Week 4: Congenital Renal Abnormalities Flashcards Preview

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Flashcards in Week 4: Congenital Renal Abnormalities Deck (12):


-Oligohydramnios: small amount of amniotic fluid (normally 90% is produced by fetal urine)
-seen in bilateral renal a genesis, renal hypoplasia
-mechanical urinary tract obstruction
-If have it before 30 weeks: strong assoc. w/ pulmonary insufficiency
-if appears after 30 weeks: little correlation with pulmonary insufficiency


Bilateral agenesis: Potters Syndrome

-severe oligohydramnios
-2x as common in males
-fetal or neonatal death due to pulmonary hypoplasia
-No effective treatment
-floppy or malformed ears
-epicanthal folds prominent
-beak like nose with flattened tip
-small chin
-abnormal positioning of arms and feet
-1/6000 live births


Unilateral renal agenesis

-1/400 live births
-more common in males
-etiology: due to absent ureteric bud or misplaced ureteric bud
-compensatory hypertrophy of contralateral kidney
-normal renal function and life expectancy
-abnormality of development of normal pronephric-mesonephric-metanephric system
-possible association with glial cell line derived neurotrophic factor


renal hypoplasia

-reduction in nephron number and size
-normal renal tissue
-Oligomeganephronia: few large nephrons
-remaining nephrons with very large long tubules
-hypoplasia and dysplasia are clinical significant, need to monitor renal insufficiency and growth


Renal dysplasia

-misplaced ureteric bud results in abnormal nephrogenesis
-abnormal differentiation of metanephric tissue resulting in nonfunctional nephrons
-persistance of embryonic elements
-coexistence of dysplasia and hypoplasia
-assoc. with cysts


Multicystic dysplastic kidney

-detected by ultrasound or as newborn abdominal mass
-extreme form of dysplasia: non functioning cystic mass
-usually unilateral
-end up with involution of MCDK and hypertrophy of contralateral kidney



distension and dilation of renal pelvis and calyces
1. unilateral
-may be secondary to uteropelvic junction obstruction
-follow with ultrasound
2. bilateral
-males: consider posterior urethral valves
-females: consider ectopic uteroceles
3. Pre-natal diagnosis
-not evident until 16-18th week, usually caught in 23rd week
-can be detected on prenatal ultrasound


Signs of renal obstructive disorders

-abdominal mass or distension
-abnormal urinary stream
-UTI due to stasis
-palpable flank or suprapubic mass


Ureteropelvic Junction Obstruction

-Leads to narrow ureter and dilated renal pelvis
-unilateral or bilateral
-2:1 male to female
-etiology: ureteral muscle abnormality, aberrant blood vessels crossing the junction, abnormal angle of insertion of the ureter into renal pelvis


Ureterovesico Junction Obstruction

-unilateral or bilateral
-abnormal insertion of ureter into bladder wall
-Uteroceles: cyst like enlargement of lower end of ureter. protrudes into bladder. Distal end of ureter is tiny and causes obstruction and ballooning
-vesicoureteral reflux: retrograde flow or urine into ureter and/or kidney. Defected flap valve. evaluated by voiding cystourethrogram. Grading system-grades I and II resolve on own (reflux in ureter and pelvis with no distension)


Posterior urethral valves

-mucosal folds at distal prostatic urethra obstructs bladder outflow
-only in males
-presents in first year of life
-absent or dribbling urinary stream
-general-->renal failure


Anomalies of form, location, rotation

1. horseshoe: fused at lower pole, asymptomatic
2. migration abnormality: 6-9th week kidneys normally ascend. If disrupted, may be lower in pelvic region. Asymptomatic
3. Ectopic kidneys
-pelvic kidneys: 1 or both kidneys have abnormal ascent
-crossed fused renal ectopia: fusion of two kidneys during ascent, and both kidneys on one side. asymptomatic
4. Duplicated collecting systems
-abnormal branching of ureteric bud
-early branching results in duplicated kidney, ureter, and vesicoureteral junction
-late branching: single kidney with 2 ureters
-few clinical consequences