Day 13 6/1/15 Flashcards Preview

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Flashcards in Day 13 6/1/15 Deck (27):


-dilation of the renal by pelvis by urine
-ureteropelvic junction obstruction is most common cause of pediatric hydronephrosis



-dilation of ureter by urine


Ureteropelvic Junction Obstruction

-obstruction between kidney and ureter
-most common cause of pediatric hydronephrosis
-obstruction is more common in boys (M>1)
-left side is involved in 67%
-s&s: abdominal mass, pain, UTI
-coexists with other congenital abnormalities ~50% of patients
-10% show ipsilateral reflux


Ureteral Duplication

-most common renal abnormality
-2 ureters ipsilaterally enter bladder
-s&s: failure to toilet train, continuous drip incontinence


Vesicoureteral Reflux

-urine traveling back up the ureter upon contraction of the detrusor of the bladder, usually resulting in hydroureter



-cystic dilation of terminal intravesical ureter
-can be obstructive if orifice is stenotic or ectopically located and can cause reflux


Urachal Remnant

-urachus connects the dome of the fetal bladder to the allantois in the umbilical ligament
-can cause pain and retraction of umbilicus during micturition
-can form cyst (closed), sinus (open at one end), or fistula (open at both ends)
-may leak out of umbilicus


Megalocystis (Megacystis)

-chronic abnormal distension of bladder by urine due to bladder outlet obstruction
-may cause prune belly in babies (eagle-barrett syndrome)


Posterior Urethral Valves

-abnormal congenital obstructing membrane loated in posterior male urethra
-results from abnormal insertion of mesonephric duct on the cloaca
-causes abnormal development of all upstream structures due to chronic increased intraluminal pressure
-most common cause of bladder outlet obstruction in boys only
-s&s: poor urine stream, UTI, incontinence in older boy


Bladder DIverticulum

-outpouching of bladder mucosa through a weakness in muscular wall



-orifice of the penile urethra at location along the ventral aspect of the penis
-results from abnormal fusion of urogenital folds from androgen insufficiency



-fibrous band causing penis to curve toward its location
-usually associated with hypospadias (orifice of penis in wrong spot)



-location of uretheral opening on the dorsal aspect of the penis (top)



-exposure of the bladder mucosa due to absence of the abdominal wall


Consequences of Fetal Urinary Tract Obstruction or Renal Agenesis

-inability excrete urin
dec. amniotic fluid (oligohydramnios)
-less room for fetal movement (Potters sign)
-loss of lung development
-amnion nodosum (nodules of squamous cells on amniotic membrane)


Renal Agenesis and Hypoplasia

-failure of metanephric diverticulum or its early degeneration
-unilateral more common
-L is more likely absent
-complete renal agenesis is lethal


Renal Dysplasia

-abnormal metanephric tissue of the kidney with cysts and heterotopic tissues such as cartilage due to pleuripotent potential of renal cells


Renal Ectopia

-failure of kidney to rise out of the pelvis or to rotate medially
-may result in ureteral obstruction
-kidneys may be discoid in shape


Horseshoe Kidney

-kidneys fuse together
-90% of time lower lobes fuse
-often ectopic and fail to rotate medially
-inc. incidence of urolithiasis


Cystic Kidney Diseases

-autosomal dominant (adult) polycystic kidney disease
-autosomal recessive (infantile) polycystic kidney disease
-multicystic dysplastic kidney disease


Autosomal Dominant Polycystic Kidney Disease

-mutations in PKD1 or PKD 2
-PKD 2 is slower
-25% of patients have no family hx
-near 100% penetrance
-presents in 4th decade with flank pain and hematuria
-HTN and chronic renal failure in 5th decade of life
-only 50% progress to end stage renal disease
-associated with: hepatic cysts, mitral valve prolapse, diverticulitis, cerebral aneurysms, pancreatic cysts


Autosomal Recessive Polycystic Kidney Disease

-due to PKHD1 which encodes fibrocystin (fibrosis of liver)
-manifests as HTN in first few years of life
-diminished urine concentrating ability and renal insufficiency
-growth retardation 25% of time
progresses to renal failure requiring dialysis or transplantation
-histology: cysts are dilated collecting tubules


Multicystic Dysplastic Kidney

-most common cause of an abdominal mass in the newborn period
-most common cystic malformation of the kidney in infancy
-often associated with ureteral or ureteropelvic atresia
-affected kidney is nonfunctional: asymptomatic and will involute over time
-results from abnormal induction of the metanephric blastema by ureteral bud


Congenital Mesoblastic Nephroma

-most common kidney tumor at birth to 6 months of age
-can be detected on US with ring sign
-bland spindle cells infiltrate
-complete resection is most important prognostic factor
-identical translocation is found in congenital fibrosarcoma
-trisomy 11 is also frequently found


Wilms Tumor (Nephroblastoma)

-most common malignant kidney tumor of childhood
-presents 4-6 years of age as a solitary abdominal mass
-treated by resection of chemotherapy (before or after)
-classic histology is triphasic (blastemal, epithelial, stromal)
-rhabdomyoblastic (skeletal muscle)
-anaplasia (unfaborable histology)


Beckwith-Weidemann Syndrome

-phenotype includes gigantism, macroglossia and abdominal wall defects
-due to imprinting abnormalities on chromosome 11p15.5
-5-7% develop Wilms tumor as well as other embryonal tumors


WAGR Syndrome

-Wilms tumor
-GU malformation
-mental Retardation
-deletion of 11p13 includes PAX6 and WT1
-30% of these pts develop Wilms tumor