Day 13 6/1/15 Flashcards
Hydronephrosis
- dilation of the renal by pelvis by urine
- ureteropelvic junction obstruction is most common cause of pediatric hydronephrosis
Hydroureter
-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
Ureterocele
- 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
Hypospadias
- orifice of the penile urethra at location along the ventral aspect of the penis
- results from abnormal fusion of urogenital folds from androgen insufficiency
Chordee
- fibrous band causing penis to curve toward its location
- usually associated with hypospadias (orifice of penis in wrong spot)
Epispadias
-location of uretheral opening on the dorsal aspect of the penis (top)
Exstrophy
-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
- adult
- 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
- ETV6-NTRK3
- 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
- Aniridia
- GU malformation
- mental Retardation
- deletion of 11p13 includes PAX6 and WT1
- 30% of these pts develop Wilms tumor
