Urinary volume in children with urolithiasis

Aggregate exposures of nine preschool children to persistent organic pollutants at day care and at home

In the summer of 1997, we measured the aggregate exposures of nine preschool children, aged 2-5 years, to a suite of organic pesticides and other persistent organic pollutants that are commonly found in the home and school environment. The children attended either of two child day care centers in the Raleigh-Durham-Chapel Hill area of North Carolina and were in day care at least 25 h/week. Over a 48-h period, we sampled indoor and outdoor air, play area soil and floor dust, as well as duplicate diets, hand surface wipes, and urine for each child at day care and at home. Our target analytes were several polycyclic aromatic hydrocarbons (PAH), organochlorine pesticides, and polychlorinated biphenyls (PCB); two organophosphate pesticides (chlorpyrifos and diazinon), the lawn herbicide 2,4-dichlorophenoxyacetic acid (2,4-D), three phenols (pentachlorophenol (PCP), nonyl phenols, and bisphenol-A), 3,5,6-trichloro-2-pyridinol (TCP), and two phthalate esters (benzylbutyl and dibutyl phthalate). In urine, our target analytes were hydroxy-PAH, TCP, 2,4-D, and PCP. To allow estimation of each child's aggregate exposures over the 48-h sampling period, we also used time-activity diaries, which were filled out by each child's teacher at day care and the parent or other primary caregiver at home. In addition, we collected detailed household information that related to potential sources of exposure, such as pesticide use or smoking habits, through questionnaires and field observation. We found that the indoor exposures were greater than those outdoors, that exposures at day care and at home were of similar magnitudes, and that diet contributed greatly to the exposures. The children's potential aggregate doses, calculated from our data, were generally well below established reference doses (RfDs) for those compounds for which RfDs are available.

Metabolic evaluation of children with urolithiasis: are adult references for supersaturation appropriate?

PURPOSE

We determined the incidence of urinary stone risk factors in pediatric patients with urolithiasis.

MATERIALS AND METHODS

Between 1998 and 2001, 71 children with urolithiasis at 2 pediatric institutions underwent metabolic evaluation. The 24-hour urine samples were analyzed outside central laboratory using adult and known pediatric references. Supersaturation and traditional metabolic parameters were determined and compared.

RESULTS

All patients had metabolic abnormalities. Calcium related abnormalities were present in 92% of children, calcium oxalate supersaturation was abnormal in 69%, calcium phosphate supersaturation was elevated in 70% and traditional calcium parameters were abnormal in 80%. While 11% of the patients had abnormal calcium phosphate or oxalate supersaturation with normal traditional calcium parameters, 10% had normal calcium oxalate or phosphate supersaturation with abnormal traditional calcium parameters. Low urinary volume was identified in 75% of the children.

CONCLUSIONS

Metabolic abnormalities are extremely common in pediatric patients with urolithiasis. Calcium related abnormalities are the most common abnormality. Urinary supersaturation values are complementary to traditional metabolic parameters and may be more sensitive predictors of recurrent stone risk. It is important to establish pediatric reference ranges to interpret these data more accurately.

The most essential nutrient: defining the adequate intake of water

Although water is quantitatively the most import nutrient, there are no recommended dietary allowances (RDA) or adequate intake (AI) values. Based on 718 assessments of 24-hour total water intake, urine volume, and urine osmolality, individual hydration status was characterized in 479 healthy boys and girls of the DONALD study aged 4.0 to 6.9 years and 7.0 to 10.9 years. Mean 24-hour total water intake ranged from 0.90 mL/kcal to 0.96 mL/kcal, and median 24-hour urine osmolality ranged from 683 mosm/kg to 854 mosm/kg. A maximum urine osmolality of 830 mosm/kg (mean - 2 SD) in healthy children with a typical affluent Western-type diet was the physiologic criterion of the upper limit of euhydration. "Water reserve" (24-hour urine volume - hypothetical urine volume to excrete 24 urine solutes at a concentration of 830 mosm/kg) was a quantitative measure of individual 24-hour hydration status and ensuring euhydration in 97% of the subjects in each group; AI values of total water in the 4 age and sex groups ranged from 1.01 mL/kcal to 1.05 mL/kcal. These procedures to quantify 24-hour hydration status may prove valuable in investigating the effects on health of different states of euhydration.

Pediatric urolithiasis

Pediatric stone disease is a frequently underestimated entity that can present unique problems in its management. The condition stems from any of a number of underlying, causative factors, and the significant possibility of recurrence must always be borne in mind. The primary care physician should be aware that the condition is readily treatable by an experienced pediatric urologist who has a range of treatment modalities at his or her disposal; however, overall success is governed by a timely referral and subsequent long-term follow-up to ensure the maintenance of a stone-free state.

Acute bioeffects of electromagnetic lithotripsy

Acute effects of extracorporeal shock wave lithotripsy (ESWL) with Siemens Lithostar on kidney and surrounding tissues were examined on 42 patients with unilateral kidney stones in the Department of Urology, Gazi University, Medical Faculty, Ankara, Türkiye. Radiological examinations were done and 24-h urine and blood samples were obtained a day before, the day after and 30 days after ESWL. Urinary excretion of proteins, glycosaminoglycan, and immunoglobulin G were significantly elevated the day after ESWL. Thirty days after excretion levels of these were statistically insignificant in regard to pretreatment levels. Creatinine clearance of the patients was significantly lowered the day after ESWL. One month later differences were insignificant. Excretory urography detected 12 (29%) kidneys with abnormalities the day after ESWL. Thirty days after only 3 (7%) of the kidneys had persistent abnormalities. The number of abnormalities with ultrasonography 24 h and 30 days after ESWL were 15 (36%) and 5 (12%) respectively. With CT-scanning kidney abnormalities 24 h after and 30 days after ESWL were 24 (57%) and 6 (14%) respectively. There was not any statistically significant difference between patients with either radiological or functional changes after ESWL and with patients without these changes in regard to patient age, sex, stone burden and shock wave number. In conclusion, electromagnetic lithotripsy induces acute renal morphologic and functional changes. Functional changes are transient and subside within a month but although decreasing either in size or number some morphologic changes persist during this period.