Polyethylene Glycol 3350 Crystal Nephropathy in Association With Glomerular Mesangial Immunoglobin A Deposition.

Polyethylene glycol (PEG) 3350, an active ingredient of over-the-counter MiraLAX, is a commonly used laxative in children and is produced by polymerization of ethylene glycol (EG). Masked EG toxicity secondary to contamination of PEG 3350 could occur. We present a 7-year-old child with developmental delay who presented with altered mental status and acute kidney injury (AKI) following intake of generic PEG 3350 for few days prior to presentation. There was high anion gap metabolic acidosis, hypernatremia, elevated osmolar gap, lactic acidosis, and AKI. Urinalysis showed tubular proteinuria, microscopic hematuria, and calcium oxalate crystals. Prior urinalyses were normal without hematuria or proteinuria. Renal biopsy revealed evidence of mesangial dominant immunoglobulin A (IgA) and complement 3 (C3) deposits along with dense tubular deposition of calcium oxalate crystals. He subsequently developed worsening oliguric AKI and required hemodialysis (HD) for several sessions. The AKI resolved within 2 weeks and further HD was not required. Mental status improved in few days. Follow-up urinalyses showed resolution of microscopic hematuria and crystalluria. We hypothesized that the generic PEG 3350 most likely was contaminated with EG leading to the presentation. A high index of suspicion of contamination of PEG 3350 with EG is required in patients presenting with unexplained high anion gap metabolic acidosis, elevated osmolar gap, lactic acidosis, AKI, calcium oxalate crystalluria, and oxalate crystals on renal biopsy. Further studies are needed to determine whether there is an association between transient glomerular mesangial IgA deposition and crystal nephropathy. Copyright 2022, Aly et al.