Unit 2: Renal and Urological System

Alterations of Renal and Urinary Tract Infection in Children Notes:

The abnormalties range from minor, nonpatholgic, or easily correctable anomalies to those incompatiable with life. Structural anomalies of the renal system account for approx. 45% of cases of renal failure in children, and many are linked to gene effects.

In children: kidney dysfunction can be associated w/ mechanisms and manifestations ( different than adults)

  • abnormalities can occur from 10-15% of the fetal population

Hypospadias: is a congential condition in which the urethral meatus is located on the ventral side or undersurface of the penis. It occurs in about 100 in 300 infant boys and appears to be increasing. The cause of this condition is due to the maternal intake of progestin, advanced maternal age, and other environemental factors.

  • can perform corrective surgery

Chordee: ( penile torsion) may cause side- tethering and shortening of the subcutaneous tissue which causes the penis to bend or bow ventrally.

Epispadias: in male epispadias the urethral opening is on the dorsal surface of the penis. In females a cleft along the ventral urethra usually extends to the bladder neck.

Exstrophy: a rare extensive congential anomaly in which the bladder wall opens directly onto the abdominal wall. This occurs in 1 in 40000 births and occurs equaly in gender.

  • it is caused by intrauterine failure of the abdominal wall and the mesoderm of the anterior bladder to fuse. This can cause a waddling gait when the child first learns to walk. The clit of girls is divided into two halves with the urethra between them and in boys the penis is epispadic.

  • Urine can then seep onto the abdominal wall fro the ureters causing a constant odor of urine and excoriation of the surrounding skin. - can bleed easily / painful

Bladder Outlet Obstruction:

Congential causes of BOO are rare and include urethral valves and polyps.

  • a urethral valve is a thin membrane of tissue that occludes the urethral lumen and obstructs urinary flow. ( mostly occur in posterior urethra)

  • urtheral polyps rarely arise but can often cause relatively severe obstruction and may impair renal embryogenesis and lead to renal failure.

  • They are both resected during the first days of life using a small cystoscope.

Ureteropelvic Junction Obstruction: ( UPJ)

is a blockage of the tapered point where the renal pelvis transitions into the ureter. It is the most common cause of hydronephrosis in neonates.

During infancy or childhood , secondary UPJ is caused by kinking or secodnary scarring in the presence of high-grade vesicoureteral reflux. This can affect the obstructed and contrallateral kidneys.

  • diagnosis can be made by ultrasound and surgical or endoscopic pyeloplasty which will relieve the obstruction

Ureterocele : occurs when a short acontractile segment of ureter develops above the ureterovesical junction. ( this is usually corrected surgically).

Hypoplastic/ Dysplastic Kidneys:

A hypoplastic kidney is usually small but normal and could develop more. They can be unilateral or bilateral.

Bilateral Hypoplastic kidney can causes chronic renal failure in children.

Renal Dysplasia usually resulrs from abnormal differeniation of the renal tissues. Dysplasia is also associated with the obstruction of the collecting system. The obstruction can begin before birth as in congential absense of abdominal muscles.

Polycystic Kidneys

Polycystic kidney disease is an autosomal dominant and autosomal recessive inherited disorder. It occurs in 1 in 1000 live births.

The affected kidney will have large fluid-filled cysts that include the tubules and collecting ducts. other organs like the liver, pancreas, or ovaries can have cysts as well. Symptoms may not devloped into adulthood.

Renal Agenesis

This is where one or both kidney are absent; they can be unilateral or bilateral and randomly occuring or hereditary. This condition can also occur as an isolated entity or as a problem associated with other urological disorders.

Unilateral Renal Agenesis occurs in aprrox. 1 in 1000 live births. Males are affected more than females , and the left kidney is usually absent.

In bilateral renal agenesis it occurs in 1 to 4 in 10000 live births, 75% being male.

Potters Syndrome: a specific group of facial anomolies ( wide- set eyes, low - set ears, beak like nose, and a longer chin.) Infants with this syndrome rarely live more than a few hours. 40% of affected infants are stillborn.

Renal Agenesis can be detected with an ultrasound.

Glomerular Disorders

Glomerulonephritis : a number of disorders in which proliferation and inflammation of the glomeruli are secondary to an immune mechanism. Chronic glomerulonephritis accounts for 53% of renal failure in children and is the causing factor for children that need dialysis and kidney transplants.

Poststreptococcal glomerulonephritis

a common immune complex- mediated renal diseases in children. This condition occurs after a throat or skin infection with certain strains of group A B-hemolytic streptococci.

pharyngeal infections are most common during cold weather. Skin infections usually occur during warm weather.

Glomerulonephritis develops with the deposition of antigen-antibody complexes in the glomerulus.

Symptoms of varying sevrity develop about 1 to 3 weeks after the streptococcal infection. The most severely affected develop acute renal failure with oliguria. The onset of symptoms in the child is abrupt and consists of flank or midabdominal pain, irritability, general malaise, and fever.

the disease usually runs its course in 1 month, but urine abnormalities may be found for up to a year after the onset. Treatment is symptom specific.

Immunoglobulin A Nephropathy

the most common form of glomerulonephritis worldwide and occurs more often in males.It is charcterized by deposition mainly of immunogloubin IgA and some IgM and some complement proteins in glomerular capillaries and the mesangium.

Deposits of IgA can cause immune injury to the glomerulus that is usually reversible.

Henoch-Schonlein purpura nephritis is a particular form of IgA nephropathy that involves a systemic vasculitis. The pathogensis is unknown.

Children with this disease may have recurrent gross hematuria. Treatment is supportive because kidney damage is generally insignificant. 20% of affected children develop the progressive form of the disease , however, with hypertension and decreasing renal function. These children eventually need dialysis and transplantation.

Nephrotic Syndrome

Nephrotic Syndrome is a symptom complex related to loss of protein in the urine. When the kidney is the only organ involved this is known as primary nephrotic syndrome and the cause is usually unkown ( idiopathic)

If it is caused by a systemic disease or other causes like drugs or toxins, it is called secondary nephrotic syndrome .

The most common causes of nephrotic syndrome are minimal change nephropathy and focal segmental glomerulosclerosis. MCN is the fusion of the glomerular podocyte foot processes. In FSGS there is a segmental loss of glomerular capillaries with proliferation of the cappilaries to the Bowman’s capsule.

Clinical Manifestation can included foamy urine, edema with periorbital swelling, ascites, respiratory diffulties, and labial or scrotal swelling. BP usually decreases and a child will have an increased susceptibility to infection.

Evalution and Treatment: a diagnosis of nephrotic syndrome is evident from the finding of protienuria, hyperlipidemia, and lipiduria. Kidney biopsies are included in testing especially if the cause is intrinsic renal disease. To treat nephrotic syndrome an individual must maintain a low -sodium diet, take diuretics, and have good skin care. Immunosuppressive agents can be given to children who have relapsed or are resistant to steroid therapy.

Hemolytic Uremic Syndrome

HUS is an acute disorder charcterize by hemolytic anemia, thrombocytopenia, and acute renal failure. HUS is the most common cause of acute renal failure in children.

HUS will occur in infats and children younger than 4 year of age and about 90% of children survive after prognosis

HUS has been associated with bacterial and viral agents. Damaged blood cells cause acute hemolytic anemia.

Fibrinolysis the process of dissolution of clot, acts on precipitated fibrin, causing the fibrin to appear in serum and urine.

Clinical Manifestations can include fever, vomiting, and diarrhea, or an upper respiratory infections. The renal failure can cause metabolic acidosis, hyperkalemia, and often hypertension.

Evaluation and Treatment: Clinical manifestations includes history of preexisting illness, presenting a blood and urine analysis. Blood transfusions with packed red cells are sometimes required

Other Renal Disorders

  • Renal Tubular Acidosis

Bladder Disorders

Urinary Tract Infections

  • they are caused by bacteria in the bloodstream that have settled in the urinary tract. They are most common in 7- 11 year old girls as a result of perineal bacteria ascending to the urethra.

Cystitis is an infection of the bladder resulting from mucosal inflammation and congestion

Vesicoureteral Reflux

VUR is the retrograde flow of urine from the bladder into the ureters. The reflux allows infected urine from the bladder to be repeatedly swept up into the kidneys.

The combination of reflux and infection is important cause of pyelonephritis, especially in children younger than 5 years.

Nephroblastoma ( Wilms Tumor)

is a rare embryonal tumor of the kidney arising from undifferentiated mesoderms and represents 5 to 6% of childhood cancers in the US. It has sporadic and inherited origins and this tumor has been linked to mutations of several tumor suppressor genes.

Clinical Manifestations: This tumor is usually large in size and is noticable because of abdominal swelling. A child may have a fever, abdominal pain, or hematuria symptoms. Nephroblastoma can occur in any part of the kidney.

Evaluation and Treatment: In a evaluation the tumor should feel firm and smooth and it is usually confined to one side of the abdomen. To remove the tumor an individual must go through surgery.

Enuresis

Enuresis is the involuntary passage of urine by a child who is beyond the age of when voluntary bladder control should occur. Most bladder control can be done by children before the age of 4 or 5. In 80% of children enuresis occurs at night only ( nocturnal enuresis). During the day this would be called diurnal enuresis.

Types of Enuresis

  • Primary Enuresis: the child has never been continent

  • Secondary Enuresis or ( Acquired Enuresis): the child has expereinced a period of dryness of at least 3 to 6 months after toilet training and then becomes incontinent

Incontinent: the inability to control a flow of urine.

Total Incontinence: Inability to store any urine; can indicate and anatomical absence.

Overflow Incontinence: frequent dribbling that relieves a constantly full bladder; occurs when the urinary outlet is obstructed.

Urge Incontinence: sudden and uncontrollable need to void that cannot be suppressed; this suggest bladder irritation

Precipitate Incontinence: Voiding without a preceding urge to void; suggest neurological origin.

Stress Incontinence: uncontrollable voiding that occurs when intravesical pressure exceeds intravesical resistance; this suggest alteration in intrinsic sphincter integrity

Paradoxic Incontinence: incontinence in spite of normal voiding; ( ex. when a young woman is constantly wet but voids normally)