Urolithiasis and Renal colic

Emergencies in Pediatric Urology

Urolithiasis (from Greek oûron, "urine" and lithos, "stone") is the condition where urinary calculi are formed in the urinary tract.

The term kidney stone (or "renal calculus") is sometimes used to refer to urolithiasis in any part of the urinary tract, however it is more properly reserved for stones that are actually in the collecting duct of the kidney itself.

The term nephrolithiasis can be used to describe the condition of having kidney stones, and ureterolithiasis can be used to describe the condition of having stones in the ureter. Obstruction of the ureter by the kidney stones causes a renal colic attack which is why intense pain is felt in groin and back.

Stone disease describes a condition in which chemicals in the urine crystallize into "stones" in the urinary tract. These stones can cause pain by creating an obstruction of the drainage of the urine. There are many different kinds of urinary tract stones, with calcium, oxalate, uric acid, and phosphate being the most common components (Table 8.1).

Stones may cause problems anywhere in the urinary tract, from the kidney to the ureter and into the bladder.

Pediatric urolithiasis differs from stone disease in adults and tends to more associated with specific metabolic disorders or anatomic abnormalities. Urolithiasis is rare in children in industrialized countries with an estimated prevalence 1/50 to 1/75 of that in adults and is usually localized to the upper urinary tract. Bladder stones are more common in boys in less developed nations, particularly in the Middle East and Asia; these typically consist of ammonium acid urate as a consequence of a low-protein diet.

Table 8.1

Commonly occurring urinary tract stones and describes their salient features.

Composition	Frequency	Radiographic Appearance	Associated Etiologic Factors
Calcium oxalate monohydrate and dihydrate (calcium oxa­late dihydrate)	40-60%	Radiopaque	Underlying metabolic disorder (eg, idio­pathic hypercalcuria or hyperoxaluria)
Hydroxy apatite (calcium phosphate)	20-60%	Radiopaque	Usually no metabolic abnormality
Struvite	5-25 %	Radiopaque	Renal infection
Uric acid	5-10%	Radiolucent	Idiopathic hyperuri­cemia or hyperuri-cosuria
Cystine	5-6%	Mildly opaque	Renal tubular defect
Brushite	2-4%	Radiopaque	---

Дата добавления: 2014-10-15