Symptomatic uraemia from bilateral obstructive uropathy secondary to metastatic urinary bladder cancer showing only unilateral hydronephrosis: a case report.

Bilateral hydronephrosis is classic for supravesical obstructive uropathy causing uraemia with dual functioning kidneys. Recently, a patient presented with uraemia and metastatic urinary bladder carcinoma but only unilateral right-sided hydronephrosis. A right ureteral stent was placed retrograde and no further intervention was planned since the left kidney appeared normal, and since the left ureteric orifice was not visualized. We insisted on a left percutaneous nephrostomy which was successful with prompt urine return. A left nephrostogram revealed unrecognized hydroureter/hydronephrosis. Following haemodialysis, kidney function normalized at 3 weeks. For symptomatic uraemia from obstruction, an antegrade and/or a retrograde decompression must be attempted bilaterally to improve renal salvage.

Background

Symptomatic supravesical obstructive uropathy in a patient with dual functioning kidneys is classically characterized by bilateral hydroureters/hydronephrosis and an empty urinary bladder [1]. This obstruction may be secondary to metastatic abdomino-pelvic and retroperitoneal malignancies, ureteric calculi and retroperitoneal fibrosis [2-5]. The evidence for obstruction may be partially or totally absent on ultrasound or computerized tomography, in one or both kidneys [6-8]. Our recent experience with a uraemic 56-year-old Caucasian showing only unilateral moderate right-sided hydronephrosis is presented.

Case report

A 56-year-old Caucasian male patient with a past medical history that included hypertension and coronary artery disease and a recent serum creatinine of 88.4 μmol/L, was diagnosed 10 days earlier with urinary tract infection (UTI). Oral ciprofloxacin was prescribed. After a few days, despite antibiotics, urinary frequency persisted. Serum creatinine increased to 212.2 μmol/L. With negative urine cultures, the antibiotic was discontinued. Two days before presentation to us, he developed worsening anorexia, nausea with vomiting and oliguria. He had 40-pack years of smoking. His father had prostate cancer and died at age 75 years from colon cancer; a sister had breast cancer and a maternal uncle had throat cancer. Physical examination revealed a blood pressure of 165/89 mmHg, pulse rate of 56/min and respiratory rate of 16/min. He was not dehydrated nor orthostatic. Except for trace ankle oedema and bilateral costo-vertebral angle punch tenderness, the physical examination was unremarkable. Rectal examination was normal. On admission, the serum creatinine was 796.5 μmol/L, CO2 14 mmol/L and potassium 5.5 mmol/L. Urinalysis showed 5–10 WBC per high-power field (PHF) and 2–5 RBC PHF. Alanine aminotransferase (ALT), aspartate aminotransferase (AST) and total creatine kinase (CK) levels were normal. The electrocardiogram (EKG) was normal except for bradycardia of 54/min. A post-void urinary bladder scan had demonstrated only 60 ml of residual urine. A renal ultrasound showed unilateral moderate right-sided hydronephrosis with suspected mass effect on the inferior urinary bladder. The left kidney appeared normal, measuring 16.2 cm × 8.1 cm, with preserved cortical thickness. Renal resistive indices were normal bilaterally. The next day, with increasing vomiting, serum creatinine 894.6 μmol/L, phosphorus 2.6 mmol/L, potassium 6.2 mmol/L and oliguria (Table 1), he started daily haemodialysis. A non-contrast computerized tomography examination, on Day 2, again showed unilateral right-sided hydronephrosis, bilateral nephric stranding and urinary bladder wall thickening suspicious for transitional cell cancer (Figure 1). Cystoscopy, on Day 3, revealed a sessile urinary bladder tumour, which was resected. The right ureter was successfully cannulated and a right ureteric stent was placed with prompt urine drainage. The left ureteric orifice was not visualized. The next day, with a strong push from nephrology, the patient consented to a percutaneous left nephrostomy procedure despite the normal appearing left kidney. A percutaneous left nephrostogram revealed a previously unrecognized mild hydronephrosis/hydroureter with obstruction at the ureterovesical junction. There was prompt return of urine from the left kidney. After six haemodialysis sessions, his serum creatinine was 152.0 μmol/L, with increasing urine output (Table 1). Haemodialysis was stopped. The left nephrostomy tube was subsequently internalized. The serum creatinine was 107.0 μmol/L after 3 weeks. The pathology report revealed high-grade urothelial carcinoma, Grade 3 of 3, with invasion of the muscularis propria. The patient is currently discussing treatment options with his Oncologist.

Table 1

Trends in serum creatinine, electrolytes and urine output over time

	3/2/09	3/3/09	3/4/09	3/5/09	3/6/09	3/7/09	3/9/09	3/20/09
Serum creatinine (μmol/L)	894.6	907.9	717.8	354.5	236.9	194.5	152.0	107.0
Urine output (ml/day)	60	225	Patient on continuous bladder irrigation	Patient on continuous bladder irrigation	Patient on continuous bladder irrigation	2300	Not available	Not available
Serum phosphorus (mmol/L)	2.6	2.8	2.1	1.6	1.0	1.0	1.1	Not available
Serum potassium (mmol/L)	6.2	4.3	4.4	3.9	3.4	3.5	3.7	5.1
Serum CO2 (mmol/L)	15	15	24	27	30	26	27	23
Haemodialysis	+	+	+	+	+	+	−	−
Decompressive procedure		Right retrograde ureteral stent		Left percutaneous nephrostomy

Fig. 1

Noncontrast computerized tomography confirming unilateral moderate right-sided hydronephrosis.

Discussion

A patient with dual functioning kidneys presenting with uraemic symptoms and suspected to have obstructive uropathy must be presumed to necessarily have bilateral renal obstruction [6-10]. This is without prejudice to the findings on conventional renal imaging with ultrasound or computerized tomography [3,6-10]. There are false negative tests with these imaging modalities, the so-called syndrome of ‘non-dilated obstructive uropathy or non-dilated obstructive nephropathy’ [6-10]. Clinical conditions associated with the absence of hydronephrosis on ultrasound and computerized tomography despite obstructed kidney(s) include acute early obstruction, the presence of retroperitoneal fibrosis or infiltrative metastatic abdomino-pelvic cancers, dehydration or septic shock and severe oliguria [2-10]. Our patient was not dehydrated and was not hypotensive but was severely oliguric (Table 1). We note that we did not rule out the presence of retroperitoneal fibrosis in our patient. This would require diagnostic pathology from biopsy material [3].

The classic picture of bilateral hydronephrosis with hydroureters and an empty urinary bladder, in symptomatic uraemia following supravesical obstruction, in patients with dual functioning kidneys, is well acknowledged [1,3]. However, the presentation of new-onset symptomatic uraemia concurrent with only unilateral hydronephrosis/hydroureter on conventional imaging (ultrasound, computerized tomography) should raise the plausibility of non-apparent obstruction of the contra lateral kidney. In such instances, the more sensitive albeit invasive percutaneous nephrostogram of the apparently normal appearing kidney is therapeutic and will lead to greater renal salvage [6-8]. We would like to remind practicing providers that symptomatic uraemia presenting in the setting of suspected obstructive uropathy must be assumed to imply bilateral renal obstruction, regardless of the results/interpretations of any form of conventional renal imaging. Therefore, necessarily, every attempt to decompress both kidneys must be the rule. This approach would result in early and improved renal salvage. Left undiagnosed and therefore untreated, this potentially reversible cause of renal failure can lead to irreversible renal failure if bilateral, [9], or to significant residual loss of renal function if missed on one side only [7,8]. We note that we were not able to carry out any split renal functional testing after recovery as the patient's primary attention at this point was to find out treatment options for his cancer.

Conflict of interest statement. None declared.