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Magnetic Resonance Imaging for Prenatal Diagnosis of Multisystem Disease: Megacystis Microcolon Intestinal Hypoperistalsis Syndrome
Pediatric Case Report Magnetic Resonance Imaging for Prenatal Diagnosis of Multisystem Disease: Megacystis Microcolon Intestinal Hypoperistalsis Syndrome Erika M. S. Munch, Lawrence J. Cisek, JR., and David R. Roth We discuss a third-trimester diagnosis of Megacystis-microcolon-intestinal hypoperistalsis syndrome (MMIHS) using magnetic resonance imaging (MRI) and consider the benefits of MRI as a noninvasive imaging technique after routine ultrasonography reveals genitourinary pathology requiring further elucidation. MMIHS is a rare cause of functional gastrointestinal and genitourinary obstruction in newborns. Because of the poor prognosis of MMIHS, prenatal diagnosis is warranted for optimal prenatal counseling and postnatal treatment. Although MMIHS commonly presents on ultrasonography, the limitations of ultrasonography make definitive diagnosis difficult. However, MRI is safe, accurate, and can be used for early prenatal diagnoses of multisystem diseases. UROLOGY 74: 592–594, 2009. © 2009 Elsevier Inc.
egacystis-microcolon-intestinal hypoperistalsis syndrome (MMIHS), a rare congenital condition characterized by an enlarged bladder and functional obstruction of the gastrointestinal tract, is usually fatal within the first year of life. We present the first case of an infant with MMIHS diagnosed by prenatal magnetic resonance imaging (MRI), revealing both gastrointestinal and genitourinary abnormalities, and discuss the benefits of using prenatal MRI for definitive prenatal diagnoses.
M
infant underwent vesicostomy for bladder decompression and emergent laparotomy for iatrogenic pneumoperitoneum. The infant’s hospital course was complicated by Candida fungemia, group B Streptococcus bacteremia, hypertension, and liver failure. Repeat renal ultrasound revealed increasing echogenicity of the cortices and persistent hydronephrosis, though urine output and serum creatinine remained within normal ranges. At 72 days, the infant died of multiorgan failure.
CASE REPORT
COMMENT
A 27-year-old gravida 2, para 1 Hispanic woman underwent a routine prenatal ultrasound at 20-week gestational age (GA), which revealed a fetus with an enlarged bladder and polyhydramnios. Amniocentesis confirmed a 46,XX karyotype. At 32-week GA, prenatal MRI revealed polyhydramnios, an enlarged bladder, bilateral hydroureteronephrosis, microcolon, a dilated esophagus, and no abdominal musculature (Figs. 1, 2, and 3). A diagnosis of MMIHS was made. The mother presented at 33 5/7 weeks GA with preterm rupture of membranes, and a female was born via cesarean section. Renal ultrasonography on day 2 of life revealed an enlarged bladder and dilated ureters; a voiding cystourethrogram performed the following day demonstrated an atonic bladder without reflux. On day 4, the
Megacystis revealed by ultrasonography is the most common prenatal presentation of MMIHS; the differential diagnosis includes posterior urethral valves, prune-belly syndrome, neurogenic bladder, ovarian cysts, and hydrocolpos.1 MMIHS treatment largely involves supportive care; the pathophysiology is not well understood, and most infants die of sepsis or parenteral alimentation complications within the first year of life. MMIHS must be diagnosed early and definitively to provide parents and caregivers with the maximum treatment options. If MMIHS can be diagnosed by the second trimester, parents have the option to terminate the pregnancy. If the pregnancy is continued, the parents can plan for delivery in a tertiary care center that specializes in high-risk infant care; medical care teams can be alerted to the special, possibly emergent needs the child will require. Alternatively, parents may choose to limit extreme, invasive measures and instead care for the child or prepare for early infant death within the support of their community hospital.
From the Scott Department of Urology, Baylor College of Medicine, Houston, Texas; and Department of Pediatric Urology, Texas Children’s Hospital, Houston, Texas Reprint requests: David R. Roth, M.D., 6621 Fannin, CCC 660, Houston, TX 77 030. E-mail: [email protected] Submitted: November 21, 2008, accepted (with revisions): February 4, 2009
592
© 2009 Elsevier Inc. All Rights Reserved
0090-4295/09/$34.00 doi:10.1016/j.urology.2009.02.071
Figure 1. T2-weighted coronal image at 32-week GA, showing megacystis and polyhydramnios.
Figure 2. T2-weighted coronal image at 32-week GA, showing bilateral hydronephrosis and mild pulmonary hypoplasia.
Because it has no ionizing radiation, MRI is safer for the fetus than computed tomography. The American College of Radiology Guidance Document for Safe MR Practices2 suggests no special consideration for mothers and fetuses undergoing MRI anytime during pregnancy. MRI is generally avoided in the first trimester; however, no conclusive evidence has suggested harmful effects on fetuses. A study of 74 women who underwent MRI during pregnancy found no statistically significant differences in intrauterine fetal growth, premature delivery, or infant birth weight between these women and infants compared to controls.3 Another study that examined 20 infants who had undergone prenatal MRI revealed no increases in disability or disease.4 MRI also provides more anatomic detail than ultrasonography and is superior to ultrasound when diagnosing prenatal findings of urinary tract abnormalities.5 A case report describes a third trimester MRI for evaluation of an infant with bilateral ureteral duplication found on ultrasonography; megacystis and bilateral hydronephrosis suggested MMIHS, which was confirmed at birth.6 Furthermore, regular and UROLOGY 74 (3), 2009
Figure 3. T2-weighted sagittal image at 32-week GA, showing megacystis, microcolon, dilated esophagus, and abdominal wall defect. No neural axis abnormalities were identified.
fast MRI allows gross evaluation of the visceral organs7 and has shown effectiveness in evaluating gastrointestinal tract abnormalities.8 Its combined imaging of the urinary and gastrointestinal tracts makes MRI the ideal imaging technique for diagnosing multisystem diseases such as MMIHS, and allowed us to do so in this case (having found both genitourinary [polyhydramnios, an enlarged bladder, and bilateral hydroureteronephrosis] and gastrointestinal [microcolon, a dilated esophagus] abnormalities simultaneously). Ultrasonography and other noninvasive imaging modalities often demonstrate nonspecific or inconsistent results in infants with MMIHS. In 1976, Berdon reported characteristic postnatal radiographic findings of distended small bowel loops enhanced by contrast enema and a displaced microcolon; hydronephrosis was noted with intravenous pyelograms.9 As ultrasonography became more common, all cases of postnatally diagnosed MMIHS were uniformly associated with prenatal megacystis; however, this was the only consistent finding on ultrasonography. Measurement of amniotic fluid was variable, with a more likely presence of oligohydramnios in second-trimester ultrasounds and of polyhydramnios in third-trimester ultrasounds.10 While a thickened bladder wall and abdominal distension were noted often on ultrasound, the findings did not help in discriminating between obstructive and nonobstructive causes of megacystis. One study suggested that renal echogenicity in the setting of bladder distention is predictive of obstructive pathology11 but lacked a definitive finding for nonobstructive causes, including MMIHS. Although prenatal vesicocentesis has been shown to improve gastrointestinal imaging with ultrasonography,12 and amniotic fluid digestive enzyme assays have been used to support diagnoses of gastrointestinal obstruction,13 these tests are invasive procedures with risks such as pregnancy loss and other complications associated 593
with amniocentesis. MRI provides equally valuable information at no risk to the mother and fetus.
CONCLUSIONS To our knowledge, we present the first case of MMIHS definitively diagnosed through prenatal imaging; genitourinary pathology found during ultrasound combined with gastrointestinal pathology revealed during prenatal MRI provided early notification to parents about the fetus’ diagnosis. In doing so, we could help the parents prepare for the birth in a tertiary care setting with trained personnel available for the infant’s care. Prenatal diagnosis of MMIHS is imperative for optimal care for both the infant and family. It helps medical staff avoid invasive, sometimes painful, prenatal procedures that do not alter the course of the disease. Prenatal diagnosis also increases the time the medical team is aware of the condition, effectively affording more time to formulate novel therapeutic procedures that can increase the chances of survival and/or improve the quality of life. MRI should be used as a noninvasive ancillary imaging technique after routine ultrasonography screening demonstrates genitourinary pathology that requires further elucidation. MRI reliably identifies gastrointestinal pathology that facilitates early, definitive prenatal diagnosis of MMIHS. References 1. White SM, Chamberlain P, Hitchcock R, et al. Megacystis-microcolon-intestinal hypoperistalsis syndrome: the difficulties with antenatal diagnosis. Case report and review of the literature. Prenat Diagn. 2000;20:697-700. 2. Kanal E, Barkovich AJ, Bell C, et al. ACR guidance document for safe MR practices: 2007. AJR Am J Roentgenol. 2007;188:14471474. 3. Myers C, Duncan KR, Gowland PA, et al. Failure to detect intrauterine growth restriction following in utero exposure to MRI. Br J Radiol. 1998;71:549-551. 4. Baker PN, Johnson IR, Harvey PR, et al. A three-year follow-up of children imaged in utero with echo-planar magnetic resonance. Am J Obstet Gynecol. 1994;170:32-33. 5. Poutamo J, Vanninen R, Partanen K, et al. Diagnosing fetal urinary tract abnormalities: benefits of MRI compared to ultrasonography. Acta Obstet Gynecol Scand. 2000;79:65-71.
594
6. Lorenzo AJ, Twickler DM, Baker LA. Megacystis microcolon intestinal hypoperistalsis syndrome with bilateral duplicated systems. Urology. 2003;62:144xiv-144xvi. 7. Amin RS, Nikolaidis P, Kawashima A, et al. Normal anatomy of the fetus at MR imaging. Radiographics. 1999;19:Spec No:S201S214. 8. Garel C, Dreux S, Philippe-Chomette P, et al. Contribution of fetal magnetic resonance imaging and amniotic fluid digestive enzyme assays to the evaluation of gastrointestinal tract abnormalities. Ultrasound Obstet Gynecol. 2006;28:282-291. 9. Berdon WE, Baker DH, Blanc WA, et al. Megacystis-microcolonintestinal hypoperistalsis syndrome: a new cause of intestinal obstruction in the newborn. Report of radiologic findings in five newborn girls. AJR Am J Roentgenol. 1976;126:957-964. 10. Chen CP, Wang TY, Chuang CY. Sonographic findings in a fetus with megacystis-microcolon-intestinal hypoperistalsis syndrome. J Clin Ultrasound. 1998;26:217-220. 11. Kaefer M, Peters CA, Retik AB, et al. Increased renal echogenicity: a sonographic sign for differentiating between obstructive and nonobstructive etiologies of in utero bladder distension. J Urol. 1997;158:1026-1029. 12. Hidaka N, Kawamata K, Chiba Y. Megacystis-microcolon-intestinal hypoperistalsis syndrome: in utero sonographic appearance and the contribution of vesicocentesis in antenatal diagnosis. J Ultrasound Med. 2006;25:765-769. 13. Muller F, Dreux S, Vaast P, et al. Prenatal diagnosis of megacystismicrocolon-intestinal hypoperistalsis syndrome: contribution of amniotic fluid digestive enzyme assay and fetal urinalysis. Prenat Diagn. 2005;25:203-209.
EDITORIAL COMMENT In the spectrum of pre- and postnatal radiological imaging, MRI provides unquestionably the most accurate anatomic details. This rare case highlights the most important aspects of the fetal diagnosis of the megacystis-microcolon-intestinal hypoperistalsis syndrome. As indicated by the authors, the use of prenatal MRI allows definitive diagnosis of this possible multisystem syndrome. This knowledge permits early parental input for further pre- and/or postnatal management. Andrew J. Kirsch, M.D., F.A.A.P., F.A.C.S., Georgia Pediatric Urology, Children’s Healthcare of Atlanta, Emory University School of Medicine, Atlanta, GA doi:10.1016/j.urology.2009.02.070 UROLOGY 74: 594, 2009. © 2009 Elsevier Inc.
UROLOGY 74 (3), 2009
egacystis-microcolon-intestinal hypoperistalsis syndrome (MMIHS), a rare congenital condition characterized by an enlarged bladder and functional obstruction of the gastrointestinal tract, is usually fatal within the first year of life. We present the first case of an infant with MMIHS diagnosed by prenatal magnetic resonance imaging (MRI), revealing both gastrointestinal and genitourinary abnormalities, and discuss the benefits of using prenatal MRI for definitive prenatal diagnoses.
M
infant underwent vesicostomy for bladder decompression and emergent laparotomy for iatrogenic pneumoperitoneum. The infant’s hospital course was complicated by Candida fungemia, group B Streptococcus bacteremia, hypertension, and liver failure. Repeat renal ultrasound revealed increasing echogenicity of the cortices and persistent hydronephrosis, though urine output and serum creatinine remained within normal ranges. At 72 days, the infant died of multiorgan failure.
CASE REPORT
COMMENT
A 27-year-old gravida 2, para 1 Hispanic woman underwent a routine prenatal ultrasound at 20-week gestational age (GA), which revealed a fetus with an enlarged bladder and polyhydramnios. Amniocentesis confirmed a 46,XX karyotype. At 32-week GA, prenatal MRI revealed polyhydramnios, an enlarged bladder, bilateral hydroureteronephrosis, microcolon, a dilated esophagus, and no abdominal musculature (Figs. 1, 2, and 3). A diagnosis of MMIHS was made. The mother presented at 33 5/7 weeks GA with preterm rupture of membranes, and a female was born via cesarean section. Renal ultrasonography on day 2 of life revealed an enlarged bladder and dilated ureters; a voiding cystourethrogram performed the following day demonstrated an atonic bladder without reflux. On day 4, the
Megacystis revealed by ultrasonography is the most common prenatal presentation of MMIHS; the differential diagnosis includes posterior urethral valves, prune-belly syndrome, neurogenic bladder, ovarian cysts, and hydrocolpos.1 MMIHS treatment largely involves supportive care; the pathophysiology is not well understood, and most infants die of sepsis or parenteral alimentation complications within the first year of life. MMIHS must be diagnosed early and definitively to provide parents and caregivers with the maximum treatment options. If MMIHS can be diagnosed by the second trimester, parents have the option to terminate the pregnancy. If the pregnancy is continued, the parents can plan for delivery in a tertiary care center that specializes in high-risk infant care; medical care teams can be alerted to the special, possibly emergent needs the child will require. Alternatively, parents may choose to limit extreme, invasive measures and instead care for the child or prepare for early infant death within the support of their community hospital.
From the Scott Department of Urology, Baylor College of Medicine, Houston, Texas; and Department of Pediatric Urology, Texas Children’s Hospital, Houston, Texas Reprint requests: David R. Roth, M.D., 6621 Fannin, CCC 660, Houston, TX 77 030. E-mail: [email protected] Submitted: November 21, 2008, accepted (with revisions): February 4, 2009
592
© 2009 Elsevier Inc. All Rights Reserved
0090-4295/09/$34.00 doi:10.1016/j.urology.2009.02.071
Figure 1. T2-weighted coronal image at 32-week GA, showing megacystis and polyhydramnios.
Figure 2. T2-weighted coronal image at 32-week GA, showing bilateral hydronephrosis and mild pulmonary hypoplasia.
Because it has no ionizing radiation, MRI is safer for the fetus than computed tomography. The American College of Radiology Guidance Document for Safe MR Practices2 suggests no special consideration for mothers and fetuses undergoing MRI anytime during pregnancy. MRI is generally avoided in the first trimester; however, no conclusive evidence has suggested harmful effects on fetuses. A study of 74 women who underwent MRI during pregnancy found no statistically significant differences in intrauterine fetal growth, premature delivery, or infant birth weight between these women and infants compared to controls.3 Another study that examined 20 infants who had undergone prenatal MRI revealed no increases in disability or disease.4 MRI also provides more anatomic detail than ultrasonography and is superior to ultrasound when diagnosing prenatal findings of urinary tract abnormalities.5 A case report describes a third trimester MRI for evaluation of an infant with bilateral ureteral duplication found on ultrasonography; megacystis and bilateral hydronephrosis suggested MMIHS, which was confirmed at birth.6 Furthermore, regular and UROLOGY 74 (3), 2009
Figure 3. T2-weighted sagittal image at 32-week GA, showing megacystis, microcolon, dilated esophagus, and abdominal wall defect. No neural axis abnormalities were identified.
fast MRI allows gross evaluation of the visceral organs7 and has shown effectiveness in evaluating gastrointestinal tract abnormalities.8 Its combined imaging of the urinary and gastrointestinal tracts makes MRI the ideal imaging technique for diagnosing multisystem diseases such as MMIHS, and allowed us to do so in this case (having found both genitourinary [polyhydramnios, an enlarged bladder, and bilateral hydroureteronephrosis] and gastrointestinal [microcolon, a dilated esophagus] abnormalities simultaneously). Ultrasonography and other noninvasive imaging modalities often demonstrate nonspecific or inconsistent results in infants with MMIHS. In 1976, Berdon reported characteristic postnatal radiographic findings of distended small bowel loops enhanced by contrast enema and a displaced microcolon; hydronephrosis was noted with intravenous pyelograms.9 As ultrasonography became more common, all cases of postnatally diagnosed MMIHS were uniformly associated with prenatal megacystis; however, this was the only consistent finding on ultrasonography. Measurement of amniotic fluid was variable, with a more likely presence of oligohydramnios in second-trimester ultrasounds and of polyhydramnios in third-trimester ultrasounds.10 While a thickened bladder wall and abdominal distension were noted often on ultrasound, the findings did not help in discriminating between obstructive and nonobstructive causes of megacystis. One study suggested that renal echogenicity in the setting of bladder distention is predictive of obstructive pathology11 but lacked a definitive finding for nonobstructive causes, including MMIHS. Although prenatal vesicocentesis has been shown to improve gastrointestinal imaging with ultrasonography,12 and amniotic fluid digestive enzyme assays have been used to support diagnoses of gastrointestinal obstruction,13 these tests are invasive procedures with risks such as pregnancy loss and other complications associated 593
with amniocentesis. MRI provides equally valuable information at no risk to the mother and fetus.
CONCLUSIONS To our knowledge, we present the first case of MMIHS definitively diagnosed through prenatal imaging; genitourinary pathology found during ultrasound combined with gastrointestinal pathology revealed during prenatal MRI provided early notification to parents about the fetus’ diagnosis. In doing so, we could help the parents prepare for the birth in a tertiary care setting with trained personnel available for the infant’s care. Prenatal diagnosis of MMIHS is imperative for optimal care for both the infant and family. It helps medical staff avoid invasive, sometimes painful, prenatal procedures that do not alter the course of the disease. Prenatal diagnosis also increases the time the medical team is aware of the condition, effectively affording more time to formulate novel therapeutic procedures that can increase the chances of survival and/or improve the quality of life. MRI should be used as a noninvasive ancillary imaging technique after routine ultrasonography screening demonstrates genitourinary pathology that requires further elucidation. MRI reliably identifies gastrointestinal pathology that facilitates early, definitive prenatal diagnosis of MMIHS. References 1. White SM, Chamberlain P, Hitchcock R, et al. Megacystis-microcolon-intestinal hypoperistalsis syndrome: the difficulties with antenatal diagnosis. Case report and review of the literature. Prenat Diagn. 2000;20:697-700. 2. Kanal E, Barkovich AJ, Bell C, et al. ACR guidance document for safe MR practices: 2007. AJR Am J Roentgenol. 2007;188:14471474. 3. Myers C, Duncan KR, Gowland PA, et al. Failure to detect intrauterine growth restriction following in utero exposure to MRI. Br J Radiol. 1998;71:549-551. 4. Baker PN, Johnson IR, Harvey PR, et al. A three-year follow-up of children imaged in utero with echo-planar magnetic resonance. Am J Obstet Gynecol. 1994;170:32-33. 5. Poutamo J, Vanninen R, Partanen K, et al. Diagnosing fetal urinary tract abnormalities: benefits of MRI compared to ultrasonography. Acta Obstet Gynecol Scand. 2000;79:65-71.
594
6. Lorenzo AJ, Twickler DM, Baker LA. Megacystis microcolon intestinal hypoperistalsis syndrome with bilateral duplicated systems. Urology. 2003;62:144xiv-144xvi. 7. Amin RS, Nikolaidis P, Kawashima A, et al. Normal anatomy of the fetus at MR imaging. Radiographics. 1999;19:Spec No:S201S214. 8. Garel C, Dreux S, Philippe-Chomette P, et al. Contribution of fetal magnetic resonance imaging and amniotic fluid digestive enzyme assays to the evaluation of gastrointestinal tract abnormalities. Ultrasound Obstet Gynecol. 2006;28:282-291. 9. Berdon WE, Baker DH, Blanc WA, et al. Megacystis-microcolonintestinal hypoperistalsis syndrome: a new cause of intestinal obstruction in the newborn. Report of radiologic findings in five newborn girls. AJR Am J Roentgenol. 1976;126:957-964. 10. Chen CP, Wang TY, Chuang CY. Sonographic findings in a fetus with megacystis-microcolon-intestinal hypoperistalsis syndrome. J Clin Ultrasound. 1998;26:217-220. 11. Kaefer M, Peters CA, Retik AB, et al. Increased renal echogenicity: a sonographic sign for differentiating between obstructive and nonobstructive etiologies of in utero bladder distension. J Urol. 1997;158:1026-1029. 12. Hidaka N, Kawamata K, Chiba Y. Megacystis-microcolon-intestinal hypoperistalsis syndrome: in utero sonographic appearance and the contribution of vesicocentesis in antenatal diagnosis. J Ultrasound Med. 2006;25:765-769. 13. Muller F, Dreux S, Vaast P, et al. Prenatal diagnosis of megacystismicrocolon-intestinal hypoperistalsis syndrome: contribution of amniotic fluid digestive enzyme assay and fetal urinalysis. Prenat Diagn. 2005;25:203-209.
EDITORIAL COMMENT In the spectrum of pre- and postnatal radiological imaging, MRI provides unquestionably the most accurate anatomic details. This rare case highlights the most important aspects of the fetal diagnosis of the megacystis-microcolon-intestinal hypoperistalsis syndrome. As indicated by the authors, the use of prenatal MRI allows definitive diagnosis of this possible multisystem syndrome. This knowledge permits early parental input for further pre- and/or postnatal management. Andrew J. Kirsch, M.D., F.A.A.P., F.A.C.S., Georgia Pediatric Urology, Children’s Healthcare of Atlanta, Emory University School of Medicine, Atlanta, GA doi:10.1016/j.urology.2009.02.070 UROLOGY 74: 594, 2009. © 2009 Elsevier Inc.
UROLOGY 74 (3), 2009