Nephrocalcinosis and Renal Dysfunction in Pediatric Intestinal Failure

Abstract

Background: Outcomes of pediatric intestinal failure (PIF) have improved recently, with other comorbidities, such as increased echogenicity/nephrocalcinosis on ultrasound (US) in long-term survivors now evident. We evaluated the significance of nephrocalcinosis over time in PIF and its impact on renal function. Methods: Retrospective analysis on a cohort of PIF patients was performed. Presence of nephrocalcinosis and/or increased renal echogenicity (identified on US), estimated glomerular filtration rate (eGFR; ml · min−1 · 1.73 m−2), renal tubular function, PN volume (ml · kg−1 · day−1) and PN exposure time (hours/day) were reviewed annually over a follow-up period of 2 years. Outcomes in the nephrocalcinosis versus normal US groups were compared. Results: Forty patients (28 boys, median age 2.7 years) were followed for 2 years. Fifteen (38%) had either increased echogenicity or nephrocalcinosis (group 1) at initial US. US were normal in the remaining 25 (62%) on initial assessment (group 2). eGFR did not differ between group 1 and group 2 at baseline (118 vs 133, P = 0.51) and year 2 (130 vs 131, P = 1.00). The percentage of patients with abnormal markers of tubular function was similar in both groups at year 2 (high urine calcium: creatinine 33 versus 30, P = 0.83; high urine calcium: citrate 39 versus 42, P = 0.87; low urine citrate: creatinine 15 versus 17, P = 1.00; high urine oxalate: creatinine 39 versus 25, P = 0.77). Conclusions: A large proportion of PIF patients with a history of parenteral nutrition (PN) exposure have nephrocalcinosis and/or increased echogenicity on US. Over a 2-year follow-up period, however, these abnormalities had no impact on eGFR or renal tubular function.

Children with Intestinal Failure Maintain Their Renal Function on Long-Term Parenteral Nutrition

“…As evidence of this, despite the high frequency of calciuria and hypocitraturia, nephrocalcinosis or renal stones were infrequent in our cohort. The rates of hypercalciuria, hypocitraturia and hyperoxaluria in our study were all slightly above the rates described recently in the pediatric cohort published by Roberts et al [11], in which the patients were younger and with a lesser duration of chronic PN treatment. The latter study, however, reported a higher incidence of nephrocalcinosis than described in our study.…”

“…The median (IQR) daily volume of the PN bags was 1200 (950-1550) mL. All patients used a cycling PN schedule at night, with a median (IQR) infusion duration of 11(10)(11)(12) h. All consumed oral or enteral nutrition during daytime as tolerated. PN provided median (IQR) energy per body weight of 50 (40.2-59.5) kcal/kg/day.…”

Normal anthropometry does not equal normal body composition in pediatric intestinal failure

“…Once a condition with a high mortality, pediatric intestinal failure is now considered a complex but survivable disorder 3 . The introduction of multidisciplinary teams and novel therapies has resulted in improved outcomes, 4 but children with intestinal failure remain at risk for multiple comorbidities and significant complications 5–10 …”

Assessment of body composition in pediatric intestinal failure: A comparison study

“…1,2 With improved survival, additional complications have emerged. [3][4][5][6] Recent data indicate that the body composition of children with IF is abnormal with a relatively high fat mass (FM) and low fat-free mass (FFM) when compared with healthy children. [7][8][9][10][11] Most concerning is that abnormal body composition is present in both normal and abnormally growing children with IF based on weight-for-age (WFA) and height-for-age (HFA) z scores.…”