Alterations of Renal and Urinary Tract Function in Children
Congenital renal disorders affect 10% to 15% of the population. These disorders range in severity from minor, easily correctable anomalies to those incompatible with life.
Hypospadias is a congenital condition in which the urethral meatus can be located anywhere on the ventral surface of the glans, the penile shaft, the midline of the scrotum, or the perineum.
Epispadias is a congenital condition in which the urethral opening is located on the dorsal surface of the penis. Epispadias is a mild form of exstrophy, a congenital condition that affects the urethra and bladder neck.
Exstrophy of the bladder is a congenital malformation in which the pubic bones are separated, the lower portion of the abdominal wall and anterior wall of the bladder are missing, and the back wall of the bladder is everted through the opening.
Urethral valves and polyps are congenital formations of tissue that block the urethra.
Ureteropelvic junction obstruction causes urethral obstruction by a malformation of junctional smooth muscle.
A dysplastic kidney is the result of abnormal differentiation of renal tissues. The hypoplastic kidney is a small but otherwise normal kidney.
Polycystic kidneys are an inherited disorder that results in large, fluid-filled cysts within the kidneys.
Renal agenesis is the failure of a kidney to grow or develop. The condition may be unilateral or bilateral and may occur as an isolated entity or in association with other disorders.
Glomerulonephritis is an inflammation of the glomeruli characterized by hematuria, edema, and hypertension. The cause is unknown but is often immune mediated. Glomerulonephritis may follow infections, especially those of the upper respiratory tract caused by strains of group A β-hemolytic streptococcus. Increases in glomerular capillary permeability lead to hematuria and proteinuria.
IgA nephropathy occurs with deposition of IgA in the glomerulus causing glomerular injury with gross hematuria.
Nephrotic syndrome is a term used to describe a symptom complex characterized by proteinuria, hypoproteinemia, hyperlipidemia, and edema. Metabolic, biochemical, or physiochemical disturbances in the glomerular basement membrane may lead to increased permeability to protein.
Hemolytic uremic syndrome is an acute disorder characterized by hemolytic anemia, acute renal failure, and thrombocytopenia.
Urinary tract infections can result from general sepsis in the newborn but are caused by bacteria ascending the urethra in older children. The bladder alone is infected in cystitis. The infection ascends to one or both kidneys in pyelonephritis. Urinary tract anomalies must be surgically corrected to prevent frequent recurrent infections.
Vesicoureteral reflux is the retrograde flow of bladder urine into the ureters providing a mechanism for pyelonephritis in children, whose ureters are shorter than those of adults.
Nephroblastoma (Wilms tumor) is an embryonal tumor of the kidney that usually presents between birth and 5 years of age. The tumor can be successfully treated by surgery, a combination of drugs, and, sometimes, radiation therapy.
Enuresis refers to the involuntary passage of urine. Enuresis may occur during the day (diurnally) or during the night (nocturnally). The disorder tends to occur during non-REM sleep and can have a variety of organic and psychologic causes.