Renal pelvis dilation

Introduction The normal fetal kidney collection system can be slightly separated, with a separation diameter of up to 6 mm, and a pelvic expansion of 10 mm after gestational age greater than 30 weeks. Renal dilatation refers to a spherical or elliptical anechoic zone within the renal pelvis, with a diameter 5 mm 10 mm.

Cause

One is that a large amount of drinking water for pregnant women can lead to fetal renal pelvis expansion, followed by a slight expansion of the renal pelvis caused by compression of the ureter when the fetal bladder is overfilled. Studies have shown that 70% of the fetuses are repeatedly observed within 2 hours, and the fetal renal sputum measurement can be small or small, resulting in "normal" and "abnormal" changes.

an examination

Related inspection

Determination of urine pressure in the renal pelvis

Despite the controversy over the diagnostic criteria, there are still some principles that are consistent. These principles are:

(1) renal pelvis expansion <4mm, most fetuses are normal fetuses.

(2) pyelectasis is 5 ~ 10mm, or there is bladder dilatation, ureteral dilatation, renal pelvic dilatation or pyelectasis (II degree pyelectasis), which can only show renal pelvis, should be followed up and observed during the subsequent pregnancy.

(3) If the renal pelvis expands within 10 mm, the ratio of anterior and posterior diameter of the renal pelvis/kidney is less than 0.5, and the fetus has no other abnormal findings, the possibility of clinical phase disease after delivery is low.

(4) The pyelectasis is >10 mm, and the possibility of renal pathological changes is significantly increased. Renal function tests and excretory bladder urography should be performed after delivery for obstruction and vesicoureteral reflux.

(5) Postpartum follow-up principle: It is best to carry out 5-7 days postpartum because the newborn is no longer affected by maternal progesterone hormones and causes smooth muscle relaxation. The mild pyelectasis has disappeared at this time, but at birth Within the first 48 hours, due to mild dehydration in the newborn, a false negative result can occur if the kidney is examined immediately after birth.

Differential diagnosis

Can be identified with hydronephrosis.

Hydronephrosis refers to the accumulation of urine in the kidneys.

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