Introduction
Megacystis-microcolon-intestinal hypoperistalsis syndrome is a rare congenital disorder that is present since birth. Walter Berdon et al. first described this disorder in 1976, and it is also referred to as Berdon syndrome. It is more common in females and presents with micro colon, giant bladder (megacystis), constipation, urinary retention, intestinal hypoperistalsis, small bowel, and hydronephrosis. It is a congenital disorder that impairs muscle contractions in the bladder and the intestines.
What Is Megacystis-Microcolon-Intestinal Hypoperistalsis Syndrome?
Megacystis-microcolon-intestinal hypoperistalsis syndrome (MMIHS) or Berdon syndrome is a congenital disorder that affects the muscles lining the bladder and intestines. It impairs the muscle contractions that help in the movement of ingested food through the digestive tract and in emptying the bladder. It is a rare disorder characterized by abdominal distention due to the presence of a large non-obstructed urinary bladder (megacystis), small colon (microcolon), and decreased intestinal mobility (hypoperistalsis).
What Causes Megacystis-Microcolon-Intestinal Hypoperistalsis Syndrome?
Megacystis-microcolon-intestinal hypoperistalsis syndrome is a genetic disorder caused by mutations in genes. ACTG2 gene mutation specifically affects the smooth muscle contractions of the urinary bladder and the intestines. Mutations in other genes have also been found to be associated with MMIHS. It is an autosomal dominant disorder, which indicates that one copy of the mutated gene in every cell can cause this disorder. If the disorder is caused by mutations in other genes, it is inherited as an autosomal recessive disorder.
What Are the Clinical Features of Megacystis-Microcolon-Intestinal Hypoperistalsis Syndrome?
Some features of megacystis-microcolon-intestinal hypoperistalsis syndrome can be diagnosed during prenatal ultrasound. The fetuses affected with this disorder show an enlarged bladder (megacystis). MMIHS is characterized by a narrow large intestine (microcolony) due to a decrease in the functional muscle lining.
The most common clinical feature of megacystis-microcolon-intestinal hypoperistalsis syndrome is abdominal distention that occurs secondary to a large dilated bladder without any mechanical obstruction. Other features include bilious emesis (bright yellow or green-colored vomit), failure to pass meconium (baby’s first stool), and inability to pass urine.
Infants and children with this disorder have impaired myopathic function of the bladder along with urological comorbidities, such as febrile urinary tract infections, vesicoureteral reflex (a disorder in which urine flows backward to the ureters and sometimes to the kidneys), and hydronephrosis (a condition in which there is the excessive back-up of urine in kidneys due to obstruction in the ureter) thereby increasing the risk of renal failure. Catheterization is required in cases of poor voiding of urine.
Gastrointestinal features of megacystis-microcolon-intestinal hypoperistalsis syndrome include micro colon, intestinal hypomotility or dysmotility, and associated gastrointestinal comorbidities such as malrotation and short bowel syndrome. The continued impairment in intestinal motility causes intestinal pseudo-obstruction (a condition in which the buildup of partially digested food in the intestines causes obstruction). Chronic intestinal dysfunction results in intestinal failure and nutritional compromise. Hence, total parenteral nutrition is recommended to prevent malnutrition.
What Are the Complications Associated With Megacystis-Microcolon-Intestinal Hypoperistalsis Syndrome?
Patients are are highly prone to develop infection and sepsis due to the presence of clean intermittent catheterization (CIC) and total parenteral nutrition (TPN). Clean intermittent catheterization can result in recurrent urinary tract infections, and the use of total parenteral nutrition can lead to central line infection. Sepsis can occur in case of ongoing infection. In addition, hydronephrosis is another complication that results in renal failure if left untreated.
Total parenteral nutrition can result in serious complications such as central line infections, liver damage, and the formation of blood clots. Patients under TPN have an IV (intravenous) line directed to the heart to deliver nutrients. An infection in or around this IV line can become potentially fatal. A person on TPN is given fats for proper nutrition. These fats can cause inflammation of the liver, which eventually results in liver damage and liver failure. The risk of formation of blood clots and associated risks are increased in TPN.
How Is Megacystis-Microcolon-Intestinal Hypoperistalsis Syndrome Diagnosed?
Megacystis-microcolon-intestinal hypoperistalsis syndrome can be diagnosed before birth and after birth. Radiographic imaging tests help diagnose MMIHS.
Prenatal Imaging Features of Megacystis-Microcolon-Intestinal Hypoperistalsis Syndrome
Prenatal ultrasound helps diagnose megacystis-microcolon-intestinal hypoperistalsis syndrome through imaging features, such as an enlarged bladder with or without hydronephrosis in the presence of normal or increased amniotic fluid volume during the second trimester of pregnancy. Gastrointestinal abnormalities are less common in prenatal ultrasound and may include abominable distention and dilated bowel loops. Abdominal distention is visible during the second-trimester ultrasound, and dilated bowel loops can be detected during the third-trimester ultrasound.
Postnatal Clinical and Imaging Features of Megacystis-Microcolon-Intestinal Hypoperistalsis Syndrome
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An abdominal radiograph helps determine abdominal distention and dilatation of bowel loops.
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Fluoroscopic upper-gastrointestinal imaging reveals the presence of dilated stomach and malrotation associated with the small intestine.
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Contrast enema imaging reveals a small colon with associated malrotation.
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Renal ultrasound and cystography show the presence of an enlarged bladder, hydronephrosis, and vesicoureteral reflex.
Clinical features include the presence of bilious emesis, abdominal distention, decreased bowel sounds, decreased bowel movements, failure to pass meconium, and failure to void urine, requiring catheterization.
How Is Megacystis-Microcolon-Intestinal Hypoperistalsis Syndrome Treated?
The treatment for megacystis-microcolon-intestinal hypoperistalsis syndrome involves symptomatic management.
Myopathic Bladder Dysfunction and Associated Urological Abnormalities:
Clean intermittent catheterization (CIC) or vesicostomy is performed to allow bladder decompression and to prevent renal failure.
Bowel Dysfunction, Microcolon, Intestinal Hypoperistalsis, and Associated Abnormalities:
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Surgical procedures such as gastrostomy or jejunostomy are performed for nutrition administration and to allow bowel decompression.
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Bowel diversion procedures such as ileostomy or colostomy are performed for distal bowel compression.
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Total parenteral nutrition (TPN) is provided to treat malnutrition caused by intestinal dysmotility and intestinal failure.
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Multivisceral or isolated intestinal transplantations are performed to treat nutritional failure and in those who cannot tolerate TPN.
Vascular Smooth Muscle Dysfunction:
It causes smooth muscle dysfunction syndrome in individuals with pathogenic gene variants. These patients are evaluated for aortic dilation, pulmonary hypertension, patent ductus arteriosus, and abnormal cerebral vasculature.
Conclusion
Megacystis-microcolon-intestinal hypoperistalsis syndrome is a rare disorder caused by genetic mutations. The prognosis for this disorder is variable and has not been well-established. The main aim of diagnosis and treatment is to offer supportive management. The treatment options aim at symptomatic management and prevention of organ failure. The major complication of this disorder is nutritional failure, which eventually results in death. Nutritional treatments aim at preventing nutritional failure and malnutrition. Various studies are being carried out to improve survival rates through advanced treatment options.
