Introduction:
Megacystis microcolon syndrome (MMS) is an uncommon congenital disorder marked by abdominal distension brought on by a significantly enlarged, unobstructed bladder (megacystis), a very small colon (microcolon), and diminished or nonexistent gastrointestinal movements (intestinal peristalsis). The other names for this condition are:
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Berdon syndrome.
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Megacystis microcolon intestinal hypoperistalsis syndrome.
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MMIH syndrome.
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MMIHS.
What Are the Causes of Microcolon-Megacystis Syndrome?
The most extensively researched gene for MMIHS is ACTG2, which can get mutated and lead to the condition. The gamma (γ)-2 actin protein is made using instructions from the ACTG2 gene. The γ-2 actin proteins form filaments crucial for the tenseness of muscle fibers (muscle contraction), particularly the smooth muscles of the urinary and intestinal systems. These contractions help the intestines move food and empty the bladder of urine. An altered gamma -2 actin protein is produced due to ACTG2 gene mutations. These modifications make it more difficult for actin filaments to develop, which reduces the smooth muscle's capacity to contract in the intestines and bladder. The main characteristics of MMIHS are caused by these issues with muscular contractions, which interfere with the release of urine and the passage of food through the intestines. Few cases of MMIHS have been linked to mutations in other genes. These genes' proteins contribute to the contraction of smooth muscle. A mutation in one identified gene is absent in about 10 percent of individuals with MMIHS. Moreover, undiscovered genes may contribute to the illness in some way.
What Is the Inheritance Pattern of Megacystis Microcolon Syndrome?
The inheritance pattern depends on the gene mutation.
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Autosomal Dominant Pattern - MMIHS has an autosomal dominant pattern resulting from ACTG2 gene mutations, indicating that only one copy of the mutated gene in each cell is required to generate the condition. These occurrences result from new (de novo) gene changes during the development of reproductive cells (eggs or sperm) or in the early stages of embryogenesis. In these situations, the affected people have no family history of the condition.
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Autosomal Recessive Pattern - MMIHS is inherited in an autosomal recessive pattern, resulting from mutations in other known genes, meaning both copies of the gene in each cell carry mutations. Each parent of a person with an autosomal recessive disorder carries one copy of the defective gene, although usually, neither parent exhibits the disease's signs and symptoms.
What Are the Symptoms of Megacystis Microcolon Syndrome?
The symptoms of megacystis microcolon syndrome are listed below:
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Abdominal distension.
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Mega Cystitis - Urinary bladder dilatation.
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Microcolon - An abnormally small colon.
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Hypoperistalsis - The reduced movement of the digestive tract.
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Nausea and Vomiting - The symptom of nausea frequently experienced is described as the unsettling, subjective feeling of impending vomiting. Vomiting is the term used to describe the violent passage of stomach, duodenum, or jejunum contents through the mouth. While it's common knowledge that nausea and vomiting occur at different times, this is not always true. In certain cases, emesis can occur without prior nausea, but less frequently, severe nausea can occur without emesis.
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Abnormality of the gastrointestinal tract.
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Hydroureter - Urine-filled distention of the ureter.
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Intestinal Malrotation - A deviation from the usual rotation and fixation of the intestines during the process of gut formation. As a result, the intestine may twist and get obstructed, resulting in necrosis.
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Multicystic Renal Dysplasia - Many cysts in the kidney, each varied in size, and the absence of a healthy pelvicalyceal system are the two main features of multicystic dysplasia of the kidney. The damaged kidney is not functioning and is linked to ureteral or ureteropelvic atresia.
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Hydraminos - The pregnancy-related accumulation of extra amniotic fluid in the uterus.
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Cardiovascular malformations.
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Cryptorchidism - Inguinal canal with testicles. Specifically, the testis or testes are absent from the scrotum because they cannot transit through the inguinal canal to the scrotum.
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Neoplasm of the Heart - Abnormal tissue growth in the heart.
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Omphalocele - A midline anterior partial closure of the abdominal wall where the abdominal viscera protrudes into the base of the abdominal cord.
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Sepsis - Infection in the bloodstream.
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Umbilical Hernia - Abdominal contents protruding due to a weakness in the abdominal wall muscles surrounding the umbilicus. The defect is covered by subcutaneous tissue and skin.
How Is Megacystis Microcolon Syndrome Diagnosed?
The different methods used to diagnose megacystis microcolon syndrome are:
Prenatal Imaging Tests:
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Prenatal Ultrasound - To assess the amniotic fluid volume and bladder abnormalities.
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Fetal MRI - To assess the esophagus dilatation and microcolon.
Postnatal (After Birth) Tests:
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Abdominal Radiograph - To assess slight bowel loop enlargement and dilatation with stomach distention and a lack of distal gas.
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Fluoroscopic Upper Gastrointestinal Series - To assess intestinal malrotation and stomach dilatation.
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Contrast Enema - To detect microcolon.
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Renal Ultrasound - To assess urological findings like dilated ureter and bladder.
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Molecular Genetic Testing - To detect the mutation of the gene.
How Is Megacystis Microcolon Syndrome Managed?
Being an MMIHS patient is challenging. Malnourished children might require nutritional supplementation. Catheterization, a procedure that involves inserting a tube into the body, can help avoid digestive and kidney problems. In rare circumstances, organ transplantation may increase survival.
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Interventions in Nutrition: There are various methods used to provide nutrition to those with MMHIS. Babies frequently get IV (intravenous) fluids and nutrients, but in most cases, this nutritional supplementation is insufficient to ensure long-term survival. Mildly ill individuals could also need dietary supplements.
What Are the Procedures Done in Managing Megacystis Microcolon Syndrome?
Some people will require a surgical small intestine ileostomy. Undigested material can now pass through this gap in the abdominal wall and into a bag outside the body without first passing through the colon. To help with urination, a catheter may be inserted into the urethra (the passageway via which urine leaves the body from the bladder). Sometimes, the urethra can be bypassed by surgically inserting a tube into the bladder to deliver urine into a bag.
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Organ Transplantation: For the treatment of MMIHS, some kids have had numerous organ transplants with variable degrees of success. For example, intestinal transplants may include attaching a small or big portion of the donor's intestine to restore the damaged child's ability to move their smooth muscles normally.
Conclusion:
In conclusion, the prognosis for MMIHS is poor, but there has been a steady improvement in patient survival. Enhancing the standard of nutritional care should be the cornerstone of Berdon's syndrome management. The clinician's top concern is avoiding long-term TPN (total parenteral nutrition) issues. Genetic counseling is recommended for families with a history of Berdon's syndrome because most cases have unknown molecular origins.
