Background: Acute kidney injury (AKI) continues to have significant mortality and morbidity and the search is on for any novel therapeutic intervention. Case characteristics: Two cases of AKI with elevated SUA (serum uric acid). Intervention: Rasburicase. Outcome: In Case 1 (late preterm male with AKI) rasburicase resulted in a significant reduction of SUA along with improvement in renal parameters. In Case 2 (6 yrs old boy with multi organ failure), rasburicase failed to provide any significant benefit despite fall in SUA.Message: The effect of rasburicase in AKI needs to be studied.

Keywords: Acute kidney injury, Child, Rasburicase.

Incidence of acute kidney injury (AKI) remains high and the search is still on for a specific therapy which will avoid dialysis and decrease the associated morbidity and mortality [1]. Recently few case reports have shown rasburicase (recombinant urate oxidase) to be effective in various forms of AKI [2-7] with raised serum uric acid. We herein report our experience of using rasburicase in 2 children with AKI (non-tumour lysis syndrome related).

Case 1: A late preterm male baby was admitted on day 4 (D4) with anuria and progressive body swelling from D2. The baby was born by normal delivery with an APGAR of 6 at 10 min. On admission his mean arterial pressure (MAP) was 35 mmHg, creatinine 5.8 mg/dL, potassium 6.5 mmol/L and sodium 121 mmol/L. He stayed anuric despite fluid boluses and ionotropes. Usual AKI measures were initiated along with urgent medical steps for reducing serum potassium. Anuria persisted even after 24 hours, with worsening renal parameters (creatinine peaked at 6.3) and hence peritoneal dialysis was considered. The parents did not consent to an invasive procedure. As his serum uric acid was elevated at 14 mg/dL, after parental consent and ruling out glucose 6 phosphate dehydrogenase (G6PD) deficiency, rasburicase was given on late D5 at 0.2 mg/kg and within 12 hours he started to produce urine. Subsequently there was a steady improvement in his urine output with a concomitant fall in creatinine which became normal by D30 (Fig. 1). Post-rasburicase, serum uric acid was 0.5 mg/dL on D7 and 2.8 mg/dL on D10.

Fig. 1 Urine output and creatinine post-rasburicase in Case 1.

Case 2: A 6-years-old　boy with multiple special needs was transferred from another hospital intubated and severe respiratory distress. He had been anuric for 48 hrs with rising urea and creatinine. He had quadriplegic cerebral palsy and epilepsy. On admission to our institute, his transaminase was >7000, creatinine phosphokinase 45000, INR was un-recordable, creatinine 3.01 mg/dL and serum uric acid 8.9 mg/dL. A provisional diagnosis of rhabdomyolysis was made but due to anuria, myoglobinuria could not be confirmed. His ventilation was stabilized and because of impaired perfusion and low arterial pressure he received normal saline boluses as well as inotropes. Despite this he remained hemodynamically unstable and anuric with worsening renal parameters along with significant coagulopathy. Dialysis was contemplated but in presence of severe coagulopathy both hemodialysis (as we do not have facilities of hemofiltration in our unit) and peritoneal dialysis were considered risky. His uric acid on the next day had risen to 9.7 mg/dL and after parental consent rasburicase was administered at 0.2 mg / kg (G6PD level was normal) around 24 hrs after admission. Despite a dramatic fall in uric acid (0.3 mg/dL by 24 hours) he passed 4 mL of urine within four hours with no further improvement in urine output and renal parameters continued to worsen. Sustained low efficiency dialysis (SLED) had to be ultimately initiated by D3 of admission but he suffered from a massive pulmonary bleed and died on D4 of admission.

In conclusion, evidence is mounting in favour of uric acid as a novel clinical biomarker and its estimation should be included in any AKI work up. Despite the high cost (Rs 15,000 for 1.5 mg ampoule) of rasburicase, if it can be demonstrated that it is effective in AKI and can reduce need for dialysis, it is likely to prove to be cost effective. Acknowledgements: Dr Amit Ray, Consultant Neonatologist; Dr Bichitrovanu Sarkar, Consultant Pediatric Intensivist, Vision Care Hospital, Kolkata; and Dr L Pandey for patient management.

Contributors: Both the authors have contributed, designed and approved the manuscript.

Funding: None; Competing interests: None stated.

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