SHM Converge Scientific Abstract ePoster Gallery-Secondary HLH - An Uncommon Manifestation of Systemic Loxoscelism

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This poster reports a rare case of secondary hemophagocytic lymphohistiocytosis (HLH) caused by systemic loxoscelism after a presumed brown recluse spider bite. An 8-year-old boy presented with fever, gross hematuria, abdominal pain, and a vesicular wound with surrounding ecchymosis and erythematous streaking. Initial findings included hemolytic anemia, stage 3 acute kidney injury, severe metabolic acidosis, transaminitis, hyperbilirubinemia, elevated inflammatory markers, and encephalopathy. He also had hypertension and required continuous renal replacement therapy for electrolyte abnormalities and kidney injury.<br /><br />Because of persistent fever, multi-organ dysfunction, and altered mental status, ferritin was checked and found to be markedly elevated at 10,858 ng/mL, prompting evaluation for HLH. Bone marrow aspirate supported the diagnosis, and additional markers such as CXCL-9, IL-2R, and IL-18 were significantly elevated. The patient met 6 of the 8 HLH-2004 diagnostic criteria.<br /><br />Treatment with dexamethasone was started, and because of the severity of illness and lab abnormalities, emapalumab was added. This led to clinical improvement, resolution of encephalopathy, and recovery of organ dysfunction.<br /><br />The authors note that systemic loxoscelism can rarely trigger HLH, with only a few cases previously reported. They emphasize that patients with suspected brown recluse envenomation who develop fever, elevated inflammatory markers, severe organ dysfunction, or encephalopathy should be evaluated for HLH. Ferritin may serve as a useful initial screening test, with further HLH workup indicated if elevated.

Asset Subtitle

Reba M. Mehaffey

Meta Tag

Author List Nandini Calamur, Reba M. Mehaffey, Sadori Khawaja

Category Clinical Vignettes

Concept Brown Recluse Spider Envenomation

Concept Systemic Loxoscelism

Concept Secondary hemophagocytic lymphohistiocytosis

Concept Hemolytic Anemia

Concept Acute Kidney Injury

Distinguished Non-Finalist

Presenter Organization Saint Louis University

Presenting Author Reba M. Mehaffey

Track Pediatric

Keywords

secondary hemophagocytic lymphohistiocytosis

HLH

systemic loxoscelism

brown recluse spider bite

ferritin

emapalumab

dexamethasone

acute kidney injury

encephalopathy

bone marrow aspirate

Brown Recluse Spider Envenomation

Systemic Loxoscelism

Secondary hemophagocytic lymphohistiocytosis

Hemolytic Anemia

Acute Kidney Injury