydipsia. The urine was markedly hyposthenuric, but no abnormalities on urinalysis were detected. There were no other abnormal clinical or neurological signs. Haematological and serum biochemical examinations showed no abnormalities and ultrasonographic and endoscopic examination of the urinar...
Ralston S, Stives M.Though horses synthesize ascorbic acid in their liver in amounts that meet their needs under normal circumstances, prolonged stress results in low plasma concentrations due to enhanced utilization and renal excretion and can reduce immune function. It was hypothesized that plasma ascorbic acid could be maintained in weanling horses by oral supplementation following prolonged transportation. Weanlings were supplemented with no ascorbic acid (Tx 0: n = 4), 5 grams ascorbic acid twice daily for 5 days (Tx 1: n = 4) or for 10 days (Tx 2: n = 4) following >50 hours of transportation. Supplementa...
Shojaei B, Kheirandish R, Azizi S.The present study describes the anatomical and microscopic features of a horseshoe kidney that was found in a 7-year-old male horse. The specimen consisted of two kidneys joined at their caudal poles by an isthmus composed of renal parenchyma and situated caudal to the caudal mesenteric artery. Six main renal arteries arose from the aorta and the external iliac arteries and ramified into 21 branches before entering the kidney. A hypoplastic and ectopic left testis, located in the inguinal canal, was observed as an associated anomaly.
Kay AT, Hunt RJ, Rodgerson DH, Spirito MA, Santschi EM, Payne RJ.To describe the characteristics of osteomyelitis lesions of the patella and to report short- and long-term outcome after treatment in 8 foals. Methods: Retrospective case series. Methods: Foals (n = 8). Methods: Medical records (2003-2007) and radiographs of foals that had osteomyelitis of the patella were reviewed. Inclusion criteria included clinical, radiographic, and surgical findings consistent with osteomyelitis of the patella, and a long-term follow-up of >15 months. Information acquired included signalment, hematologic and serum biochemical profile results, clinical and radiographic si...
Draper AC, Bowen IM, Hallowell GD.The aims of this study were to establish a normal reference range (mean ± 2 SD) and assess reliability of renal dimensions obtained using transabdominal ultrasonography in Thoroughbred horses (n = 7). A minimum of three ultrasonographic cineloops were obtained from each intercostal space and the left paralumbar fossa by two observers daily for three consecutive days. Renal length, width, and thickness and cortex, medulla, and pelvic dimensions were obtained. Measurements were undertaken by both observers, who were unaware of prior measurements, to assess reproducibility and measured on three ...
Draper AC, Bowen IM, Hallowell GD.The aims of this study were to establish a normal reference range (mean ± 2 SD) and assess reliability of renal dimensions obtained using transabdominal ultrasonography in Thoroughbred horses (n = 7). A minimum of three ultrasonographic cineloops were obtained from each intercostal space and the left paralumbar fossa by two observers daily for three consecutive days. Renal length, width, and thickness and cortex, medulla, and pelvic dimensions were obtained. Measurements were undertaken by both observers, who were unaware of prior measurements, to assess reproducibility and measured on three ...
Nouws JF, Firth EC, Vree TB, Baakman M.Plasma disposition, protein binding, urinary recovery, and renal clearance of sulfamethazine (SMZ), sulfamerazine (SMR), and sulfadiazine (SDZ) and their N4-acetyl and hydroxy derivatives were studied in 4 horses in a crossover trial. The plasma concentration-time curves of the metabolites paralleled those of the parent drug in the elimination phase. Sulfamethazine and SMR were extensively metabolized. In plasma and urine, the main metabolite of the 3 sulfonamides tested was the 5-hydroxypyrimidine derivative, which was highly glucuronidated. Difference in elimination half-life of SMZ, SMR, an...
Hinchcliff KW, Muir WW.Furosemide, a diuretic, is frequently administered to horses for the prophylaxis of exercise-induced pulmonary hemorrhage and the treatment of a number of clinical conditions, including acute renal failure and congestive heart failure. Furosemide increases the rate of urinary sodium, chloride, and hydrogen ion excretion. Plasma potassium concentration decreases after furosemide administration but urinary potassium excretion in horses is minimally affected. Renal blood flow increases after furosemide administration. Systemically, furosemide increases venous compliance and decreases right atrial...
Divers TJ.Nephrotoxic and hemodynamically mediated disorders are the most common causes of acute renal failure (ARF) in horses and foals. Leptospira spp. is the most common infectious cause of ARF. Initial treatments for ARF include elimination of nephrotoxic drugs, correction of predisposing disorders, and fluid therapy to promote diuresis. Horses and foals with polyuric ARF often have a good prognosis, while those with oliguric or anuric ARF have a guarded to poor prognosis. When fluid therapy is unsuccessful in improving urine production, various drugs treatments have been used in an attempt to incre...
Siwińska N, Żak A, Pasławska U.Diagnosis of acute kidney injury (AKI) in horses is difficult at the subclinical stage, due to nonspecific clinical signs. The aim of this study was to evaluate the concentrations of selected serum and urinary biomarkers in healthy horses, horses at risk of AKI, and those with clinical AKI. Methods: Thirty healthy horses, 30 horses at risk of AKI and 11 horses with clinical AKI and azotaemia were included in the study. Serum and urinary neutrophil gelatinase-associated lipocalin (NGAL) and cystatin C were measured using commercially available enzyme immunoassay tests. Results: The median and (...
Riviere JE, Coppoc GL, Hinsman EJ, Carlton WW, Traver DS.Gentamicin pharmacokinetics and nephrotoxic potential were evaluated in twelve 2 to 3 month-old horses. Whereas recent evidence in our clinic indicated that young horses may be especially susceptible to gentamicin nephrotoxicity, young rabbits and rats are usually resistant. Gentamicin (4.5 mg/kg) was given by rapid intravenous injection. Serum gentamicin concentrations over a 13-hour period were fitted to an open, two-compartment, pharmacokinetic model. Subsequently, the same horses were divided into groups of 3 horses each. Each group received 0, 2.2, 4.4 or 8.8 mg gentamicin/kg, intramuscul...
Ehnen SJ, Divers TJ, Gillette D, Reef VB.Eight adult horses with obstructive nephrolithiasis and/or ureterolithiasis were examined between 1981 and 1987. One horse had bilateral ureteral obstruction at hospital admission; the others had unilateral ureteral obstruction. All horses had similar bilateral renal pathologic findings that were compatible with chronic intermittent or complete obstruction. Horses were referred for evaluation of weight loss, poor performance, and/or decreased appetite. Clinical findings, laboratory results, and/or postmortem findings in all horses supported the diagnosis of chronic renal failure. Age of the 8 ...
Wise LN, Bryan JN, Sellon DC, Hines MT, Ramsay J, Seino KK.Renal carcinoma is a rare tumor of horses. Objective: Presenting complaints and clinical signs of this disease are vague and early diagnosis increases survival time. Methods: Data were collected from the medical records of 4 horses presented to Washington State University as well as the 23 previously published case reports of horses with renal carcinoma. Methods: Retrospective study. Results: Renal carcinoma affects horses of all ages with most cases observed in geldings and Thoroughbreds. The most common presenting complaints are nonspecific and usually do not occur until late in the course o...
Whitwell KE, Harris P, Farrington PG.Four out of 12 horses grazing a field in Berkshire, England, suffered a prostrating illness and died within 12 to 72 h. Serum biochemical abnormalities, including markedly elevated muscle enzymes, were demonstrated and at post mortem widespread myodegeneration was found in both skeletal muscle and myocardium. Urine analysis revealed myoglobinuria, and renal changes were seen histologically. Although similar pathologically, the clinical syndrome and circumstances of the outbreak were not typical of equine exertional rhabdomyolysis (EER). The outbreak bore a striking resemblance to other reporte...
Alward A, Corriher CA, Barton MH, Sellon DC, Blikslager AT, Jones SL.Ingestion of wilted red maple leaves by horses can result in severe hemolytic anemia and methemoglobinemia. Little is known about what factors influence the outcome of red maple leaf toxicosis in horses. Objective: Our hypothesis was that physical examination findings, clinicopathologic variables or therapeutic modalities may predict outcome in horses with red maple leaf toxicity. Methods: Horses with red maple leaf toxicosis presented to referral hospitals in the southeast region of the United States. Methods: A multi-institutional retrospective study was designed to identify factors that pre...
Frączkowska K, Trzebuniak Z, Żak A, Siwińska N.The reference values of the serum and urine biochemical parameters have not been well-studied in donkeys. This study aimed to assess the normal values of the selected renal biomarkers, such as: serum creatinine, blood urea nitrogen (BUN), albumin, total protein (TP), electrolytes and symmetric dimethylarginine (SDMA), urine protein concentration (UPC), urine protein/creatinine ratio (UPCR), the urine gamma-glutamyl transferase (GGTP)-to-creatinine ratio, serum creatinine-to-urine creatinine ratio (sCr/uCr), serum BUN-to-serum creatinine ratio (sBUN/sCr) and UPC-to-TP ratio, as well as the frac...
Seanor JW, Byars TD, Boutcher JK.Renal dysfunction secondary to GI disorders may be relatively common in horses. Persistent dehydration of 8-10% of body weight can lead to prerenal azotemia, which may result in renal ischemia and renal disease if uncorrected. Dehydrated azotemic horses with a urine specific gravity less than 1.018 may have renal disease. Urine specific gravity readings greater than 1.025 usually indicate normal kidney function. A urine Na level less than 20 mEq/L and a urine/plasma creatinine ratio greater than or equal to 20:1 indicate prerenal problems. Use of nephrotoxic drugs should be avoided in septicem...
Bayless RL, Moore AR, Hassel DM, Byer BJ, Landolt GA, Nout-Lomas YS.Detection of equine acute kidney injury (AKI) is hindered by limited markers of early renal damage in horses. N-acetyl-β-D-glucosaminidase (NAG), a lysosomal enzyme in renal tubular epithelium released into urine during tubular insult, has shown promise for early identification of AKI in humans and other species. We validated an assay for NAG in equine urine and measured urinary NAG in 7 azotemic and 7 non-azotemic client-owned adult horses. The enzymatic NAG assay was validated using within- and between-run coefficients of variation (CVs), recovery following standard addition, and linearity ...
Abrahams S, Greenwald L, Stetson DL.In mammals, the length of the loops of Henle increases with increasing body size without a concomitant rise in urinary concentrating ability. Because mass-specific metabolic rate falls with increasing body mass, this study sought to determine the extent to which this decline in metabolic rate could explain the low urinary concentrating ability of large mammals with long loops of Henle. Mitochondrial ultrastructural parameters were measured in the medullary thick ascending limbs (mTALs) of a series of nine mammalian genera ranging in body mass from 0.011 kg (bats) to approximately 400 kg (horse...
Baggot JD.The neonatal period in foals refers to the first 7 days of postnatal life. The effects of drugs (pharmacologic agents) may be different in neonatal foals, particularly during the first 3 days of postnatal life, from those in older foals and adult horses. The changed drug effects decrease as the physiologic processes that affect absorption, distribution, and elimination (metabolism and excretion) of drugs mature. Dosage regimens should take into account the altered pharmacokinetic profiles of drugs, and because of wide individual variation, the response to therapy should be closely monitored fo...
Broughton Pipkin F, Ousey JC, Wallace CP, Rossdale PD.Plasma renin substrate concentration was measured in 18, four-day-old pony foals after the administration of the natriuretic agent frusemide. Thirteen foals had been delivered spontaneously; labour had been induced in the remaining five mares. Plasma aldosterone concentration was measured in 12 of the spontaneously delivered foals. Renin substrate concentration had risen sharply within 15 mins (P less than 0.005) and peaked at 1 h. The response was consistently greater in the induced foals. Serum sodium concentration fell rapidly in the induced foals (P less than 0.002 by 60 mins) but was bett...
Rossier Y, Divers TJ, Sweeney RW.The urinary GGT/urinary creatinine (uGGT/uCR) ratio was measured on Days 1, 3 and 10 in 4 adult, healthy horses; in 6 adult, healthy horses treated with gentamicin at recommended dosages and 9 adult horses treated for pleuropneumonia with gentamicin at recommended dosages. Plasma creatinine and gentamicin trough concentrations were measured on the same days. The uGGT/uCr ratio was higher in the normal horses (mean +/- s.d. 22.85 +/- 13.69) than previously reported normal values (10.5 +/- 6.8) (Adams and McClure 1985). Analysis of variance for repeated measures was used to compare the ratio in ...
Jones SL, Langer DL, Sterner-Kock A, Snyder JR, Carlson GP.A 4-month-old male Trakehner foal with a history of hematuria, poor growth, and abnormal hair was found to have unilateral hydronephrosis and hydroureter, as determined by ultrasonography and surgical exploration. Nephrectomy and ureterectomy were performed as treatment. Gross examination of the ureter and kidney revealed renal pelvic and ureteral polyps causing obstruction and subsequent hydronephrosis. The histologic features were consistent with renal dysplasia. The polyps and renal dysplasia were likely to be congenital, but the etiopathogenesis is not known. The finding that urinary outfl...
Sykes CA, Uzal FA, Mete A, Ochoa J, Filigenzi M, Poppenga RH, Asin J.A presumptive postmortem diagnosis of oleander () poisoning is made based on the histological observation of cardiomyocyte degeneration and necrosis, which is considered to be a reliable diagnostic marker, and can be confirmed via the detection of oleandrin in tissues or fluids. However, cardiac lesions may not be present in every case, and autolysis can often preclude the identification of subtle changes in the cardiomyocytes. Several studies of experimental oleander poisoning have noted the presence of renal lesions in multiple mammalian species, and case studies of accidental exposure have ...
Geor RJ.Acute renal failure (ARF) in horses is usually prerenal or renal in origin and is most often caused by hemodynamic or nephrotoxic insults. The clinical management of patients that have ARF is largely supportive, including correction of fluid deficits and electrolyte and acid-base disturbances and treatment and reversal of the underlying cause. Use of dopamine and mannitol to promote renal blood flow and urine output is no longer recommended.
Gunson DE, Kowalczyk DF, Shoop CR, Ramberg CF.Several suspect causes of chronic zinc/cadmium toxicosis in horses near a zinc smelter were investigated following observations of lameness, swollen joints, and unthriftiness, particularly in foals. Two foals born and raised near the smelter were lame and had joint swellings that were attributable to severe generalized osteochondrosis. Zinc and cadmium concentrations were markedly increased in the pancreas, liver, and kidney. The serum of 1 foal, zinc and potassium concentrations were high, whereas calcium and magnesium concentrations were low. Marked nephrocalcinosis and osteoporosis were obs...
Edwards DJ, Brownlow MA, Hutchins DR.Urine and blood samples were taken at the same time from normal adult horses presented for routine investigations to establish reference values for a variety of parameters reported to be useful in the clinical evaluation of renal function. Blood biochemical values were consistent with previous studies and had well-defined normal ranges. Parameters representing urine concentration and electrolyte excretion however, varied widely reflecting the ability of the healthy kidney to change the composition of urine in response to differences in environment and management. Percent creatinine clearance r...
Gallatin LL, Couëtil LL, Ash SR.A 15-year-old Paso Fino gelding was evaluated because of acute renal failure following an episode of exertional rhabdomyolysis. The horse was azotemic and treated conservatively at another referral practice with no improvement in the azotemia. With conservative treatment and intermittent peritoneal dialysis, the horse had minimal improvement. Continuous-flow peritoneal dialysis (CFPD) was instituted on day 7 and continued for 3 consecutive days. Dramatic changes in the horse's attitude and serum creatinine concentration were detected within the first 24 hours of CFPD treatment. The horse remai...
Sams RA, Ruoff WW.The pharmacokinetics and bioavailability of cefazolin given (IV, IM) to horses at the dosage of 11 mg/kg were investigated. The disposition of cefazolin given by IV route was characterized by a rapid disposition phase with a half-life of 5 to 10 minutes and a subsequent slower elimination phase with a half-life of 35 to 46 minutes. The total plasma clearance of cefazolin averaged 5.51 ml/min/kg and was due mainly to renal clearance (5.39 ml/min/kg) of unchanged drug. The volume of distribution at steady-state averaged 188 ml/kg. Plasma protein binding of cefazolin at a concentration of 10 micr...
Green SL, Conlon PD, Mama K, Baird JD.The effects of hypoxia and azotaemia on the pharmacokinetics of amikacin were evaluated in 20 full-term neonatal critically ill foals which required 24-h supportive care, antibiotics and dextrose-supplemented polyionic fluids given intravenously, nasal insufflation with oxygen and nutritional supplementation. There was no association between sepsis score or survival and pharmacokinetic parameters. Concurrent hypoxia and azotaemia were associated with significantly decreased clearance and increased peak and trough serum concentrations of amikacin; however, peaks or troughs did not exceed toxic ...
Chaney KP, Holcombe SJ, Schott HC, Barr BS.To (1) determine the occurrence of spurious hypercreatininemia in a population of hospitalized foals<2 days old, (2) assess the resolution of the hypercreatininemia, and (3) determine its association with survival in these foals. Methods: Retrospective case series. Methods: 2 Referral hospitals. Methods: Foals442 micromol/L (>5.0 mg/dL) from 2 referral hospitals. Methods: None. Results: The medical records of 33 foals were reviewed. Twenty-eight had spurious hypercreatininemia and 5 had acute renal failure. Admission creatinine was not significantly different between the 2 groups (mean [...
Walsh DM, Royal HD.Glomerular filtration rate (GFR) was measured in 12 clinically normal horses, using the standard inulin clearance method, and values were compared with values for 2 methods, using a single rapid IV injection of 99mTc-labeled diethylenetriaminepentaacetic acid (99mTc-DTPA). The first 99mTc-DTPA method used a 2-compartment model to calculate GFR blood clearance of the tracer. The second method used sequential digital gamma camera images of the kidneys to determine fractional accumulation of the total dose of the tracer in the kidneys (percentage of injected dose, gamma camera) from 0 to 10 minut...
Tydén E, Tallkvist J, Tjälve H, Larsson P.P-glycoprotein (P-gp) is an important drug transporter, which is expressed in a variety of cells, such as the intestinal enterocytes, the hepatocytes, the renal tubular cells and the intestinal and peripheral blood lymphocytes. We have studied the localization and the gene and protein expression of P-gp in these cells in horse. In addition we have compared the protein sequence of P-gp in horse with the protein sequences of P-gp in several other species. Real time RT-PCR and Western blot showed gene and protein expression of horse P-gp in all parts of the intestines, but there was no strict cor...
