[An avoidable cause of parental anxiety and unnecessary medical workup: diaper crystals (pannolithiasis)]

Five infants aged 6 to 23 months had a history of passing crystals in urine. They were not ill, but micturition was reported to be associated with pain in two of them. Physical examination was normal, and urinalysis and culture were negative. In one case we observed "jelly-like crystals" of about 2 mm diameter which dissolved spontaneously in tap water. When the parents were re-questioned it became evident that all used a new brand of highly absorbent diapers. "Jelly-like crystals" developed in our laboratory when the absorbent material of the new diapers was put in contact with urine or tap water. The new highly absorbent diapers help to keep the baby dry. However, "jelly-like crystals" may be observed and possibly alarm both parents and physicians. Information for parents and physicians may avoid unnecessary anxiety or medical workup.