Acute Kidney Injury Requiring Prolonged Kidney Replacement Therapy After Loxosceles Envenomation in an Adolescent: A Case Report with 14-Month Follow-Up

Loxoscelism is the clinical syndrome that follows envenomation by spiders of the genus Loxosceles. The venom is dominated by phospholipases D, which produce dermonecrosis, intravascular hemolysis, thrombocytopenia, and renal failure in experimental models. Acute kidney injury (AKI) is the least common of the systemic manifestations and the most lethal, and children account for a disproportionate number of deaths. Here, we present a case report of a previously healthy 15-year-old boy bitten on the left lower limb during a trip to Monterrey, in northeastern Mexico. He presented four days later with severe limb pain, progressive necrotic skin lesions, and shock, and was admitted to the pediatric intensive care unit with multiorgan failure. The nephrology service documented KDIGO stage 3 AKI, with a serum creatinine of 6.5 mg/dL, an estimated glomerular filtration rate of 9.9 mL/min/1.73 m², and a urine sediment showing uncountable erythrocytes and granular casts. Creatine kinase peaked at 89,637 U/L, with disseminated intravascular coagulation, hemolysis, and thrombocytopenia; blood cultures grew Streptococcus pyogenes. He received four sessions of continuous kidney replacement therapy followed by intermittent hemodialysis over four weeks, alongside fasciotomy, serial debridement with negative-pressure wound therapy, and a split-thickness skin graft, and was discharged after 59 days. The two filtration markers did not agree: before discharge the estimated glomerular filtration rate was 118.4 mL/min/1.73 m² by creatinine and 43.1 mL/min/ 1.73 m² by cystatin C. The gap narrowed over the following year, and at fourteen months the estimated glomerular filtration rate was 98 mL/min/1.73 m² without proteinuria. Because dialysis-treated AKI in the setting of multiorgan failure carries a long-term risk of chronic kidney disease and hypertension, and because creatinine alone may overestimate recovery after rhabdomyolysis, recovery of glomerular filtration should not be taken as the end point of nephrology follow-up.