Blue toe syndrome as a clue to the underlying cause of acute renal failure

[2]. Renal Doppler ultrasound, CT angiography, magnetic resonance angiography or venography can be used for the documentation of the degree of left renal vein compression [5]. NCS presented with FMF was first reported in 2009 by Ozcan et al., which was similar to our case [6]. Here, we presume that actually, from the beginning, our patient’s proteinuria was due to NCS. For mild haematuria or proteinuria, conservative treatment is proposed, whereas for recurrent severe haematuria or flank pain, endovascular stent surgical treatment is proposed for NCS [2]. Here, we proposed the conservative treatment. Mild proteinuria is a benign condition, but it can be persistent, and therefore, conservative treatment should be continued for several years. Although amyloidosis should be considered first in clarifying the aetiology of proteinuria in FMF, NCS, another rare entity, should be kept in mind and should also be excluded by non-invasive techniques when possible or by invasive techniques if necessary in FMF patients.