Keywords
99mTc-Ethylenedicysteine - acute urinary obstruction - diuretic - furosemide - renal
scintigraphy - renal stone disease
Introduction
Diuretic renal scintigraphy is an established, safe, and effective diagnostic study
in evaluating both renal function and drainage with minimal intraprocedural complications.
We report a patient of renal stone disease, who developed acute urinary obstruction
during the renal scintigraphy, likely owing to the forced diuresis imparted by the
furosemide. Diuretic renal scintigraphy is reported to be useful in the emergency
setting, and the timely intervention helped in relieving urinary retention in this
patient.
Case Report
A 60-year-old male presented with a history of right flank pain. On investigation,
both ultrasonogram and intravenous pyelography showed left renal calculi and right
midureteric calculus. The patient was referred for a diuretic renography to evaluate
renal function and drainage. His renal function tests were within normal limits, and
he had a normal urinary output before the study.99m Tc-ethylenedicysteine (99m Tc-EC)
diuretic renography was done after injecting 148 MBq (4 mCi) of99m Tc-EC with furosemide
injection (40 mg bolus dose) 10 min after the radiotracer injection. The study showed
cortical retention of tracer in both kidneys without visualization of tracer activity
in ureters and urinary bladder. Uprising renograms of both kidneys indicate urinary
obstruction [Figure 1]. Corroborative history of increasing flank pain and absence of urinary output was
also observed in the patient pointing toward the development of an acute urinary obstruction
in the patient. With suspicion of acute urinary obstruction, the patient was referred
to the emergency urology where after evaluating the patient's symptoms, an on-spot
noncontrast computed tomography (CT) (kidneys, ureters, and bladder) was done which
showed bilateral hydronephrosis and renal calculi in both distal ureters suggesting
acute ureteric obstruction. An emergency double J stenting was done in both ureters,
which relieved patients symptoms followed by normalization of urinary output [Figure 2]. A repeat99m Tc-EC diuretic renography done (with urinary catheter in situ) 4 days
after the procedure showed normal cortical function and drainage from the left kidney
and slow drainage from the right kidney [Figure 3] as suggested from the dynamic (a), prevoid (b), postvoid (c), delayed (d) images,
and the renogram curves (e).
Figure 1 The initial dynamic images (a) as well as the prevoid (b) postvoid (c) and delayed
(d) 3 h images of 99mTc-ethylene dicysteine diuretic renography in the patient showing no tracer clearance
from both the kidneys with absence of visualization of tracer in either ureters or
urinary bladder. The renogram (e) also showed an uprising curve for both kidneys
Figure 2 Emergency noncontrast computed tomography (kidneys, ureters, and bladder) showing
bilateral hydronephrosis (a) and renal calculi in the both distal ureters (b and c;
arrows) suggesting acute ureteric obstruction. Double J stenting was done in both
ureters which can be seen in the postintervention X-ray image (d)
Figure 3 Repeat 99mTc-ethylene dicysteine diuretic renography done 4 days after the procedure showing
normal cortical function and drainage as suggested from the dynamic (a), prevoid (b),
postvoid (c), delayed (d) images and the renogram curves (e)
Discussion
Diuretic renal scintigraphy is a safe, noninvasive, and effective technique in the
evaluation of renal function and drainage in a single procedure.[1] This test is based on a high endogenous rate of urine flow stimulated by the administration
of furosemide. A high-grade obstruction usually manifests as acute and often presents
with persistent parenchymal uptake and an empty pelvis as in this case and can rapidly
leads to loss of function.[2],[3] Few pilot studies show that diuretic renal scintigraphy in the emergency room can
have a substantial impact on the management of patients presenting with renal colic
and a ureteral calculus documented by unenhanced CT.[4],[5],[6] Nonvisualization of the tracer activity in urinary bladder along with development
of clinical symptoms and anuria points toward an acute obstruction, requiring emergency
intervention”can be changed to “Non-visualization of the tracer activity in urinary
bladder along with development of clinical symptoms and anuria suggest an acute obstruction,
requiring emergency intervention. The sudden development of acute urinary obstruction
intraprocedurally during the renal scintigraphy, as in the index case, is very unusual,
and the forced diuresis imparted by furosemide injection may be the plausible culprit,
in the context of known bilateral renal stone disease. Apart from concerns regarding
sulfonamide-related allergic response,[7] furosemide at a standard dose of 0.5 mg/kg in adults is well-tolerated and safe
intervention.[8] However, in the setting of renal stone disease, the chance of development of an
acute obstruction cannot be excluded, and watchful monitoring is needed intraprocedurally
in these patients to look for the same.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms.
In the form the patient(s) has/have given his/her/their consent for his/her/their
images and other clinical information to be reported in the journal. The patients
understand that their names and initials will not be published and due efforts will
be made to conceal their identity, but anonymity cannot be guaranteed.
