Autosomal dominant polycystic kidney disease (ADPKD) is a common inherited disorder. Ultrasound (US) findings can include enlarged echogenic kidneys in utero and cysts in multiple organs in adults. Though a highly penetrant disease, due to varied clinical expression and the typical late onset of symptoms, reproductive-aged women may not know their carrier status. We present two cases in which fetal US findings suggested ADPKD and additional evaluation identified likely maternal ADPKD as well.
Autosomal dominant polycystic kidney disease (ADPKD) is the most common renal cystic disease.1, 2, 3 As ADPKD typically does not manifest until adulthood, many individuals enter their reproductive years with normal fertility and with no knowledge of their disease. Here we present two cases in which fetal findings lead to the diagnosis of concurrent maternal disease.
W.A., a 33-year-old G1 P0, underwent routine anatomical ultrasound (US) at 20 weeks gestational age. Her prenatal course was uncomplicated and she reported no known medical or family history. At her initial prenatal visit, her blood pressure was 104/70 mm Hg with an unremarkable physical exam. Serum screening for aneuploidy showed no elevated risks. Fetal US findings were notable for an echogenic appearance of both kidneys with bilateral pyelectasis and renal enlargement (>95th percentile) without discrete cysts. The fetal anatomic survey was otherwise unremarkable with normal amniotic fluid (maximal vertical pocket of 5.7 cm) and estimated fetal weight at the 51st percentile.
On the basis of these findings, maternal renal US was performed showing bilateral renal enlargement with multiple cysts, the largest measuring 1.5 cm in diameter. Subsequent magnetic resonance imaging (MRI) confirmed both the fetal and maternal findings.
Overall, the clinical picture was consistent with fetal and maternal ADPKD, and further questioning revealed that the patient’s father might have had renal cysts. Further studies showed no laboratory evidence of maternal disease. She delivered her male infant at 41 weeks’ gestation and neonatal US at 3 weeks of life showed bilaterally enlarged and echogenic kidneys with the suggestion of tiny cysts in cortical and medullary regions.
T.G., a 41-year-old G5 P1031, was referred for a detailed US at 19 weeks’ gestation due to anomalies noted on initial scan. Owing to advanced maternal age, cell-free fetal DNA testing had been completed with no increased risk for aneuploidy. She denied any significant medical or family history. Fetal US confirmed enlarged echogenic kidneys, measuring greater than the 95th percentile bilaterally without visible cysts (Figure 1). The amniotic fluid quantity was normal with fetal weight >95th percentile (renal enlargement produced a large abdominal circumference). Fetal MRI confirmed these findings without additional diagnoses.
Maternal renal US revealed bilaterally enlarged kidneys (each measuring 13.4 × 6.0 × 6.4 cm) with multiple cysts (Figures 2a and b). The largest cyst diameters were 3.9 cm on the right and 6.2 cm on the left. Full maternal evaluation showed normal renal function and normal blood pressures. Further questioning of the patient’s family history disclosed that her father had a simple renal cyst, which had been followed without progression or other evidence of ADPKD. At 37 weeks’ gestation, she delivered a female infant who had an uncomplicated neonatal course. Physicians for this infant plan to pursue further imaging at age 6 months.
With an incidence of 1/500 to 1/1000 live births, ADPKD is the most common lethal dominantly inherited disorder.4 There is large interfamilial and intrafamilial variability with ADPKD, with disease signs and symptoms commonly not presenting until later in life.2 The lack of a known family history in many affected individuals, demonstrated by the cases reported here, is indicative of the potential mild course of the disease.
As such, many individuals do not know they or their offspring could be affected or at risk. In a multicenter series of 27 cases, 59% of patients did not know they were ADPKD carriers before fetal US.5 As prenatal ultrasonography has become the standard of care, possible cases of fetal ADPKD are increasingly identified.4 Fetal US findings suggestive of ADPKD are enlarged hyperechoic kidneys with normal amniotic fluid volumes. Renal cysts are seen in the minority of fetal cases.3, 5 The chief differential diagnosis is between autosomal recessive polycystic kidney disease (ARPKD) and ADPKD. In the dominant form, the fetal kidneys are moderately enlarged, typically 1.5 to 2 s.d. above the mean5 versus much greater renal enlargement in ARPKD (4 to 6 s.d. above the mean). Fetal renal cysts and reduced amniotic fluid are more commonly associated with ARPKD.6 In adults with ADPKD, renal US findings include normal echogenicity, enlarged discrete cysts and overall enlargement.3 With a known family history of ADPKD, two or more renal cysts in patients younger than 30 years or two cysts in each kidney in patients older than 30 years is considered diagnostic.2 Nephromegaly is seen in all patients and may account for the acute and chronic pain suffered by some patients. Hypertension can occur in 30% of children and up to 60% of adults before renal insufficiency.1
Women with ADPKD and normal renal function generally have uncomplicated pregnancies. Conversely, women with compromised renal function before pregnancy require close monitoring for hypertension and preeclampsia.7 Pregnancy may impact renal function in ADPKD patients, as some data suggest that three or more pregnancies were associated with an earlier age of onset of renal insufficiency.1 Up to 50% of ADPKD patients have hepatic cysts with an age-related incidence. Hepatic cysts may be influenced by female steroid hormones; they are more common in multiparous women and often are larger in multiparous women or those who have taken oral contraceptive pills.2 Intracranial aneurysms can also occur in ADPKD with incidence from 0 to 41%, and some obstetrical providers consider cerebral imaging to rule out cerebral aneurysms before delivery.1
In summary, the diagnosis of ADPKD should always be considered when echogenic enlarged kidneys are found on fetal US, even if the mother reports no history of disease. We present these cases as an important reminder that pregnancy can serve as an important opportunity for identification of this disease for both mother and child.
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The authors declare no conflict of interest.
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Euser, A., Sung, J. & Reeves, S. Fetal imaging prompts maternal diagnosis: autosomal dominant polycystic kidney disease. J Perinatol 35, 537–538 (2015). https://doi.org/10.1038/jp.2015.50