Moccasin Envenomation Treatment & Management

Do nothing to injure the patient or impede travel to the ED.

Support the airway, breathing, and circulation per advanced cardiac life support (ACLS) protocol with oxygen, monitors, large-bore intravenous lines, and fluid challenge. Minimize activity (if possible), remove jewelry or tight-fitting clothes in anticipation of swelling, and transport the patient to the ED as quickly and as safely as possible. Every 15 minutes, use a pen to mark and time the border of advancing edema.

In recent studies, no benefit was demonstrated when a negative pressure venom extraction device (eg, The Extractor from Sawyer Products) was evaluated; additional injury can result.^{[8, 9]} Incision across fang marks is not recommended. Mouth suction is contraindicated.

Lymphatic constriction bands and pressure immobilization techniques may inhibit the spread of venom, but whether they improve outcome is not clear. These techniques may actually be deleterious for pit viper envenomation if they increase local necrosis or compartment pressure. Tourniquets are not recommended.

Maintain the limb in a neutral position.

First aid that lacks therapeutic value or is potentially more harmful than the snakebite includes electric shock, alcohol, stimulants, aspirin, ice application, and various folk and herbal remedies.^{[10, 11]}

Cost and risk of acute adverse reactions generally preclude field use of antivenom.^[10]

Attempts to capture or kill the snake are not recommended because of the risk of additional injury.

In the United States, all pit viper (rattlesnake, pygmy rattlesnake, and moccasin) envenomations are treated similarly, based on the severity of presenting signs and symptoms. Therefore, if the patient shows signs of envenomation (eg, pain, swelling), then species identification is not necessary. The exception to this rule is Mohave rattlesnakes, whose neurotoxic venom requires special consideration. However, because there is little overlap between the natural range of Mohave rattlesnakes and that of the moccasins (except for the Trans-Pecos region of Texas), this is rarely a clinical dilemma.^{[12, 13]}

If the venomousness of a particular snake is uncertain, consider taking photographs of the snake from a safe distance of at least 6 feet away using a digital or Polaroid camera.

Adequate hydration with intravenous fluids is indicated. Patients with hypotension should be resuscitated first with 2 isotonic sodium chloride solution challenges (eg, 20 mL/kg). Treat persistent shock with colloids, followed by pressors as indicated.

Managing envenomations is a dynamic process; administer additional antivenom as indicated by a worsening clinical course. When considering the use of antivenom, the risk of allergy to antivenom must be weighed against the benefits of reducing venom toxicity. See the algorithm^[14] below.

In the United States, the nationwide Poison Help! number, 1-800-222-1222 will connect the caller the nearest poison control center. Certified poison centers have trained personnel to assist physicians in the management of poisonings, including snake bites, with 24-hour access to medical toxicologists for specific questions.

In addition, medical toxicologists are available to provide bedside patient care at some medical centers. Medical toxicologists have specific training and expertise in snakebite management.

The manufacturer of Crotaline Fab antivenom provides a technical assistance hotline at 1-877-SERPDRUG (877-377-3784).

Consider consulting a surgeon (eg, general, orthopedic, hand) if compartment syndrome is suspected or, in the subacute phase of illness, if debridement of clearly necrotic tissue is required.

Occupational therapy, physical therapy, physiatry (rehabilitative medicine), and/or pain management consultation may be helpful to assist patients with persistent pain, swelling, or other limitations.