Symptoms and Management of Painful Progressive Swelling in Eswatini Snakebite Patients: A Prospective Observational Study

Abstract

In Eswatini, bites from snakes with cytotoxic venoms inflict substantial morbidity on humans through blistering, swelling, and tissue necrosis. Despite its widespread use, there is little evidence regarding the efficacy of antivenom in preventing snakebite-induced tissue damage. We conducted a prospective observational study in nine hospitals in Eswatini to describe and quantify symptoms of local tissue toxicity. Our secondary aim was to examine the use of antivenom. Data from 125 snakebite patients with extensive or rapidly progressive swelling were analyzed. The median increase in circumference of envenomed limbs was 12%. Necrosis developed in 31 (25%) patients, primarily in distal extremities. Seventy patients (56%) received South African Institute for Medical Research (SAIMR) Polyvalent antivenom (South African Vaccine producers, Johannesburg South Africa), which was administered for indications related to local tissue damage. Upon hospital presentation, patients treated with antivenom exhibited slightly more severe swelling. Ten out of 11 patients with necrosis upon admission received antivenom. At least seven patients developed necrosis after admission despite previous antivenom therapy. In this nonrandomized observational study, no relationship was observed between the rate at which swelling receded and antivenom treatment. Adverse reactions to antivenom occurred in 49% of patients. Although our analysis has its limitations, it emphasizes the compelling need for research into the indications for and outcomes of antivenom treatment for local tissue damage.

Figure 1.

(A) Anatomic locations of 130 snakebites (125 patients with 130 bites; five patients had two bites). (B) Anatomic locations of necrosis that developed within the first 5 days of hospital presentation in a total of 31 snakebite patients.

Figure 2.

Images showing the progression of tissue necrosis in a patient bitten by a light brown snake of ∼50 cm in length (species unknown) on the left hand. The bite was sustained on the dorsal aspect of the second ray, approximately at the height of the metacarpophalangeal joint. A tourniquet was applied to the affected limb and the bite site before the patient attended the hospital. The patient presented to the hospital 3 hours after the bite and received a single dose of five vials of SAIMR Polyvalent antivenom 3 hours and 45 minutes after the bite. Necrotic skin was debrided on day 10 (after the bite), and a skin graft was performed on day 24. Images are labeled according to the time elapsed after the bite. Images are published with permission from the patient and legal guardian.

Figure 3.

Flow diagram representing the quantity of repeated antivenom dosing.