Potter sequence

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Potter's Sequence is the atypical physical appearance of an infant caused by an oligohydramnios experienced while in the uterus. These include swollen feet, pulmonary hypoplasia and skull anomalies associated with oligohydramnios. Oligohydramnios is a decrease in the volume of amniotic fluid sufficient to cause deformation in infant morphogenesis.

Oligohydramnios is the cause of the Potter sequence but there are many things that can cause oligohydramnios. It can be caused by kidney disease such as bilateral renal agenesis (BRA), ureteral or urethral atresia leading to urinary tract obstruction, polycystic or multicystic kidney disease, renal hypoplasia, ruptured membranes, toxemia, or uteroplacental insufficiency of maternal hypertension.

The term Potter sequence was originally intended to refer only to cases caused by BRA; however, it is now commonly used by many physicians and researchers to refer to any cases that arise with oligohydramnios or anhydramnios without regard to sources of amniotic fluid loss.

Video Potter sequence

Signs and symptoms

Metaefro failure to develop in the case of BRA and some cases involving unilateral kidney agenesis (URA) is mainly due to mesonephric channel failure to produce ureteral shoots capable of inducing metanephric mesenchyme. The failed induction will lead to subsequent degeneration of methropo by apoptosis and other mechanisms. The mesonefric (s) channel of the agentic kidney (s) will also degenerate and fail to connect with the bladder. Therefore, the means by which the fetus is to produce urine and transport it to the bladder for excretion into the amniotic sac has been compromised (in the case of URA), or completely eliminated (in the case of BRA). A decrease in the volume of amniotic fluid causes a growing fetus to be compressed by the mother's uterus. This compression can cause many physical defects of the fetus, the most common being the Potter facies. Lower extremity anomalies often occur in these cases, which often occur in the legs being beaten and/or bent on the legs. Sirenomelia, or "Mermaid syndrome" (which occurs in approximately 1: 45,000 births) may also be present. In fact, almost all reported cases of sirenomelia also present with BRA.

Other anomalies of the classic Potter baby sequence include parrot beak nose, excess skin, and most common characteristics of infants with BRA which is the skin folds of tissue stretching from the medial canthus across the cheeks. Her ears were rather low and pressed to her head making it look great. The adrenal glands often appear as small oval discs pressing the posterior abdomen in the absence of upward kidney pressure. The bladder is often small, incurable and can be filled with a small amount of fluid. In men vas deferens and seminal vesicles may be absent, while in women the uterus and upper vagina may not exist. Other disorders include anal atresia, absence of rectum and sigmoid colon, esophageal and duodenal atresia, and single umbilical artery. The presence of diaphragmatic hernia also occurs frequently in the fetus/infant. In addition, the alveolar sac of the lung fails to thrive as a result of reduced amniotic fluid volume. Labor is often induced between 22 and 36 weeks of pregnancy (however, some of these pregnancies can last a considerable period of time) and infants who can not be cured usually survive only a few minutes to several hours. These babies will eventually die as a result of pulmonary hypoplasia or renal failure.

Maps Potter sequence

Cause

The order of Potter is due to limited ability for certain organs to grow due to severe oligohydramnios.

In one study, the causes causing the Potter sequence were bilateral renal agenesis in 21.25% of cases; cystic dysplasia at 47.5%; obstructive uropathy in 25%; and others 5.25%.

bilateral renal agenesis

Bilateral bilateral agenesis has been estimated to occur at frequencies of about 1: 4000 to 1: 8000 fetuses and neonates. However, recent analyzes predict that such conditions can occur at much larger frequencies. This condition has been reported to occur twice as often in men as in women, suggesting that certain genes of the Y chromosome may act as a modifier. However, no candidate genes on the Y chromosome have been identified.

BRA appears to have a dominant genetic etiology and many cases are the most severe manifestations of dominant autosomal conditions with incomplete penetration and variable expressiveness. There are several genetic pathways that can produce this condition. In 2017 researchers identified an autosomal dominant mutation inherited to the GREB1L gene in two unrelated families as the cause of BRA and URA utilizing Exome Sequencing and direct sequence analysis. This is the first reported genetic lesion involved in the activation of the Target Retinoic Acid Receptor (RAR) that has been associated with renal agenesis in humans. The majority of possible genetic pathways of other candidates are autosomal recessive and do not coincide with the frequency or penetration in which BRA usually occurs in human populations. In addition, the candidate's genetic path will be expected to involve genes expressed in the development of the urogenital system (UGS). Often, these same interacting gene and/or gene pathways are also expressed in developing UGS as well as the central nervous system (CNS), intestines, lungs, limbs, and eyes.

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Type

Since the initial character, the Potter sequence has been defined to be five different subclassifications. There are people in the medical and research fields who use the Potter sequence to specifically refer to only the BRA case, while other groups use the term to refer freely to all instances of oligohydramnios and anhydramnios irrespective of the specific cause. The nomenclature setting for various causes (types) is used to help clarify these differences, but this subclassification and nomenclature system has not been captured in the medical and research community.

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Pathogenesis

Mature kidney development begins between week 5 and 7 of pregnancy. Fetal urine production begins early in pregnancy and consists of most of the amnionic fluid in the second and third trimesters of pregnancy. The fetus continues to swallow the amniotic fluid, which is reabsorbed by the gastrointestinal tract and then reintroduced into the amniotic cavity by the kidneys through the urine. Oligohydramnios occur when the amniotic fluid volume is less than normal for the appropriate pregnancy period. Fetal urine is essential for proper lung development by assisting in airway expansion - alveoli, by means of hydrodynamic pressure and by also supplying proline which is an essential amino acid for lung development. Alveoli is a small sac in the lungs that exchange oxygen with blood. If the alveoli, and thus the lungs, are less developed at birth the baby will not be able to breathe the air properly and will experience respiratory distress immediately after birth due to pulmonary hypoplasia (undeveloped lung). This is the leading cause of death in the baby sequence of Potter which is the cause of renal failure. Fetal urine also serves to protect the fetus from being compressed by the mother's uterus as it grows.

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Prognosis

The result of a bad Potter sequence. A series of 23 patients in 2007 recorded 7 deaths, 4 in the neonatal period. All 16 survivors had chronic kidney disease, with half the end-stage renal failure developing (median age of 0.3 years, range of 2 days to 8.3 years). Victims experienced growth problems (44%) and cognitive and motor developmental delays (25%)

The first surviving child of Bilateral Renal Agenesis (BRA), Abigail Rose Herrera Beutler, was born in July 2013 to US Congressman Jaime Herrera Beutler. A few weeks before he was born, Dr. Jessica Bienstock, an associate professor of maternal-fetal medicine at Johns Hopkins Hospital, gave a series of injections of saline solution into the mother's womb to help the baby's lungs develop. After Abigail was born, the procedure was considered a success. The baby does not need artificial respiration and can breathe on his own. Her parents kept her on kidney dialysis at home until it was old enough to transplant the kidneys. On February 8, 2016, at the age of two, Abigail received a kidney from his father at Lucile Packard Children's Hospital, Stanford in California.

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History

Bilateral renal agenesis (BRA) was first recognized as a defect in human fetal development in 1671 by Wolfstrigel.

In 1946, Edith Potter (1901-1993) described a series of 20 cases in the absence of a kidney, noting the typical appearance of the head and lungs. Until now, the condition itself is considered very rare. However, partly for Potter's work, it has been revealed that this condition presents much more frequently than previously reported. Potter analyzed about 5000 cases of autopsy performed on the fetus and newborn for ten years and found that 20 infants were presented with BRA, all of which had distinctive facial characteristics that did not appear to have a specific embryological correlation with renal anomalies. It was only moments later when he and others connected some of the congenital defects, including the features of Potter facies and also pulmonary hypoplasia, caused by the lack of old amniotic fluid. These facial characteristics are then referred to as the Potter facies. From his analysis, he was able to deduce the sequence of events leading to what is now known as the Potter sequence.

Potter then became a pioneer in the field of human kidney development and its contribution is still used and appreciated by doctors and researchers to this day.

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Terminology

Potter syndrome is not technically a syndrome because it does not collectively present with the same signs and symptoms in each case. This is more accurately described as a "sequence" or chain of events that may have different beginnings (no kidneys, cystic kidneys, blocked ureters or other causes), but all of which end up with the same conclusion (amniotic fluid volume is absent or reduced). This is why Potter's syndrome is often called the sequence of Potter or oligohydramnios sequentially by several doctors and researchers. The term Potter syndrome is most often associated with oligohydramnios sequence conditions regardless of the root cause of the absence or decrease in amniotic fluid volume. However, as mentioned in this article, the term Potter syndrome was originally created to refer to fetuses and infants with BRA. It was not until later that the term became more inclusive as it was noted that other causes of fetal urine failure also produced similar physical characteristics and fetal and infant prognosis with BRA (originally described by Potter in 1946). Since then, the term Potter syndrome has become a mistake and experts have tried not to remove terminology, but to modify it in a way so as to determine the root causes of the different ones by creating the nomenclature of the system. However, this classification system has not been captured in clinical and research fields.

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See also

• Kidney development

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References

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External links

• Iowa Potter University Syndrome Research Group
• 00350 in CHORUS

Source of the article : Wikipedia