Presentation
Two days of central abdominal pain, occasionally radiating to the right flank. Associated hypotension, nausea and vomiting.
Patient Data
Portal venous phase IV contrast-enhanced CT abdomen/pelvis. Reversed corticomedullary differentiation in the kidneys bilaterally in keeping with acute cortical necrosis. 6 mm obstructing calculus at the pelvic ureteric junction, with associated moderate right hydronephrosis. No left hydronephrosis. 2.5 cm left inferior pole renal cyst.
Moderate volume free fluid throughout the abdomen, most prominent in the pelvis and perihepatic regions. Periportal edema and mild hepatomegaly. Mild edema in the large bowel wall, which may be related to overall fluid overloaded state.
Conclusion: Acute renal cortical necrosis, which may be secondary to septicemia from right renal calculus causing obstructive pyelonephritis. Gross fluid overload noted.
Case Discussion
The patient presented with abdominal pain, vomiting, and systolic blood pressure of 60 mmHg. Bloods demonstrated acute renal failure with creatinine 186 micromol/L (normal range 45 to 90), eGFR 27 (normal > 90), lactate 7.1 mmol/L (normal range 0.2 to 1.8). E. coli was subsequently detected in blood cultures, and purulent urine was visualized at the time of right nephrostomy insertion, thus confirming the diagnosis of urosepsis.
CT abdomen/pelvis with contrast demonstrating relative hypoenhancement of the renal cortex and normal enhancement of the renal medulla, in keeping with the reverse rim sign seen in renal cortical necrosis. Renal cortical necrosis can be due to a variety of causes, including severe hemodynamic shock (sepsis, traumatic or post-partum hypovolemia), microangiopathic hemolysis, and acute renal transplant rejection. In this particular case, the cause was septic shock due to an obstructed renal calculus.