Nefrotoisia

Nefrotoisia, also known as nephroptosis or floating kidney, is a condition in which one or both kidneys descend abnormally when a person moves from lying down to standing. The descent typically exceeds approximately 5 cm or more than two vertebral bodies and is related to loss or thinning of supportive perinephric tissue and laxity of the renal pedicle and surrounding fascia (Gerota's fascia). It may be acquired (e.g., after significant weight loss, pregnancy) or present congenitally.

Most individuals with nephroptosis are asymptomatic. When symptoms occur, they are usually related to positional change and include flank or abdominal pain that worsens on standing and improves when lying down, sometimes accompanied by nausea, headaches, or intermittent urinary symptoms. In some patients, ureteral kinking can lead to hydronephrosis or obstruction, and venous congestion may contribute to varicocele in men.

Diagnosis relies on demonstration of renal mobility on imaging, typically with upright or provocative studies. Upright intravenous urography, CT urography, MR urography, or renal ultrasound performed in standing or seated positions can show descent of the kidney and any ureteral obstruction.

Treatment ranges from watchful waiting in asymptomatic cases to surgical intervention for persistent symptoms or complications. Nephropexy, the surgical fixation of the kidney, can be performed via open, laparoscopic, or robotic approaches, and has a favorable success rate in selected patients. The prognosis depends on symptom burden and the development of complications.