Diagnosis

Clinical presentation

Epidemiology

Peak presentation for adults is middle age. Children can present with stones at any age (eg, premature newborn to teenager).

In children, calcium stones are most common (adults also are most often afflicted with calcium oxalate or calcium phosphate stones).

In some cases, the primary cause of stone formation cannot be identified.

Stones are more frequent in men than in women (4:1), although the boy-to-girl ratio (3:2) is closer to equal.

 

In adults, upper tract calculi present in a characteristic fashion in the form of renal colic. This severe, intermittent, refractory pain, often accompanied by nausea and vomiting, is a less common presentation in children.

The most common symptoms of kidney stones include:

· Pain in the belly or back

· Blood in the urine (hematuria)

· Nausea or vomiting

· Needing to rush to the bathroom to urinate

However, some children, particularly young children, do not have any symptoms, and the kidney stone is found when an imaging test (like an X-ray) is done for another reason. Some kidney stone symptoms are similar to those of a bladder infection.

Pain is noted in 50% of children with urolithiasis. The pain can localize to the upper abdomen, flank, or pelvis and may radiate to the umbilicus or groin. Associated nausea and vomiting are not uncommon.

The typical patient with renal colic moves constantly trying unsuccessfully to find a comfortable position as opposed to the patient with peritonitis who attempts to remain still. Hematuria may be noted in 30% to 90% of children with stones, but gross hematuria is relatively uncommon.

Although classic renal colic does occur in children, more commonly, stones involving both the upper and lower tract are detected during the radiologic evaluation for urinary tract infection (UTI) or hematuria. Younger children in particular may also present with nonspecific abdominal pain accompanied by microscopic hematuria or, less frequently, with outlet obstruction.

 

History and physical examination are key components to rule out other causes of abdominal and back pain. The history should include a dietary and urologic history.

One clue to the presence of urolithiasis is a positive family history for kidney stones, which may be present in up to 37% of children with stone disease.

Other underlying medical conditions that may predispose children to urolithiasis include hyperparathyroidism, renal tubular acidosis, inflammatory bowel disease, seizure disorders treated with a ketogenic diet, cystic fibrosis, and Dent disease.

Laboratory Studies: urinalysis and hematuria, urine pH, crystals in the sediment, and UTI. Baseline serum electrolytes, blood urea nitrogen, creatinine, calcium, uric acid, phosphorus, and magnesium levels should also be obtained. A 24-hour urinalysis for stone risk assessment should be obtained after treatment of the presenting stone.