pictured below are the CT scan and the delayed image.
Why is she having pain?
Our patient had a calyceal rupture caused by a 2 mm stone. Calyceal or forniceal rupture is accompanied by urinary extravasation which can be seen on CT both in intraperitoneal and retroperitoneal areas. The majority of cases involve ureteral calculi but vascular compression from abdominal aortic aneursyms and malignancy have also been reported. Rarely, pregnancy can significantly obstruct the ureter, as well as a foley catherer balloon in one case.
75% of the stones causing rupture were distal, below the sacroiliac vessels. Calculi were small with a mean size of 4mm. Only 5% of patients in theGershman study showed signs of infection.
The physiologic reason for the rupture of the kidney is not known however it is presumed that pressure increases as the kidney increases in size, in accordance with Laplace’s law which states that the pressure tangent to the circumference of an object equals the product of the pressure across the wall and the radius of the object. It has been suggested that rupture protects the kidney by decreasing pressure in the collecting system.
Our patient was nauseated and given ondansetron and promptly developed the rhythm below.
She was treated with 4 gm of Mg ( goal of 2.5) and her K was raised to 4.0 . The polymorphic v tach resolved and she went to the OR where the stone was removed and a stent was placed in the R ureter.
She underwent a Left heart cath showing only 30% lesions so the final diagnosis was v tach secondary to QT prolongation and ondansetron. She had no further episodes of v tach and was discharged. And kudos to Phil who noticed the pelvic fracture. ( It had occurred earlier)
Gershman B, Kulkarni N, Sahani D, Eisner B. Causes of renal forniceal rupture, BJUI 2011. 108: 1909-1912.
Spurlock J, Burke T, Dunn N, et al. Calycealrupture with perirenal urinoma in a patient with cervical carcinoma.
Heffernan E, Skehan. Calyceal rupture secondary to ureteric obstruction by recurrent colorectal ca. Clin Nucl Med 2007;32:199-200.
Satoh S, Okuma A, Fuita Y, Tamaka M, Nakano H. spontaneous rupture of the renal pelvis during pregnancy: a case report and review of the literature. Am J Perinatology 2002;19:189-95.