KIDNEY DYSFUNCTION

Much like adults, children can also be affected by a number of kidney diseases and disorders, some of which typically appear in infants, with onset during the first year of the child's life, and others affecting older children and adolescents.

The forms affecting very young children generally relate to alterations in kidney growth during fetal development.

Some of these alterations are based on genetics (e.g. polycystic kidney disease), where other family members are affected by the same disease, and other forms may occur due to abnormal fetal development and are individual cases within the family. These forms vary in their extent and gravity, from those deeply altering the overall development of the fetus - and therefore resulting in fetal death - to serious conditions diagnosed in utero (observed during gestation) - to those that go unobserved during the pregnancy and appear during the first few months to a year of the child's life.

While the most critical forms very rarely go undetected or undiagnosed during pre-natal examinations, other forms may not be observed until the first few months after the child is born, with completely non-specific signs and symptoms. Insufficient growth during the first few months, lack of appetite, or polyuria (excessive urination associated with increased thirst), or general malaise in the child, especially if the symptoms linger over time, or even instances of fever not relating to any other determinable cause, could all be warning signs of kidney disease.

There are many conditions that can cause this type of disorder, but the most frequent by far are forms of interstitial nephropathy due to vesicoureteral reflux (abnormal flow of urine from bladder to kidney caused by malformations in the ureters which expel urine produced by the kidney), and primary or secondary congenital obstructions (distal ureter valves, stenosis of the ureter or pelvo-ureteral junction, megaureter). These abnormal conditions are often the cause of kidney infections (pyelonephritis) which, if serious and recurrent, can lead to a critical reduction of kidney mass and therefore, compromised functioning with chronic deficiency, until dialysis becomes necessary.

In these cases, there are just a couple of first-round tests that the child's parents can request of the family pediatrician. In fact, simple urinalysis (which provides information on urine pH and density, thus revealing cases of acidosis and defects in the renal tubule) and a urine culture (to test for infections, the urine sample is collected using a special bag sold in pharmacies) are sufficient enough to formulate an initial diagnostic orientation. If any of these tests should result positive, the parents, assisted by the family pediatrician, will have to then seek assistance at facilities specializing in pediatric kidney disease to schedule a medical visit and second-round testing (e.g. ultrasound and possibly cystography and blood tests).

Metabolic disorders, such as primary hyperoxaluria, can also cause chronic kidney disease in very young children. In older children, acquired forms of nephropathy take on a greater role and, despite being less common than the congenital forms, they progress much more quickly.

Among the children treated with dialysis, approximately one fourth have a chronic form of glomerulonephritis (GN). Chronic forms of GN cause kidney inflammation, often based on immune system disorders (defects and/or alterations in the system of blood cells serving to protect the body against bacteria, viruses, and chemical and physical agents). With certain conditions, especially if there is a predisposition, the immune system may lead to kidney inflammation, often progressing towards the formation of scar tissue, a loss in kidney mass, and resulting decrease in function - to the point where dialysis and kidney transplants become necessary.