EXPERIMENTAL AND CLINICAL TRANSPLANTATION

Nutcracker phenomenon is the condition that occurs most commonly at the morphologic type by compression of the left renal vein between the aorta and superior mesenteric artery. The diagnosis is often delayed because of the variability in manifestations and absence of consensus on diagnostic criteria. We report a 30-year-old woman who presented gross hematuria several days after a kidney transplant. Nutcracker syndrome was established intraoperatively during open surgical approach for bladder clot evacuation. Renal repositioning was done with relief in the degree of hematuria intraoperatively. No episode of gross hematuria was observed on follow-up after 8 months.

Key words : Kidney transplant, Gross hematuria, Nutcracker syndrome

Renal transplant is the preferred treatment choice for patients with end-stage renal disease. Although it offers better quality of life and greater longevity than dialysis, it has several complications. Urologic complications are among the most frequent complications after a renal transplant. Posttransplant gross hematuria may be related to the native kidneys or to the transplanted kidney that is present in 2 models of early and late ones. We report a case of a kidney transplant that presented with severe posttransplant gross hematuria owing to an unusual cause.

A 30-year-old woman with end-stage renal disease owing to chronic glomerulonephritis underwent a kidney transplant from a deceased donor. Postoperatively, her urine output was adequate, and her plasma creatinine level gradually decreased. Five days after surgery, she developed painless gross hematuria. A 3-way Foley Fr-22 was inserted, and continual bladder irrigation was begun with normal saline. Color Doppler ultrasonography of the transplanted kidney revealed no significant hydronephrosis with the ureteral stent in the proper place, normal arterial and venous flow with no signs of vascular stenosis or intraluminal thrombosis. Contrary to conservative management for about
48 hours, the patient’s gross hematuria continued and her hemoglobin level dropped. The second color Doppler ultrasonography of the vasculature and ultrasonography of the urinary tracts revealed large clots in the urinary bladder. The radiologist reported dilatation of the grafted renal vein with no signs of thrombosis. Endoscopic clot evacuation under general anesthesia failed and open clot evacuation was decided. Through the previous Gibson incision line, the transplanted kidney and the urinary bladder were explored. The urinary bladder was opened and all clots were removed. No active bleeding was seen around the site of ureteroneocystostomy, but an efflux of bloody urine from the ureteral catheter into the urinary bladder was observed.

After evacuation of the urinary bladder clots, the renal hilum was checked. Exploration of the renal hilum and grafted vein and artery revealed that the renal vein was compressed between the renal artery and perinephric tissue (Figure 1). We eliminated this compressive effect by shifting the position of the kidney medially (toward the peritoneum) and fixing the transplanted kidney to the posterior rectus fascia. A Hemovac drainage system (Zimmer, Warsaw, IN, USA) was placed beside the transplanted kidney and the wound was closed. A day after the operation, the patient had clear urine output and she was finally discharged home from our ward with clear urine output and normal plasma creatinine level (114.92 μmol/L). In 8 months of follow-up, the patient was well with normal plasma creatinine level (97.24 μmol/L) with no history of gross hematuria.

Posttransplant gross hematuria is related to native or transplanted kidneys and has several causes like inflammatory conditions, trauma, acute rejection, recurrence of baseline disease, urinary calculi,¹ and a malignant process that involves the native urinary tract² or the transplanted kidney.³ One of the most common causes of the posttransplant gross hematuria is related to the native kidneys and usually presents as the late onset posttransplant gross hematuria. Early onset posttransplant gross hematuria is usually caused by bleeding from the site of ureteroneocystostomy that is managed by conservative therapy and continues bladder irrigation. Cystoscopic management with fulguration of the bleeding site(s) is another modality in the individualized cases. Open approaches may be needed in the setting that bleeding does not respond to the previous mentioned therapies.

The other causes of early onset posttransplant gross hematuria are renal vein thrombosis, pseudoaneurysm,⁴ or arteriovenous fistula formation after invasive procedures that they subject the transplanted kidney. Infections^5,6 and mucosal injuries caused by the ureteral catheter are other conditions that are associated with posttransplant gross hematuria. Renal vein thrombosis is suspected when the patient who has undergone a kidney transplant develops gross hematuria, decreased urine output, proteinuria, and swelling of the transplanted kidney. Renal vein thrombosis is usually diagnosed with color Doppler ultrasonography and immediate thrombectomy with revision of the anastomosis should be attempted.

Arteriovenous fistula emerges mostly after the biopsy from transplanted kidney. The diagnosis is made by color Doppler ultrasonography or renal angiography, and angioinfarction of the affected site is the treatment of choice.

The term nutcracker was first described by Grant, although de Schepper was the first to show episodes of hematuria related to the presence of nutcracker syndrome in a 16-year-old boy.⁷ Nutcracker syndrome refers to the condition in which the left renal vein is compressed between the aorta and superior mesenteric artery. This compression results in raising the pressure of the left renal vein and developing collateral veins. Gross hematuria associated with this phenomenon is caused by rupture of the thin wall septum that lies between hypertensive small veins and collecting system in the calyceal fornices or communication between dilated venous sinuses and adjacent renal calyces.⁸

The nutcracker syndrome is difficult to diagnose, and recognition of this phenomenon is almost always based on exclusion of the other possibilities for gross hematuria. Color Doppler ultrasonography, computed tomographic angiography, and magnetic resonance angiography are the most reliable noninvasive modalities for diagnosis of nutcracker syndrome. There are several surgical procedures for treatment of this condition, but renal vein related procedures such as transposition of the left renal vein or renal autotransplant are the treatments of choice.^9,10

In conclusion, compression of the grafted renal vein by renal artery and perinephric tissue may mimic a phenomenon just like the nutcracker syndrome that presents with gross hematuria, of which the transplant surgeons should be aware. Although in this case, change in the position of the transplanted kidney resolved the patient’s problem. In this circumstance, revision of the venous anastomosis should be taken into account.

Volume: 14 Issue: 1 February 2016

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