Saudi Journal of Kidney Diseases and Transplantation

: 2010  |  Volume : 21  |  Issue : 6  |  Page : 1140--1142

Nonobstructive hydronephrosis of a kidney transplant

Quaid J Nadri, Zahid Nabi 
 Department of Medicine, Division of Nephrology, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia

Correspondence Address:
Quaid J Nadri
Department of Medicine, Division of Nephrology, King Faisal Specialist Hospital and Research Center, Riyadh
Saudi Arabia

How to cite this article:
Nadri QJ, Nabi Z. Nonobstructive hydronephrosis of a kidney transplant.Saudi J Kidney Dis Transpl 2010;21:1140-1142

How to cite this URL:
Nadri QJ, Nabi Z. Nonobstructive hydronephrosis of a kidney transplant. Saudi J Kidney Dis Transpl [serial online] 2010 [cited 2021 Oct 18 ];21:1140-1142
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Full Text

To The Editor,

Urinary tract obstruction manifested by hydro­nephrosis with or without renal graft dysfunc­tion is the most common complication of renal transplantation occurring in 1.3-10.2% of all transplants. [1] We present here an interesting teaching case of incidental discovery of hydro­nephrosis with normal kidney function in a renal transplant recipient.

A 40-year-old female who had received living related renal transplant in April 2000 presented to ER with acute right upper quadrant pain without any urinary symptoms. Physical exa­mination revealed RUQ tenderness and renal allograft in right iliac fossa was non tender. Renal profile showed creatinine level of 86 μmol/L and urine analysis was completely nor­mal. Ultrasound abdomen showed two stones in gall bladder with no wall thickening and huge hydronephrosis with hydroureter of trans­plant kidney [Figure 1] and [Figure 2]. During lapa­roscopy, the patient was found to have inflamed appendix. She underwent laparoscopic chole­cystectomy and appendectomy without com­plication. Her renal function remained normal. Unfortunately, there was no ultrasound in pre­vious five years. With asymptomatic hydro­nephrosis and stable renal function, provisional diagnosis of functional obstruction was contem­plated and percutaneous nephrostomy was not considered. Voiding cystourethrogram showed no reflux. Dynamic renal scan (MAG3) with diuretic showed good perfusion with adequate uptake and prompt parenchymal secretion and mild urine outflow resistance with no evidence of urine outflow obstruction [Figure 3]. The patient was discharged in a stable condition and her graft function remained normal on follow-up.{Figure 1}{Figure 2}{Figure 3}

Two types of hydronephrosis, obstructive and nonobstructive, have been described. Causes of obstructive hydronephrosis in early post trans­plant period include blood clots within ureter or bladder and edema of ureteroneocystostomy. Late obstruction usually occurs in a distal ure­ter secondary to ureteric stricture, occurring as a result of ischemia, rejection and infection due to CMV and polyoma virus. [1] Less common causes include periureteric fibrosis, sloughed pa­pillae, extrinsic compression by pelvic fluid collection such as hematoma, urinoma, seroma, lymphocele, abscess, and lymphadenopathy or pelvic tumor. [2] Obstruction due to calculi is a rare cause. Causes of non obstructive hydrone­nephrosis are vesicoureteral reflux in up to 86% of cases, decreased ureteral tone secon­dary to denervation or rejection.

Hydronephrosis can be readily identified with sonography but its significance should be in­terpreted in conjunction with renal function and clinical data. [3] Though most common investi­gation for assessing urinary tract obstruction is antegrade nephrostogram which provides ex­quisite anatomic detail, being an invasive pro­cedure, it has its own risk. The incidence of sepsis after nephrostomy tube placement has been reported to be 1.4 - 21%. Inadvertent in­jury of adjacent organs is uncommon. [4] There­fore, it is sometimes necessary to assess by noninvasive way, especially when hydroneph­rosis and serum creatinine is stable, suggesting nonobstructive hydronephrosis. This can be done by dynamic renal scintigraphy, particularly with diuretics. Diuretics are administered typically, approximately 20 minutes after tracer injection MAG3. Rapid (within 5 minutes) washout of tracer is characteristic of stasis without an ana­tomic obstruction. No change in the amount of radioactivity in the renal collecting system after diuretic is indicative of a complete obs­truction. This can be further confirmed by pre and post void images for delineation of the nature and extent of obstruction, especially when incomplete [Figure 4]. In our case, since com­plete washout and post void imaging showed no obstruction, we assume denervated ureter and close proximity of renal pelvis to bladder with short ureter size could be the possibility of functional stasis and hydronephrosis. This case highlights the importance of awareness of nonobstructive hydronephrosis in a transplant kidney and noninvasive assessment by using MAG3 diuretic scintigraphy with high sen­sitivity and specificity [5],[6] in order to avoid un­necessary invasive intervention and its asso­ciated complication. Serial ultrasound moni­toring of hydronephrosis and kidney function is warranted.{Figure 4}


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