27. Congenital anomalies of the urinary tract and kidneys. Urinary tract infections. Urolithiasis. Flashcards
what causes congenital anomalies to the urinary tract and kidneys ?
exposure to ACE and ARB during pregnancy
True unilateral renal agenesis - aused by a failure of the ureteral bud to communicate with metanephric blastema in the first few weeks of gestation
mcdk - due to failure of union of the ureteric bud with the renal mesenchyme resulting in a non functioning kidney that is replaced by large, non communicating cysts of varying sizes with no renal cortex and atretic ureter. By definition, therefore, it can only be unilateral in a surviving infant
Twice as common in males
what re the clinical manifestations of congenital anomalies to the urinary tract and kidneys ?
asymptomatic mostly
hydronephrosis
recurrent UTI in less than 24 months
what are the antenatal congenital anomalies ?
Renal tract dilatation which may be of the renal pelvis and/or calyces/ hydronephrosis/ and / or ureter
= detection does not necesserily indicate the presence of obstruction in the affected kidney
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bladder diverticulosis ,thick walled , poor emptying
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Absent kidney - renal agenesis
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cystic kidney
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duplex kidneys
In both cases the kidney is usually larger than normal
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renal hypoplasia - reduced ne=umber of nephrons
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renal dysplasia abnormal development of kidney that results in non functional kidney with abnormal features - cysts, increased amount of connective tissue)
=obstructive cystic dysplasia
=medullary sponge kidney
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anomalies of kidney migration
1) horseshoe kidney - fusion of the left and right inferior poles
2) renal dystopia and renal ectopia - displacement of kidney within the retroperitoneum
3) crossed dystopia - displacement of the kidneyy - located on the same side of the spine
4) malrotationn - torsion of the kidney
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Pelvi-ureteric junction obstruction
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Megaureter describes an abnormally wide ureter
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POSTERIOR URETHRAL VALVES
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if all of these are unilateral usually asymptomatic
if bilateral - renal insufficiency and potter sequence
what are the different classification for duplex kidneys ?
complete duplication - kidney has 2 separate pelvicalyceal systems + 2 ureters that enter the bladder at different points
leads to complications - no kidney function in one moiety
the end of the ureter can prolapse into the bladder - obstruction by ureterocele
- prenatal hydronephrosis
postnatal UTI
vesicoureteral reflex - because the valves have not been made properly
ureteral strictures
hydronephrosis
UTI
ureter may bypass the external sphincter and insert directly in the vagina, resulting in incontinence
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incomplete duplication -the kidney has two collecting systems, the ureters joining as oneresulting in a single osmium in the bladder
or blind ureter
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in both cases can occur :
ectopic ureter - ureter sis located caudal to the normal insertion site of the bladder - prenatal hydronephrosis
postnatal ITI
uteropelvic junction obstruction
may present as kidney of different sizes
what causes horseshoe kidney ?
- usually in trisomy - 13 , 12 , turner syndrome
what is the symptom of horseshoe kidney ?
usually asymptomatic
or
UTI,
haematuria,
abdominal pain are common presenting features
ureteropelvic junction obstruction due to abnormal path of the ureter - which can lead to renal calculi symptoms
UTI secondary to VUR
renal cortical scarring from VUR or obstruction
Increased risk of renal cancer -Wilms tumor
how can we diagnose urterocele ?
MICTURATING CYSTOURETHROGRAM
equires cathetirization of the bladder and radiation dose is relatively
what are the characteristics of ureteropelvic obstruction
40 percent bilateral
More commn in boys
what are the clinical manifestation ureteropelvic obstruction ?
newborns and infants
Palpable upper abdominal mass
Failure to thrive
Recurrent pyelonephritis
Children and adults
Flank pain or upper abdominal pain that may be triggered or worsened during states of increased diuresis (e.g., after caffeine or alcohol consumption).
UTI, Recurrent pyelonephritis
a palpeble flank mass, or rupture following minor trauma
Nausea/vomiting
Hematuria
diagnosis of uretropelvic obstruction
congenital ureteropelvic junction obstruction are diagnosed hydronephrosis on prenatal ultrasound.
PUJO is more likely where the antenatal hydronephrosis is > 20 mm
dynamic renography
MAG3 renal radionucleotide scan - to determine split renal function
or DTPA
IV pyelogram : excludes vesicoureteral reflux and assesses ureteral patency
used in in adults and older children sometimes
what is the treatment of uretoropelvic obstruction ?
Surgery: symptomatic patients or those with > 40% loss of renal function
Anderson-Hynes pyeloplasty: open or laparoscopic resection of the obstructed segment and anastomosis of the ureter to the remaining renal pelvis
what are the characteristics of megaurter ?
defined as ureteral dilation > 7 mm
more common in boys;
More often involves the left ureter;
25% of cases are bilateral;
what is the classification of megaureter ?
Primary megaureter congenital :
1) Primary obstructed megaureter
Congenital developmental defect of the muscular layer of the terminal ureter
Distal aperistaltic segment of ureter causing functional obstruction
Increased intraureteral pressure in dilation
2) Primary refluxing megaureter: dilation of the ureter secondary to primary vesicoureteral reflux (VUR)
===== Secondary obstructed megaureter Bladder outlet obstruction High intracystic pressure Functional obstruction of the vesicoureteral junction (VUJ) Urine can not pass into the bladder Ureteral dilation Secondary refluxing megaureter : bladder outlet obstruction with ureteral dilation caused by secondary vesicoureteral reflux
what is the clinical manifestation of megaureter
present in infancy, urinary tract infection
hydronephrosis
abdominal pain
uremia - anorexia, nausea, vomiting, pruritus, pericarditis, pleuritis, peripheral neuropathy, and CNS abnormalities (confusion, lethargy, seizures, somnolence, coma), and an increased risk of infection and bleeding
Renal calculi can form within the dilated system causing pain and haematuria
what is the diagnosis of megaureter?
US >7mm
Voiding cystourethrography (VCUG): to identify retrograde reflux of urine into the ureters
Radionuclide renal scanning : to identify obstruction and evaluate renal function
what are the characteristic of posterior urethras valves ?
occurring exclusively in male infants
what is the clinical manifestation of posterior uretheral valves ?
obstruct the membranous and prostatic urethra
with severe obstruction “Potter sequence”
Abdominal distension causing bladder distension
may result in VUR, - hydronephrosis,
or calyceal rrupture causing a urinoma and renal dysplasia
Late manifestations: Difficulty voiding, poor urinary stream UTIs → urosepsis Diurnal enuresis Failure to thrive
effect on renal function is very variable and related to the degree of renal dysplasia which occurs secondary to the obstruction or may be part of the abnormality itself
what is the diagnosis of PUV?
majority of cases are diagnosed as a result of antenatal US scaning which may show the presence of oligohydramnions with bilateral hydronephrosis and hydroureters, bladder wall thikening and posterior urethral dilatation
Diagnosis by
Voiding cystourethrogram (diagnostic study of choice) demonstrates
Dilation/elongation of the posterior urethra during voiding
Signs of vesicoureteral reflux (if present)
what is the treatment of PUV ?
temporary insertion of urinary catheter and correction of electrolyte imbalance
First-line: primary valve ablation
Performed during cystoscopy
Second-line: vesicostomy
A surgical procedure in which a connection is formed between the bladder and the outside of the lower abdominal wall to allow for the drainage of urine
Also indicated in patients with functional bladder outlet obstruction (e.g., neurogenic bladder)
Renal transplantation may become necessary during the course of disease.
Fetal vesicoamniotic shunting is associated with procedure-related risks without evidence of long-term benefits for renal function
what is the complication of PUV ?
Long term complications of posterior urethral valves is chronic renal failure.
what causes vesicourteral reflux ?
primary
Short intramural ureter → vesicoureteric junction (VUJ) fails to close completely during bladder contraction
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secondary
1) Bladder outlet obstruction
high pressure within the bladder → reflux of urine through the VUJ
Anatomic: posterior urethral valves ; urethral meatal stenosis
Functional: bladder and bowel dysfunction ; neurogenic bladder
Cystitis
2) Congenital anomalies of the ureter Ureteral duplication Ectopic ureter Ureterocele Iatrogenic
what are the clinical manifestation of vesicoureteralreflux ?
Neonates: irritability, fever, and listlessness
Older children: urinary urgency, frequency, incontinence, and dysuria associated with fever
hypertension
recurrent UTI
pyelonephritic infection can result in renal injury or scarring - extensive renal scarring impairs renal function and can result in renin- mediated hypertension, renal insufficiency or end- stage renal disease
Reflux nephropathy once accounted for as much as 15-20% of end- stage renal disease in children and young adults - HYPERTENSION , kidney failure , uraemia
Flank or abdominal pain before or during voiding
what is the diagnosis of vesicourteral reflux ?
Urinalysis and urine culture: indicated in all children with hydronephrosis to rule out infection
Renal function tests: serum creatinine, urea, and electrolytes - Uremia may be present in bilateral VUR because of renal parenchymal scarring
US - hydronephrosis and dilated ureter
contrast voiding cysturethehogram - Retrograde reflux of the contrast into the ureters during micturition is diagnostic of VUR.
gold standard investigation to detect and grade VUR and PUV/ posteroir urethral valve
Reflux severity is graded
DMSA renal scan - assessment of cortical tissue , renal function and scarring
MGA3 scan ( Isotope injected with furosemide) - detects VUR especially caused by obstruction (ndicated by the isotope not passing beyond a certain point) , measures renal function- llows measurement of glomerular filtration rate
what is the grading system in vesicoureteral reflux ?
grade 1 - no reflux
grade 2 - reflux up to renal pelvis , no ureteral dilation
grade 3 - reflux to renal pelvis
mild dilation of ureter
blunting of calyces
grade 4 - reflux to renal pelvis
gross dilation of ureter
moderate ureteral tortuosity
grade 5 - gross dilation of the ureter , pelvis , calyces
significant ureteral tortuisity
loss of papillary impressions
