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Quiz Page April 2013
QUIZ PAGE APRIL 2013 Recurrent Episodes of Acute Kidney Injury in a Kidney Transplant Recipient CLINICAL PRESENTATION A 59-year-old man who had undergone orthotopic heart transplantation developed calcineurin inhibitor nephrotoxicity, which led to a deceased donor kidney transplantation. Five years later, he presented with an increase in serum creatinine level from 1.1 mg/dL (corresponding to an estimated glomerular filtration rate [eGFR] of 71 mL/ min/1.73 m2 calculated by the CKD-EPI [Chronic Kidney Disease Epidemiology Collaboration] equation) to 3.2 mg/dL (eGFR, 19 mL/min/1.73 m2). He had no urinary symptoms, but reported discomfort in the abdomen and back
after working on his boat. On physical examination, his kidney transplant was not readily palpable, but a bruit was audible. Urinalysis showed proteinuria (3⫹) and hematuria (4⫹), as well as 3-5 granular casts, 2-3 white blood cells, and occasional tubular epithelial cells per high-power field. Kidney biopsy (Fig 1) and ultrasonography (Fig 2) were performed. Spontaneously, urine output increased with a marked improvement in serum creatinine level to 1.2 mg/dL (eGFR, 64 mL/min/1.73 m2), and he was discharged. He was readmitted a month later with abdominal pain,
vomiting, diarrhea, fevers, chills, and acute kidney injury (AKI). Results of computed tomography (CT) of the abdomen and pelvis were consistent with transplant pyelonephritis. He was treated with intravenous fluids and antibiotics, although his urine culture remained negative. He was initially oliguric and his serum creatinine level peaked at 9 mg/dL (eGFR, 6 mL/min/1.73 m2), but then improved upon resolution of his abdominal symptoms. Comparing the initial CT scan to a CT angiogram that was obtained 3 months later (Fig 3) yielded the diagnosis.
What are the causes of late-onset decreased transplant function? What are the biopsy and radiographic findings? What is your diagnosis? What is the treatment of this condition?
Glomerulus shows segmental capillary loop wrinkling with collapse of some capillary lumen (blue arrows). Also note the “tubularization” of parietal epithelial cells in the upper half of the glomerulus. (Jones methenamine silver stain; original magnification, ⫻60.)
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Figure 1.
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Am J Kidney Dis. 2013;61(4):xxii-xxiv
Figure 2. Kidney ultrasound with color Doppler shows parvus tardus waveforms in the (A) superior and (B) inferior pole intrarenal.
Computed tomography of the abdomen in coronal view (A) without and (B) with contrast, 3 months apart, show that the transplant has shifted from (A) a longitudinal orientation during the episode of acute kidney injury to a (B) transverse orientation with improvement in the patient’s symptoms and kidney function.
Figure 3.
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Am J Kidney Dis. 2013;61(4):xxii-xxiv
QUIZ PAGE APRIL 2013 ANSWERS DISCUSSION
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f What are the causes of late-onset decreased transplant function? Causes of late-onset decreased transplant function (in which “late” is ⱖ6 months after transplantation) can be grouped into prerenal, vascular, immunologic, infectious, and other intrinsic renal and urologic causes. Traditional causes of AKI, such as acute tubular necrosis, decreased kidney perfusion, and obstruction, remain important causes of late-onset decreased transplant function. Vascular causes include renal artery stenosis and thrombotic microangiopathy. Urologic causes include ureteric strictures, nephrolithiasis, and bladder outlet obstruction. Immunologic causes include late acute rejection and chronic transplant glomerulopathy. Common infectious causes of lateonset decreased transplant function include polyoma (BK) virus nephropathy and urinary tract infections. Intrinsic renal causes include calcineurin inhibitor nephrotoxicity and recurrent or de novo glomerular disease. f What are the biopsy and radiographic findings? The biopsy specimen (Fig 1) shows ischemic wrinkling of glomerular basement membranes, mild chronic interstitial fibrosis, and mild tubular atrophy. There is no evidence of tubulitis or tubular injury that would suggest interstitial nephritis, cellular rejection, or tubular necrosis. The spectral color Doppler ultrasound (Fig 2) shows parvus tardus waveforms in the superior and inferior intrarenal xxiv
arteries. Ultrasound findings are concerning for renal artery stenosis, but this diagnosis does not readily explain the spontaneous improvement in symptoms and kidney function. f What is your diagnosis? The patient has experienced torsion of the transplant kidney around its vascular pedicle. The CT angiogram shows the transplant kidney in the left pelvis, but in a different orientation than was observed in the CT performed during the second admission with AKI (Fig 3). The ultrasound findings of parvus tardus waveforms can be explained by kinking of the renal artery after the kidney had moved further into the pelvic cavity and away from the left external iliac vessels. It rotated 90° on its long axis to be oriented cephalad to caudad. This is an under-recognized vascular cause of late-onset decreased transplant function that to our knowledge has been described in only intraperitoneally placed transplanted kidneys.1 Review of the patient’s surgical procedure showed that the kidney had been anastomosed to the left external iliac artery and then placed in an intraperitoneal position due to poor positioning when placed extraperitoneally. f What is the treatment of this condition? Complete torsion warrants emergent surgical exploration and detorsion to salvage the kidney from total infarction. Episodic partial torsion with spontaneous detorsion (as in our case) should be managed by fixing the transplant to the anterior abdominal wall (nephropexy), which eliminates
the risk of recurrence of torsion of the kidney transplant.2
FINAL DIAGNOSIS Recurrent torsion of a transplanted kidney resulting in AKI.
REFERENCES 1. Lucewicz A, Isaacs A, Allen RDM, Lam VWT, Angelides S, Pleass HCC. Torsion of intraperitoneal kidney transplant. ANZ J Surg. 2012;82:299-302. 2. Merkel FK, Miller JL, Ahmad N, Zahid M, Sadiq R, Sodhi B. Advantages of intraperitoneal placement of renal transplants. Transplant Proc. 1997;29(7):2765-2766. CASE PROVIDED AND AUTHORED BY Fadi A. Tohme, MD,1 Daniel A. Katz, MD,2 Danniele G. Holanda, MD,3 and Christie P. Thomas, MD,1,4,5 Departments of 1Internal Medicine, 2Surgery, 3Pathology, and 4Pediatrics, Carver College of Medicine, University of Iowa; and 5Medicine Service, Department of Veterans Affairs Medical Center, Iowa City, IA. Address correspondence to Christie P. Thomas, Organ Transplant Center, SE419 GH, University of Iowa, 200 Hawkins Dr, Iowa City, IA 52242. E-mail: [email protected] Published by Elsevier Inc. on behalf of the National Kidney Foundation, Inc. This is US Government Work. There are no restrictions on its use. http://dx.doi.org/10.1053/j.ajkd. 2012.12.020 SUPPORT: None. FINANCIAL DISCLOSURE: The authors declare that they have no relevant financial interests.
Am J Kidney Dis. 2013;61(4):xxii-xxiv
after working on his boat. On physical examination, his kidney transplant was not readily palpable, but a bruit was audible. Urinalysis showed proteinuria (3⫹) and hematuria (4⫹), as well as 3-5 granular casts, 2-3 white blood cells, and occasional tubular epithelial cells per high-power field. Kidney biopsy (Fig 1) and ultrasonography (Fig 2) were performed. Spontaneously, urine output increased with a marked improvement in serum creatinine level to 1.2 mg/dL (eGFR, 64 mL/min/1.73 m2), and he was discharged. He was readmitted a month later with abdominal pain,
vomiting, diarrhea, fevers, chills, and acute kidney injury (AKI). Results of computed tomography (CT) of the abdomen and pelvis were consistent with transplant pyelonephritis. He was treated with intravenous fluids and antibiotics, although his urine culture remained negative. He was initially oliguric and his serum creatinine level peaked at 9 mg/dL (eGFR, 6 mL/min/1.73 m2), but then improved upon resolution of his abdominal symptoms. Comparing the initial CT scan to a CT angiogram that was obtained 3 months later (Fig 3) yielded the diagnosis.
What are the causes of late-onset decreased transplant function? What are the biopsy and radiographic findings? What is your diagnosis? What is the treatment of this condition?
Glomerulus shows segmental capillary loop wrinkling with collapse of some capillary lumen (blue arrows). Also note the “tubularization” of parietal epithelial cells in the upper half of the glomerulus. (Jones methenamine silver stain; original magnification, ⫻60.)
QUIZ PAGE
Figure 1.
xxii
Am J Kidney Dis. 2013;61(4):xxii-xxiv
Figure 2. Kidney ultrasound with color Doppler shows parvus tardus waveforms in the (A) superior and (B) inferior pole intrarenal.
Computed tomography of the abdomen in coronal view (A) without and (B) with contrast, 3 months apart, show that the transplant has shifted from (A) a longitudinal orientation during the episode of acute kidney injury to a (B) transverse orientation with improvement in the patient’s symptoms and kidney function.
Figure 3.
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QUIZ PAGE
Am J Kidney Dis. 2013;61(4):xxii-xxiv
QUIZ PAGE APRIL 2013 ANSWERS DISCUSSION
QUIZ PAGE
f What are the causes of late-onset decreased transplant function? Causes of late-onset decreased transplant function (in which “late” is ⱖ6 months after transplantation) can be grouped into prerenal, vascular, immunologic, infectious, and other intrinsic renal and urologic causes. Traditional causes of AKI, such as acute tubular necrosis, decreased kidney perfusion, and obstruction, remain important causes of late-onset decreased transplant function. Vascular causes include renal artery stenosis and thrombotic microangiopathy. Urologic causes include ureteric strictures, nephrolithiasis, and bladder outlet obstruction. Immunologic causes include late acute rejection and chronic transplant glomerulopathy. Common infectious causes of lateonset decreased transplant function include polyoma (BK) virus nephropathy and urinary tract infections. Intrinsic renal causes include calcineurin inhibitor nephrotoxicity and recurrent or de novo glomerular disease. f What are the biopsy and radiographic findings? The biopsy specimen (Fig 1) shows ischemic wrinkling of glomerular basement membranes, mild chronic interstitial fibrosis, and mild tubular atrophy. There is no evidence of tubulitis or tubular injury that would suggest interstitial nephritis, cellular rejection, or tubular necrosis. The spectral color Doppler ultrasound (Fig 2) shows parvus tardus waveforms in the superior and inferior intrarenal xxiv
arteries. Ultrasound findings are concerning for renal artery stenosis, but this diagnosis does not readily explain the spontaneous improvement in symptoms and kidney function. f What is your diagnosis? The patient has experienced torsion of the transplant kidney around its vascular pedicle. The CT angiogram shows the transplant kidney in the left pelvis, but in a different orientation than was observed in the CT performed during the second admission with AKI (Fig 3). The ultrasound findings of parvus tardus waveforms can be explained by kinking of the renal artery after the kidney had moved further into the pelvic cavity and away from the left external iliac vessels. It rotated 90° on its long axis to be oriented cephalad to caudad. This is an under-recognized vascular cause of late-onset decreased transplant function that to our knowledge has been described in only intraperitoneally placed transplanted kidneys.1 Review of the patient’s surgical procedure showed that the kidney had been anastomosed to the left external iliac artery and then placed in an intraperitoneal position due to poor positioning when placed extraperitoneally. f What is the treatment of this condition? Complete torsion warrants emergent surgical exploration and detorsion to salvage the kidney from total infarction. Episodic partial torsion with spontaneous detorsion (as in our case) should be managed by fixing the transplant to the anterior abdominal wall (nephropexy), which eliminates
the risk of recurrence of torsion of the kidney transplant.2
FINAL DIAGNOSIS Recurrent torsion of a transplanted kidney resulting in AKI.
REFERENCES 1. Lucewicz A, Isaacs A, Allen RDM, Lam VWT, Angelides S, Pleass HCC. Torsion of intraperitoneal kidney transplant. ANZ J Surg. 2012;82:299-302. 2. Merkel FK, Miller JL, Ahmad N, Zahid M, Sadiq R, Sodhi B. Advantages of intraperitoneal placement of renal transplants. Transplant Proc. 1997;29(7):2765-2766. CASE PROVIDED AND AUTHORED BY Fadi A. Tohme, MD,1 Daniel A. Katz, MD,2 Danniele G. Holanda, MD,3 and Christie P. Thomas, MD,1,4,5 Departments of 1Internal Medicine, 2Surgery, 3Pathology, and 4Pediatrics, Carver College of Medicine, University of Iowa; and 5Medicine Service, Department of Veterans Affairs Medical Center, Iowa City, IA. Address correspondence to Christie P. Thomas, Organ Transplant Center, SE419 GH, University of Iowa, 200 Hawkins Dr, Iowa City, IA 52242. E-mail: [email protected] Published by Elsevier Inc. on behalf of the National Kidney Foundation, Inc. This is US Government Work. There are no restrictions on its use. http://dx.doi.org/10.1053/j.ajkd. 2012.12.020 SUPPORT: None. FINANCIAL DISCLOSURE: The authors declare that they have no relevant financial interests.
Am J Kidney Dis. 2013;61(4):xxii-xxiv