Spontaneous ureteral rupture during pregnancy: a case report and literature review.

A 38-year-old pregnant female (G2P0) who presents at 25 weeks of gestation was admitted to our emergency room, complaining of acute left sided flank pain for 1 day. She had no fever, but presented with nausea and multiple episodes of non-bloody, non-bilious emesis. The patient’s past medical history was significant for antiphospholipid antibody syndrome, endometriosis and intestinal adhesiolysis 8 years ago. She had no history of urolithiasis. Prior to this pregnancy, the patient underwent routine renal ultrasonography, which demonstrated no evidence of urinary calculi, hydronephrosis, or ureteral dilation. Her physical examination revealed left costovertebral angle tenderness and a nontender abdomen. Laboratory test revealed a normal leukocyte count of 85,200/mm 3 with an increased neutrophil of 85%. Serum creatinine level was 51.2 µmol/L. Urinalysis remained normal. Renal ultrasonogram only showed dilation of bilateral pelvis and ureter. Then non-contrast magnetic resonance urography (MRU) was performed. Images showed discontinuity of the left upper ureter wall and perirenal fluid collection measuring 5.0 cm × 1.5 cm ( Figure 1 ). Non-contrast magnetic resonance urography showing left ureteral rupture and urine extravasation. (A) Axial abdominal view, with the arrow indicating discontinuity of the left ureteral wall. (B) Arrow indicating urine extravasation. (C) Coronal abdominal view, with the arrow indicating discontinuity of the left ureteral wall. To protect renal function and avoid the potential risk of infection due to urinary extravasation, we performed left-sided percutaneous nephrostomy. Infection prophylaxis was achieved through intravenous administration of cefotiam at a dose of 1.0 g twice daily. Over the course of her stay, the patient clinically improved, and the leukocyte count remained normal. She was then discharged home with oral antibiotics. During the follow-up period, the patient’s nephrostomy tube remained patent, with a daily urine volume of 1,400 mL. No stone fragments were identified in either her bladder urine or nephrostomy drainage. At 35 weeks of gestation, she underwent a successful cesarean section as planned. Eight weeks postpartum, she underwent left-sided antegrade urography, which showed a patent ureter ( Figure 2 ). The nephrostomy tube was subsequently removed without complications. Antegrade urography performed at 8 weeks postpartum, demonstrating a patent ureter. All procedures performed in this study were in accordance with the Declaration of Helsinki and its subsequent amendments. This research was approved by the Ethics Committee of Peking University First Hospital (approval No. 2019134). Written informed consent was obtained from the patient for publication of this case report and accompanying images. A copy of the written consent is available for review by the editorial office of this journal.

Spontaneous ureteral rupture is a rare and emergent urological entity, which is defined as urinary extravasation from the ureter secondary to a non-traumatic and non-surgical etiology ( 1 ). Pathogenetic pathway underlying spontaneous ureteral rupture is an increasing intraluminal pressure resulting from urinary calculi, ureteral stricture, tumor obstruction, etc. Pregnancy induced physiological changes may result in increased intraluminal pressure and hydronephrosis, thereby predisposing to this condition. If not treated promptly, urine extravasation may lead to urinoma, abscess formation, sepsis, and renal failure. Due to its rarity, management and treatment of this condition is unclear. We report a rare case of spontaneous ureteral rupture during pregnancy treated with percutaneous nephrostomy. We present this article in accordance with the CARE reporting checklist (available at https://tau.amegroups.com/article/view/10.21037/tau-2025-533/rc ).

Spontaneous ureteral rupture is a rare and emergent urological entity with only few reported cases. The most frequent cause of spontaneous ureteral rupture is calculi, accounting for approximately 70% of patients ( 2 ). Other causes include ureteral stricture, tumor, pregnancy and connective tissue diseases ( 3 , 4 ). In some cases, the cause is unknown ( 5 ). Intravenous pyelography is considered the gold standard for diagnosing spontaneous ureteral rupture, as it can localize the site of injury by demonstrating contrast extravasation. The management of spontaneous ureteral rupture remains unstandardized due to the limited availability of systematic reports and high-level evidence. In previous literature, minimally invasive treatments and conservative management have generally yielded favorable outcomes. As reported by Chen et al. , 13 patients achieved recovery following ureteral stent placement, while five patients improved with conservative management ( 3 ). These findings have been corroborated by other studies ( 4 , 5 ). Due to the mechanical compression and endocrine factors, physiological hydronephrosis and hydroureter during pregnancy can be seen in about 90% of pregnant women ( 6 ). However, pregnancy is still a rare cause of spontaneous ureteral rupture. Therefore, potential precipitating factors such as urinary calculi should be ruled out in cases of spontaneous ureteral rupture during pregnancy. Our patient had no history of urolithiasis. The pre-pregnancy ultrasonography revealed no urinary calculi or obstruction. During the current admission, repeated ultrasonography and MRU showed no evidence of calculi. Although small stones may not always be detected on ultrasonography or MRU, the consistent absence of imaging findings suggests that hydronephrosis caused by pregnancy is the most likely cause of ureteral rupture. To the best of our knowledge, this is the second reported case of spontaneous ureteral rupture caused by pregnancy. Given the absence of direct physiological data in reported cases, the following mechanistic explanation is speculative and based on clinical inference. We hypothesize that the mechanism underlying spontaneous ureteral rupture is an increased intraluminal pressure within the ureter. Rupture can occur at any segment of collecting system, but is usually seen at the fornix and upper ureter ( 7 ). According to the Laplace’s law (T ∝ P×R), the tensile stress imparted upon a dilated collecting system would increase with size. Therefore, a more dilated fornix or upper ureter is more prone to rupture ( 8 ). Besides, the lower ureter has three layers of myometrium, whereas the upper ureter has only two layers. This could explain why a lower ureteral obstruction can lead to rupture of the upper ureter. We speculated on the pathological process of ureteral rupture in our patient. During pregnancy, mechanical compression of the enlarging uterus led to elevated pressure within the collecting system. The patient’s past medical history, including antiphospholipid syndrome, endometriosis, and prior abdominal surgery, contributed to adhesions and fixation of the distal ureter. Ultimately, the hydrostatic stress resulted in the tear of the upper ureteral wall. The clinical presentation of spontaneous ureteral rupture in pregnancy can be confused with other acute abdominal conditions, including but not limited to ureteral calculi, appendicitis, cholecystitis, uterine rupture, and abruption placentae. Ultrasonography is the first-line diagnostic method for spontaneous ureteral rupture and is able to detect fluid collections in the perinephric or retroperitoneal areas. However, as illustrated by our case, not all patients with spontaneous ureteral rupture will show fluid collection on ultrasonography at the time of evaluation. McKnoulty et al. reported that the positive rate was only 52% ( 9 ). A repeated ultrasonography may help address this limitation. Delayed post-contrast computed tomography urography and intravenous pyelography are considered the gold standard for diagnosing spontaneous ureteral rupture, as they can clearly show excreted free contrast leaking into the abdomen ( 10 ). However, due to their radiation exposure, these modalities are not suitable for pregnant women. Therefore, MRU serves as an excellent alternative to these radiological examinations. Notably, MRU theoretically has the potential to cause fetal hearing damage and tissue heating, and is not recommended for use in pregnant patients during the first trimester ( 11 ). Spontaneous ureteral rupture should be taken seriously since it can lead to severe complications, such as urinoma, abscess formation, and even sepsis ( 12 , 13 ). To date, there are no standardized guidelines for the treatment of spontaneous ureteral rupture, and therapeutic strategies must be individualized. Minimally invasive procedures, such as ureteral stent placement or percutaneous nephrostomy, have been shown to yield excellent outcomes. Chen et al. reported a series of 18 spontaneous ureteral rupture cases, with 13 of them successfully managed with ureteral stents ( 3 ). Similarly, McKnoulty et al. summarized 39 cases of collecting system rupture during pregnancy, in which 13 patients (46%) received ureteral stent placement, while five patients (13%) underwent percutaneous nephrostomy ( 9 ). In this case, we opted for percutaneous nephrostomy to drain the urine. This decision was made because of the presence of significant urinary extravasation, as nephrostomy provides better drainage in such scenarios. Additionally, we were concerned that placing a ureteral stent may convert a partial ureteral rupture into a complete one. This case underscores the importance of considering spontaneous ureteral rupture in pregnant women presenting with acute flank pain, even in the absence of urinary calculi. It also highlights the role of MRU as a radiation-free modality for definitive diagnosis, and supports early drainage via percutaneous nephrostomy when retrograde access is challenging. As a single case report, this presentation cannot establish causality or generalize findings. Long-term outcomes and optimal management strategies require validation through additional cases and systematic reporting.

Spontaneous ureteral rupture during pregnancy is an extremely rare urological condition that can easily be confused with other acute abdominal diseases. Repeated ultrasonography and MRU are recommended for accurate diagnosis. Percutaneous nephrostomy is a safe and effective intervention for this condition, allowing adequate urinary drainage while minimizing risks to both mother and fetus.

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