congenital anomalies

Question 1

renal agenesis results when

Answer 1

ureteric buds do not develop OR the primordia (stalks of buds) of ureters degenerate

Question 2

renal agenesis also called

Answer 2

renal hipoplasia

Question 3

why is there kidney development failure in renal agenesis/ hipoplasia

Answer 3

failure of buds to penetrate metanephrogenic blastema

= no nephrons are induced by the collecting tubules to develop from blastema

Question 4

causes of renal agenesis/ hipoplasia

Answer 4

probably has a multifactorial cause

clinical evidence suggests polycystic kidneys (many cysts) could be a cause

Question 5

types of renal agensis

Answer 5

unilateral renal agenesis (absence of 1 kidney)

bilateral renal agenesis (absence of both kidneys)

Question 6

unilateral renal agensis

Answer 6

1/1000 births, more common in males
non fatal
causes no symptoms
usually present kidney undergoes hypertrophy and compensates for missing kidney
should be suspected in children with a single umbilical artery

Question 7

bilateral agenesis

Answer 7

1/3000
fatal
associated with Potter syndrome (20% of cases caused by bilateral agenesis)
associated with oligohydramnios (little/ no urine excreted into amniotic cavity)

Question 8

potter syndrome characteristics

Answer 8

wide set eyes + palpebronasal folds (epicanthic folds)
ears are low set
nose is broad and flat
chin is receding
limb clubbing/ anomalies
respiratory anomalies

Question 9

common cause of death by bilateral renal agenesis

Answer 9

death shortly after birth due to pulmonary hypoplasia (small/ underdeveloped lungs) = respiratory insufficiency

Question 10

ectopic kidneys

Answer 10

one or both kidneys in abnormal position
non fatal
most located in pelvis

Question 11

types of ectopic kidneys

Answer 11

pelvic kidneys
crossed renal ectopia
unilateral fused kidney

Question 12

which congenital anomalies can result in kidneys fusing together

Answer 12

pelvic kidneys: form a discoid/ pancake kidney
crossed renal ectopia: 90% are fused
unilateral fused kidney: developing kidneys fuse after they leave pelvis
horseshoe kidney: usually fused at lower poles

Question 13

what percentage of crossed renal ectopia cases have fused kidneys

Answer 13

90%

Question 14

horseshoe kidney

Answer 14

very rare: 0.2%
non fatal
associated with turner syndrome (7% of cases have horseshoe kidney)
usually no symptoms

Question 15

what percentage of turners syndrome have horseshoe kidney

Answer 15

7%

Question 16

what anomaly is associated with turners syndrome

Answer 16

horseshoe kidney

Question 17

what anomaly is associated with potter syndrome

Answer 17

bilateral renal agenesis

Question 18

what percentage of potter syndrome have bilateral renal agenesis

Answer 18

20%

Question 19

malrotated kidney

Answer 19

hilum faces anteriorly: retains embryological position
hilum faces posteriorly: kidney rotated too much
hilum faces laterally: rotation in wrong direction
often associated with ectopic kidneys

Question 20

what other anomaly are malrotated kidneys associated with

Answer 20

ectopic kidneys

Question 21

duplications of urinary tract

Answer 21

non fatal
common
result from abnormal division of ureteric bud

Question 22

how are duplications of urinary tract created

Answer 22

incomplete division IN A DIVIDED KIDNEY of ureteric bud = bifid ureter

complete division IN A NON DIVIDED KIDNEY of ureteric bud = double kidney with bifid ureter or separate ureters

Question 23

ectopic ureter

Answer 23

non fatal
pee cannot be stored in bladder (pee will exit whenever)
differs from male and females

Question 24

differences of ectopic ureters for male and females

Answer 24

in males: ureter inserts into urethra, ductus deferens, prostatic utricle, OR seminal gland

in females: ureter inserts into bladder, urethra, vagina OR cavity of vagina

Question 25

cause of ectopic ureter

Answer 25

ureter not incorporated into the trigone between the openings of the ureter in the posterior part of bladder - instead carried caudally with mesonephric duct + incorporated into middle pelvic portion of vesicle part of urogenital sinus

Question 26

cystic kidney disease

Answer 26

autosomal recessive polycystic kidney disease OR multicystic dysplastic kidney disease

Question 27

autosomal recessive polycystic kidney disease

Answer 27

fatal w/o dialysis and kidney transplant 1/20000 kidneys contain many small cysts = renal insufficiency death occurs shortly after birth

Question 28

what disease is associated with pulmonary hypoplasia

Answer 28

``` autosomal recessive polycystic kidney disease (25%) potter syndrome (100%) ```

Question 29

what percentage of autosomal recessive polycystic kidney disease is associated with pulmonary hypoplasia

Answer 29

25%

Question 30

mutation of what gene causes most polycystic kidney and congenital hepatic fibrosis

Answer 30

PKHD1 gene

Question 31

mutation of PKHD1 gene causes

Answer 31

polycystic kidney and congenital hepatic fibrosis

Question 32

multicystic dysplasia kidney disease

Answer 32

mostly non fatal (75% survive) abnormal development of renal system unilateral in 75% of cases fewer cysts that in autosomal recessive polycystic kidney disease

Question 33

which disease has more cyst formation within kidneys a) autosomal recessive polycystic kidney disease OR b) multicystic dysplasia kidney disease

Answer 33

A) autosomal recessive polycystic kidney disease has more cyst formation which causes renal insufficiency

Question 34

cause of multicystic dysplasia kidney disease

Answer 34

dysmorphology: abnormal development of renal system

Question 35

old hypothesized cause of cyst formation in multicystic dysplasia kidney disease

Answer 35

old reason: failure of ureteric bud derivatives to join tubules derived from metanephrogenic blastema

Question 36

new hypothesized cause of cyst formation in multicystic dysplasia kidney disease

Answer 36

new reason: cystic structures are wide dilations of parts of continuous nephrons (especially the loops of henle)

Question 37

difference in cyst frequency and size for both cystic kidney diseases

Answer 37

ARPKD: most cysts, small in size MDKD: least cysts, vary in size (from mm to cm)

Question 38

probable embryological basis of defect: unilateral renal agenesis

Answer 38

absence of ureteric bud | = no reciprocal induction of metanephrogenic blastema by ureteric bud = no kidney on one side

Question 39

probable embryological basis of defect: divided kidney + bifid ureter

Answer 39

divided ureteric bud | = caused growth of 2 ureter stems

Question 40

probable embryological basis of defect: pelvic kidney

Answer 40

divided ureteric bud | = can grow around preliminary blood supply vessel (common iliac artery) and prevent ascension

Question 41

probable embryological basis of defect: malrotation of kidney

Answer 41

complete division of ureteric bud | = allows kidney to rotate the opposite way (laterally instead of medially)

Question 42

probable embryological basis of defect: double kidney (supernumerary kidney)

Answer 42

complete division of ureteric bud | = 2 ureteric buds that induce the formation of metanephrogenic blastema = 2 kidneys on one side

Question 43

probable embryological basis of defect: fused kidneys (crossed renal ectopia)

Answer 43

migration of one kidney to the other side | = both kidneys on one side are pushed together and fuse

Question 44

probable embryological basis of defect: discoid kidney (pelvic kidney)

Answer 44

fusion of kidneys