Congenital malformations - Edocr

CHAPTER 42 POSTERIOR URETHRAL VALVES 279
is almost 12 times higher in these patients compared
to the general population. Posterior urethral
valves is an isolated abnormality in a large
proportion of cases but has also been reported
as part of a well-defined syndrome or multiple
congenital anomaly disorder which are listed in
Table 42-1.
EVALUATION
With widespread use of prenatal ultrasound,
most infants with posterior urethral valves are
diagnosed prenatally but only half of all cases
can be diagnosed before 24 weeks of gestation. 3
Initial evaluation of an infant either with a prenatal
diagnosis of posterior urethral valves or
suspected of having posterior urethral valves
should include renal ultrasound, voiding cystourethrogram
(VCUG), urinalysis, urine culture,
serum electrolyte, blood urea nitrogen,
and creatinine. Renal ultrasound should include
images of ureters and bladder; and could provide
important information about renal dysplasia,
hydronephrosis, bladder wall thickening, and
posterior urethral dilatation. Fluoroscopic VCUG
is the gold standard for the diagnosis of posterior
urethral valves. Cystourethroscopy and isotope
TABLE 42-1
Syndromes Associated with Posterior Urethral Valves
Syndrome Other Common Clinical Features Etiology
Caudal regression Incomplete development of sacrum, Unknown, more common
syndrome flattening of buttocks, disruption in infants of diabetic
of distal spinal cord, poor growth
mothers
and skeletal deformities of lower
extremities
Cloacal exstrophy Persistence of cloaca, omphalocele, Unknown
sequence
hydromyelia, cryptorchidism,
pelvic kidneys, multicystic kidneys
Kaufman-McKusick Postaxial polydactyly, cardiac Autosomal recessive
syndrome
anomalies, hypospadias,
hydrometrocolpos, vaginal septum
Limb-body wall Thoraco-and/or abdominoschisis, Unknown
complex
limb defects, encephalocele,
facial clefts
Russell-Silver IUGR, skeletal asymmetry, Unknown
syndrome
small/triangular facies, micrognathia,
café au lait spots, syndactyly,
heart defects
Townes-Brocks Ear anomalies, thumb anomalies, Autosomal dominant
syndrome
anal malformations, microcephaly,
cardiac defects, duodenal atresia
syndactyly
Urorectal septum Ambiguous genitalia, imperforate anus, Unknown
malformation sequence rectal fistulas, müllerian duct defects
VACTERL association Vertebral, anal, cardiac, tracheal, Unknown, more common
esophageal, renal, and limb anomalies, in infants of diabetic
single umbilical artery, spinal dysraphia, mothers
genital abnormalities
IUGR, intrauterine growth retardation.