Potter Syndrome - Causes, Symptoms, Diagnosis, and Treatment

What Is Potter Syndrome or Bilateral Renal Agenesis?

During pregnancy, a clear fluid known as the amniotic fluid is present around the fetus. Under normal conditions, this fluid protects the babies from mechanical injuries and pressure and allows their normal uterine growth and development. In the case of Potter syndrome, the amniotic fluid is not present in sufficient quantities. As a result, the pressure exerted due to pregnancy damages the respiratory and skeletal systems of the baby. It becomes difficult for the babies to survive because they are unable to breathe due to an underdeveloped respiratory system. Potter syndrome is named after Edith Potter, who discovered this condition in newborns when she was working in Chicago.

What Are the Causes of Potter Syndrome?

There are multiple causes of Potter syndrome, but the most common cause is bilateral renal agenesis. It has been described below:

• Bilateral Renal Agenesis - It is a condition in which the kidneys are either absent or have failed to form by birth. The kidneys are a crucial organ of the urogenital system. They filter the blood, form urine, and maintain fluid and electrolyte levels in the body. The kidneys play a crucial role in the growth and development of the fetus. The major part of the amniotic fluid is formed from the urine produced by the kidneys. If the kidneys are absent, the amniotic fluid is not present in sufficient amounts to support the fetus. As a result, the pressure on the fetus rises and results in a change in the facial and skeletal features of the baby. Defects in the fibroblast growth factor 20 (FGF 20) and growth-regulating estrogen receptor binding 1 (GREB 1) genes are also responsible for causing bilateral renal agenesis.

The other causes of Potter syndrome have been described below:

• Autosomal Recessive Polycystic Kidney Disease - It is a hereditary disease that rarely occurs. There are multiple fluid-filled sacs or cysts present on the surface of the kidneys in babies. As a result, the kidneys become enlarged and fail to function, resulting in the scarcity of amniotic fluid.

• Prune Belly Syndrome - It is a condition that occurs as a result of the incomplete development or absence of the abdominal muscles. The development of the kidneys also gets affected if the abdominal muscles are absent.

• Obstructive Uropathy - In this condition, the urine flows back to the urinary system instead of flowing outside the body. The urine collects in the kidneys and results in swelling and damage. The presence of stones, tumors, and other abnormalities in the urinary system of the baby is responsible for the backward flow of urine.

• Preterm Rupture of Membranes - Normally, the amniotic fluid is bounded by membranes on all sides. However, when the membranes surrounding the fluid collapse, it leaks out before the delivery date. In such a condition, the baby needs to be delivered early, which is harmful.

What Are the Signs and Symptoms of Potter Syndrome?

The signs and symptoms of Potter syndrome are listed below:

1. Potter Facies - Potter syndrome affects the facial features of the child, and the following changes are usually seen:

   • The chin recedes or moves back towards the neck, known as a receding chin.

   • The nasal bridge appears flat and depressed.

   • The distance between the eyes is more than normal, known as ocular hypertelorism.

   • The ears are low-set and lack cartilage.

   • The skin folds near the inner part of the eyes are prominent, known as epicanthal folds.

2. Features of Prune Belly Syndrome - If Potter syndrome is due to prune belly syndrome, the following symptoms are observed:

   • The stomach of the child appears wrinkled, with the skin showing multiple folds, and the appearance is similar to the prune, which is a dried plum.

   • Testes, the organs responsible for reproduction in males, also fail to move out of the body into the scrotum bag, a fragile layer of skin. Instead, the testes sometimes remain attached to the ureter.

   • The tube-like structures that connect the kidney to the bladder, known as ureters, also show defects in them like; they may be so narrow sometimes that they block the passage of urine and lead to the retention of urine in the kidneys.

3. Respiratory Difficulties - It becomes difficult for the child to breathe because of the underdeveloped lungs. Flaring of the nose, wheezing, and a weird sound (grunting) while breathing is commonly seen.

4. Skeletal Deformities - The following skeletal deformities are usually seen:

   • The spine is only half-formed (hemivertebra).

   • The lower part of the spine is missing or incompletely formed.

5. Ophthalmologic Problems - The patients suffer from cataracts, and the lens present in the eyes move out from their normal position.

6. Heart Diseases - The tissues present in the heart fail to develop properly, resulting in an irregular heartbeat.

What Methods Are Used to Diagnose Potter Syndrome?

The diagnosis of Potter syndrome is based on a physical exam, medical history, laboratory tests, and imaging tests. The diagnostic methods are described below:

• Medical History Form - The medical history gives an idea about the symptoms of the condition, the time of their onset, other conditions the patient is suffering from, the medications being taken, and the family history.

• Physical Examination - The doctor checks the physical signs of Potter syndrome-like changes in the facial feature, respiratory difficulties, and features associated with prune belly syndrome.

• Laboratory Tests - The doctor recommends the following laboratory tests in the case of Potter syndrome:

  • Urinalysis - The urine sample obtained from the child is sent to the laboratory for examination under a microscope. The levels of electrolytes like sodium, potassium, calcium, and magnesium are usually high in the urine because the kidneys have failed to work.

  • Blood Tests - The doctor recommends the patient undergo a blood test to check the creatinine levels. Creatinine is a waste product present in the blood due to muscle activity. Normally the creatine is removed from the bloodstream by the kidneys. However, the levels of creatinine are usually high in Potter syndrome because of kidney failure.

  • Amniocentesis - In this test, a small amount of amniotic fluid is removed from the amniotic sac by injecting a needle into the body. The amniotic fluid sample is then sent to the laboratory for examination. This test is done before the baby is born to check the defective genes present.

• Imaging Tests - The following imaging tests are recommended to diagnose abnormalities related to the kidneys in Potter syndrome:

  • Abdominal Ultrasound - It is an imaging technique in which images of the developing fetus are obtained. The pregnant female is laid on a table, and a gel is applied to the abdomen. The doctor then moves a device known as a transducer over the abdomen to send sound waves into the body. As a result, the images are obtained on the computer screen. These images help to check if the kidneys have developed properly or not and if they are functioning well. The levels of amniotic fluid can also be detected with the help of ultrasound.

  • Doppler Ultrasound - This test is similar to ultrasound except that the blood vessels and the blood flow that is not visible in the abdominal ultrasound are visible in doppler ultrasound.

  • Antenatal Magnetic Resonance Imaging (MRI) Technique - As the name suggests, this test uses both magnetic fields and radio waves to create images of the internal organs. It can be safely done in pregnant females because the exposure to radiation is very low. The X-ray images obtained after the procedure help to detect the abnormalities in the lungs, kidneys, heart, and other organs of the baby.

  • Chest X-rays - The X-ray images of the chest are obtained after birth to check if the lungs have developed completely or are underdeveloped due to Potter syndrome.

  • Fetal Echocardiography - In this test, sound waves are sent to the body to obtain images of the heart. This test helps to check if the heart of the baby has formed completely or if any abnormalities are present.

What Are the Treatment Options for Potter Syndrome?

The functioning of the kidneys and the lungs should be assessed in children born with Potter syndrome. The following conditions need to be managed first:

1. Kidney Failure - If the kidneys have failed to function, the electrolyte levels need to be carefully monitored. The following treatment options help to manage kidney failure:

   • If the calcium levels of the body are low, calcium carbonate and vitamin D3 tablets can be given to restore the levels.

   • Erythropoietin stimulating agents and iron supplements are to be administered if anemia develops due to chronic kidney disease.

   • If the child suffers from hypertension or high blood pressure due to kidney failure, calcium channel blockers and diuretics are of great help.

   • Gastric feeding tubes can be used to feed the babies to make sure that the nutrition supply is adequate.

2. Respiratory Diseases - If the lungs have not formed completely, oxygen is supplied to the body by means of a ventilator or a chest tube to help the baby breathe.

3. Surgery - The surgical options for Potter syndrome include the following:

   • Peritoneal Dialysis Catheter - In this procedure, a tube known as a catheter is inserted into the body. Next, the tube is connected to a drain bag at one end and dialysis solution at the other end. The peritoneum of the abdominal lining of the body filters the blood naturally with the help of a dialysis solution and sends the waste products out through the tube. It is an effective treatment for kidney failure.

   • Vesicostomy - This procedure is done when the child is suffering from bladder problems and is unable to pass urine normally. A hole or an opening is made in the abdominal region below the belly button to allow the drainage of urine.

   • Kidney Transplant - A healthy kidney (donor's kidney) is transferred to the body to replace the infected one.

   • Nephrectomy - In this procedure, the kidneys or their parts are removed to treat cancer or other abnormalities due to which they have stopped working.

What Are the Complications of Potter Syndrome?

Potter syndrome presents with renal and pulmonary complications, mainly making it difficult for the baby to survive. The complications have been described below:

• Kidney Failure - If the kidneys fail to function, the fluid and electrolyte levels of the body are disturbed to a large extent. The urine does not normally follow due to obstructive uropathy, and the risk of urinary tract infections increases.

• Respiratory Difficulties - The child is unable to breathe due to incompletely developed lungs. The skin of the baby appears blue in color (cyanosis) because of the reduced blood and oxygen supply to the body. The risk of respiratory acidosis increases as carbon dioxide accumulates in the body, causing severe respiratory complications.

Conclusion:

Bilateral renal agenesis is one of the major causes of Potter syndrome. The condition is present by birth and affects babies to a large extent. The kidneys are either missing or incompletely formed, due to which the amniotic fluid is not present in a sufficient quantity around the baby. Ultrasound and other imaging tests help to diagnose the condition even before the baby is born. The treatment of Potter syndrome aims to control the problems associated with renal and pulmonary failure. The condition is not incurable, but the babies born with Potter syndrome need intensive medical care and attention throughout their life.