Megaloblastic Anemia Progressing to Severe Thrombotic Microangiopathy in Patients with Disordered Vitamin B12 Metabolism: Case Reports and Literature Review.

We describe 2 children with cobalamin G disease, a disorder of vitamin B12 metabolism with normal serum B12 levels. They presented with megaloblastic anemia progressing rapidly to severe thrombotic microangiopathy. In infants presenting with acute thrombotic microangiopathy, cobalamin disorders should be considered early as diagnosis and targeted treatment can be lifesaving.

Neonatal extracorporeal renal replacement therapy-a routine renal support modality?

Peritoneal dialysis (PD) is generally considered the preferred extracorporeal therapy for neonates with acute kidney injury (AKI). However, there are situations when PD is not suitable, such as in patients with previous abdominal surgery, hyperammonemia and significant ascites or anasarca. Additionally, with a need to start PD soon after catheter placement, there is increased risk of PD catheter leak and infection. Extracorporeal continuous renal replacement therapy (CRRT) is challenging in severely ill neonates as it requires obtaining adequately sized central venous access to accommodate adequate blood flow rates and also adaptation of a CRRT machine meant for older children and adults. In addition, ultrafiltration often cannot be set in sufficiently small increments to be suitable for neonates. Although CRRT practices can be modified to fit the needs of infants and neonates, there is a need for a device designed specifically for this population. Until that becomes available, providing the highest level of care for neonates with AKI is dependent on the shared experiences of members of the pediatric nephrology community.

Regional citrate anticoagulation for continuous renal replacement therapy in pediatric patients with liver failure.

Pediatric liver failure patients frequently develop multiple organ failure and require continuous renal replacement therapy (CRRT) as part of supportive therapy in the pediatric intensive care unit. While many centers employ no anticoagulation for fear of bleeding complications, balanced coagulation disturbance predisposes these patients to clotting as well as bleeding, making maintenance of longer circuit life to deliver adequate dialysis clearance challenging. Regional citrate anticoagulation (RCA) is an attractive option as it avoids systemic anticoagulation, but since citrate metabolism is impaired in liver failure, concerns about toxicity has limited its use. Pediatric data on RCA with liver failure is very scarce. We aimed to establish safety and efficacy of RCA in pediatric liver failure patients on CRRT. Retrospective review of pediatric patients with liver failure receiving CRRT over 30 months. Demographic data and CRRT related data were collected by chart review. Citrate accumulation (CA) was defined as total calcium (mg/dl) /ionized calcium (mmol/L) ratio >2.5 for > 48 hours. Efficacy was assessed by filter life. Safety was assessed by frequency of adverse events ((AEs) defined as bleeding, hemodynamic instability, arrhythmias). Fifty-one patients (median age 3.5 (IQR 0.75-14.2) years) received 861 CRRT days; 70% experienced at least one episode of CA, only 37% were recorded as such in the medical record. AE rate was 93/1000 CRRT days and did not differ between CA days and others. Median filter life was 66 hours (IQR 29-74); 63% filters lasted longer than 48 hrs. Though common, CA was not associated with increased AEs on in pediatric liver failure patients on CRRT receiving RCA. Filter life was adequate. RCA appears an effective anticoagulation for CRRT in pediatric liver failure. Application of a structured definition would increase recognition of CA to allow timely intervention.

Reversal of hypercalcemic acute kidney injury by treatment with intravenous bisphosphonates.

We present the details of three children with hypercalcemia-induced acute kidney injury (AKI). After traditional therapy with fluids, loop diuretics, steroids and calcitonin had failed to correct the hypercalcemia, they were given treatment with low doses of intravenous (i.v.) pamidronate, which resulted in normalization of serum calcium and kidney function. In one child Doppler renal ultrasound revealed dampened arterial blood flow, which resolved with normalization of serum calcium. On the basis of cumulative data and our experience, we suggest that i.v. application of bisphosphonates be moved from the second to the first line of treatment of hypercalcemic AKI.