Clinical Imaging 38 (2014) 340–345
Contents lists available at ScienceDirect
Clinical Imaging journal homepage: http://www.clinicalimaging.org
Right nutcracker syndrome associated with left-sided inferior vena cava, hemiazygos continuation and persistant left superior vena cava: a rare combination☆ Adalet Elcin Yildiz a,⁎, Fatma Semsa Cayci b, Sinan Genc a, Nilgun Cakar b, Suat Fitoz a a b
Department of Radiology, Ankara University School of Medicine, 06100 Ankara, Turkey Department of Pediatric Nephrology, Ankara Child Health, Hematology, Oncology, Education and Research Hospital, Ankara, Turkey
a r t i c l e
i n f o
Article history: Received 14 October 2013 Received in revised form 3 December 2013 Accepted 12 December 2013 Keywords: Nutcracker syndrome Left-sided inferior vena cava Doppler US MR angiography
a b s t r a c t The term nutcracker syndrome refers to compression of left renal vein between aorta and superior mesenteric artery causing renal venous hypertension. Right nutcracker syndrome associated with a left-sided inferior vena cava is an extremely rare anomaly. Reported two cases in English literature were diagnosed by ultrasonography and computed tomography angiography in adulthood. Herein, we present a case of right nutcracker syndrome with left-sided inferior vena cava and hemiazygos continuation in a 12-year-old girl. © 2014 Elsevier Inc. All rights reserved.
1. Introduction Nutcracker phenomenon is a well described anatomic anomaly which is usually associated with left renal vein (LRV) compression between the superior mesenteric artery (SMA) and aorta. Nutcracker phenomenon is called “nutcracker syndrome” when the compression of the renal vein becomes symptomatic as a result of renal venous hypertension, hilar and ureteral varices, and disruption of the small renal veins into the collecting system. The most commonly related symptoms are hematuria, proteinuria, flank pain, varicocele and chronic fatigue syndrome [1–3]. As well as its classical form there are also uncommon causes that result in compression of LRV, such as posterior nutcracker phenomenon (compression between aorta and vertebral column), compression between SMA and right renal artery or compression of a left-sided inferior vena cava (IVC) between SMA and aorta (Fig. 1A-D) [4–6]. On the other hand, not only the LRV but also the right renal vein (RRV) can be compressed and result in the right nutcracker syndrome. In English literature, there are a few case reports of right nutcracker syndrome; one was associated with pregnancy and two of them were associated with a left-sided IVC [1,2,7]. Related to the type of IVC anomaly-associated renal vein compression may be on either side; right or left (Fig. 1D-F) [1,2,6].
☆ No funding was received from any source. The authors declare no conflicts of interest. ⁎ Corresponding author. Department of Radiology, Ankara University School of Medicine, 06100 Ankara, Turkey. Tel.: +90 505 8053 836. E-mail address: [email protected] (A.E. Yildiz). 0899-7071/$ – see front matter © 2014 Elsevier Inc. All rights reserved. http://dx.doi.org/10.1016/j.clinimag.2013.12.007
We reported here a case of a child with right nutcracker syndrome associated with left-sided IVC and hemiazygos continuation diagnosed by Doppler ultrasonography (US) and magnetic resonance angiography (MRA) to avoid risk of radiation in this age group. 2. Case report A 12-year-old girl was admitted to the hospital for the evaluation of microscopic hematuria. The patient had been followed up for intermittent microscopic hematuria episodes for the previous 7 years. She had been examined with renal sonography 6 times with normal abdominal findings. Past medical history was unremarkable. There was no history of gross hematuria, trauma, urinary tract infection, arthralgias, or skin rashes. Family history was negative for hematuria, deafness, rheumatologic disease, or end-stage renal disease. The physical examination, ear and audiological examinations were entirely normal. Laboratory test results of complete blood count, serum electrolytes, and renal function tests were entirely in normal limits. Urine red blood cell count was 10–33 per high-power field. Remaining urine test results were normal. There was not any abnormality on kidney-bladder ultrasonography. On the basis of clinical and laboratory findings, she was referred to radiology department for renal Doppler US. At initial evaluation, renal Doppler US showed the absence of a right-sided IVC except its suprahepatic segment. However, at the left side of the aorta, there was a persisting left IVC being formed by right and left common iliac veins. Both the renal veins were draining into the left-sided IVC and right renal vein was compressed while passing between aorta and SMA. The diameters of RRV at the hilar and aortomesenteric stenotic portion were 7.7 and 1.1 mm, respectively (Fig. 2A, B). At spectral Doppler US
A.E. Yildiz et al. / Clinical Imaging 38 (2014) 340–345
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Fig. 1. Illustrations (A-F) show common and rare forms of nutcracker syndrome. In classical form (A) left renal vein is compressed between SMA and aorta. In posterior nutcracker phenomenon (B) left renal vein is compressed between aorta and vertebral column. Left renal vein compression between SMA and right renal artery (C) and compression of a left sided IVC between SMA and aorta (D) are rare types of left nutcracker syndrome. Compression of right renal vein between aorta and vertebral column and left-sided IVC between aorta and vertebral column (E) is a form of bilateral nutcracker syndrome. Compression of right renal vein between SMA and aorta associated with left-sided IVC (F) is another rare form of left nutcracker syndrome.
analysis of the RRV at the hilar portion and aortomesenteric stenotic portion, the peak velocities were 21.9 cm/s and 103.9 cm/s, respectively (Fig. 3A, B). SMA angle measurements in the supine and upright positions were 28° and 11°, respectively (Fig. 4A, B). The diameter and peak velocity ratios between dilated and stenotic portions of the RRV (7 and 4.7, respectively) and SMA angle were consistent with nutcracker phenomenon. The suprarenal segment of the left-sided IVC could be traced to the diaphragmatic level on the left side of midline. For further evaluation of this rare vascular anomaly at both sides of diaphragm we also performed contrast enhanced MRA. MRA was performed by using a 1.5 T MRI system. In addition to Doppler US findings, MRA revealed that left sided IVC continuation with a dilated hemiazygos (Fig. 5). The hemiazygos was draining into persistent left superior vena cava (SVC) with the left brachiocephalic venous system and finally to the left coronary sinus (Fig. 6). As the patient is a child and had not experienced any symptom with the episodes of microscopic hematuria, no intervention was planned and conservative management with regular followup was recommended. 3. Discussion In normal anatomical formation, IVC lies on the right side of aorta and comprise four segments: hepatic, suprarenal, renal, and infrarenal. Embryogenesis of the IVC is a complex process which may
result in different variations with renal vein anomalies. In the embryonic life during the sixth to eighth week of gestation, three pairs of fetal veins—posterior cardinal, subcardinal, and supracardinal veins—develop, regress, and form anastomoses between each other in an order and finally form the infrarenal IVC on the right side [8]. Although anomalies of IVC are rare, there are almost 14 theoretical variations in the anatomy of the infrarenal IVC described by the investigators. Left-sided IVC anomaly with a type of joining with the left renal vein and crossing anterior to the aorta to unit with the right renal vein and form a normal right-sided pre-renal IVC has a prevalence of 0.2–0.5% [7]. Persistence of the left supracardinal vein with regression of the right supracardinal vein leads to this anomaly. Besides, a left-sided IVC can also show an azygos or hemiazygos continuation. If a hemiazygos vein continuation occurs it can either drain into the azygos or join the coronary vein by a persistent left SVC or drain into left brachiocephalic vein by an accessory hemiazygos continuation [7]. If the left-sided IVC is compressed while passing between SMA and aorta it may result in nutcracker syndrome as reported with a few cases in the literature (Fig. 1D) [6,9,10]. Recently, two other types of left-sided IVC anomalies associated with nutcracker syndrome were reported in the literature: a left-sided IVC with azygos continuation and a left-sided IVC with hemiazygos continuation, the latter one is similar to our case [1,2]. In the first case reported by Luo et al. [1], nutcracker syndrome was obtained on both sides: right renal vein
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Fig. 2. Transverse gray scale (A) and color Doppler (B) sonograms show a left sided inferior vena cava (arrowhead) and compressed right renal vein between aorta and superior mesenteric artery.
was retroaortic and compressed between aorta and vertebral column and left IVC was compressed between aorta and vertebral column leading to LRV dilatation while crossing the midline (Fig. 1E). In the case reported by Ekwenna et al. [2] right nutcracker syndrome was diagnosed by the compression of RRV between SMA and aorta and showed hemiazygos continuation (Fig. 1F). Both of these cases were diagnosed in adulthood. We demonstrated a leftsided IVC anomaly associated with hemiazygos continuation and a right nutcracker syndrome—compressed between aorta and SMA—in a 12-year-old girl. Hemiazygos vein was draining into persistent left SVC with the left brachiocephalic venous system and finally to the left coronary sinus which has not been reported before. IVC anomalies are generally asymptomatic and usually diagnosed incidentally while being investigated for other reasons. Moreover, another reason for incidentally diagnoses of IVC anomalies is widespread availability of cross-sectional imaging methods at the present time. They rarely may result in a nutcracker syndrome and become symptomatic as shown with the limited number of cases in the literature. Its typical symptoms are hematuria, proteinuria, pain and varicoceles which are all related to venous renal hypertension [1,2,6,8–10].
Diagnosis of nutcracker syndrome mainly depends on imaging modalities including renal venography, Doppler US, computed tomographic angiography and MRA. Recently, renal venography is not a preferred imaging modality of choice because of its invasiveness, especially in children. Spectral Doppler analysis with gray scale and spectral Doppler US findings generally sufficient to diagnose a nutcracker syndrome. In adults, Kim et al. [11] suggested that a ratio of the AP diameter, and peak velocity (PV) between the hilar and aortomesenteric portions of the LRV of greater than 5.0 could be used as the cutoff level for the diagnosis of nutcracker syndrome with a sensitivity of 80% and a specificity of 94%. In children, Fitoz et al. [12] investigated diameter ratio, PV ratio and SMA angle parameters both in supine and upright positions and suggested that imaging in upright position reveals narrower SMA angles and more pronounced entrapment findings when compared with supine position. For the diameter ratio, their results showed cutoff values in supine and upright position greater than 3.8 (sensitivity: 78.4%, specificity: 92.3%) and 5.58 (sensitivity: 87%, specificity: 92.3%), respectively. For the PV ratio their results showed cutoff values in supine and upright position greater than 4.23 (sensitivity: 69.6%, specificity: 76.9%) and 5.14 (sensitivity: 100%, specificity: 88.5%), respectively. And suggested the cutoff values for the SMA angle measurement in supine and upright position less than 41° (sensitivity: 69.6%, specificity: 61.5%) and 21° (sensitivity: 87.0%, specificity: 76.9%), respectively. In our case, the diameter and PV ratios between the hilar and aortomesenteric portions were 7 and 4.7, respectively, and the SMA angle measurements in supine and upright positions were 28° and 11°, respectively. All the measurements were consistent with the diagnosis of nutcracker syndrome. The treatment of nutcracker syndrome mainly depends on the patient’s age and degree of clinical symptoms. If the patient is younger than 18 and/or has mild hematuria and associated pain conservative management and follow-up without any intervention for at least 2 years is recommended. In approximately 75% of patients will show complete resolution of hematuria with this approach. Surgical or endovascular interventional procedures are indicated if severe or persistent gross hematuria, pain and renal insufficiency coexist with nutcracker syndrome. Surgical procedures include medial nephropexy, LRV bypass, SMA transposition, LRV transposition, renal-to-IVC shunt, renal autotransplantation and even nephrectomy for persistent hematuria. Intravascular or external stenting are also treatment options which are recently applied [13]. In conclusion, although rare, congenital anomalies of IVC may coexist with the nutcracker syndrome. To be aware of this rare vascular anomaly is important for both the accurate diagnosis and to avoid complications at any endovascular intervention or surgery. To the best of our knowledge, this is the first case of left IVC with hemiazygos and persistent left SVC continuation associated with right nutcracker syndrome demonstrated on Doppler US and MRA in a child. References [1] Luo XL, Qian GN, Xiao H, Zhao CL, Zhou XD. Posterior nutcracker syndrome associated with interrupted left inferior vena cava with azygos continuation and retroaortic right renal vein. Korean J Radiol 2012;13(3):345–9. [2] Ekwenna O, Gorin MA, Castellan M, Casillas V, Ciancio G. Inverted nutcracker syndrome: a case of persistent hematuria and pain in the presence of a left-sided inferior vena cava. ScientificWorldJournal 2011;11:1031–5. [3] Park SJ, Lim JW, Cho BS, Yoon TY, Oh JH. Nutcracker syndrome in children with orthostatic proteinuria; diagnosis on the basis of Doppler sonography. J Ultrasound Med 2002;21:39–45. [4] Qin J, Zheng X, Jiang H. Posterior nutcracker phenomenon in patient with renal arteriovenous malformation. Urology 2012;80(6):e73–4. [5] Polguj M, Topol M, Majos A. An unusual case of left venous renal entrapment syndrome: a new type of nutcracker phenomenon? Surg Radiol Anat 2013;35: 263–7. [6] Fitoz S, Yalcinkaya F. Compression of left inferior vena cava: a form of nutcracker syndrome. J Clin Ultrasound 2008;36(2):101–4. [7] Radisic MV, Feldman D, Diaz C, Froment RO. Unexplained hematuria during pregnancy: right-sided nutcracker phenomenon. Int Urol Nephrol 2007;39:709–11.
A.E. Yildiz et al. / Clinical Imaging 38 (2014) 340–345 [8] Bass JE, Redwine MD, Kramer LA, Huynh PT, Harris JH. Spectrum of congenital anomalies of the inferior vena cava: cross-sectional ımaging findings. RadioGraphics 2000;20:639–52. [9] Ulusan S, Koc Z. Left inferior vena cava associated with nutcracker phenomenon. Firat Tip Dergisi 2007;12:151–3. [10] Gupta A, Naik N, Gulati GS. Mesoaortic entrapment of a left inferior vena cava. Indian J Radiol Imaging 2010;20:63–5.
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[11] Kim SH, Cho SW, Kim HD, Chung JW, Park JH, Han MC. Nutcracker syndrome: diagnosis with Doppler US. Radiology 1996;198:93–7. [12] Fitoz S, Ekim M, Ozcakar ZB, Elhan AH, Yalcinkaya F. Nutcracker syndrome in children; the role of upright position examination and superior mesenteric artery angle measurement in the diagnosis. J Ultrasound Med 2007;26:573–80. [13] Kurklinsky AK, Rooke TW. Nutcracker phenomenon and nutcracker syndrome. Mayo Clin Proc 2010;85:552–9.
Fig. 3. Spectral Doppler US analysis of right renal vein at hilar (A) and stenotic (B) portions demonstrate the peak velocities 21.9 and 103.9 cm/s, respectively.
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Fig. 4. Midline sagittal sonograms show the SMA angle measurements 28° and 11° in supine (A) and upright (B) positions, respectively.
A.E. Yildiz et al. / Clinical Imaging 38 (2014) 340–345
Fig. 5. Coronal reconstructed (MIP) MRA image (TR, 3.5 ms; TE, 1.2 ms; slice thickness, 3.2 mm; 20 slices in 3D slab; flip angle, 30°; NEX, 0.7; matrix, 380×380 mm) reveals a left sided inferior vena cava formed by the right and left common iliac veins and its continuation with a dilated hemiazygos vein (arrow).
Fig. 6. Axial MRA image (TR, 3.5 ms; TE, 1.2 ms; slice thickness, 3.2 mm; 20 slices in 3D slab; flip angle, 30°; NEX, 0.7; matrix, 380×380 mm) shows a dilated hemiazygos vein (arrow) posterolateral to descending aorta and a persistent left superior vena cava (arrowhead) which drains into coronary sinus (not shown here).
345
Contents lists available at ScienceDirect
Clinical Imaging journal homepage: http://www.clinicalimaging.org
Right nutcracker syndrome associated with left-sided inferior vena cava, hemiazygos continuation and persistant left superior vena cava: a rare combination☆ Adalet Elcin Yildiz a,⁎, Fatma Semsa Cayci b, Sinan Genc a, Nilgun Cakar b, Suat Fitoz a a b
Department of Radiology, Ankara University School of Medicine, 06100 Ankara, Turkey Department of Pediatric Nephrology, Ankara Child Health, Hematology, Oncology, Education and Research Hospital, Ankara, Turkey
a r t i c l e
i n f o
Article history: Received 14 October 2013 Received in revised form 3 December 2013 Accepted 12 December 2013 Keywords: Nutcracker syndrome Left-sided inferior vena cava Doppler US MR angiography
a b s t r a c t The term nutcracker syndrome refers to compression of left renal vein between aorta and superior mesenteric artery causing renal venous hypertension. Right nutcracker syndrome associated with a left-sided inferior vena cava is an extremely rare anomaly. Reported two cases in English literature were diagnosed by ultrasonography and computed tomography angiography in adulthood. Herein, we present a case of right nutcracker syndrome with left-sided inferior vena cava and hemiazygos continuation in a 12-year-old girl. © 2014 Elsevier Inc. All rights reserved.
1. Introduction Nutcracker phenomenon is a well described anatomic anomaly which is usually associated with left renal vein (LRV) compression between the superior mesenteric artery (SMA) and aorta. Nutcracker phenomenon is called “nutcracker syndrome” when the compression of the renal vein becomes symptomatic as a result of renal venous hypertension, hilar and ureteral varices, and disruption of the small renal veins into the collecting system. The most commonly related symptoms are hematuria, proteinuria, flank pain, varicocele and chronic fatigue syndrome [1–3]. As well as its classical form there are also uncommon causes that result in compression of LRV, such as posterior nutcracker phenomenon (compression between aorta and vertebral column), compression between SMA and right renal artery or compression of a left-sided inferior vena cava (IVC) between SMA and aorta (Fig. 1A-D) [4–6]. On the other hand, not only the LRV but also the right renal vein (RRV) can be compressed and result in the right nutcracker syndrome. In English literature, there are a few case reports of right nutcracker syndrome; one was associated with pregnancy and two of them were associated with a left-sided IVC [1,2,7]. Related to the type of IVC anomaly-associated renal vein compression may be on either side; right or left (Fig. 1D-F) [1,2,6].
☆ No funding was received from any source. The authors declare no conflicts of interest. ⁎ Corresponding author. Department of Radiology, Ankara University School of Medicine, 06100 Ankara, Turkey. Tel.: +90 505 8053 836. E-mail address: [email protected] (A.E. Yildiz). 0899-7071/$ – see front matter © 2014 Elsevier Inc. All rights reserved. http://dx.doi.org/10.1016/j.clinimag.2013.12.007
We reported here a case of a child with right nutcracker syndrome associated with left-sided IVC and hemiazygos continuation diagnosed by Doppler ultrasonography (US) and magnetic resonance angiography (MRA) to avoid risk of radiation in this age group. 2. Case report A 12-year-old girl was admitted to the hospital for the evaluation of microscopic hematuria. The patient had been followed up for intermittent microscopic hematuria episodes for the previous 7 years. She had been examined with renal sonography 6 times with normal abdominal findings. Past medical history was unremarkable. There was no history of gross hematuria, trauma, urinary tract infection, arthralgias, or skin rashes. Family history was negative for hematuria, deafness, rheumatologic disease, or end-stage renal disease. The physical examination, ear and audiological examinations were entirely normal. Laboratory test results of complete blood count, serum electrolytes, and renal function tests were entirely in normal limits. Urine red blood cell count was 10–33 per high-power field. Remaining urine test results were normal. There was not any abnormality on kidney-bladder ultrasonography. On the basis of clinical and laboratory findings, she was referred to radiology department for renal Doppler US. At initial evaluation, renal Doppler US showed the absence of a right-sided IVC except its suprahepatic segment. However, at the left side of the aorta, there was a persisting left IVC being formed by right and left common iliac veins. Both the renal veins were draining into the left-sided IVC and right renal vein was compressed while passing between aorta and SMA. The diameters of RRV at the hilar and aortomesenteric stenotic portion were 7.7 and 1.1 mm, respectively (Fig. 2A, B). At spectral Doppler US
A.E. Yildiz et al. / Clinical Imaging 38 (2014) 340–345
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Fig. 1. Illustrations (A-F) show common and rare forms of nutcracker syndrome. In classical form (A) left renal vein is compressed between SMA and aorta. In posterior nutcracker phenomenon (B) left renal vein is compressed between aorta and vertebral column. Left renal vein compression between SMA and right renal artery (C) and compression of a left sided IVC between SMA and aorta (D) are rare types of left nutcracker syndrome. Compression of right renal vein between aorta and vertebral column and left-sided IVC between aorta and vertebral column (E) is a form of bilateral nutcracker syndrome. Compression of right renal vein between SMA and aorta associated with left-sided IVC (F) is another rare form of left nutcracker syndrome.
analysis of the RRV at the hilar portion and aortomesenteric stenotic portion, the peak velocities were 21.9 cm/s and 103.9 cm/s, respectively (Fig. 3A, B). SMA angle measurements in the supine and upright positions were 28° and 11°, respectively (Fig. 4A, B). The diameter and peak velocity ratios between dilated and stenotic portions of the RRV (7 and 4.7, respectively) and SMA angle were consistent with nutcracker phenomenon. The suprarenal segment of the left-sided IVC could be traced to the diaphragmatic level on the left side of midline. For further evaluation of this rare vascular anomaly at both sides of diaphragm we also performed contrast enhanced MRA. MRA was performed by using a 1.5 T MRI system. In addition to Doppler US findings, MRA revealed that left sided IVC continuation with a dilated hemiazygos (Fig. 5). The hemiazygos was draining into persistent left superior vena cava (SVC) with the left brachiocephalic venous system and finally to the left coronary sinus (Fig. 6). As the patient is a child and had not experienced any symptom with the episodes of microscopic hematuria, no intervention was planned and conservative management with regular followup was recommended. 3. Discussion In normal anatomical formation, IVC lies on the right side of aorta and comprise four segments: hepatic, suprarenal, renal, and infrarenal. Embryogenesis of the IVC is a complex process which may
result in different variations with renal vein anomalies. In the embryonic life during the sixth to eighth week of gestation, three pairs of fetal veins—posterior cardinal, subcardinal, and supracardinal veins—develop, regress, and form anastomoses between each other in an order and finally form the infrarenal IVC on the right side [8]. Although anomalies of IVC are rare, there are almost 14 theoretical variations in the anatomy of the infrarenal IVC described by the investigators. Left-sided IVC anomaly with a type of joining with the left renal vein and crossing anterior to the aorta to unit with the right renal vein and form a normal right-sided pre-renal IVC has a prevalence of 0.2–0.5% [7]. Persistence of the left supracardinal vein with regression of the right supracardinal vein leads to this anomaly. Besides, a left-sided IVC can also show an azygos or hemiazygos continuation. If a hemiazygos vein continuation occurs it can either drain into the azygos or join the coronary vein by a persistent left SVC or drain into left brachiocephalic vein by an accessory hemiazygos continuation [7]. If the left-sided IVC is compressed while passing between SMA and aorta it may result in nutcracker syndrome as reported with a few cases in the literature (Fig. 1D) [6,9,10]. Recently, two other types of left-sided IVC anomalies associated with nutcracker syndrome were reported in the literature: a left-sided IVC with azygos continuation and a left-sided IVC with hemiazygos continuation, the latter one is similar to our case [1,2]. In the first case reported by Luo et al. [1], nutcracker syndrome was obtained on both sides: right renal vein
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Fig. 2. Transverse gray scale (A) and color Doppler (B) sonograms show a left sided inferior vena cava (arrowhead) and compressed right renal vein between aorta and superior mesenteric artery.
was retroaortic and compressed between aorta and vertebral column and left IVC was compressed between aorta and vertebral column leading to LRV dilatation while crossing the midline (Fig. 1E). In the case reported by Ekwenna et al. [2] right nutcracker syndrome was diagnosed by the compression of RRV between SMA and aorta and showed hemiazygos continuation (Fig. 1F). Both of these cases were diagnosed in adulthood. We demonstrated a leftsided IVC anomaly associated with hemiazygos continuation and a right nutcracker syndrome—compressed between aorta and SMA—in a 12-year-old girl. Hemiazygos vein was draining into persistent left SVC with the left brachiocephalic venous system and finally to the left coronary sinus which has not been reported before. IVC anomalies are generally asymptomatic and usually diagnosed incidentally while being investigated for other reasons. Moreover, another reason for incidentally diagnoses of IVC anomalies is widespread availability of cross-sectional imaging methods at the present time. They rarely may result in a nutcracker syndrome and become symptomatic as shown with the limited number of cases in the literature. Its typical symptoms are hematuria, proteinuria, pain and varicoceles which are all related to venous renal hypertension [1,2,6,8–10].
Diagnosis of nutcracker syndrome mainly depends on imaging modalities including renal venography, Doppler US, computed tomographic angiography and MRA. Recently, renal venography is not a preferred imaging modality of choice because of its invasiveness, especially in children. Spectral Doppler analysis with gray scale and spectral Doppler US findings generally sufficient to diagnose a nutcracker syndrome. In adults, Kim et al. [11] suggested that a ratio of the AP diameter, and peak velocity (PV) between the hilar and aortomesenteric portions of the LRV of greater than 5.0 could be used as the cutoff level for the diagnosis of nutcracker syndrome with a sensitivity of 80% and a specificity of 94%. In children, Fitoz et al. [12] investigated diameter ratio, PV ratio and SMA angle parameters both in supine and upright positions and suggested that imaging in upright position reveals narrower SMA angles and more pronounced entrapment findings when compared with supine position. For the diameter ratio, their results showed cutoff values in supine and upright position greater than 3.8 (sensitivity: 78.4%, specificity: 92.3%) and 5.58 (sensitivity: 87%, specificity: 92.3%), respectively. For the PV ratio their results showed cutoff values in supine and upright position greater than 4.23 (sensitivity: 69.6%, specificity: 76.9%) and 5.14 (sensitivity: 100%, specificity: 88.5%), respectively. And suggested the cutoff values for the SMA angle measurement in supine and upright position less than 41° (sensitivity: 69.6%, specificity: 61.5%) and 21° (sensitivity: 87.0%, specificity: 76.9%), respectively. In our case, the diameter and PV ratios between the hilar and aortomesenteric portions were 7 and 4.7, respectively, and the SMA angle measurements in supine and upright positions were 28° and 11°, respectively. All the measurements were consistent with the diagnosis of nutcracker syndrome. The treatment of nutcracker syndrome mainly depends on the patient’s age and degree of clinical symptoms. If the patient is younger than 18 and/or has mild hematuria and associated pain conservative management and follow-up without any intervention for at least 2 years is recommended. In approximately 75% of patients will show complete resolution of hematuria with this approach. Surgical or endovascular interventional procedures are indicated if severe or persistent gross hematuria, pain and renal insufficiency coexist with nutcracker syndrome. Surgical procedures include medial nephropexy, LRV bypass, SMA transposition, LRV transposition, renal-to-IVC shunt, renal autotransplantation and even nephrectomy for persistent hematuria. Intravascular or external stenting are also treatment options which are recently applied [13]. In conclusion, although rare, congenital anomalies of IVC may coexist with the nutcracker syndrome. To be aware of this rare vascular anomaly is important for both the accurate diagnosis and to avoid complications at any endovascular intervention or surgery. To the best of our knowledge, this is the first case of left IVC with hemiazygos and persistent left SVC continuation associated with right nutcracker syndrome demonstrated on Doppler US and MRA in a child. References [1] Luo XL, Qian GN, Xiao H, Zhao CL, Zhou XD. Posterior nutcracker syndrome associated with interrupted left inferior vena cava with azygos continuation and retroaortic right renal vein. Korean J Radiol 2012;13(3):345–9. [2] Ekwenna O, Gorin MA, Castellan M, Casillas V, Ciancio G. Inverted nutcracker syndrome: a case of persistent hematuria and pain in the presence of a left-sided inferior vena cava. ScientificWorldJournal 2011;11:1031–5. [3] Park SJ, Lim JW, Cho BS, Yoon TY, Oh JH. Nutcracker syndrome in children with orthostatic proteinuria; diagnosis on the basis of Doppler sonography. J Ultrasound Med 2002;21:39–45. [4] Qin J, Zheng X, Jiang H. Posterior nutcracker phenomenon in patient with renal arteriovenous malformation. Urology 2012;80(6):e73–4. [5] Polguj M, Topol M, Majos A. An unusual case of left venous renal entrapment syndrome: a new type of nutcracker phenomenon? Surg Radiol Anat 2013;35: 263–7. [6] Fitoz S, Yalcinkaya F. Compression of left inferior vena cava: a form of nutcracker syndrome. J Clin Ultrasound 2008;36(2):101–4. [7] Radisic MV, Feldman D, Diaz C, Froment RO. Unexplained hematuria during pregnancy: right-sided nutcracker phenomenon. Int Urol Nephrol 2007;39:709–11.
A.E. Yildiz et al. / Clinical Imaging 38 (2014) 340–345 [8] Bass JE, Redwine MD, Kramer LA, Huynh PT, Harris JH. Spectrum of congenital anomalies of the inferior vena cava: cross-sectional ımaging findings. RadioGraphics 2000;20:639–52. [9] Ulusan S, Koc Z. Left inferior vena cava associated with nutcracker phenomenon. Firat Tip Dergisi 2007;12:151–3. [10] Gupta A, Naik N, Gulati GS. Mesoaortic entrapment of a left inferior vena cava. Indian J Radiol Imaging 2010;20:63–5.
343
[11] Kim SH, Cho SW, Kim HD, Chung JW, Park JH, Han MC. Nutcracker syndrome: diagnosis with Doppler US. Radiology 1996;198:93–7. [12] Fitoz S, Ekim M, Ozcakar ZB, Elhan AH, Yalcinkaya F. Nutcracker syndrome in children; the role of upright position examination and superior mesenteric artery angle measurement in the diagnosis. J Ultrasound Med 2007;26:573–80. [13] Kurklinsky AK, Rooke TW. Nutcracker phenomenon and nutcracker syndrome. Mayo Clin Proc 2010;85:552–9.
Fig. 3. Spectral Doppler US analysis of right renal vein at hilar (A) and stenotic (B) portions demonstrate the peak velocities 21.9 and 103.9 cm/s, respectively.
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Fig. 4. Midline sagittal sonograms show the SMA angle measurements 28° and 11° in supine (A) and upright (B) positions, respectively.
A.E. Yildiz et al. / Clinical Imaging 38 (2014) 340–345
Fig. 5. Coronal reconstructed (MIP) MRA image (TR, 3.5 ms; TE, 1.2 ms; slice thickness, 3.2 mm; 20 slices in 3D slab; flip angle, 30°; NEX, 0.7; matrix, 380×380 mm) reveals a left sided inferior vena cava formed by the right and left common iliac veins and its continuation with a dilated hemiazygos vein (arrow).
Fig. 6. Axial MRA image (TR, 3.5 ms; TE, 1.2 ms; slice thickness, 3.2 mm; 20 slices in 3D slab; flip angle, 30°; NEX, 0.7; matrix, 380×380 mm) shows a dilated hemiazygos vein (arrow) posterolateral to descending aorta and a persistent left superior vena cava (arrowhead) which drains into coronary sinus (not shown here).
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