Case 26.21:
Questions:
1) What is shown on the CT urogram image in Figure 1A?
CT urogram reveals papillary extravasation around the edge of the papilla with contrast from the collecting system extending into the excavation in the right kidney (lobster-claw sign-long arrow) as well as hydroureteronephrosis (short arrow).
2) What is shown on the CT urogram image in Figure 1B?
CT urogram demonstrates small collections of contrast material (arrow) in the papillary regions peripheral to the calyces in the left kidney (ball-on-tee sign).
3) What is the diagnosis?
Renal papillary necrosis is the cause of hematuria and flank pain in this patient. Underlying sickle cell trait and use of NSAIDs were major factors increasing risk for development of acute papillary necrosis. The renal medulla and papillae are susceptible to ischemic damage due to the presence of a hypertonic and relatively hypoxic environment. Conditions associated with risk for ischemia such as sickle cell trait or disease, analgesic abuse, urinary tract obstruction, acute pyelonephritis, diabetes mellitus and vasculitis can worsen this environment and lead to stasis, thrombosis, and tissue infarction. Imaging with CT urography is often diagnostic in the setting of acute papillary necrosis. A number of findings are considered characteristic of papillary necrosis and include lobster claw and ball in cup or tee to name a few.
Case 27.21:
Questions:
1) What is shown on image of the urine in the collection bag in Figure 1A?
Urine in the catheterized urine collection bag had a dark reddish brown appearance.
2) What is shown on spun and unspun urine test tube images in Figure 1B?
The test tube on the left contains uncentrifuged urine. The test tube on the right contains centrifuged urine (1800 rpm for 5 minutes). The centrifuged urine showed persistent red brown discoloration of the supernatant. Dipstick urinalysis was heme positive. These findings are consistent with the presence of heme pigment (hemoglobin) in the urine.
3) What is the diagnosis?
Intravascular hemolysis with hemoglobinuria resulted in the dark colored urine (dark red/brown) in this patient. LVAD pump failure in the setting of subtherapeutic anticoagulation caused LVAD thrombosis, which resulted in intravascular hemolysis and hemoglobinuria. The combination of urine discoloration and the disparity between blood positive urinalysis and lack of erythrocytes in the urine sediment suggested the presence of a heme protein. Centrifuged urine that remains discolored and heme positive suggests hemoglobinuria in this patient with an LVAD rather than hematuria. Myoglobinuria from rhabdomyolysis can also cause discolored urine and blood positive urinalysis in the absence of erythrocytes in the urine sediment. Distinguishing which heme piment in the urine requires evaluation for hemolysis and hemoglobinuria (plasma color pink/red, low haptoglobin, high LDH-1 and -2, negative urine myoglobin) and rhabdomyolysis and myoglobinuria (plasma color normal, high CPK, high LDH-4 and -5, positive urine myoglobin). Once hemoglobinuria is determined, the cause of intravascular hemolysis should be determined. In patients with LVADs, hemolysis can result from shear stress or pump thrombosis. LVAD interrogation will display high power consumption, high pump speeds, but decreased pump flow in patients with pump thrombosis.
Case 28.21:
Questions:
1) What is shown on the magnetic resonance (MR) urogram in Figure 1A?
Magnetic Resonance urogram demonstrates a large perinephric collection engulfing the transplant ureter (arrow) with proximal ureteric dilatation and hydronephrosis (arrowhead).
2) What is shown on the computed tomography (CT) scan image in Figure 1B?
Computed Tomography of the abdomen/pelvis shows resolution of the perinephric collection with placement of a ureteric stent.
3) What is shown on the kidney ultrasound image in Figure 1C?
Ultrasound of the transplanted kidney demonstrates resolution of hydronephrosis and a normal appearing allograft after removal of ureteric stent.
4) What is the diagnosis?
A perinephric collection, in this case a hematoma, tracked down and engulfed the transplant ureter causing obstruction and acute kidney injury. The MRI demonstrated dilatation of the ureter proximal to the collection thereby confirming the cause of obstruction. In general, fluid collections adjacent to a kidney transplant are not uncommon. These collections occur in approximately 50% of those with kidney transplants and include hematomas, lymphoceles, seromas, urinomas and abscesses. Perinephric hematomas vary in incidence but are not typically associated with ureteric compression severe enough to cause obstruction and graft dysfunction. In this case, compressive obstruction was treated with stent placement, which relieved obstruction and avoided percutaneous nephrostomy tube placement or additional surgical procedures.