Dr Angela Au1, Dr Venkat Manickavasagam1, Dr Brendan Litton2, Dr Victoria Sasongko1
1Department of Renal Medicine, Lismore Base Hospital, Lismore , Australia, 2Department of Radiology, Lismore Base Hospital, Lismore, Australia
Biography:
Angela Au is a second year Renal Advanced Trainee currently working at Royal Prince Alfred Hospital network in Sydney, NSW. She graduated from University of Newcastle in 2019 and is currently studying a Masters of Medicine at the University of Sydney.
Background:
Acute tubular necrosis (ATN) is a common cause of acute kidney injury. We describe two cases with concerning multifocal renal hypodensities on CT imaging secondary to ATN.
Case 1:
A 26-year-old male presented with two days of severe lower abdominal pain and nausea following excess ethanol intake in hot weather. CT abdomen/pelvis revealed bilateral parenchymal heterogenous cortical hypoenhancement with no stranding, consistent with acute renal cortical necrosis. Admission Creatinine was 163 umol/L (Baseline 70 umol/L), no haematuria but moderate proteinuria (Urine Protein: Creatinine 94mg/mmol).
Subsequent CT intravenous pyelogram exhibited poor contrast excretion with heterogenous renal cortical density. He had gradual improvement of his renal function and urinary protein with return to baseline on subsequent blood test 6 months after admission.
Case 2:
A 30-year-old well male presented with a one-week history of bilateral flank pain. CT abdomen/pelvis showed bulky kidneys with non-homogenous contrast enhancement suggestive of infection/ infiltration/ infarcts. Admission Creatinine was 177 umol/L, urine microscopy showed no haematuria and minimal albuminuria (urine Albumin: Creatinine 17 mg/mmol). Renal ultrasound showed no masses and MRI revealed multifocal T1/T2 hyperintense renal lesions with reduced diffusion. A targeted renal biopsy done demonstrated mild ischaemic changes with mild regenerative changes in the tubules. Ten days after presentation, Creatinine improved to 80umol/L without any intervention.
Conclusions:
Contrast CT scans are rarely performed on patients with acute kidney injury. ATN can mimic renal lesions due to impaired contrast excretion and tubular obstruction by cellular debris. These cases highlight the unusual appearance of the kidneys with ATN in MRI and contrast-CT abdomen and the need for careful interpretation of cross-sectional imaging.