Urogenital ImagingNephroptosis
(also called
renal ptosis, or floating kidney), an abnormal caudal movement of the kidney when the patient changes from the supine to erect position. The excessive mobility may be attributed to the deficiency of supporting perirenal fasciae. It differs from
congenital ectopia in which the kidney has not ascended to its normal position. In ptosis, the
ureter is of normal length, becoming kinked when the patient is erect, whereas in
congenital ectopia the
ureter is short. The kinking of the
ureter near the ureteropelvic junction in the erect position has historically been cited as a cause of
obstruction, but this is currently believed by most authorities to reflect misdiagnosis of ureteropelvic junction
obstruction as nephroptosis (see
Dietls crisis. Nephroprexy was performed in the past to stabilize the kidney. Presently surgery is not recommended. In fact some consider up to a 10 cm descent of the kidney in the erect position as normal. Diagnosis can be made during
intravenous urography, by obtaining erect films.
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