Pelvic Entrapment of the Bladder
Stacey R. Byers
Definition and Etiology
In pelvic entrapment of the bladder, the apex and fundus of the bladder are displaced caudodorsally into the pelvic cavity, resulting in impaired urine outflow.
It has been reported in cattle, sheep, and an alpaca cria. Occurrence has been associated with postpartum straining, perineal hernia, vaginal prolapse, and suspected vaginal irritation or secondary bladder displacement from trauma.1-3Clinical Signs and Differential Diagnoses
Bladder emptying is impaired, and the presence of the bladder in the pelvic inlet induces straining. An affected animal may show tenesmus, pollakiuria, and stranguria. On rectal palpation a soft, fluctuant mass may be detected beside the vagina. Radiography with contrast can be used to demonstrate the pelvic position of the bladder.1,2 Ultrasonographic examination can be used in larger animals.3
Differential diagnoses include proctitis, vaginitis, retained placenta, bladder paralysis, cystitis, and perivaginal abscess. Needle aspiration of the bladder per vaginam has been used to make a definitive diagnosis, although the danger of uterine puncture should be considered.
Treatment and Prognosis
Draining the bladder through catheterization or needle aspiration facilitates replacement of the bladder by manipulation per vaginam. However, fibrinous adhesions between the bladder and vagina may make laparotomy necessary to replace the bladder. Ventral midline laparotomy with replacement and fixation was successfully performed in an alpaca cria.2