Clinical findings and diagnostic procedures in 270 small ruminants with obstructive urolithiasis

Abstract

Background: Details of the clinical signs of obstructive urolithiasis in male small ruminants have not been documented in a large population.

Objective: To describe the clinical presentation and diagnostic procedures in a large group of small ruminants with urolithiasis.

Animals: Two hundred and seventy small ruminants (158 sheep and 112 goats).

Methods: Retrospective study of 270 cases identified based on clinical records.

Results: 81.2% affected goats were castrated and 91.7% sheep were intact males; 65.5% of the animals had been sick ≤2 days before referral. Common abnormalities included dysuria (93.6%), indigestion (84.4%), reduced general state of health (79.5%), signs of pain (73%), increased heart and respiratory rates (53.6% and 39.1%), and azotemia (89.4%). Blood urea nitrogen (BUN) and creatinine concentrations were strongly correlated (r² = 0.81). Hypochloremia (52.2%), hyponatremia (43.3%), hypophosphatemia (52.4%), and abnormal potassium concentrations (26.2% hypokalemia and 24.5% hyperkalemia) were the most common serum electrolyte imbalances. Packed cell volume (PCV), plasma proteins, potassium, BUN, and creatinine concentrations were significantly increased in animals with uroperitoneum. Ultrasonography allowed for confirmation of diagnosis in 83.9% of the cases (135/161 with sufficient available information), uroliths were visible on 34 of 56 plain radiographs.

Conclusions and clinical importance: Our study confirmed that clinical and ultrasonographic examinations are sufficient to diagnose urolithiasis. Clinical signs can be divided into an early stage with discrete unspecific clinical signs, a painful stage with frequent straining, expression of pain and moderately reduced general condition, and an advanced stage with a markedly reduced general condition and eventually recumbency.

Keywords: clinical signs; diagnosis; goats; sheep; urinary calculi.

Figure 1

Plain radiograph of the caudal abdomen of a male goat with obstructive urolithiasis. Multiple radiopaque urinary calculi in the urinary bladder (dotted circle), along the pelvic and sigmoid flexure (arrowheads indicate beginning and end of the urolith line) and in the distal part of the urethra (arrow). Courtesy of the Radiology Unit of the Vetsuisse Faculty, University of Bern

Figure 2

Box‐plots of BUN and blood creatinine concentrations and distribution among the three consecutive stages of disease: early (normal demeanor), painful (slight depression and active expression of pain), and advanced (profound depression to recumbency). Different superscripts within a box‐plot indicate significant differences (P < 0.05)