doi:10.5455/vetworld.2013.233-238 Obstructive urolithiasis in ruminants – A review

Obstructive urolithiasis is the retention of urine subsequent to lodgment of calculi anywhere in the urinary conduct from up to urethral orifice. The disease results in heavy economic losses to the livestock industry as it is attributed the fifth most prevalent cause of death in feedlot. Obstructive urolithiasis is a serious, potentially fatal condition, most commonly causing symptoms in castrated male animals, but also occurring in breeding males. Many surgical approaches and techniques for the diagnosis and the treatment of the disease have been described with their relative merits and demerits in the literature.


Incidence
fattening cattle receive rations high in cereal grain and oil meals.These feedstuffs have high levels of Urolithiasis affects both sexes, but urinary phosphorous and magnesium but relatively low level of blockade is a major problem only in males.Steers are calcium and potassium predispose to disease condition most commonly affected by the obstructive form of the [9].A calcium phosphorous imbalance results in high disease because of the anatomical confirmation of their urinary phosphate excretion which is an important urinary tract.Urethral obstructon has been extensively factor in the genesis of phosphate calculi [11].reported in ruminant species [1] and is a common Numerous additional factors have been incriminated as problem encountered in male sheep, goat and cattle [2].
contributing causes of the development of phosphate Among the bovine species, buffalo calves, 81.25% calculi with resultant obstructive urolithiasis in cattle.suffered more frequently than the cow calves9.82% These include heavy concentrate-low roughage diets, and bullocks 8.92% [3].The calculi are mostly found in limited intake or deprived of water, dehydration, urine urinary bladder, but can also occur in renal pelvis & alkalinity, mineralized artesian water, alkaline water urethra [4].The calculi dislodged from bladder may get supplies, excess of sodium bicarbonate in diet, vitamin trapped in narrow male urethra, Sigmoid flexure [5] or imbalance e.g hypovitaminosis and hypervitaminosis at preputial opening.Urinary obstruction may also and high protein rations [9,12].Less frequently uroliths occur due to cystitis.composed of silica, carbonates or oxalate.Livestock An overall incidence of 5.04 percent in animals grazing in pastures containing large quantities of has been reported in India [6].The species wise oxalates, estrogen or silica are prone to develop these incidence has been reported as: goats 49.83 percent, types of calculi [13].Urolithiasis in castrated beef cattle cattle 32.87 percent, dogs 14.53 percent, horses 1.38 has been reported to be associated with diethylstilpercent, sheep 1.04 percent and cats 0,34 percent [6].
bestrol implants [14].Geographical and seasonal From Kashmir valley an overall incidence of 12 influences play an important role for range herds in percent in cases of obstructive urolithiasis in cattle semi-arid areas.In addition, the anatomy of the male calves has been reported [7].Incidence of urolithiasis ruminant urinary tract also contributes due to the potential narrowness of the passage and tortuous route.as high as13.4%, in Anantnag, 12.6%, Budgam 11.9%, The sigmoid flexure is a common site for uroliths to Pulwama 6.9%, and Srinagar 10.5% in male cow lodge in all ruminant species [14].Uroliths may also be calves [8] fount on lesser occasion at the ischial arch.In small secretion, significantly reduced glomerular filteration Cystine is poorly soluble in urine and crystallizes rate and renal blood flow, thus post renal obstructive spontaneously within the physiological range of urine uropathy and uraemia develops either due to pH. 6.0 and limit of solubility is 1.33 mmol/L.The obstruction to urine flow or destruction of renal main therapeutic option for avoiding cystine parenchyma or both [1].Because of retrograde pressure crystalization is to maintain urine pH above 7.5 to consequent to obstruction of urethra, renal pelvis gets improve cystine solubility and to ensure appropriate enlarged at the cost of renal parenchyma and the hydration with a minimum of 3.5 L/day [23].Stones exclusion of the blood flow due to increased pressure formed by crystal ized compounds of the drugs, causing inside the inexpansible renal capsule which leads to a crystalization of urine like Amoxicillin/ampicillin, Cefdisuse atrophy [9].triaxone, Ciprofloxacin, Ephedrine, Indinavir, Magnesium Due to continuous formation of urine and its trisilicate and Sulfonamide result in unfavorable accumulation in the bladder subsequent to urethral changes in urine composition under drug therapy [24].
obstruction the bladder gets distended.The increasing In an attempt towards in-depth understanding of pressure and distended stretching of bladder wall resulted the phenomenon, investigation into pathophysiological in inflammation, pressure ischaemia, devitalization, changes from onset of the urolithiasis workers have thinning, trabeculae formation, herniation of mucosa developed varieties of experimental models of urolithiasis through the musculature of the urinary bladder leading but they could not fetch much about the aspect other to seepage or voiding of whole of the stagnated urine than damages restricted to lower urinary conducts.
into the the peritoneal cavity resulting in uroperitoneum Studies on urodynamics during obstructive uropathy and peritonitis ,more so in bovine urolithiasis very little revealed damage to bladder wall, ureters, kidneys and is documented about uropathy.The data regarding it is urine peritonitis [25].Casts and cells are also observed available mostly in dogs or human beings.There in animals having long standing obstruction of urethra.
occurs a secondary damage to kidney caused by a This is due to pathological changes that commence as a retrograde intracystic pressure in complete urinary result of accumulation of urine inside the bladder [26].
obstructed cases resulting in the uraemia [25].In the early stages of urinary obstruction, the animal Clinical signs attempts to urinate and the tail may be seen to have a pumping action.As the bladder continues to distend, The clinical signs associated with urolithiasis the animal may kick at its abdomen, wring its tail and depend upon the degree of obstruction to free flow of lie down frequently.Continued obstruction leads to urine.Severity of surrounding tissue reactions [25].perforation of the urethra of the penis and/or rupture of The major clinical signs reported during the onset of the urinary bladder.Upon perforation or rupture, the urolithiasis include anorexia, suspended rumination animal may not show signs of discomfort any more and decreased water intake.Animals suffering from [27].Even with appropriate treatment urethral stricture partial obstruction dribble blood tinged urine after or hydronephrosis may present long term complicaprolonged, painful attempts of urination, as the disease progress the symptoms depicted are abdominal a more reliable index under clinical situations.bilateral distention, tenesmus, colic, and weight As the clinical manifestation of the disease shifting, and grinding of teeth, urethral pulsation [9] advances and the animal turns anorexic there occurs a and tendency of rectal prolapsed.Animals may have an decrease in plasma glucose levels [30].Advanced arched stance, tread their feet, swish the tail, or kick at obstructive nephropathy, poor renal perfusion, uroperitheir belly.Urolithiasis should always be near the top of toneum, metabolic acidosis and hemolysis results in the differential list in male ruminants with signs of Hyperkalemia.The cardiotoxic effects of hyperkalemia colic, particularly in sheep and goats.Stranguria, may be excerbated by concurrent hyponatremia or anuria, oliguria, hematuria, mineral deposits on the hypocalcemia.A consequent digestive disorder results urethral hairs, uremic odor to the breath, urinary in Hypochloraemia due to sequestration of chloride bladder distention and pulsations of the pelvic urethra ions in the digestive tract.There occurs a retention of may also be present.Less specific signs include rectal chloride in the gut to compensate for large increase in prolapse, rumen stasis, tachycardia and tachypnea.
potassium ions, decrease intake of chloride following There is severe damage to the bladder and urethral anorexia, diffusion of chloride to peritoneal cavity [32] mucosa by uroliths which leads to haematuria [30], and total body water expansion relative to total body oligouria and dysuria [9].In terminal stages, the chloride.Thus, in urolithiasis there is derangement of temperature start decreasing, due to retention of acid-base balance and electrolyte.Majority of the metabolic wastes and their reabsorption results in animals develop alkalosis but metabolic acidosis have toxaemia [9].Complete urethral obstruction results in also been recorded [5].Uraemia due to Urolithiasis is a death due to uraemia [13].
threat to survival of animals.As the animal start taking normal feed and water after initiation of treatment,

Laboratory findings
PCV, Hb, TEC shows slight fall probably due to The available literature regarding haematobiorehydration and return of the Creatinine and BUN chemical alterations during the phase of urolithiasis are levels near normal.dynamic.There is haemoconcentration due to dehydra-

Compostion of urolith tion as a result of fluid leakage across peritoneum and
The composition of urinary stones varies with neutrophilia.The increase in PCV, TLC and TEC was geographical location.The basic mineral compositions also reported [31,30].An increase in nuetrophil count of urinary calculi are usually varies in different aniamls and leuckocytosis is due to stress [32,33].The most [34].Silica, magnesium ammonium phosphate prominent and descriptive meaure of uraemia due to [phosphatic, struvite], calcium carbonate, and calcium urolithiasis is Blood urea nitrogen [BUN], that can be oxylate are the most common types of crystals found in used as an index of uraemia because of its depenruminants.Silica urolithiasis typically occurs in the dability and simplicity in assessment [9].There is western United States in animals that are grazing rising trend of BUN [25,32] during urolithiasis from pastures or eating feeds harvested from pastures with the normal values in bovine which stand estimated so high silicate concentrations [21].Struvite uroliths for by different workers as in bullocks, 19.71mg% and [magnesium, ammonium or phosphorous] occur due to in calves 7.27mg%.During the phase of obstruction high grain feeding and low dietary calcium to BUN levels are much higher ranging from 136.0-420 phosphorous ration [35].Struvite uroliths form when mg%.There has been a progressive increase in BUN the urine become supersaturated with magnesium, levels at the rate of 53 mg% per day in an induced ammonium or phosphorous and when urine pH is > 6.5 obstruction in Bullocks, however BUN above 200 [24].The difference in susceptibility to struvite formation mg% are reported to be detrimental for the surgical is due to magnesium oxide promoting the formation of treatment.There occurs a regulation of BUN through alkaline urine whereas magnesium chloride promotes saliva in ruminants; otherwise the values of urea formation of acidic urine.In ruminants, silica nitrogen would be much higher in blood than are urolithiasis is associated with high dietary calcium to estimated [8].
phosphorous ratio, grazing on semiarid ranges; increased A creatinine test is used to measure the amount of creatine in a patient's blood or urine.This helps feed intake of silica and reduced water intake.determine how well the kidneys are able to filter small Chemical analysis of calculi molecules, such as creatine out of blood.Healthy A better understanding of physiochemical principles individuals usually have about 0.8-1.4milligrams of underlying the formation of calculus has led to a need creatine per deciliter of blood.Elevated levels indicate for the precise information on the chemical compokidney disease.As the disease progresses there is sition of uroliths [11].Qualitative chemical tests provide increase in the levels and creatinine [25,32].As the only a rough indication of the relative amounts of anorexia progresses there is severe muscle break down different constituents in a mixed stone.A number of with resultant hypoprotinemia elevated alkaline physical methods are used for the analysis of calculi phosphate.Possible tissue hypoxia following retained including optical crystallography, X-ray diffraction, urine with breakdown of high energy phosphate infrared spectroscopy, X-ray spectroscopy and thermocompounds cause hyperphosphataemia which serve as Treatment gravimetry whereas chemical analysis remains the most convenient procedure to evaluate uroliths.The Various treatment modalities, both medical and method is relatively rapid, detects minor components surgical for the management of urolithiasis have been of mixed calculi and readily can be made quantitative.
developed in almost all the species [26,28].In A method for the quantitative chemical analysis of ruminants, obstructive urolithiasis can be successfully urolith is described [15].treated if recognized early in the clinical course [9, 42,43].In mild cases, the animals can be treated by using Diagnostic imaging of urolithiasis tranquilizers and antispasmodics [44], litholytic drugs Diagnosis is based on history, clinical signs, and like cystone.Diuresis should not be used before the physical examination.Making a diagnosis involves removal of calculi and afterwards their administration integrating findings from the signalment, history, is generally not required.Since there is hyperkalemia, physical examination, clinical signs, time course of the hyponatremia and hypocalcaemia, therefore stabilizadisease and urinary tract imaging [9].However tion of such metabolic derangements often involves radiology & ultrasonography may be required to administration of intravenous fluids for several hours, differentiate patients with uroliths from urinary tract with repeated assessment of hydration, acid-base infections, granulomatous urethritis, prostatic disease balance and serum electrolyte concentrations.Such and neoplasia.
treatments occasionally involve concerns about exacerbation of bladder distention in animals with an Radiology: Uroradiology is an up-to-date, imageintact bladder.The animals that shows raised levels of oriented reference in the style of a teaching file that has BUN and creatinine can be effectively treated by been designed specifically to be of value in clinical peritoneal dialysis [25,45].practice [36].The modality of imaging chosen may The treatment of obstructive urolithiasis is include a combination of plain abdominal radiographs.
primarily surgical [46].Recurrent urolithiasis, calculi Location of calculi can be determined by radiography at multiple sites, badly damaged urethra, atonic bladder [37].Radiography helps in differentiating between or severe cystitis leads to failure of surgical repair in different types of uroliths as their radio densities obstructive urolthiasis [26].Urethrotomy, either post provide a clue to the stone type [15].Multiple stone in scrotal or post-ischial at the site of calculi lodgement is urethra and urinary bladder can also be recorded by widely recommended and practiced to relieve the radiography.
obstruction [8,41].However, postoperative leakage of Ultrasonography: Sonography is a non-invasive, urine from the site of obstruction leads to necrosis of reproducible and inexpensive method for diagnosis of urethra and subcutaneous tissues.Further, postoperative urolithiasis, localization urethral calculi and rupture of urethral constriction and recurrent urolithiasis are urethra or the urinary bladder [38].It is safer for both potential factors that results in the unfavorable patient and the operator as it does not involve the use of outcome after urethrotomy, [26,47].Other surgical ionizing radiation.If available, ultrasonography should methods include penile catheterization [48] cystotomy and bladder fistulation [44], intra pelvic cystic be used as the primary diagnostic imaging tool catheterization and peile amputation [48] and, tube although pain relief, or any other emergency measures cystotomy is in voyage.The technique of tube should not be delayed by imaging assessments.It can cystotomy is a method of fixation of tube in the urinary identify stones located in the calices, pelvis, and pyelobladder for the free passage of urine, followed by ureteric and vesicoureteric junctions, as well as upper chemical dissolution of calculi which shows excellent urinary tract dilatation.For stones > 5 mm, ultrasound results.has a sensitivity of 96% and specificity of nearly 100%.
Cystotomy tubes provide a practical method for For all stone locations, sensitivity and specificity of the urinary diversion when more radical surgical ultrasound reduces to 78% and 31%, respectively [34].
procedures are not feasible [26].Cystotomy tubes The volume, size and shape of the urinary bladder can bypass urinary outflow obstructions or as an alternative be detected by cystosonography [39], besides changes to the urethral catheterization [49].Several different in the wall thickness, intraluminal defects and seat of types of tubes are available, including Foleys catheters, calculi lodgement can be detected.Abdominal sono-Mushroom tip catheters and percutaneous catheters; graphy is useful to evaluate the bladder [40] but is more recently low profile gastrostomy tubes have been unrewarding for evaluation of the entire length of the adapted for the use in cystotomy tubes [26].Cystotomy urethra.It can detect small calculi, radiolucent calculi tubes should remain in place for at least 14 days before and bladder mass like polyps neoplasia [9], stones of 1 removal to ensure adequate adhesions between the to 2mm of diameter that can not be seen on X-ray, bladder and the body wall to reduce the possibility of structures of varying size 1.50 to 2.7 cm floating in urine leakage or peritonitis [26].Tube cystotomy is not anechoic fluid [urine] in the urinary bladder with strong free from complications and some complications involved distal acoustic shadow can be detected.Scanning of are urine leakage, wound infection or dehiscence bladder revels rounded to unevenly hyperechoic problems with the tube itself such as irritation at the shadows with multiple spread tiny hyperechoic stoma site, obstruction or accidental dislodgment and patterns [41].clinically.
. (2006) Prevelance and clinical management of problems related to ascending infection due to the obstructive urolithiasis in cattle calves.M.V.SC Thesis presence of the tube.
grazing may increase the daily amount of water intake, 15.Kannan KVA & Lawrence KE (2010) Obstructive which may in turn dilute urine, thus limiting calculourolithiasis in a Saanen goat in New Zealand, resulting in a genesis.Changing from legume to grass hay and feeding ruptured bladder NZ Vet.J.58 [5]:269-271.16.Honeck P, Wendt-Nordahl G, Krombach P, et al. (2009) open ammonium chloride may move the dietary balance of stone surgery still play a role in surgery still play a role in the strong cations and anions towards greater concentratreatment of urolithiasis.Data of a primary urolithiasis tion of strong anions.Those areas where sheep center.J Endourol 23[7]:1209-12.exclusively are fed on paddy grasses in winters due to 17. Sharma, A.K.; Mohindroo, J.; Aithal, H.P. (2009) Physiological, urological changes and surgical management non availability of pastures, fortifi-cation of the dry of urethal obstruction in bovine 25 cases [2001-2006].J Am paddy grass need to be undertaken to reduce the oxalate Vet Med Assoc; 234:249-252.content of the grass[53].Provision of clean water in 18. Dusty W. Nagy (2009) Urolithiasis in small ruminants multiple sites and intentional salting moistened grass [Proceedings] CVC in Kansas City procedings.hay, induction of diuresis and maintenance of dilute 19.David C and Van Metre (2010) urolithiasis in small ruminants [Proceedings], Cvc In Kansas City Proceedings.urine would help a long way keeping urolithiasis in 20.Vengai Mavangira, Jennifer M. Cornish,John A. Angelos check [54].Screening of the animals be treated (2010) Effect of ammonium chloride supplementation on mandatory [55,56] to categorize them as stone formers urine pH and urinary fractional excretion of electrolytes in and non-stone formers before the disease is manifested goats Journal of the American Veterinary Medical Association , 237 (11): 1299-1304.
nidus ,concencrtation of urine and lastly tions.Clinical signs will vary depending on the duration the precipitation of various salts from urine.Formation of obstruction, the site of obstruction, and whether a of urinary calculi is dependent on supersaturation of rupture has occurred[28].Cosequent to localization of urine with soluble ionized minerals.Crystal formation calculi in urethral tract.Complete blockage of the occurs when the inhibitory capacity of mucopolyurinary flow from a kidney decreases glomerular saccharides, ions, and organic acids is exceeded.[18,filtration rate and, if it persists for more than 48 hours, 19].A variety of risk factors exist for the development may cause irreversible renal damage [29].
Pathophysiologypredisposing etiology factors[9], but exact mechanism Despite sophisticated surgical techniques and of stone formation and growth is not fully known.varioussupportivetreatmentsprognosis of urolithiasis Urinary calculi formation usually results from a in bovine still remains unpredictable[16,17]. combination of various physiological, nutritional and Formation of calculi and development of urolithiasis is management factors.It may occur due to excessive or a complex process and occurs in aseries of phases from imbalanced intake of minerals [10] in feedlots while formation of submitted to Sher-e-Kashmir University of Agricultural Sciences and Technology of Kashmir, Shalimar, Srinagar.Clotide, E.M.P., Cappelaro, D.M., Nobre, D and Campedelli, alfa and grain feeding respectively.Besides potentially P. (1980) Urolithiasis in bovines.Biologico, Sao.Panlo.46:altering the mineral content of the diet, free access to 77-80.