Copyright 2008
Definition
Vicarious excretion is the excretion of intravenous contrast material through means other than glomerular filtration via the hepatobiliary system. There is normally a small amount of intravenous contrast excreted in the bile, but this increases significantly and is caused by renal dysfunction when high concentrations of contrast material in the gallbladder is radiographically apparent and particulalrly well seen on CT images.
Structurally, there is no change in the gallbladder, though on imaging the luminal contents appear slightly radioopaque.
There is no change in gallbladder function per se, although it is associated with significant pathological impairment of at least one kidney. As contrast is normally 98% filtered through the kidneys, in the setting of impaired function, this leads to increased preference for hepatobiliary excretion. Creatinine levels will also be elevated chronically due to impaired function and acutely due to contrast administration.
The diagnosis is based usually on CT scan which is sensitive to the contrast density.
Treatment is directed to the kidneys and not the gallbladder since vicarious excretion itself is not of any clinical significance.
Renal Failure |
| In this 81 year old patient with hydronephrosis of the right kidney and the atrophy of the left kidney resulted in renal failure and contrast given to the patient a few days earlier showed as a sediment of dense vicarious excretion of contrast.
24075 81Y F with LLQ pain s/p cardiac catheterization gallbladder fx fluid -fluid level fx high density sediment fx vicarious excretion of contrast s/p heart catheter kidney fx small left kidney fx enlarged right kidney with hydronephrosis muscle fx hematoma dx pelvic hematoma CTscan Courtesy Ashley Davidoff MD |
Renal Failure |
| This patient who has long standing diabetes and chronic renal failure shows bilaterally small kidneys and vicarious excretion of the contrast in the gallbladder. Note that unlike milk of calcium bile where a distinct fluid fluid level is formed, in vicarious excretion where the SG of the contrast and bile is only minimally higher than the bile alone, the level is not well defined between the two fluids.
25328b02 Courtesy Ashley Davidoff MD code kidney fx small is only + dx diabetes dx chronic renal failure code pancreas + fx enlarged + fx dense + fx induration fx small + dx pancreas transplant + dx pancreatitis + imaging radiology CTscan code gallbladder + fx dense + dx vicarious excretion of contrast |
Sigmoid Gallbladder |
| The sigmoid gallbladder with dilated cystic duct shows multiple levels of accumulated vicarious excretion of bile.
82453c01.8s 88F p/w abdominal pain no known prior study gallbladder shape character sinusoidal shape to “s” shape fluid fluid level milk of contrast bile vicarious excretion anatomy CTscan Courtesy Ashley DAvidoff MD |
References
Dyer, R. B.; Gilpin, J. W.; Zagoria, R. J.; Chen, M. Y. & Case, L. D. Vicarious contrast material excretion in patients with acute unilateral ureteral obstruction. Radiology, Department of Radiology, Bowman Gray School of Medicine, Winston-Salem, NC 27103., 1990, 177, 739-742