Spontaneous rupture of renal calyx in pregnancy

A primigravida in her 20s presented to the emergency department at 30 weeks gestation with acute onset, sharp right lower abdominal pain with associated nausea and emesis. Symptoms were refractory to intravenous antiemetics and multimodal pain regimen. Laboratory work-up was unremarkable. Abdominal ultrasound showed mild right hydronephrosis with perinephric oedema and complex fluid collection. Follow-up MRI revealed a large fluid collection in the right retroperitoneum, consistent with a right renal forniceal rupture. A right double-J ureteral stent was placed with resolution of symptoms. The remainder of the pregnancy was uncomplicated. The patient had a spontaneous vaginal delivery at 38 weeks. The ureteral stent was removed 4 weeks postpartum. Renal forniceal rupture is a rare manifestation of obstructive uropathy. Several of the renal and endocrine physiologic changes in pregnancy make pregnancy itself a risk factor. It can mimic common pregnancy complications, requiring a broad differential diagnosis and prompt imaging.