Teaching Case

The patient previously underwent chemo-radiotherapy for adenosquamous carcinoma of the cervix, and subsequently developed recurrent ureteric strictures that required multiple ureteric stent insertions. She had an obstructed right-sided metallic memokath stent and nephrostomy in situ, and presented acutely with abdominal pain, frank haematuria causing haemodynamic instability, and right leg swelling.

An unenhanced CT at the time of presentation showed a possible right psoas haematoma without clear cause (Fig. 1).

Ultrasonography of the right lower limb revealed a large deep vein thrombus (DVT) of the femoral vein (Fig. 2).

After initiating anti-coagulation for the DVT, haematuria worsened and she became haemodynamically unstable. Subsequent contrast-enhanced CT imaging revealed that the possible psoas haematoma was actually a 5.5cm pseudoaneurysm arising from the right common iliac artery in close apposition to the metallic ureteric stent (Fig. 3a+b).

The right lower limb DVT was likely caused by venous stasis from compression of the right iliac vein by the pseudoaneurysm.

Provocative angiography revealed a pseudoaneurysm originating close to the origin of the right internal iliac artery (Fig. 4).

The likely ureteroarterial fistula was successfully managed by insertion of a stent graft extending from the right common iliac artery into the mid-right external iliac artery (Fig. 5).

It is inferred that the iliac artery pseudoaneurysm and presentation with gross haematuria was due to the formation of an ureteroarterial fistula (UAF) caused by the metallic ureteric stent in situ. UAFs are rare but recognised causes of gross haematuria, leading to potentially life-threatening blood loss [1, 2].

Primary causes include the presence of an aortoiliac aneurysm or advanced atherosclerotic disease [3], while the majority (85%) of UAFs are secondary to radiotherapy or extensive surgery for malignancies arising within the pelvis, and long term indwelling ureteric stents – these patients often have multiple risk factors present [1].

Radiation endarteritis and radical surgery leads to devascularisation of the ureter, the presence of foreign bodies (ureteric stents) within this fragile ureter, and pulsation of the adjacent artery against the stent causing pressure necrosis of the artery and ureter wall, have been implicated in the formation of UAFs [4, 5].

Patients are typically elderly and present with massive haematuria and have pre-disposing factors similar to those described above, however, there have been cases reported in patients as young as 29 years of age [6].

The first line investigation of choice, contrast-enhanced CT, will reliably demonstrate a pseudoaneurysm. Delayed phase scanning may be required to demonstrate extravasation of contrast into the ureter, but this may be impossible to demonstrate if bleeding is intermittent but this can be inferred if clinically suspected [7]. Provoked angiography and ureterography is the most successful method of diagnosis, but risks massive haemorrhage [8, 9].

Endovascular repair of the involved artery with a stent graft is now the mainstay of treatment, but prior to the late 1990s direct operative repair with revascularisation was necessary, in a typically difficult surgical field of a co-morbid patient [7, 10].

Few studies have investigated the long-term outcomes of patients following UAF endovascular repair. Known complications include graft infection, recurrent fistulation, graft rupture, and graft occlusion, indicating that careful follow-up is essential [3]. From a small 11 patient study, 59.4% had recurrent haematuria, and at 2 years UAF related mortality and all-cause mortality was 14.3% and 45.5% respectively [11].

The radiological investigation of haematuria depends on the clinical features of each case. In the presence of a metallic ureteric stent or previous radiotherapy, the rarer possibility of an UAF should be considered and multiphase contrast-enhanced CT performed. Failure to do so may lead to delay in diagnosis and treatment with severe consequences in terms of morbidity and mortality.