two kidneys, which filter waste materials and excess water from the blood
two ureters, which carry urine from the kidneys to the bladder
the bladder, where urine is stored until it is released
the urethra, where urine flows out
of the body
Normal urinary tract
We rely on our kidneys and urinary system to keep fluids and natural
chemicals in our bodies balanced. While a baby is developing in the mother's
womb, much of that balancing is handled by the mother's placenta. The baby's
kidneys begin to produce urine at about 10 to 12 weeks after conception, but the
mother's placenta continues to do most of the work until the last few weeks of
the pregnancy. Wastes and excess fluid are removed from the baby's body through
the umbilical cord. The baby's urine is released into the amniotic sac and
becomes part of the amniotic fluid. This fluid plays a role in the baby's lung
development.
Sometimes, a birth defect in the urinary tract will block the flow of urine
in an unborn baby. As a result, urine backs up and causes the ureters and
kidneys to swell. Swelling in the kidneys is called hydronephrosis. Swelling in
the ureters is called hydroureter.
Swelling in the kidney is called hydronephrosis. Swelling in the ureter is
called hydroureter.
Hydronephrosis is the most common problem found during ultrasound examination
of babies in the womb. The swelling may be barely detectable or very noticeable.
The results of hydronephrosis may be mild or severe, but the long-term outcome
for the child's health cannot always be judged by the severity of swelling.
Urine blockage may damage the developing kidneys and reduce their ability to
filter. The blockage may also raise the risk that the child will develop a
urinary tract infection (UTI). Recurring UTIs can lead to more permanent kidney
damage. In the most severe cases of urine blockage, the amniotic sac is so
reduced that the lack of fluid threatens the baby's lung development.
Types of Defects in the Urinary Tract
Hydronephrosis can result from many
types of defects in the urinary tract. Doctors use specific terms to describe
the type and location of the blockage.
Vesicoureteral reflux (VUR). The openings where the ureters empty urine into
the bladder should work like valves to keep urine from backing up into the
ureters. Sometimes the valve doesn't work properly and urine flows back into the
kidneys. The urine may flow only a short way back into the ureters, or it may go
all the way back to the kidneys, causing the ureters and kidneys to swell. VUR
may occur in only one ureter or in both. Kidneys with severe reflux may not
develop normally, and after birth kidneys with reflux may be at risk for damage
from infections.
Ureteropelvic junction (UPJ) is the point where the ureter joins the kidney.
Ureteropelvic junction (UPJ) obstruction. The point where the ureter joins
the kidney is called the ureteropelvic junction. If urine is blocked here, only
the kidney swells. The ureter remains at a normal size. UPJ obstruction usually
only occurs in one kidney.
Bladder outlet obstruction (BOO). BOO describes any blockage in the urethra
or at the opening of the bladder. The obstruction may occur in boys or girls.
The most common form of BOO seen in newborns and during prenatal ultrasound
examinations is posterior urethral valves (PUV). BOO caused by PUV occurs only
in boys.
Posterior urethral valves (PUV). In boys, sometimes an abnormal fold of
tissue in the urethra keeps urine from flowing freely out of the bladder. This
defect may cause swelling in the entire urinary tract, including the urethra,
bladder, ureters, and kidneys.
Ureterocele. If the end of the ureter does not develop normally, it can
bulge, creating what is called a ureterocele. The ureterocele may obstruct part
of the kidney or the bladder.
Ureterocele. The inset shows a cross-section of the ureter bulging into the
interior of the bladder.
Nerve disease. Urination requires coordinated nerve signals between the
bladder, spinal cord, and brain. Spina bifida and other birth defects that
affect the spinal cord may interrupt nerve signals and lead to urine retention
in newborns.
Although a fever technically is any body temperature above the normal of 98.6 degrees F. (37 degrees C.), in practice a person is usually not considered to have a significant fever until the temperature is above 100.4 degrees F (38 degrees C.). Fever is part of the body's own disease-fighting arsenal: rising body temperatures apparently are capable of killing off many disease- producing organisms.
Nausea is an uneasiness of the stomach that often precedes vomiting. Nausea and vomiting are not diseases, but they are symptoms of many conditions. The causes of vomiting differ according to age, and treatment depends upon the cause of nausea and vomiting.
Hydronephrosis is a condition in which the kidney swells, due to a backup of urine. Hydronephrosis generally occurs with another disease.Symptoms of hydronephrosis include nausea, vomiting, urinary tract infection, fever, painful urination, increased urinary frequency and urgency, flank pain, and swelling of the abdomen. Treatment of hydronephrosis depends on the cause.
Birth defects have many causes and currently, are the leading cause of death for infants in the first year of life. Some of the causes of birth defects include genetic or chromosome problems. Exposure of the mother to rubella or German measles during pregnancy, or using drugs or alcohol during pregnancy. The treatment for birth defects depends upon the condition of the effected child.
Spina bifida is the most common neural tube defect in the United States. There are four types of spina bifida; 1) occulta, 2) closed neural tube defects, 3) meningocele, and 4) myelomeningocele. The cause of spina bifida is not known. Theories include genetic, nutritional, and environmental factors. Lack of folic acid during pregnancy is highly suspected. Symptoms of spina bifida vary from individual to individual. Treatment depends on the type of spina bifida the person suffers.
Urinary tract infections (UTIs) are very common in children. Symptoms and signs include fever and abdominal pain. Associated symptoms and signs include flank pain, vomiting, and blood in the urine. Treatment for a UTI involves antibiotic therapy.
Fever refers to an elevation in body temperature. Technically, any body temperature above the normal oral measurement of 98.6 F (37 C) or the normal rectal temperature of 99 F (37.2 C) is considered to be elevated. However, these are averages, and
one's normal body temperature may actually be 1 F (0.6 C) or more above or below the average of 98.6 F. Body temperature can also vary up to 1 F (0.6 C) throughout the day.
Fever is not considered medically significant until body temperature is above 100.4 F (38 C). Anything above normal but below 100.4 F (38 C) is considered a low-grade fever. Fever serves as one of the body's natural defenses against bacteria and viruses which cannot live at a higher temperature. For that reason, low fevers should normally go untreated, unless accompanied by troubling symptoms.
Also, the body's defense mechanisms seem to work more efficiently at a higher temperature. Fever is just one part of an illness...