LETTER TO THE EDITOR

An unusual case of posterior nutcracker syndrome

Antonio Granata • Anna Clementi •

Fulvio Floccari • Luca Di Lullo • Antonello Basile

Received: 4 December 2013 / Accepted: 8 January 2014

� Japanese Society of Nephrology 2014

Keywords Posterior nutcracker syndrome � Proteinuria

To the Editor

Nutcracker syndrome commonly refers to left renal vein

compression between aorta and superior mesenteric artery,

resulting in increased venous pressure, kidney congestion

and proteinuria. Posterior nutcracker syndrome is a rare

variant, linked to retro-aortic position of the last tract of the

left renal vein which remains compressed between aorta

and spinal column.

We report an unusual case of posterior nutcracker syn-

drome in a 22-year-old man with congenital solitary left

kidney who was admitted to our department because of

proteinuria of 700 mg/24 h and microhematuria.

Upon admission, blood pressure was 120/70 mmHg.

Mild pitting edema was present in his lower limbs. Labo-

ratory workup showed a normal renal function with a cre-

atinine of 1.1 mg/dl. Urinalysis revealed the presence of rare

hyaline and granular casts and isomorphic erythrocytes. No

previous episodes of left flank pain were reported.

Ultrasonography was performed showing the absence of

the right kidney, compensatory hypertrophy of the left

organ and dilation of the left renal vein. After a few cen-

timeters from the hilum, the left renal vein presented an

abnormal course, addressed in cranio-caudal direction until

merging into inferior vena cava just below common iliac

arteries (Fig. 1a). Proximal venous dilation was also noted

(antero-posterior diameter 13.8 mm in the hilar area,

1.6 mm in the narrow portion, ratio 8.6). Doppler peak

velocities were 25 cm/s in the hilar area and 111 cm/s in

the narrow portion (ratio 4.4).

An abdomen contrast-enhanced computed tomography

was then carried out, confirming the anomalous course of the

vein. Compression of the vein was evident between left

common iliac artery and a lumbar vertebral body (Fig. 1b, c).

In order to confirm the diagnosis, a right femoral vein

approach was performed, and the left renal vein was

visualized in a contrast-enhanced phlebography (Fig. 1d).

It was dilated, with a pressure gradient of 8 mmHg versus

inferior vena cava. Endovascular stenting was then carried

out and a self-expandable 14–40 mm stent made of nitinole

was inserted where the vein narrowed.

Post-procedural phlebography documented normal flow

through the vessel, with no significant pressure gradient

between the left renal vein and inferior vena cava. 24-h

proteinuria promptly fell below 300 mg/day.

Posterior nutcracker syndrome is characterized by the

abnormal retro-aortic position of the left renal vein and its

subsequent compression between aorta and spinal column

[1–3]. Similar to the ‘‘anterior nutcracker phenomenon’’,

this syndrome usually leads to renal venous hypertension

and it should be considered among the causes of recurrent

left flank pain, proteinuria and hematuria.

A. Granata (&) � A. Clementi

Nephrology and Dialysis Unit,

San Giovanni Di Dio Hospital, Agrigento, Italy

e-mail: antonio.granata4@tin.it

A. Granata

Gruppo di Studio di Ecografia Nefro-Urologica/SIUMB, Rome,

Italy

F. Floccari

Nephrology and Dialysis Unit, San Paolo Hospital,

Civitavecchia, Italy

L. Di Lullo

Nephrology and Dialysis Unit, San Giovanni Ev. Hospital,

Tivoli, Italy

A. Basile

Radiology Unit, ARNAS Garibaldi Hospital, Catania, Italy

123

Clin Exp Nephrol

DOI 10.1007/s10157-014-0932-y

Diagnostic imaging such us Doppler ultrasound, com-

puted tomography, or magnetic resonance angiography

might be suggestive, but only phlebography can provide a

definitive diagnosis.

Some authors reported open surgical repair for this

condition, but endovascular stenting is obviously less

invasive [4]. Although long-term effectiveness of this

treatment is yet to be established, promising results of

endovascular stenting for anterior nutcracker syndrome

have been reported by some investigators [5].

To our knowledge, this is the first reported case of

posterior nutcracker phenomenon in a solitary congenital

kidney, with a renal vein compression between spine and

iliac arteries.

Nephrologists should always remember that posterior

nutcracker syndrome may have unusual clinical manifesta-

tions and that angiographic techniques are needed both for its

diagnosis and for its treatment.

Conflict of interest The authors have declared that no conflict of

interest exists.

References

1. Basile A, Tsetis D, Calcara G, et al. Nutcracker syndrome due to

left renal vein compression by an aberrant right renal artery. Am J

Kidney Dis. 2007;50:326–9.

2. Kurklinsky AK, Rooke TW. Nutcracker phenomenon and nut-

cracker syndrome. Mayo Clin Proc. 2010;85(6):552–9.

3. Lee S, Kim W, Kang KP, Kwak HS, Park SK. Microscopic

hematuria and the posterior nutcracker phenomenon. Kidney Int.

2007;72(8):1037.

4. Marone EM, Psacharopulo D, Kahlberg A, Coppi G, Chiesa R.

Surgical treatment of posterior nutcracker syndrome. J Vasc Surg.

2011;54(3):844–7.

5. Wang X, Zhang Y, Li C, Zhang H. Results of endovascular

treatment for patients with nutcracker syndrome. J Vasc Surg.

2012;56(1):142–8.

Fig. 1 a Ultrasonography showing the presence of the nutcracker

phenomenon between common iliac arteries and lumbar spine,

demonstrated by accelerated blood flow at the compressed point of

the left renal vein. b Enhanced computed tomography showing

anomalous course of the left renal vein (white arrow). c Enhanced

computed tomography showing the compression of the left renal vein,

due to a posterior nutcracker phenomenon, between right common

iliac artery and vertebral column (white arrow). d Phlebography,

performed by a right common femoral vein approach, showing an

aberrant renal vein with late contrast drainage to inferior cava vein

(white arrow). A clear stenosis is not demonstrated in anterior–

posterior projection

Clin Exp Nephrol

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