An Adolscent Boy with Nutcracker-Syndrome and IgA Nephropathy

Case report

A 16-year-old Turkish boy was referred to our clinic with a 1-month history of persistent macroscopic hematuria accompanied by weakness and occasional nausea; notably, these symptoms were not associated with flank pain or dysuria. The macroscopic hematuria had initially appeared 3 days after an upper respiratory tract infection. His urine exhibited a brownish color that was darker in the morning and lighter in the evening. Physical examination revealed a healthy young male with normal blood pressure (110/70 mmHg) and a body mass index of 20.8 kg/m² (25^th–50^th percentile). The patient had a family history of renal stones of unknown type. Laboratory tests revealed a normal serum creatinine level (0.52 mg/dL), C3 level, C4 level, antistreptolysin O titer, complete blood count, and coagulation profile and a negative antinuclear antibody; moreover, urine culture yielded no growth. Urinalysis revealed 410 red blood cells (RBCs) per high-power field and no RBC casts. The urine protein/creatinine ratio was 0.28 mg/mg, and the 24-hour urine calcium excretion was 1 mg/kg/day. Hearing tests yielded normal results. Spiral computed tomography (CT), prompted by a family history of renal stones, did not reveal any stones. Renal Doppler ultrasonography (DUS) showed normal renal artery blood flow and no entrapment of the left renal vein (LRV) ([Fig. 1]). The peak systolic and diastolic velocity of the main renal arteries were 100 and 40 cm/s, respectively, and the left and right resistive indices were 0.68 and 0.72, respectively. LRV flow velocity at the aorto-mesenteric angle (AMA) was 34 cm/s. However, CT angiography revealed a reduced AMA of 27° (normal: 38–65°) and an aorto-mesenteric distance of 5.5 mm (normal: 11.5±5.3 mm in boys) ([Fig. 2a], b). Notably, a diagnosis of nutcracker syndrome (NCS) was made based on the CT angiography findings. Urinalysis performed on fully automated machines in our center does not evaluate erythrocyte morphologies, but the patient’s persistent macroscopic hematuria and brownish urine discoloration raised suspicion of glomerulonephritis. Consequently, a renal biopsy was performed. The total number of glomeruli in the biopsy was 26. Renal biopsy revealed mild diffuse mesangial proliferation, matrix expansion, and endocapillary proliferation in specific glomeruli. In addition, a few tubules contained RBC casts. IgA nephropathy (IgAN) was diagnosed based on the immunofluorescence microscopic findings, revealing C3 and IgM deposits with a predominance of IgA in the mesangium ([Fig. 3]).

Fig. 1 Normal sonographic presentation of aorta (A), superior mesenteric artery (SMA), and left renal vein (LRV).

Fig. 2 a Computed tomography angiography reveals a reduced aorto-mesenteric angle (AMA) (sagittal plane). b Left renal vein compression (black arrow-axial plane).

Fig. 3 Immunofluorescence showing moderate mesengial IgA deposits (x200).

The patient began treatment with enalapril due to nephritic-level proteinuria (10.3 mg/m²/h) and its renoprotective effects. The patient and his parents were prepared for the possible need for LRV transposition.

Publication History

Article published online:
06 May 2024