A 24-year-old woman comes to the office for a routine antenatal ultrasound. She is 19 weeks pregnant by her last menstrual period. This is the patient's third pregnancy, and there have been no complications. Her family history is unremarkable, and both of her children are healthy. The ultrasound reveals a male fetus with bilaterally enlarged fetal kidneys with diffuse small cysts. The amniotic fluid volume is very low. No other anomalies are seen. Which of the following will most likely be present in the newborn after delivery?

Question

A 24-year-old woman comes to the office for a routine antenatal ultrasound.  She is 19 weeks pregnant by her last menstrual period.  This is the patient's third pregnancy, and there have been no complications.  Her family history is unremarkable, and both of her children are healthy.  The ultrasound reveals a male fetus with bilaterally enlarged fetal kidneys with diffuse small cysts.  The amniotic fluid volume is very low.  No other anomalies are seen.  Which of the following will most likely be present in the newborn after delivery?

Quizplus · Accepted Answer

11ec160b_3751_c685_9249_69edd025e30a_MD0001_00 Bilaterally enlarged, cystic fetal kidneys and oligohydramnios are findings consistent with autosomal recessive polycystic kidney disease (ARPKD). ARPKD is caused by a mutation in PKHD1, the gene for fibrocystin. Fibrocystin is found in the epithelial cells of both the renal tubule and the bile ducts; deficiency leads to the characteristic polycystic dilation of both structures. Mutations can be inherited in an autosomal recessive pattern or can be spontaneous mutations. Age at presentation is determined by the severity of ARPKD. In its most severe form, ARPKD can be detected on prenatal ultrasound. Oligohydramnios is usually present because amniotic fluid is composed of fetal urine and renal filtration is severely impaired in ARPKD. The reduced amniotic fluid volume leads to characteristic findings (Potter sequence: flattened facies, limb deformities, pulmonary hypoplasia) due to the resultant compression of the fetus. Less severe phenotypes more often present with hepatic complications (eg, hepatomegaly, portal hypertension) and hypertension during childhood or early adulthood. Patients with ARPKD - especially when it presents in infancy - often need dialysis or renal transplant. (Choice A) Bladder distension is caused by urethral obstruction as found in posterior urethral valves. Cysts are not seen in children with posterior urethral valves. (Choice B) Cerebral aneurysms are a common complication of autosomal dominant polycystic kidney disease, occurring in almost 25% of patients; cerebral aneurysms are not associated with ARPKD. (Choice C) Hypertension is a common finding in ARPKD. However, hypertension usually is not present at birth but instead develops over the first few months in children with ARPKD who survive the neonatal period. (Choice E) Vertebral anomalies in association with renal anomalies are suggestive of VACTERL association (vertebral, anal atresia, cardiac defects, tracheoesophageal fistula, renal defects, and limb defects). Common renal anomalies in VACTERL include atresia, dysplasia, and/or duplications but do not include ARPKD. Educational objective: In its most severe phenotype, autosomal recessive polycystic kidney disease can be detected on prenatal sonogram along with oligohydramnios. Potter sequence (flattened facies, limb deformities, pulmonary hypoplasia) is caused by oligohydramnios and is associated with high mortality. __________ References: Neonatal polycystic kidney disease. (http://www.ncbi.nlm.nih.gov/pubmed/25155726)

A 24-Year-Old Woman Comes to the Office for a Routine