Fetal Megacystis - Causes, Diagnosis, Complications, and Treatment

Introduction

Fetal megacystis is a condition seen in developing fetuses which affects the urinary system and is characterized during prenatal development by an abnormally enlarged urinary bladder. Megacystis means the excessive enlargement of the urinary bladder beyond the normal size. During the normal development of the fetus, the kidney produces urine, and it will be transported to the urinary bladder through the ureters. The urine will be stored in the urinary bladder and will be expelled from the body. In fetal megacystis, there will be a malfunction or obstruction in the urinary tract, which will prevent the urine from flowing normally from the bladder. It will create an accumulation of urine and will result in enlargement of the bladder.

What Are the Causes and Risk Factors of Fetal Megacystis?

The actual cause of fetal megacystis is unknown. The common causes and risk factors associated with fetal megacystis include the following:

• Anatomical Abnormalities - These can be caused due to the presence of structural abnormalities in the urinary tract. Some of the structural abnormalities include narrowing or blockage of the ureters, bladder outlet, or urethra, which will change the normal urine flow and will result in enlargement of the urinary bladder.

• Genetic Factors - It can be associated with genetic syndromes or abnormalities. Some genetic conditions can result in abnormalities in the development of the urinary tract and urinary system which will increase the chance of abnormalities related to the urinary bladder and megacystis.

• Infections - Infection during the pregnancy in the urinary tract can result in fetal megacystis. The infection can result in damage and inflammation to the urinary bladder, which will result in enlargement.

• Maternal Drug Exposure - Some substances or medications used during the pregnancy period can have a higher risk of developing fetal megacystis. It can result in abnormalities in the bladder of the developing fetus.

• Maternal Diabetes - Poorly controlled diabetes is a potential risk factor for the development of fetal megacystis.

How Is Fetal Megacystis Diagnosed?

Fetal megacystis is diagnosed by:

• Ultrasound Examination - It uses high-frequency sound waves that help in creating an image of the organs and fetus within the uterus.

• Identification of Enlarged Bladder - In an ultrasound examination, the medical professional will examine the urinary system of the fetus, including the bladder. If there is an abnormally enlarged bladder, then fetal megacystis is suspected. The bladder size measurement is compared with the normal or standard measurement of the fetal bladder for the appropriate gestational age in order to confirm bladder enlargement.

• Associated Findings - Other potential symptoms or complications associated with fetal megacystis will be assessed. It includes a decreased amount of amniotic fluid level, compression of surrounding organs, or any abnormality in the kidney.

• Other Diagnostic Tests - Additional diagnostic tests will be performed in order to confirm the diagnosis and assess the severity of the condition. It includes extraction and analysis of the fluid in the amniotic cavity, called amniocentesis or fetal magnetic resonance imaging, which will provide a detailed image of the urinary system of the fetus.

What Are the Complications of Fetal Megacystis on Fetal Development?

The complications of fetal megacystis on the development of a fetus include the following:

• With the enlargement of the urinary bladder, there will be pressure exerted on the nearby organs, which will result in the compression of surrounding organs. The compression of the surrounding organs can result in reduced development or function of organs like the intestine or lungs.

• The enlargement of the urinary bladder can result in a reduced amount of amniotic fluid level. It will result in a decreased amount of amniotic fluid production and circulation. The amniotic fluid is important for the development of the fetus, including the development and growth of different organs, limbs, and other structures.

• It can have an impact on kidney functions. The obstruction in the urine flow can result in pressure and damage to the kidney. It will affect the ability to filter waste materials and will face difficulty in maintaining electrolyte and fluid balance.

• The stagnant urine present in the urinary bladder will create an environment for the growth of bacteria and will have a high chance of developing urinary tract infections in the fetus. It will compromise the function of the kidney and will result in overall fetal distress.

• In some conditions, fetal megacystis can result in increased production of amniotic fluid levels. It is due to the overproduction of urine by the kidney, and the bladder will have difficulty storing urine properly.

• It can be associated with underlying syndromes or genetic abnormalities. Complications, like reduced amniotic fluid level, organ compression, and impaired function of the kidney, can affect fetal development and will have a high risk of developing abnormalities.

How Is Fetal Megacystis Managed and Treated?

The management and treatment depend on the severity of the condition and associated complications. Some of the common management and treatment approaches used for fetal megacystis include the following:

• Conservative Management - In mild fetal megacystis, there will be no significant complications, and in such cases, conservative management will be preferred. It includes close monitoring of the fetus about the condition with the help of ultrasound examination in order to assess the bladder size, level of the amniotic fluid, and overall well-being of the fetus. The medical professional will monitor the signs and symptoms of the fetus.

• Medications - In some cases, medications are prescribed to reduce the complications and associated symptoms. Antibiotics are used to treat and prevent infections associated with the urinary tract. Medications are also used to manage the amniotic fluid level.

• Fetal Interventions - In severe cases, fetal intervention may be needed. It includes vesicoamniotic shunting, in which a shunt will be inserted into the bladder of the fetus, which will allow drainage of the excess urine present in the bladder directly into the amniotic sac, which will release the pressure present in the bladder. It will decrease the complications associated with the enlargement of the bladder. Fetal cystoscopy will be performed in which there is an insertion of a thin instrument in which a camera will be attached through the abdomen of the mother, which helps in visualization of the uterus and will help in treating the obstruction present in the bladder. Other surgical procedures help in reducing specific complications and underlying causes of fetal megacystis. It helps in solving the anatomical abnormalities present in the urinary tract.

• Multidisciplinary Care - The management of fetal megacystis needs a multidisciplinary approach. Specialists like pediatric urologists, neonatologists, maternal-fetal medicine specialists, geneticists, and other health professionals are needed in order to collaborate on the approach and to give comprehensive monitoring and treating the condition.

Conclusion

In conclusion, fetal megacystis is characterized by abnormal enlargement of the urinary bladder in the fetus. It is basically diagnosed during the prenatal ultrasound scanning and can result in different implications for both the fetus and the pregnancy. It can be caused by different reasons, including anatomical abnormalities present in the urinary tract, or it can be due to any genetic syndrome. This condition can result in various complications like decreased amniotic fluid level, compression of organs, and reduced function of the kidneys. The treatment will be based on the severity of the condition. Conservative interventions like drainage procedures and fetal surgery will be necessary in some cases.