SUPPORTIVE CARE & ONGOING MANAGEMENT

Provide supportive care and address secondary issues related to the envenomation as follows:

1. Anticipate the need for aggressive airway management with intubation and prolonged ventilation in all patients presenting with neurotoxic envenomation, particularly those who present late with impending respiratory failure or fail to respond to antivenom. Ptosis is an early sign of central neurotoxicity indicating need for antivenom and likely progression to respiratory failure without timely antivenom administration.

For any neurotoxic snakebite producing a cholinergic crisis, consider atropine 0.5 mg IV/IO titrated by auscultation to dry up bronchial and oral hypersecretions posing a risk to airway or breathing.

Repeat original dose every 5 minutes until resolution of crackles, rales, and bronchospasm has been achieved. Pediatric atropine doses should be weight based at a dose of 0.01 mg/kg, up to 0.5 mg.

For neurotoxic snakebites in the Middle East, North Africa, and Central Asia without cholinergic crisis, but causing ptosis and respiratory muscle weakness, consider administering, in addition to antivenom, a trial dose of 0.5 mg atropine followed by 1.0 mg neostigmine IV/IO to temporarily reverse neuromuscular weakness and delay the need for intubation. Pediatric doses should be weight based at a dose of 0.01 mg/kg, up to a maximum of 0.25 mg atropine with 0.5 mg neostigmine.^54,74–77

Not all patients will respond, but those who do will show temporary improvement (reversal of ptosis, increased respiratory muscle strength, etc.). If no response to neostigmine, do not readminister. If positive response is achieved, repeat every 1 - 4 hours as needed (maximum dose in 24 hours = 10 mg adults / 5 mg pediatric) until antivenom has definitively reversed the paralysis.

2. For hemotoxic envenomations, all internal and external active bleeding should cease within 30 – 60 minutes of antivenom administration once the appropriate dose has been given. Packed red blood cell or whole blood transfusion can be considered if the patient is in hemorrhagic shock.^{17,69,70, 78-82}Platelets, fresh frozen plasma, cryoprecipitate, TXA, and other agents are not effective in these cases due to the mechanism of the venoms.

3. Ketamine and fentanyl are preferable for analgesia. Histamine release from morphine may mimic signs of an allergic reaction or worsen hypotension. Acetaminophen may be used but NSAIDs are contraindicated.

4. It is important to keep the limb significantly elevated (> 60º is ideal) whenever possible to limit dependent edema and swelling.

5. DO NOT routinely de-roof or aspirate blisters, bullae, or blebs unless they are causing significant discomfort or uncontrolled rupture appears imminent. If abscess is suspected, treat according to existing protocols for abscess management.

6. Avoid fasciotomy for snakebites unless absolutely necessary. Compartment syndrome is rare in snakebites, and evidence suggests that patients treated with antivenom alone – without fasciotomy – generally experience better outcomes, including shorter recovery times and reduced long-term morbidity.^83–86 Appropriate use of antivenom should typically resolve elevated intracompartmental pressures caused by envenomation. However, in deployed settings, constraints such as limited antivenom supplies due to delayed procurement or depletion during evacuation may complicate management. In such cases (prior to performing a fasciotomy), consult a DoD ADVISOR toxicologist to guide decision-making and ensure the best possible outcomes.

7. DO NOT routinely administer PROPHYLACTIC ANTIBIOTICS unless signs and symptoms of an infection are present. Direct infections are rare from most snakebites when prompt, appropriate treatment is given (washing with soap and water).⁵⁴ Bites from certain snakes (Asian cobras) have higher rates of infection.

8. ADMINISTER ANTIBIOTICS FOR SUSPECTED INFECTIONS, which may be common in local nationals with late-presenting bites who arrive with significant secondary infections due to unsanitary traditional treatments, poor hygiene conditions + widespread tissue compromise.