Potter's Syndrome
Potter sequence (also known as Potter's syndrome, Potter's sequence or Oligohydramnios sequence) is the atypical physical appearance of a fetus or neonate due to oligohydramnios experienced in the womb.[1] Oligohydramnios is the decrease in amniotic fluid volume sufficient to cause disruptions in morphogenesis of the fetus.
Oligohydramnios is the causative agent of Potter sequence, but there are many things that can lead to oligohydramnios. It can be caused by renal diseases such as bilateral renal agenesis (BRA), atresia of the ureter or urethra causing obstruction of the urinary tract, polycystic or multicystic kidney diseases, renal hypoplasia, amniotic rupture, uteroplacental insufficiency from maternal hypertension or toxemia.
Potter's sequence is known in the medical field as clubbed feet, pulmonary hypoplasia and cranial anomalies related to the oligohydramnios.
Classic Potter sequence occurs when the developing fetus has bilateral renal agenesis, which also presents with agenesis of the ureters. BRA has been estimated to occur at a frequency of approximately 1:4000 to 1:8000 fetuses and neonates.
Oligohydramnios is the causative agent of Potter sequence, but there are many things that can lead to oligohydramnios. It can be caused by renal diseases such as bilateral renal agenesis (BRA), atresia of the ureter or urethra causing obstruction of the urinary tract, polycystic or multicystic kidney diseases, renal hypoplasia, amniotic rupture, uteroplacental insufficiency from maternal hypertension or toxemia.
Potter's sequence is known in the medical field as clubbed feet, pulmonary hypoplasia and cranial anomalies related to the oligohydramnios.
Classic Potter sequence occurs when the developing fetus has bilateral renal agenesis, which also presents with agenesis of the ureters. BRA has been estimated to occur at a frequency of approximately 1:4000 to 1:8000 fetuses and neonates.
Importance of Fetal Urine
Development of the mature kidney begins between weeks 5 and 7 of gestation. Fetal urine production begins in early gestation and comprises the majority of the amniotic fluid in the second and third trimesters of pregnancy. The fetus continuously swallows amniotic fluid, which is reabsorbed by the gastrointestinal tract and then reintroduced into the amniotic cavity by the kidneys via urination. Oligohydramnios occurs if the volume of amniotic fluid is less than normal for the corresponding period of gestation. The fetal urine is critical to the proper development of the lungs by aiding in the expansion of the airways - alveoli, by means of hydrodynamic pressure and by also supplying proline which is a critical amino acid for lung development. Alveoli are the small sacs in the lungs that exchange oxygen with the blood. If the alveoli, and thereby the lungs, are underdeveloped at the time of birth the infant will not be able to breathe air properly and will go into respiratory distress shortly after birth due to pulmonary hypoplasia (underdeveloped lungs). This is the primary cause of death to Potter sequence infants secondary to renal failure. The fetal urine also serves to cushion the fetus from being compressed by the mother's uterus as it grows.
Physical Characteristics
The failure of the metanephros to develop in cases of BRA and some cases involving unilateral renal agenesis (URA) is due primarily to the failure of the mesonephric duct to produce a ureteric bud capable of inducing the metanephric mesenchyme. The failed induction will thereby cause the subsequent degeneration of the metanephros by apoptosis and other mechanisms. The mesonephric duct(s) of the agenic kidney(s) will also degenerates and fail to connect with the bladder. Therefore, the means by which the fetus produces urine and transports it to the bladder for excretion into the amniotic sac has been severely compromised (in the cases of URA), or completely eliminated (in the cases of BRA). The decreased volume of amniotic fluid causes the growing fetus to become compressed by the mother's uterus. This compression can cause many physical deformities of the fetus, most common of which is Potter facies. Lower extremity anomalies are frequent in these cases, which often presents with clubbed feet and/or bowing of the legs. Sirenomelia, or "Mermaid syndrome" (which occurs approximately in 1:45,000 births)[6] can also present. In fact, nearly all reported cases of sirenomelia also present with BRA.[7]
Other anomalies of the classic Potter sequence infant include a parrot beak nose, redundant skin, and the most common characteristic of infants with BRA which is a skin fold of tissue extending from the medial canthus across the cheek. The ears are slightly low and pressed against the head making them appear large. The adrenal glands often appear as small oval discs pressed against the posterior abdomen due to the absence of upward renal pressure. The bladder is often small, nondistensible and may be filled with a minute amount of fluid. In males the vas deferens and seminal vesicles may be absent, while in females the uterus and upper vagina may be absent. Other abnormalities include anal atresia, absence of the rectum and sigmoid colon, esophageal and duodenal atresia, and a single umbilical artery. Presence of a diaphragmatic hernia is also common in these fetuses/infants. Additionally, the alveolar sacs of the lungs fail to properly develop as a result of the reduced volume of amniotic fluid. Labor is often induced between 22 and 36 weeks of gestation (however, some of these pregnancies may go to term) and unaborted infants typically survive for only a few minutes to a few hours. These infants will eventually expire as either a result of pulmonary hypoplasia or renal failure.
Other anomalies of the classic Potter sequence infant include a parrot beak nose, redundant skin, and the most common characteristic of infants with BRA which is a skin fold of tissue extending from the medial canthus across the cheek. The ears are slightly low and pressed against the head making them appear large. The adrenal glands often appear as small oval discs pressed against the posterior abdomen due to the absence of upward renal pressure. The bladder is often small, nondistensible and may be filled with a minute amount of fluid. In males the vas deferens and seminal vesicles may be absent, while in females the uterus and upper vagina may be absent. Other abnormalities include anal atresia, absence of the rectum and sigmoid colon, esophageal and duodenal atresia, and a single umbilical artery. Presence of a diaphragmatic hernia is also common in these fetuses/infants. Additionally, the alveolar sacs of the lungs fail to properly develop as a result of the reduced volume of amniotic fluid. Labor is often induced between 22 and 36 weeks of gestation (however, some of these pregnancies may go to term) and unaborted infants typically survive for only a few minutes to a few hours. These infants will eventually expire as either a result of pulmonary hypoplasia or renal failure.
Prognosis
In recorded medical and research history Potter's Syndrome has proved to be 100% lethal in all cases of singleton births. Though recently, there has been a case of a Potter's baby living but we have yet to see the outcome of a prolonged life.
*Borrowed from the web, I do not take credit for writing this information
*Borrowed from the web, I do not take credit for writing this information