19.8 Medications Used in Patients with PUV

•Potential complications of cutaneous ureterostomies include:

–Ureteral devascularization

–Inadequate drainage

–Stomal stenosis

•Secondary bladder surgery:

–Augmentation cystoplasty:

•Indications for bladder augmentation include:

–Inadequately low bladder storage volumes and high bladder pressures despite anticholinergic medication and clean intermittent catheterization.

–Augmentation cystoplasty can significantly improve patient lifestyle in those who have intractable incontinence due to poor compliance and bladder overactivity.

–By lowering intravesical pressures, the upper urinary tract may also be protected.

–The ileum is most commonly used; however, large bowel, stomach, and ureter are also used.

–Augmentation should only be offered to patients willing to commit to lifelong intermittent catheterization.

–Potential complications include:

•Bladder rupture (approximately 10 % of patients)

•Electrolyte disturbances, which may be worsened by the placement of intestinal mucosa in contact with urine, especially in those with a serum creatinine greater than 2 mg/dL.

•Mucus production, which can be a source of catheter blockage and may be a nidus for stone formation.

•The future risk of neoplasia has not yet been defined in these patients, but several cases of malignant degeneration in augmented bladder have been reported.

–Continent appendicovesicostomy:

•In children with PUVs, institution of clean intermittent catheterization through the sensitive urethra can be difficult.

•In addition, some patients may have a much dilated proximal urethra which may not be easily catheterized.

•The procedure involves placement of a nonrefluxing tubular conduit for catheterization between the bladder and skin to provide an alternative channel for catheterization.

•This is also called the Mitrofanoff technique

•The catheterizable tubular conduit can be formed from:

–The appendix

–The ureter

–Tubularized bowel

•The stoma often can be hidden in the umbilicus to provide acceptable cosmesis.

•Some patients with PUV:

–Continue to suffer from urinary tract infection

–Their renal function remains fragile or deteriorates

–Have a significant deterioration in the appearance of the upper tracts

–Their bladder emptying is incomplete

•The aim in these children should be to maximize their renal potential and to delay or avoid renal replacement.

•These patients can be managed by early urinary diversion, either by vesicostomy or bilateral ureterostomy or pyelostomy. This aims to protect the upper urinary tracts and minimize the risks of infection.

•A recent development is the use of a refluxing ureterostomy as a form of urinary diversion. The refluxing ureterostomy is particularly useful in boys with fragile renal function. This technique will minimize the potential harmful effects of the high-pressure bladder that is present in the early period following valve ablation.

19.8Medications Used in Patients with PUV

•The primary medications involved in bladder management are anticholinergic medications used to improve bladder compliance.

•Other medications that may be needed include prophylactic antibiotics and medications used in the management of renal insufficiency.

–Anticholinergic medications are used to improve bladder capacity and compliance in the patient with elevated detrusor pressures, which may cause hydronephrosis, UTI, or incontinence.

–Early use of anticholinergic medications has been associated with improved bladder function in infants with high voiding pressures and low storage volumes.

–Oxybutynin chloride (Ditropan) inhibit the muscarinic action of acetylcholine on smooth muscle and exerts an antispasmodic effect on bladder smooth muscle (anticholinergic action) leading to its relaxation.

–Hyoscyamine sulfate (Levbid, Levsin) inhibit the postganglionic cholinergic receptors on smooth muscle cells.

–Tolterodine (Detrol) is a new more selective antimuscarinic drug targeted for detrusor smooth muscle.

–Antibiotics

•Patients with history of recurrent UTI may benefit from antibiotic prophylaxis, especially in the presence of vesicoureteral reflux.

–Prophylactic dosage is usually one quarter of the therapeutic dose administered once per day.

–More appropriate antibiotics in children include trimethoprim (TMP), sulfamethoxazole (SMZ), nitrofurantoin, and amoxicillin.

–Trimethoprim and sulfamethoxazole (Bactrim, Septra, Cotrim) alone or in combination with SMZ is the most commonly used antibiotic for both treatment and prophylaxis of UTI.

19.9Prognosis and Follow-Up

•PUV is a lifelong condition that requires continued medical management.

•Subsequent renal deterioration and bladder changes can be treated and minimized with adequate follow-up care.

•These patients need periodic radiologic and urodynamic evaluation to monitor the upper urinary tract and bladder changes to determine bladder capacity, compliance, and post void residual urine volumes.

•They should have periodic renal sonography and serum creatinine levels.

•Urinary incontinence: Approximately one third of patients with PUVs have problems with diurnal enuresis when older than 5 years. Diurnal enuresis may be caused by the bladder changes that lead to elevated storage pressures and poor emptying.

•Rarely, sphincteric dysfunction secondary to valve ablation can be present. Treatment includes:

–Anticholinergic medications

–Clean Intermittent Catheterization (CIC)

–In some patients, bladder augmentation

•Pulmonary hypoplasia secondary to intrauterine renal dysfunction and oligohydramnios is the primary cause of death.

•Other complications of PUV are generally secondary to chronic bladder changes, leading to elevated detrusor pressures which subsequently lead to progressive renal damage, infection, and incontinence.

•Renal insufficiency and end stage renal disease is expected in those with severe posterior urethral valve.

–Approximately 25 % of those with PUVs die of renal insufficiency in the first year of life

–Approximately 25 % of those with PUVs die later in childhood

–Approximately 50 % survive to adulthood with varying degrees of renal function

–Today, with good follow-up, early diagnosis and treatment, and advent of better techniques in the treatment of pediatric renal insufficiency, most of these children can be expected to survive. This also include early diagnosis and aggressive treatment of infections and bladder dysfunction.

•There are several risk factors for progression of PUV related complications which include:

–Elevated nadir creatinine defined as greater than 1 mg/dL measured during the first year of life.