engleski

Radionuclide functional investigation of floating kidneys

Floating kidney (lat. ren mobilis) is condition in which kidney move (nephroptosis) from their lumbar position to the pelvis. Mobil ptosis of the kidney is a relatively frequent phenomenon, existing in about 20% females and 2% of males, with a predominance of the right kidney in both sexes, find not necessarily in underweight individuals, but as well as in normal and obese patients. With grow of interest in renovascular hypertension much more attention was provided to mobile kidney. Significant caudal shift of the kidney (more than one third of a kidney length) stretches renal artery and disturbs the minute renal flow. Secondary to the intermittent stretching, fibro muscular dysplasia of renal artery and consequent hypertension may develop. In the first phase functional intermittent stenosis is only in upright position, which diminishes or disappears in horizontal position when the kidney returns to lumbar place. In the second phase organic definitive stenosis develop due to fibro muscular dysplasia and irreversible changes. Other associated complications of mobile kidneys, such as intensive abdominal pains in an upright position, hematuria, recurrent pyelonephritis and calculosis, are common in this group of patients. It is also possible that the excessive mobility of the kidney led to the stenosis of the renal artery and consequent fixed functional lesion of the kidney. Nephropexy, surgery procedure of mounting floating kidney to lumbar position, can prevent development of hypertension due to caudal shift of kidneys. Radionuclide investigation of floating kidney could discover early functional disturbances of mobile kidney, identify still reversible functional changes and detailed follow-up of this group of patients. Radionuclide functional investigations of floating kidneys pro¬ vide important information regarding disturbances in ERPF and RPF of mobile kidney in orthostatic position and recognize is this condition reversible in horizontal location. Functional elaboration of movable kidney included: a) Determination of ERPF and RPF during dynamic renal Tc-99m-MAG3 scintigraphy in horizontal and sitting positions, b) Analysis of renographic curve in horizontal and sitting position, c) Measuring kidney caudal shift by static renal scintigraphy with Tc-99m-DMSA in horizontal and standing po¬ sition. Caudal shift of the kidney greater than 5 cm consider as pathologic movement. Reversible changes of ERPF consider: a) The change in ERPF of the kidney between horizontal and orthostatic position greater than 120/mL/min, and b) The change in RPF of mobile kidney greater than 43/mL/min in horizontal position.During long-term follow-up of patients with floating kidney we performed two large studies. In the first study, which included 622 patients, the existence of the correlation be¬ tween the caudal shift of the floating kidney and the degree of changes in effective renal plasma flow (ERPF) and renal plasmatic flow (RPF) in an upright position was investigated. There is a correlation between the extent of caudal shift of mobile kidney in an upright position and the fall in ERPF and RPF. The group of pa¬ tients with kidney mobility greater than 5% of body height should be followed-up more frequently because of possible development of associated complications.In the second study ERPF and RPF, in lying and sitting position, were examined before and after nehropexy in 86 patients. The results of those examinations confirmed a significant postoperative rise in functional capacity of the mobile kidney in orthostatic position after nephropexy. Renal mobility disappeared as well as the pain, and urinary tract infection and orthostatic hypertension have become less frequent

floating kidney; radionuclide functional investigation

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