CASE OF THE MONTH

Question: The patient shows you a picture of the snake that bit him.  What is the best way to provide information to the receiving hospital on the snake type to guide treatment?

1. Capture the snake and bring it to the Emergency Department
2. Get close enough to describe the shape of the snake’s eyes
3. Get close to take a high-resolution picture
4. Take a picture from a distance if able, though treatment will be the same

Answer:  4. A picture can be used to confirm the type of snake but one should never risk safety by getting too close to the snake. Of note, rattlesnakes (pit vipers) in North America have elliptical shaped eyes but this finding alone is not sufficient to distinguish venomous from nonvenomous snakes (e.g. coral snakes native to the southern United States are highly venomous but have round eyes). All envenomations from snakes native to Southern California are treated with the same type of antivenom, so the history provided (i.e. I was bitten by a wild  (local) snake) is sufficient to determine treatment.

The patient’s presentation points directly to a snake bite given the history, exam findings of snake fang marks, and picture of the snake presented.  Currently, the patient does not have any swelling or discoloration and the pain experienced could be from the trauma of the bite itself or early effects of the venom if envenomation occurred. Sometimes, snake bites result in “dry bites” where a bite occurs, but no venom is released. It is too early in the patient’s clinical course to distinguish if a “dry bite” or an envenomation occurred. This needs to be determined at the hospital based on serial examinations and laboratory studies. Therefore, this patient should be treated as if an envenomation occurred by limiting activity, splinting the extremity and elevating it to at least the level of the heart, and transporting the patient to an appropriate receiving facility.

Question: In a snakebite, what findings suggest that envenomation occurred? Select ALL that apply

1. Bruising / Ecchymosis
2. Severe Pain
3. Skin discoloration (black, blue) or foul odor
4. Swelling

 Answer: All are true.  While all patients presenting with a snake bite should be treated as if envenomation occurred, findings suggestive of envenomation include rapid swelling, severe pain, bruising (venom and affect clotting factors), and tissue necrosis (a late finding, tissue necrosis may be noted by skin turning black or dark blue, and developing a foul odor).

The patient’s vital signs are as follows:

BP 102/66, HR 117, RR 18, SpO₂ 100%

A full physical assessment shows no other injuries.

As you load the patient for transport you notice increasing swelling to the ankle around the bite.  The patient complains of worsening pain and now complains of nausea.

The history in this case points directly to a snakebite as the underlying cause of the patient’s symptoms. However, the patient was also mountain biking.  History should be obtained to evaluate for other trauma.  A trauma assessment is performed to ensure that a separate traumatic injury was not overlooked.

Rapid swelling is a sign that envenomation occurred. Other clinical findings that can develop include bruising/ecchymosis, nausea and vomiting, tachycardia, and mild hypotension. Some patients may complain of a metallic taste in their mouth.

Pain management can be performed with an intravenous opioid (morphine or fentanyl prn).

Snake envenomation can be complicated by coagulopathy and therefore it is preferable to avoid ketorolac in these patients. Nausea can be treated with Ondansetron 4mg ODT/IV/IM per Treatment Protocol, Ref 1202, General Medical. 

The patient is tachycardic.  Paramedics may perform a 12-lead ECG to assess the rhythm if there are any concerns for arrhythmia.

Question: What type of venomous snake is local to Los Angeles County?

1. Coral snake
2. Gopher snake
3. King snake
4. Rattlesnake

Answer:  4. All species of rattlesnake are venomous and are found in the wild in Los Angeles County.  While coral snakes are venomous, they are not local to Los Angeles County.  Gopher and King snakes are common in Los Angeles County but are not venomous.

Several minutes after administering fentanyl and ondansetron and initiating transport, you reassess the patient, who reports decreased pain and nausea. You note that the edema and discoloration of the right ankle has increased and spread to the foot. You recheck pulses in the foot, strength, and sensation – all remain normal. You consider your options for hospital destination with several hospitals within a 30-minute transport time.

Yes. Base Contact can be helpful in this case.  Since the patient is symptomatic, it is highly likely an envenomation occurred. The patient will require treatment with antivenom and hospital admission.  Direct transportation to a hospital with antivenom available can expedite the needed treatment.  If there is a nearby receiving hospital with a toxicologist on call, this can be considered as well.  Toxicologists are subspecialty trained physicians with expertise in snakebite management.

A “Quick Reference Guideline” (QRG) has been added to the RAPID LA County Medic App displaying 911 Receiving Hospitals in Los Angeles County with antivenom and toxicology services.  You can access this resource directly with the RAPID app as described in the following video:
https://vimeo.com/1193638618?fl=ml&fe=ec

Question: What is the most appropriate destination for this patient?

1. MAR
2. MAR with antivenom
3. Trauma Center
4. Trauma Center with antivenom

Answer: 2. The patient does not meet trauma criteria so a MAR is appropriate. However, destination to a receiving center that has antivenom can expedite treatment for the patient. Some centers have toxicologists who can consult on appropriate management for the patient and arrange follow-up.

When you contact the Base, the MICN refers to the RAPID LA County Medic App and confirms that one of the nearby receiving hospitals has antivenom and a toxicology service, while the others do not. For this reason, you are directed to transport the patient to the hospital with antivenom.

Upon arrival in the ED, the patient is tachycardic and mildly hypotensive with his blood pressuring having decreased further to 92/54. ED staff initiate IV fluids. Blood work is obtained to assess for coagulopathy. The swelling to his ankle has increased and his foot and lower leg are swollen with patchy redness.  This worsening physical examination confirms that an envenomation occurred. The antivenom Crotalidae polyvalent immune Fab (CroFab) is ordered and administered by hospital staff and the patient is admitted to the intensive care unit.

The patient improves after the first dose of CroFab with a decrease in pain and swelling to the leg.  Laboratory results from blood drawn in the ICU show that he had developed a mild coagulopathy; but this improved by the next day after receiving antivenom, and he is transferred to the medical ward. The patient is discharged on hospital day #3. On outpatient follow-up with the toxicologist, he demonstrates a full recovery.

• For snake bites, splint the affected limb to limit its movement and elevate the limb to a level at or above the heart.
• Administer medications to treat pain and nausea for patients with snake bites and these symptoms.
• When feasible, transport patients with snake bites to a receiving hospital with antivenom available.
• Refer to the RAPID app QRG and Contact Base for destination guidance – Base can confirm availability of antivenom with the receiving hospital.