Radiographic and ultrasonographic appearance of pyometra with unilateral uterine torsion in a domestic shorthair cat.

An 8-year-old female domestic shorthair, presenting for a 3-day history of lethargy and hyporexia, was obtunded, dehydrated, tachypneic, and had abdominal distension on physical exam with no vaginal discharge or pyrexia. Abdominal radiographs revealed a large, ovoid soft tissue mass and a tortuous, tubular soft tissue structure in the abdomen. Abdominal ultrasound revealed a severely fluid-distended uterus with a left uterine torsion, which was demonstrated by a "whirl sign." Emergency ovariohysterectomy surgically confirmed a 360° torsion of the left uterine horn with a fluid-distended right uterine horn. Histopathology confirmed a diagnosis of pyometra, and the cat recovered uneventfully.