Fetal Genitourinary System Flashcards
*When and where should the kidneys be seen in the fetus?
- *by 20 wks, kidneys should be consistently seen adjacent to the fetal spine bilaterally
- renal cortex, medulla, and sinus can be well differentiated within the fetus
Where do the gonads develop?
-in the upper fetal abdomen and descend into the pelvis
When do the testicles move down into the scrotum?
-during the 7th month of gestation
When is the earliest the fetal bladder can be seen and when should it be seen by?
-can be seen as early as 13 wks and should always be seen by 15 wks
Are normal fetal ureter perceived with sonography?
No, so if there is *visualization then it would indicate some pathologic process
What is renal agenesis?
- failure of a kidney to form
- can be unilateral or bilateral
What are the two sonographic finding that help make sonographic diagnosis of renal agenesis?
- First, when kidney is absent in the abdomen, the adrenal gland can be noted in parallel, flattened position, a sonographic finding known as “lying down” adrenal sign
- Secondly, color doppler can be employed over the renal artery branches of the abdominal aorta- when there is absence of the kidney, there will be no identifiable renal artery branches
*Which type of renal agenesis is the most common?
-unilateral renal agenesis
What is the prognosis and amniotic fluid involved with unilateral renal agenesis?
-most often, an average amount of amniotic fluid and the prognosis is good
What should the sonographer do before making the conclusion of unilateral renal agenesis?
-*always analyze the fetal pelvis for a pelvic kidney, as this is the most common location of an ectopic kidney
What is the most common location for an ectopic kidney?
the pelvis
What are the sonographic findings of unilateral renal agenesis?
- absent kidney
- compensatory hypertrophy of the contralateral kidney
- visible urinary bladder
- normal amniotic fluid volume
- unilateral lying down adrenal sign
- undetectable renal artery branch with color Doppler (unilateral)
What is compensatory hypertrophy?
-when the existing kidney will enlarge taking on the workload of both kidneys
What is another name for bilateral renal agenesis?
-*Potter’s syndrome
What is bilateral renal agenesis?
- *a fatal condition
- absence of both of the fetal kidneys
Why is it extremely beneficial to utilize color Doppler to investigate the renal area in bilateral renal agenesis?
- b/c it can be difficult to detect sonographically, secondary to the lack of amniotic fluid surrounding the fetus
- it can be helpful to determine the location of the renal vessels leading into the kidney or lack of vessels and kidney
What are trustworthy findings consistent with bilateral renal agenesis?
non-visualization of the urinary bladder and kidneys; associated with severe oligohydramnios
What are the sonographic findings of bilateral renal agenesis?
- absent kidneys
- absent urinary bladder
- severe oligohydramnios
- bilateral lying down adrenal signs
- undetectable renal artery branches with color doppler (bilateral)
What is Potter’s sequence?
- deformities with bilateral renal agenesis that are caused by lack of amniotic fluid (causes uterine walls to place pressure on the fetus, not allowing for proper development and growth) :
- flat nose
- recessed chin
- abnormal low set ears
- wide set eyes (hypertelorism)
- abnormal or malpositioned limbs)
What is the prognosis for bilateral renal agenesis?
- in most cases, this condition is not compatible with life outside the womb-usually fatal within the first few days of life
- some newborns can survive IF they have chronic dialysis. Factors such as overall health, and medical support determine the success of this treatment with the goal to sustain the infant until it is strong enough to have a kidney transplant
What is renal hypoplasia?
- congenitally small kidney
- can be unilateral or bilateral
- hypoplastic kidney contains a reduced number of nephrons, but has a relatively normal architecture
- functionality is determined by the severity of the hypoplasia-which may eventually lead to renal failure
Where do the kidneys develop and when is the migration complete?
-initially develop close together in the pelvis and gradually migrate into the abdominal cavity by 9th wk of gestation
What is renal ectopia?
-when the kidney (most cases only one that remains in the pelvic cavity) fails to migrate to the abdominal cavity
What is crossed ectopia?
when both kidney are located on the same side of the body and may be fused together
What is the prognosis of renal ectopia?
- based on possible associated anomalies including:
- gynecologic, gastrointestinal, cardiovascular, skeletal
What are other possible locations for an ectopic kidney?
iliac region and thoracic cavity-but these are very uncommon
What is horseshoe kidney?
-occurs when there is fusion of the kidneys at the lower poles. The isthmus, typically consists of functional parenchymal renal tissue, (less commonly non-functioning fibrous tissue) which lies anterior to the aorta
What is hydronephrosis/pelvocaliectasis?
- a general term used to describe the dilation of the renal collecting system due to an obstruction of normal urine outflow
- *most common fetal abnormality noted during an obstetric sonogram
- may occur as unilateral or bilateral process