Nephroptosis: The wandering kidney

A 40-year-old woman presented with long-term right loin pain. There was a notable right sided dragging sensation on postural change, particularly on standing from a supine position. The patient also experienced occasional symptoms of urinary tract infection. No hematuria or proteinuria was detected on urine microscopic analysis. No family history of urinary tract abnormalities was present. Clinical examination was largely unremarkable. The abdomen was soft with no tenderness on palpation. The kidneys were not ballotable. Ultrasound of the kidneys was unremarkable. Intravenous pyelography was performed due to clinical suspicion of nephroptosis. This test revealed descent of the right kidney by > 2 vertebral bodies (i.e., 9 cm in this patient) when the patient moved from a supine (Fig. 1A) to erect posture (Fig. 1B). No filling defect or hydronephrosis was noted. Abdominal computed tomography showed no abnormal position of the right kidney. Conservative treatment and clinical follow-up were provided for this patient, as the symptoms were not severe and no obstruction of the pelvicalyceal system was observed.

Figure 1. Intravenous pyelography (IVP) findings.

Compared with the supine position (A), descent of the right kidney by approximately 9 cm was demonstrated on erect IVP (B).

Nephroptosis, also known as floating or wandering kidney, was first described in the 13th century. Surgical management is considered when symptoms such as obstruction of the collecting system or of renal blood flow are encountered. Nephropexy, either performed via laparoscopic or open surgery, is used to affix the affected kidney to retroperitoneal tissues. Long-term outcome studies have reported an improvement in the quality of life and reduction in pain after this surgery.