What are the signs of fetal renal agenesis?

            Every parent wants the best for their child. To have a healthy child starts from way before pregnancy occurs and of course, great care during pregnancy and eventually childbirth. Providing the best for the child allows the child to be healthy and have a bright future ahead. This is why it is important to take care of your health as health not only affects you as an individual, but also your future child. In this article, we will be learning about one of the many conditions that can affect a baby known as fetal renal agenesis.

            Renal agenesis is a complete absence of one (unilateral) or both (bilateral) kidneys. A kidney may be absent because it never developed which is rare or because of complete regression of a kidney. Unilateral renal agenesis occurs in 1 out of 2000 births whereas bilateral renal agenesis occurs in 1 out of 5000 births. This shows that fetal renal agenesis is quite a rare condition.

            It is not known why renal agenesis occurs. Most cases are not inherited from parents. However, in some cases, it is said to be caused by genetic mutations causing the kidney unable to grow or form properly. These mutations of genes are passed on by the parents. Due to the fact that renal agenesis is part of a syndrome, these children may have other problems with other systems in the body such as digestive system, nervous system, cardiovascular system and musculoskeletal system. These problems might have been caused by the gene mutations. Bilateral renal agenesis tends to occur when at least mother or father has kidney malformations or unilateral kidney agenesis.

            Babies born with unilateral renal agenesis can show signs and symptoms at birth, childhood or even later in life. Symptoms include high blood pressure, urine with protein or blood and swelling in the face, hands or legs. Some may have genital anomalies or abnormalities. Signs of bilateral renal agenesis are usually the wide-set eyes, a “parrot beak” nose, a receding chin and large low set ears deficient in cartilage. Other symptoms include excess and dehydrated skin, prominent folds at the corner of each eye, facial expression of an older infant and deformities of the hands and feet. Other associated syndromes found in 10% cases include Fraser syndrome, VACTERL association and MURCS association.

            Babies born with bilateral renal agenesis are commonly referred to as lethal conditions. This is because when a fetus completely lacks both kidneys, oligohydramnios develop. Oligohydramnios is the insufficient amount of amniotic fluid. This can lead to pulmonary hypoplasia and the Potter sequence. Pulmonary hypoplasia is a rare congenital anomaly characterised by incomplete development of the lung tissues. Such anomaly causes the impairment of the respiratory function, making it difficult for the fetus to breathe normally at birth. The Potter sequence describes the typical physical appearance caused by pressure in the uterus due to oligohydramnios.

            Due to the fact that renal agenesis may affect the baby greatly, what can be done by parents to be prepared with such a possibility of the disease is to ensure they do have discussion with the doctor. Fetal kidneys can be visualised by ultrasound at 12 weeks of gestation or pregnancy. Diagnosis of renal agenesis is typically made during ultrasound examination. Renal agenesis is conclusively diagnosed only through direct assessment by abdominal ultrasound, CT or MRI scan, surgery or autopsy. Bilateral renal agenesis is always considered in an infant with Potter sequence. Unilateral renal agenesis may not be visible at delivery if the opposite side of the kidney is functioning, hence, diagnosis may take months or years.

            Parents should expect their children will have a range of outcomes depending on the severity of the renal agenesis. While children with unilateral renal agenesis do not have long-term problems, the other kidneys are expected to grow larger due to overwork of compensating the work of 2 kidneys. Small number of children may have higher risk for health problems in later life such as vesicoureteric reflux (urine flows backward from the bladder into the ureters or kidneys), high blood pressure and protein in the urine. The good thing is, the children are able to do many things and be active just as other children their age do.

            Unfortunately, fetal bilateral renal agenesis is often difficult to thrive after birth. 40% of these babies will be stillborn and even born alive, will only live for a few hours. Although there are rare chances of having a child with bilateral renal agenesis, parents can actually expect a baby with this condition to survive as there are new treatments available. The first known baby to survive bilateral renal agenesis has been recorded in 2013 thanks to the new treatment and received a kidney transplant a few years later. The new treatment is the injection of saline solutions to restore amniotic fluid and allow lung development. This shows that there is hope for those with these severe conditions to live a long life.

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