Diagnostic Clues in Pediatric Nutcracker Syndrome: From Two Clinical Cases to Current Literature Analysis

Abstract

Nutcracker syndrome (NCS) is a rare pediatric disease caused by left kidney vein compression. Besides the “Triade’s symptoms”, including hematuria, proteinuria, and flank pain, a wide spectrum of clinical manifestations has been reported. As the significant hemodynamic changes secondary to the dilatation of the left renal vein, serious consequences such as renal vein thrombosis and severe anemia might occur in these children. NCS diagnosis includes a variety of invasive and non-invasive imaging tools, but cutoff values need to be further validated. A conservative treatment represents the most common therapeutic approach for these patients, but operative options are available in selected cases. To complicate matters, a standard diagnostic and treatment algorithm is currently lacking and scientific pediatric evidence in this field is still poor and limited. In this perspective, early recognition of NCS is crucial but challenging for pediatricians. Therefore, a better knowledge of the disease is recommended. Starting from two different clinical presentations of NCS, we aimed to provide a comprehensive overview of the disease in children.

Nutcracker syndrome and glomerulonephritis in pediatric patients: A causal or coincidental association?

“…Atypical presentations such as a splenic cyst, left gonadal varicocele, syncope, anemia, and so on were observed in our patients. While persistent severe hematuria is considered as a cause of anemia in the NCS [29], sustained hematuria was present only in one (case 7) out of 4 patients with anemia. Given that anemia is often associated with clinical signs of congestion [30], renal congestion induced by NCP can compromise microvascular blood ow, which may contribute to renal hypoxia, ineffective erythropoiesis, and resultant anemia [31].…”

“…Diagnosis of NCS can be con rmed by a variety of tools such as kidney Doppler US, contrast-enhanced CT, MRI, and venography. The rst imaging tool with suspected NCS is Doppler US [29]. Although venography is considered the gold standard for the diagnosis of NCS, it remains unclear whether the invasive procedure for measuring the pressure gradient is truly needed [23,32].…”

Nutcracker syndrome in childhood

“…Various imaging modalities such as Doppler ultrasonography (DUS), computed tomography (CT), magnetic resonance imaging (MRI), and retrograde venography are used for the diagnosis of NCS. 5,22,23 DUS, being non-invasive and radiation-free, is the first-line imaging modality in suspected cases of NCS. It has high sensitivity (69-90%) and specificity (89-100%) for diagnosing NCS.…”

“…It is not commonly performed in patients without severe symptoms. 3,23,24 TREATMENT Management of NCS in childhood is primarily based on clinical findings and the severity of the left renal vein hypertension. A conservative approach (e.g., "watch and wait" strategy) is strongly supported as the first-line treatment in patients with mild symptoms.…”