Presentations

Abstract

Introduction: Snakebite evaluation and management review with a Copperhead snakebite

Case Information: A 46-year-old male presented for worsening swelling and pain from a copperhead snake bite on his left palm, extending up to his left shoulder. On the prior day, he had initially been admitted to another hospital for the same snakebite but with only minor swelling and pain in his palm (Figure 1). Poison Control recommended reserving antivenom for symptom progression, and he left AMA. Upon arrival here, his entire left upper extremity was swollen and tender up to the shoulder without ecchymosis or bleeding and with soft compartments (Figure 2). Laboratory findings were unremarkable except for slightly elevated d-dimer. Despite antivenom therapy, diffuse edema worsened, limiting elbow flexion from swelling and pain. The affected arm was positioned below the level of his heart per Poison Control. His CBC, CPK, and coagulation studies remained stable. 48 hours after envenomation, his swelling decreased to mid-forearm level, and he was discharged without complications.

Discussion/Clinical Findings: Almost 5000 venomous snake bites are reported yearly, mostly from Crotalinae snakes (rattlesnakes, cottonmouths, and copperheads), with copperheads causing about half. While 25% of bites involve no venom and result in only local irritation needing supportive care, envenomation raises the main concern for hemotoxicity (for rattlesnake, cottonmouth, copperhead) and neurotoxicity (for rattlesnakes, coral snakes), in addition to local tissue damage, bleeding tendency, rhabdomyolysis, compartment syndrome, gastrointestinal distress, and shock although true anaphylaxis is rare. Venom from these snakes contains toxic compounds like phospholipase, metalloproteinases, and etc. Bites with envenomation typically show two puncture wounds and have local toxicity in over 90% of cases, with pain, swelling, erythema, and ecchymoses developing within an hour or more. Proximal spread of swelling or tenderness signals progressive envenomation, requiring antivenom treatment. Hemotoxicity includes prolonged PT, thrombocytopenia, and hypofibrinogenemia and is monitored with CBC, fibrinogen, and PT/INR, though life-threatening bleeding is rare. Neurotoxicity is uncommon but can cause paresthesia and myokymia with rattlesnake bites, and delayed weakness beginning with ocular and bulbar weakness with coral snake bites, necessitating observation for 24 hours. Airway monitoring is crucial, as myokymia, bulbar symptoms, or face/neck bites can lead to airway compromise. Additional tests like Chest X-ray, EKG, creatine kinase, and BMP are warranted for systemic toxicities, such as hypotension and rhabdomyolysis. Consultation with a toxicologist or poison control center is advised for all snake bites. Antivenom therapy is recommended for the proximal spread of local reaction, hemotoxic, neurotoxic, or systemic venom effects. It functions through the fragment antigen binding (Fab) portion of digested IgG antibodies, neutralizing the venom. However, it may lead to acute severe reactions, with or without hypersensitivity, and delayed onset hemotoxicity. Although some experts suggest elevation of the affected extremity, its appropriateness should be individualized due to potential risks of exacerbating systemic toxicity.

Conclusion: For venomous snakebites, it is important to identify different snake species, monitor any sign of progression of local reaction, and monitor hematologic, neurologic, and systemic toxicities for appropriate resuscitation and airway monitoring, and early antivenom administration.