Resumo
Background: Urolithiasis is a metabolic disease of ruminants castrated and uncastrated. The formation of uroliths causes trauma and obstruction in the tract urinary. The nutrition and management are the main predisposing factors for this disease. Many cases occur sporadically, but outbreaks can occur or become an endemic problem. This paper describes a case of obstructive urolithiasis in Nelore cattle uncastrated in Recôncavo of Bahia, Brazil. Case: An 4-year-old Nelore cattle, uncastrated male was sent to the Centro de Desenvolvimento da Pecuária da Universidade Federal da Bahia (CPD-UFBA), Bahia, Brazil. by presenting a swelling on the ventral abdomen 5 days ago. Clinical examination revealed the exposure with mucosal necrosis and hemorrhage preputial, and continuous dripping of urine. The animal was euthanized in extremis and submitted to necropsy. The animal was necropsied and samples collected from the abdominal cavity, thoracic cavity, and nervous system. The samples were fixed in 10% formalin, cleaved, processed routinely for histology, embedded in paraffin, cut at five microns thick and stained with hematoxylin and eosin (HE). Urinary stones collected during necropsy were sent for analysis of chemical composition. The macroscopic had swelling in the ventral abdominal region. By cutting this region was the formation of cavities and filled with red liquid and odor uremic in the subcutaneous. At the opening of the sigmoid flexure of the penile urethra was found urinary calculi with 2 x 1 cm, rough and porous, light brown and rocklike consistency, occluding the urethral light. There was rupture of the urethral mucosa and necrosis of adjacent tissue, plus hemorrhage, and hydronephrosis. Kidney had multiple white areas on the natural surface. In the cut surface of the kidney was observed dilatation of renal calices, some with uroliths. In microscopy of the urethra was observed coagulation necrosis diffuse mucosa and and submucosa with hemorrhage and neutrophilic inflammatory infiltrate. Kidney was observed areas of intense intersticial infiltrate inflammatory, periglomerular fibrosis and peritubular and interstitial collagen deposition. Chemical analysis of uroliths demonstrated the presence of calcium carbonate and calcium oxalate in its composition. Discussion: The diagnosis of obstructive urolithiasis was based from the clinical signs and gross lesions. Works related to obstructive urolithiasis in cattle in Brazil are uncommon. The cases are described more often in small ruminants, usually associated with feed intake unbalanced. In cattle the disease usually occurs in castrated males reared in intensive system. Ventral edema in the perineum, inguinal region, the ventral abdomen and prepuce, are clinical signs that indicate urethral rupture as observed in this case. The pathological changes observed in this case were similar to those described by other authors. In ruminants, the predominant types of uroliths are compounds of struvite, silicates, carbonates and oxalates. The formation of uroliths composed of calcium carbonate associated with the consumption of fodder with a high calcium content and low phosphorus and magnesium. The mechanism of formation of calcium oxalate uroliths is unclear. Unable to determine the factors that have led to the formation of uroliths in this case.