(529) Plasmapheresis in a Severe Case of Pediatric Loxoscelism

Introduction: Envenomation by a brown recluse spider (Loxosceles reclusa) manifests with a focal cutaneous inflammatory reaction and may progress to dermonecrosis. Rarely, patients develop a systemic inflammatory reaction characterized by fever, acute hemolytic anemia, disseminated intravascular coagulation (DIC), rhabdomyolysis and acute renal failure known as systemic loxoscelism. Treatment for loxoscelism is primarily supportive, with limited literature on other modalities such as plasmapheresis (PLEX).

Description: A previously healthy 7-year-old boy presented with fever, abdominal pain and swelling. Lab work revealed leukocytosis, thrombocytopenia, elevated creatinine, LDH and CK, and lactic acidosis. A sub centimeter erythematous, eroded plaque was noted to the right mid abdomen and CT with contrast demonstrated an underlying multi centimeter abdominal wall abscess vs hematoma. There was no history of trauma or bite. He was treated with broad spectrum antibiotics and pain control. Pediatric surgery recommended observation over drainage, and he was admitted to the PICU. Within hours the patient developed worsening Coombs negative hemolysis, DIC and rhabdomyolysis. He was intubated for encephalopathy, combined acidosis, and hemodynamic instability requiring vasoactive support. Antibiotics were broadened to vancomycin, meropenem and doxycycline. Massive transfusion protocol was initiated. Tennessee Poison Control agreed his case was consistent with severe loxoscelism. PLEX was rapidly initiated and continued for 3 rounds. Hemodynamics, coagulopathy, rhabdomyolysis and exam improved with each successive round. The abdominal fluid collection did not develop into a defined hematoma or abscess. The area of the bite was not debrided due to no dermonecrosis, clinical improvement and risk of toxin spread. He was extubated on hospital day 3 and transferred to the floor on day 5. The patient was discharged home on day 7 without ongoing complications.

Discussion: In systemic loxoscelism, hemolysis is likely caused by direct toxin-mediated or complement-mediated erythrocyte damage. PLEX may facilitate toxin and complement removal. This case demonstrates the utility of early PLEX in the treatment of systemic loxoscelism with multiorgan failure in a pediatric patient. Further research is needed.