Urol Radiol 14:159-160 (1992)
Urologic Radiology ©Springer-VerlagNewYorkInc.1992
Acute Renal Cortical Necrosis: Contrast-Enhanced CT and Pathologic Correlation Carlos M. Badiola-Varela Department of Radiology, Hartford Hospital, Hartford, Connecticut, USA
Abstract.
Acute renal cortical necrosis is a rare cause o f acute renal failure that is usually associated with third trimester obstetrical complications. The appearance o f this condition on contrast-enhanced c o m p u t e d t o m o g r a p h y (CT) has rarely been described. A case o f acute cortical renal necrosis is presented and the findings on contrast-enhanced CT are described. The pathologic correlation is also presented. Key words: sign.
Cortical necrosis, C T -- Cortical rim
Case Report A 74-year-old woman was transferred to our institution with a diagnosis of a type A aortic dissection. She was treated with a dacron interposition graft. Her postoperative course was complicated by hypotension, acute renal and hepatic failure, and ARDS. She was referred for CT scanning in order to exclude further extension of the aortic dissection. Although the patient's renal function was markedly impaired, it was felt that contrast administration would be necessaryin order to obtain a diagnostic examination. The CT scan demonstrated extension of the dissection inferior to the level of the renal arteries, as well as into
Address offprint requests to: Carlos M. Badiola-Varela, M.D.,
Department of Radiology,Hartford Hospital, 80 Seymour Street, Hartford, CT 06115, USA
the celiac and superior mesenteric arteries. There was bilateral lack of enhancement of the renal cortices with a thin peripheral rim of preserved enhancement (Fig. 1). The patient died shortly after the CT examination. Pathologic examination of the kidneys showed bilateral diffuse cortical necrosis with a thin peripheral rim of preserved tissue (Fig. 2).
Discussion Acute cortical renal necrosis is an u n c o m m o n cause o f acute renal failure that is usually associated with third trimester hemorrhagic complications, particularly abruptio placentae. Other causes include posttraumatic and septic shock, severe dehydration, v e n o m o u s snake bite, diethylene glycol poisoning, and renal transplant complication. The extent o f the necrotic process can vary from small microscopic foci to diffuse destruction o f the entire renal cortex. The process is usually bilateral, although unilateral cases have been reported. Pathologically, there is a characteristic sparing o f a thin rim o f peripheral cortex related to its separate capsular blood supply. This sparing is not present in cases o f acute cortical necrosis involving transplanted kidneys because collateral capsular blood supply is nonexistent in the transplanted organ [1, 5]. Only rarely are the changcs o f acute renal cortical necrosis d e m o n s t r a t e d on contrast-enhanced CT due to the potential nephrotoxic effects o f intravenous contrast. A review o f the literature revealed only three previously described cases o f acute
160
C.M. Badiola-Varela: Acute Renal Cortical Necrosis
Fig. 1. Contrast-enhanced CT scan demonstrates medullary enhancement and lack of cortical enhancement. A thin rim of preserved cortical enhancement is present (arrows).
renal cortical necrosis i m a g e d with c o n t r a s t - e n h a n c e d C T [2-4]. J o r d a n a n d c o w o r k e r s d e s c r i b e d three features t h a t t h e y felt were diagnostic o f acute renal cortical necrosis o n c o n t r a s t - e n h a n c e d CT: (a) e n h a n c e m e n t o f the renal m e d u l l a , (b) n o n e n h a n c e m e n t o f the renal cortex, a n d (c) lack o f excretion o f c o n t r a s t m a t e r i a l i n t o the collecting s y s t e m [2]. T h e o t h e r t w o p u b l i s h e d cases d e s c r i b e d similar findings [3, 4]. As in the present case, t h e y also n o t e d sparing o f a t h i n r i m o f peripheral cortex related to the presence o f a separate c a p s u l a r b l o o d supply. A l t h o u g h acute renal cortical necrosis is a rare cause o f acute renal failure, it a p p e a r s to h a v e a characteristic a p p e a r a n c e o n c o n t r a s t - e n h a n c e d CT. T h e presence o f m e d u l l a r y e n h a n c e m e n t c o u p l e d with lack o f cortical e n h a n c e m e n t bilaterally s h o u l d be c o n s i d e r e d diagnostic o f this c o n d i t i o n . I n addition, as d e m o n s t r a t e d b y G o e r g e n a n d c o w o r k e r s , as well as in the present case, sparing o f the m o s t peripheral regions o f cortex m a y o c c u r p r o d u c i n g a cortical r i m sign o n c o n t r a s t - e n h a n c e d CT.
References
Fig. 2. Pathologic examination of the hemisected left kidney demonstrates cortical necrosis (open arrows) with sparing of a peripheral rim of cortex (closed arrows). Similar findings were present on the fight. Note the close correlation between the hemisected specimen and the appearance of the kidneys on contrastenhanced CT.
1. Heptinstall RH: Pathology of the Kidney, 4th ed. Boston, Toronto, London: Little, Brown and Company, 1992, lap 12891299 2. Jordan J, Low R, Jeffrey RB: CT findings in acute renal cortical necrosis. JCAT 14:155-156, 1990 3. Goergen TG, Lindstrom RR, Tan H, Lilley J J: CT appearance of acute renal cortical necrosis. AJR 137:176-177, 1981 4. Laupacis A, Ulan RA, Rankin RN, Stiller CR, Keown PA: CT findings in postpartum renal cortical necrosis. J Canad Assoe Radiol 34:53-55, 1983 5. Hann L, Pfister RC: Renal subeapsular rim sign: New etiologies and pathogenesis. A JR 138:51-54, 1982
Urologic Radiology ©Springer-VerlagNewYorkInc.1992
Acute Renal Cortical Necrosis: Contrast-Enhanced CT and Pathologic Correlation Carlos M. Badiola-Varela Department of Radiology, Hartford Hospital, Hartford, Connecticut, USA
Abstract.
Acute renal cortical necrosis is a rare cause o f acute renal failure that is usually associated with third trimester obstetrical complications. The appearance o f this condition on contrast-enhanced c o m p u t e d t o m o g r a p h y (CT) has rarely been described. A case o f acute cortical renal necrosis is presented and the findings on contrast-enhanced CT are described. The pathologic correlation is also presented. Key words: sign.
Cortical necrosis, C T -- Cortical rim
Case Report A 74-year-old woman was transferred to our institution with a diagnosis of a type A aortic dissection. She was treated with a dacron interposition graft. Her postoperative course was complicated by hypotension, acute renal and hepatic failure, and ARDS. She was referred for CT scanning in order to exclude further extension of the aortic dissection. Although the patient's renal function was markedly impaired, it was felt that contrast administration would be necessaryin order to obtain a diagnostic examination. The CT scan demonstrated extension of the dissection inferior to the level of the renal arteries, as well as into
Address offprint requests to: Carlos M. Badiola-Varela, M.D.,
Department of Radiology,Hartford Hospital, 80 Seymour Street, Hartford, CT 06115, USA
the celiac and superior mesenteric arteries. There was bilateral lack of enhancement of the renal cortices with a thin peripheral rim of preserved enhancement (Fig. 1). The patient died shortly after the CT examination. Pathologic examination of the kidneys showed bilateral diffuse cortical necrosis with a thin peripheral rim of preserved tissue (Fig. 2).
Discussion Acute cortical renal necrosis is an u n c o m m o n cause o f acute renal failure that is usually associated with third trimester hemorrhagic complications, particularly abruptio placentae. Other causes include posttraumatic and septic shock, severe dehydration, v e n o m o u s snake bite, diethylene glycol poisoning, and renal transplant complication. The extent o f the necrotic process can vary from small microscopic foci to diffuse destruction o f the entire renal cortex. The process is usually bilateral, although unilateral cases have been reported. Pathologically, there is a characteristic sparing o f a thin rim o f peripheral cortex related to its separate capsular blood supply. This sparing is not present in cases o f acute cortical necrosis involving transplanted kidneys because collateral capsular blood supply is nonexistent in the transplanted organ [1, 5]. Only rarely are the changcs o f acute renal cortical necrosis d e m o n s t r a t e d on contrast-enhanced CT due to the potential nephrotoxic effects o f intravenous contrast. A review o f the literature revealed only three previously described cases o f acute
160
C.M. Badiola-Varela: Acute Renal Cortical Necrosis
Fig. 1. Contrast-enhanced CT scan demonstrates medullary enhancement and lack of cortical enhancement. A thin rim of preserved cortical enhancement is present (arrows).
renal cortical necrosis i m a g e d with c o n t r a s t - e n h a n c e d C T [2-4]. J o r d a n a n d c o w o r k e r s d e s c r i b e d three features t h a t t h e y felt were diagnostic o f acute renal cortical necrosis o n c o n t r a s t - e n h a n c e d CT: (a) e n h a n c e m e n t o f the renal m e d u l l a , (b) n o n e n h a n c e m e n t o f the renal cortex, a n d (c) lack o f excretion o f c o n t r a s t m a t e r i a l i n t o the collecting s y s t e m [2]. T h e o t h e r t w o p u b l i s h e d cases d e s c r i b e d similar findings [3, 4]. As in the present case, t h e y also n o t e d sparing o f a t h i n r i m o f peripheral cortex related to the presence o f a separate c a p s u l a r b l o o d supply. A l t h o u g h acute renal cortical necrosis is a rare cause o f acute renal failure, it a p p e a r s to h a v e a characteristic a p p e a r a n c e o n c o n t r a s t - e n h a n c e d CT. T h e presence o f m e d u l l a r y e n h a n c e m e n t c o u p l e d with lack o f cortical e n h a n c e m e n t bilaterally s h o u l d be c o n s i d e r e d diagnostic o f this c o n d i t i o n . I n addition, as d e m o n s t r a t e d b y G o e r g e n a n d c o w o r k e r s , as well as in the present case, sparing o f the m o s t peripheral regions o f cortex m a y o c c u r p r o d u c i n g a cortical r i m sign o n c o n t r a s t - e n h a n c e d CT.
References
Fig. 2. Pathologic examination of the hemisected left kidney demonstrates cortical necrosis (open arrows) with sparing of a peripheral rim of cortex (closed arrows). Similar findings were present on the fight. Note the close correlation between the hemisected specimen and the appearance of the kidneys on contrastenhanced CT.
1. Heptinstall RH: Pathology of the Kidney, 4th ed. Boston, Toronto, London: Little, Brown and Company, 1992, lap 12891299 2. Jordan J, Low R, Jeffrey RB: CT findings in acute renal cortical necrosis. JCAT 14:155-156, 1990 3. Goergen TG, Lindstrom RR, Tan H, Lilley J J: CT appearance of acute renal cortical necrosis. AJR 137:176-177, 1981 4. Laupacis A, Ulan RA, Rankin RN, Stiller CR, Keown PA: CT findings in postpartum renal cortical necrosis. J Canad Assoe Radiol 34:53-55, 1983 5. Hann L, Pfister RC: Renal subeapsular rim sign: New etiologies and pathogenesis. A JR 138:51-54, 1982
