Fetal megacystis as a prenatal challenge: megacystis–microcolon–intestinal hypoperistalsis syndrome in a male fetus

Abstract

The prenatal detection of megacystis is only the first step towards identifying the etiology and deciding on suitable treatment for this condition. Here we present a report highlighting the difficulties in the prenatal diagnosis of this severe fetal anomaly.A 28-year-old healthy primigravida was referred at 24 weeks' gestation to a tertiary hospital after an ultrasound scan at 18 weeks revealed megacystis and unilateral hydronephrosis in a male fetus with normal karyotype. On referral, a further ultrasound examination revealed a large bladder with a dilated posterior urethra (the 'keyhole sign') and normal wall thickness. Based on these findings, posterior urethral valves (PUV) syndrome was first suspected. Following weekly clinical and ultrasound surveillance, a progressive and unexpected increase in the amniotic fluid index (AFI) was observed in the third trimester, with polyhydramnios and grade IV hydronephrosis (Figures 1 and 2). These findings were suggestive of the rare megacystis-microcolonintestinal hypoperistalsis syndrome (MMIHS). Correspondence to: Dr L. Machado, Serviço de Ginecologia e Obstetrícia, Centro Hospitalar de São João, EPE, Alameda Hernani Monteiro, At 32 weeks' gestation, fetal magnetic resonance imaging (MRI) showed a dilated bladder measuring 135 × 111 × 86 mm that was compressing the abdominal organs, and severe bilateral hydronephrosis (21 mm right and 18 mm left); in addition, the stomach was clearly visible, but not the intestines (Figure 3). Vesicocentesis was performed for fetal urinalysis (sodium, potassium, calcium, phosphorus, creatinine, urea, total proteins and β2-microglobulin), and amniocentesis for evaluation of digestive enzymes (including γ-glutamyl transferase, alkaline phosphatase and biliary salts); findings from these tests were consistent with MMIHS. A Cesarean section was performed at 33 weeks, after spontaneous rupture of membranes. The neonate weighed 2950 g and had Apgar scores of 8 and 8 at 1 and 5 min, respectively. During the neonatal period the diagnosis was confirmed, and vesicostomy and total parenteral nutrition were needed. At 12 months, the infant had normal physical and neurological development, but still needed parenteral nutrition and vesicostomy.

Ultrasound prenatal diagnosis of typical megacystis, microcolon, intestinal hypoperistalsis syndrome

“…However, in female fetuses with megacystis and polyhydramnios, MMIHS should be suspected, as LUTO rarely affects females and almost always causes oligohydramnios. MMIHS should not be ruled out in male fetuses with megacystis, especially if there is no oligohydramnios . Progressive hydronephrosis is usually suggestive of LUTO, but hydronephrosis can be seen in both MMIHS and LUTO .…”

“…MMIHS should not be ruled out in male fetuses with megacystis, especially if there is no oligohydramnios . Progressive hydronephrosis is usually suggestive of LUTO, but hydronephrosis can be seen in both MMIHS and LUTO . Fetal MRI studies can contribute to the prenatal diagnosis .…”

“…Progressive hydronephrosis is usually suggestive of LUTO, but hydronephrosis can be seen in both MMIHS and LUTO . Fetal MRI studies can contribute to the prenatal diagnosis .…”

Megacystis Microcolon Intestinal Hypoperistalsis Syndrome (MMIHS): A Rarity

“…MMIHS is a rare cause of neonatal intestinal obstruction with around 230 cases reported in the literature. [1][2][3] It was first described by Berdon and colleagues in 1976. [2] Females are 3 -4 times more commonly affected than males.…”

What is your diagnosis?

“…In the second and third trimester, lower urinary tract obstruction (LUTO) frequently can be caused by posterior urethral valve (PUV) in male fetuses with megacystis. Keyhole sign in sonographic examination is important for the diagnosis of PUV (4). Survival of fetuses with megacystis in the second and third trimester is better than in the first trimester (1).…”