Background: Vancomycin (VCM) is a commonly used antibiotic for treatment of methicillin-resistant Staphylococcus aureus (MRSA) as well as other gram-positive bacteria. VCM poisoning results in renal failure and ototoxicity. We report a case of VCM toxicity in a 7 day-old infant with subsequent renal dysfunction that was successfully treated with plasma exchange transfusion (PET).
Case Report: A 7 day-old girl born at 34 weeks, 1 day, weighing 1,847 g was treated with VCM, 12.5 mg/kg every 12 hours, concomitantly with gentamicin for suspected necrotizing enterocolitis (NEC). Her VCM blood level after 3 doses returned at 328 mcg/mL (target range 5-20 mcg/mL) and was similarly elevated to 317 mcg/mL and 323 mcg/mL on 2 additional measurements over the next 6 hours. On her 11th day of life she was transferred to a specialty center due to renal dysfunction; her serum creatinine (SCr) had risen from 0.48 mg/dL at birth to 1.71 mg/dL with a decline in her urine output (UOP) to 1.5 mL/kg/hr. Her gentamicin level was 4.8 (therapeutic range 5-10 mcg/mL). Given the acute renal dysfunction, decreased UOP and significantly elevated VCM level, PET was initiated. The VCM level 13 hours after completion of PET was 130 mcg/ml. A second PET was performed; the VCM level 7 hours later was 44.6 mcg/ml and her UOP improved to 6 mL/kg/hr with the addition of furosemide. Twenty hours after the second PET, the VCM level was 8.8 mcg ml. She continued to improve and was transferred back to the original hospital after 4 days with a SCr of 0.48 mg/dL. Iatrogenic error was identified as the likely cause of her elevated VCM level.
Discussion: VCM is being used with increasing frequency as clinicians deal with the increased prevalence of MRSA. Renal dysfunction is a known complication of VCM. As VCM is cleared via the kidneys renal failure prolongs the VCM t1/2 which in turn causes higher VCM levels and increased toxicity. Case reports of the use of various treatment modalities, including multi-dose activated charcoal (MDAC), hemodialysis (HD), and PET to treat increased VCM levels exist. Our case presented some unique clinical challenges. HD would have been extremely difficult and potentially dangerous given this child's size. MDAC was not an option since the child was NPO for her suspected NEC. A previous case report of PET used to treat VCM overdose showed this method to be largely ineffective. Our case, however, illustrates the possible benefit of PET in the appropriate clinical circumstance.
Conclusion: Plasma exchange transfusion may be beneficial in the treatment of some cases of vancomycin toxicity in neonates, particularly when other options may not be feasible.