Infants and children with bilateral dysplasia often require additional sodium and water due to renal wasting. With MCD surgical removal of the kidney is rarely indicated unless severe HTN or recurrent UTI occurs.
Treatment of HTN can prolong maintenance of renal function. General therapy of CKD (see Chapter 165) can improve growth and development.
UT obstruction often requires drainage or surgical correction. Treatment of posterior urethral valve consists of either primary valve ablation or diversion (usually via vesicostomy) if ablation is not possible. Ectopic ureters are frequently obstructed; when this happens, surgical intervention is required.
Children with neurogenic bladder are prone to UTI and renal impairment from poor urine emptying. Clean intermittent catheterization or a urinary diversion is used to help minimize these complications.
Urinary tract calculi are called nephrolithiasis or urolithiasis. Primary bladder stones can be seen with recurrent urinarytract infections (UTIs), neurogenic bladder or bladder surgery(sutures serve as a nidus), and intestinal bladder augmentation.Renal stones can result from obstructive abnormalities or an underlying metabolic predisposition. In industrialized societies,most stones (>90%) in children arise in the urinary tract (UT)and become symptomatic with passage or if lodged (commonlyat the ureteropelvic junction or the ureterovesical junction).Metabolic causes include idiopathic familial hypercalciuria(IHC), hyperoxaluria, uric acid disorders, distal renal tubularacidosis, cystinuria, hypercalcemic hypercalciuria, and primaryhyperparathyroidism. Some children with UT abnormalitiesand stones have a concomitant metabolic predisposition.
Acute obstruction of urine flow is the cause of renal colic, a severe sharp intermittent pain in the flank or lower abdomen often radiating to the groin. Vomiting, distress, and inability to relieve pain with position changes are characteristic. In younger children, classic symptoms may not be apparent; fussiness and vomiting may be the only symptoms. Hematuria may be gross or microscopic and typically clears rapidly with passage of gravel or stone material.
Renal ultrasound may identify kidney stones in the kidney but can easily miss UT stones. Computed tomography (CT), particularly a helical CT, can identify stones throughout the UT, but stones can be obscured by oral or intravenous contrast material. Etiologic diagnosis is facilitated when stone material can be obtained and sent for analysis. Spot or 24-hour urine studies for mineral and electrolyte determinations, obtained on a typical diet for the child, are important to characterize any underlying metabolic predisposition and are valuable even when a stone is available for analysis.
Acute treatment of urinary calculi consists of hydration and analgesia. Chronic treatment for all types of metabolic stonesinvolves vigorous fluid intake, usually twice maintenance rates.Infection-related stones require treatment of infection and oftenremoval of the stone as well as correction of any predisposinganatomic abnormality. Specific metabolic conditions require specific treatments; for IHC, normal calcium intake with low sodium and low oxalate intake is prescribed. For some children with IHC,potassium citrate or thiazides are required to minimize stonerecurrence. Lithotripsy or surgery by a pediatric urologist may berequired for children with large, infected, or obstructing stones.