Kidney Stones 01: Presentation

This is part of the four part PEMBlog series on kidney stones. Throughout you’ll learn about diagnosis and management of an increasingly recognized problem in the Pediatric Emergency Department.

History

Family history is suggestive in about 1/7 children with stones. Metabolic disorders (intestinal malabsorption) are risk factors. In children with metabolic disorders and delayed development think stones when the presenting complaint includes excessive crying, fussiness or undifferentiated pain. Recurrent UTI (especially Proteus and Klebsiella) as well as urogenital tract structural anomalies are also risk factors you should be aware.

In general a personal history of urolithiasis, a history of nausea and vomiting, the presence of flank pain on examination, and >2 red blood cells per high-power field in urine microscopy were positively associated with urolithiasis – see Persaud et al.

Exam

Obviously do a thorough one – especially the abdomen and GU. If the BP is elevated it could be due to pain, or renal injury. Febrile patients with stones have an obviously higher level of concern for UTI. In general patients with obstructing ureteral stones look very uncomfortable. They are often pale and diaphoretic, tachycardic and can’t find a position of comfort.

Pain

Less than 1/5 are actually symptomatic upon presentation – which is still a lot. Often younger children (especially under 5) will have their stones seen on imaging studies obtained for other indications. In general as you’d expect pain is the most common symptom. It is seen in up to 75% of patients. This includes both flank and abdominal pain. Classic renal colic is severe and intermittent. I liken it to a severe “charley horse” inside the abdomen. Other patients have a persistent dull ache. Children under 5 can’t describe pain as accurately, so they may have nonspecific, poorly localized abdominal pain instead.

Pain is more likely to be seen upon presentation in adolescents than school-aged children (see Milliner et al). Ureteral stones are more painful, as the spasm is intense, and older children and adolescents have them two thirds of the time.

Hematuria

Gross hematuria is less frequent than the microscopic version in one-third to one-half of patients. Note that some voids may be bloody, others not for the individual patient. Arízaga-Ballesteros et al. noted that the absence of gross hematuria had a 100% NPV – but it was only 24 patients.

Dysuria

Only one in ten will have discomfort with urination. Urgency, hesitancy and other symptoms suggestive of UTI are also seen. Note that UTI can be a factor related to stone formation – so this makes sense. These symptoms are more likely if a stone is rumbling about the bladder or hanging out in the urethra.