Description
The kidneys play a critical role in the body: Acting as the body's
filtering system, they help control water levels and eliminate wastes
through urine (pee). They also help regulate blood pressure, red blood
cell production, and the levels of calcium and minerals.
But sometimes the kidneys don't develop properly and, as a result, don't function as they should. Often these problems are genetic and not due to anything a parent did or didn't do.
Many of these problems can be diagnosed before a baby is born through routine prenatal testing and treated with medication or surgery while the child is still young. Other problems may appear later, with symptoms such as urinary tract infections (UTIs), growth problems, or high blood pressure (hypertension).
In some cases, the problems can be severe and require surgical treatment.
How the Kidneys Work
The kidneys are like the body's garbage collection and disposal system. Through microscopic units called
nephrons,
the kidneys remove waste products and extra water from the food a
person eats, returning chemicals the body needs (such as sodium,
phosphorus, and potassium) back into the bloodstream. The extra water
combines with other waste to become urine, which flows through thin
tubes called
ureters to the bladder, where it stays until it exits through the
urethra (the tube that carries urine out of the body from the bladder) when someone goes to the bathroom.
The kidneys also produce three important hormones: erythropoietin,
which stimulates the bone marrow to make red blood cells; renin, which
helps regulate blood pressure; and the active form of vitamin D, which
helps control the calcium balance in the body and maintain healthy
bones.
Kidney failure, which is also called
renal failure,
is when the kidneys slow down or stop properly filtering wastes from
the body, which can cause buildups of waste products and toxic
substances in the blood. Kidney failure can be
acute (sudden) or
chronic (occurring over time and usually long lasting or permanent).
-
Acute kidney injury (sometimes called acute kidney failure) may be
due to bacterial infection, injury, shock, heart failure, poisoning, or
drug overdose. Treatment includes correcting the problem that led to the
kidney injury and, in some cases, dialysis.
- Chronic kidney failure involves a deterioration of kidney function
over time. In kids and teens, it can result from acute kidney failure
that fails to improve, birth defects, chronic kidney diseases, or
chronic severe high blood pressure. If diagnosed early, chronic kidney
failure can be treated. The goal of treatment usually is to slow the
decline of kidney function with medication, blood pressure control, and
diet. At some point, a kidney transplant may be needed.
Childhood Kidney Diseases
The most common kidney diseases in children are present at birth. They include:
Posterior urethral valve obstruction: This narrowing
or obstruction of the urethra affects only boys. It can be diagnosed
before the baby is born or just after and is treated with surgery.
Fetal hydronephrosis: This enlargement of one or
both of the kidneys is caused by either an obstruction in the developing
urinary tract or a condition called
vesicoureteral reflux (VUR)
in which urine abnormally flows backward (or refluxes) from the bladder
into the ureters. Fetal hydronephrosis is usually diagnosed before the
child is born and treatment varies widely. In some cases the condition
only requires ongoing monitoring; in others, surgery must be done to
clear the obstruction from the urinary tract.
Polycystic kidney disease (PKD): This is a condition
in which many fluid-filled cysts develop in both kidneys. The cysts can
multiply so much and grow so large that they lead to kidney failure.
Most forms of PKD are inherited. Doctors can diagnose it before or after
the child is born. In some cases, there are no symptoms; in others, PKD
can lead to UTIs, kidney stones, and high blood pressure. Treatment for
PKD varies — some cases can be managed with dietary changes; others
require a kidney transplant or dialysis.
Multicystic kidney disease (MKD): This is when large
cysts develop in a kidney that hasn't developed properly, eventually
causing it to stop working. (While PKD always affects both kidneys, MKD
usually affects just one kidney.) Fortunately, the unaffected kidney
takes over and most people with MKD will have normal kidney function.
MKD usually is diagnosed by prenatal ultrasound before birth. Doctors
manage it by monitoring blood pressure and screening for UTIs when
needed. Very rarely, surgical removal of the kidney might be necessary.
Renal tubular acidosis: This is when the kidneys do
not properly control the amount of acid in the body. It can cause kidney
stones and affect a child's growth, but usually can be treated with
medications.
Wilms tumor:
This type of childhood cancer involves the kidney, and usually is
diagnosed within the first 2 years of life. It can be treated with
surgery and chemotherapy.
Glomerulonephritis:
This is an inflammation or infection of the glomeruli, which are parts
of the nephrons that contain tiny blood vessels. It can affect the
kidney's ability to filter waste and can lead to swelling, blood in the urine,
and a reduction in urine production. Some cases can be treated with
medication, while others require dialysis or a kidney transplant.
Nephrotic syndrome: This is when the body loses
large amounts of protein through the urine, usually because of a change
in the nephrons. Most cases are diagnosed after a child is a year old.
Swelling of the face, abdomen, and extremities are among the main
symptoms, and are often relieved with medication.
Congenital problems with the urinary tract: As a
baby develops in the womb, part of the urinary tract can grow to an
abnormal size or in an abnormal shape or position. These problems
include:
- duplication of the ureters, in which a kidney has
two ureters instead of one. This can lead to urinary tract infections
over time and can be treated with medication or, in some cases, with
surgery.
- horseshoe kidney, where the two kidneys are fused
(connected) into one arched kidney that usually functions normally, but
is more prone to develop problems later in life. An uncomplicated
horseshoe kidney does not need medical or surgical treatment, but it
does need to be checked regularly by doctors.
Symptoms of Kidney Problems
The signs and symptoms of urinary tract or kidney problems vary and include:
- fever
- swelling around the eyes, face, feet, and ankles (called edema)
- burning or pain during peeing
- significant increase in the frequency of urination
- difficulty in controlling urination in kids who are mature enough to use the toilet
- recurrence of nighttime bedwetting (in kids who have been dry for several months)
- blood in the urine
- high blood pressure
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