IMMEDIATE FIRST AID
for bites by
In the event of an actual or probable bite from a Black Snake, execute the following first aid measures without delay.
- Make sure that the responsible snake or snakes have been appropriately and safely contained, and are out of danger of inflicting any additional bites.
- Immediately call for transportation.
- Keep the victim calm and reassured. Allow him or her to lie flat and avoid as much movement as possible. If possible, allow the bitten limb to rest at a level lower than the victim's heart.
- Immediately wrap a large crepe bandage snugly around the bitten limb starting at the site of the bite and working proximally up the limb (the full length if possible). The bandage should be as tight as one might bind a sprained ankle.
- Secure the splint to the bandaged limb to keep the limb as rigid and unmoving as possible. Avoid bending or moving the limb excessively while applying the splint.
- DO NOT remove the splint or bandages until the victim has reached the hospital and is receiving Antivenom.
- Have the BLACK SNAKE ANTIVENOM (Commonwealth Serum Laboratories) ready for the Lifeflight crew to take with the victim to the hospital. Give them the following:
- the available antivenom (at least 5 vials)
- the accompanying instruction (protocol) packet
- the victim's medical packet
cut or incise the bite siteDO NOT
apply ice to the bite site
Summary for Human Bite
The bite of the Black Snake with subsequent envenomation is a medical emergency and can be fatal if the patient is not treated appropriately.
- First Aid:
- Bandage and Immobilize the bitten limb with crepe bandages and splint as described in the Immediate First Aid section. Rest this extremity below the level of the patient's heart (if practical).
- Transport to U.C.S.D. Medical Center Trauma Service.
- Medical Management:
- Call your local Poison Control Center, or the San Diego Regional Poison Control Center (800 876-4766). They should locate a consultant to help you treat this patient.
- Observe for Signs and Symptoms of Envenomation.
- If significant systemic signs or symptoms are present, perform the following:
- Administer Lactated Ringers Solution at 250 mls per hour.
- Draw samples and collect initial laboratory data.
- Dilute the contents of 1 vial (18,000 units) of
Commonwealth Serum Laboratories Black Snake Antivenom in Lactated Ringers Solution to a total volume of 250 ml. Give the antivenom I.V. piggyback at the following initial doses and rates: Administer 250 ml diluted antivenom over approximately 30 minutes at the rate of 500ml/hour (i.e. one vial or 18,000 units over 30 minutes).
The combined rate of diluted antivenom and Lactated Ringers Solution may be adjusted accordingly to avoid fluid overload, however a brisk urine output should be a treatment goal.
- After 15 minutes of antivenom administration, remove the splint and crepe bandage slowly over a period of 10 minutes. If symptoms progress rapidly, reapply the bandage, wait 10 minutes, and then again release the bandage slowly over 10 minutes while antivenom administration is continuing.
- Allergic or untoward reactions to the antivenom should be treated with Benadryl, Epinephrine, and/or Corticosteroids. A patient with known sensitivity to horse serum may be pretreated with 1 gm of Solumedrol, administered I.V. push.
- Monitor signs, symptoms, and laboratory data, and administer additional antivenom in half vial increments at a rate of 1/2 vial (9,000 units) every 15 minutes as necessary to control the progession of symptoms.
- The required amount of antivenom will vary with the severity of envenomation and the species of snake which caused the bite. One should anticipate using (including the initial dose):
0-1 vial total for a minor bite with envenomation.
1-5 vials may be necessary for moderate or severe bites.
for bites by
This person has received a bite and probable envenomation from a Black Snake (Pseudechis species). This is a very venomous and dangerous snake native to Australia and New Guinea. Envenomation may cause both local as well as systemic manifestations and left untreated, may well result in marked morbidity and even mortality.
Please read and execute the following procedures without delay.
- A crepe bandage and splint have been applied as immediate first aid adjuncts to retard the absorption of the venom. DO NOT remove until the patient has arrived at the hospital and is receiving the antivenom.
- Make sure that at least 5 vials of CSL Black Snake Antivenom are present with the patient. This antivenom is specific and is only available directly from the San Diego Zoo Reptile Department. Refrigerate the antivenom upon arrival to the hospital.
- If the patient has been envenomated, the treatment is 1-5 vials of intravenous antivenom. Envenomation is diagnosed by the presence of characteristic signs and symptoms. Necessary information follows and is organized in sections:
- Signs and Symptoms of Envenomation
- Medical Management
- General Considerations
- Special Considerations
Signs and Symptoms of Envenomation:
- Local Affects:
- Pain and swelling
- Tissue necrosis
- Neurological and Neuromuscular: These signs and symptoms are manifest within one hour after envenomation, however not all will necessarily develop, even with severe envenomation. Respiratory muscle paralysis requiring intubation and ventilatory support is a rare complication of a Black Snake bite.
- Blurred vision, ptosis
- Dysphagia, dysarthria
- Limb paralysis
- Loss of respiratory muscle function
- Transient hypotension/loss of consciousness
- Sinus tachycardia
- Circulatory shock
- Coagulation defects
- Spontaneous bleeding:
- Bright red blood per rectum
- Renal failure secondary to myoglobinuria
- Abdominal pain
- Regional lymphadenopathy
- Fang Marks: The presence of fang marks does not always imply envenomation as the Black Snake is known to bite without injecting venom into the victim. However, the absence of fang marks does not necessarily preclude the possibility of a bite, nor does it give any indictaion of the severity of the bite.
Fang marks may be present as one or more well defined punctures, as a series of small lacerations or scratches, or there may not be any noticeable or obvious markings where the bite occurred. Finally, multiple bites inflicted by a single snake are possible and should be noted if present.
- Admit patient to the Trauma Service and call consultants listed on the last page. Dr. Terence M. Davidson, M.D. is the local consultant for snake bites, and should be notified immediately.
- Begin a peripheral intravenous infusion (16 gauge catheter) of Lactated Ringers Solution at a rate of 250 cc/hour.
- Draw blood from the contralateral arm, and collect urine for the following laboratory tests. Mark STAT.
- Type and Cross Match TWO units of Whole blood.
- CBC with differential and platelets.
- Coagulation Parameters:
- Prothrombin Time (PT)
- Partial Thromboplastin Time (PTT)
- Fibrinogen levels
- Fibrin Degradation Products
- Serum Electrolytes, BUN/Creatinine, Calcium, Phosphorus.
- Lactate Dehydrogenase (with Isoenzyme analysis). Isoenzyme analysis may indicate multiple targets of the venom components which may dictate further management.
- Urinalysis (Macroscopic and Microscopic Analysis).
Must include analysis for:
- Free Protein
- Electrocardiogram (Sinus Tachycardia would be expected).
- Continuous Urine Output Monitoring (Indwelling Foley
Catheter if unconscious). Watch for possible oliguria or anuria.
- Additional Tests as needed or indicated by patient's
hospital course, ie. CPK and coagulation parameters at four hour intervals.
- It may be necessary or practical to repeat some of the above serum and urine tests periodically over the hospital course to monitor the effects of antivenom therapy or to detect late changes in laboratory values.
- OBSERVE PATIENT CLOSELY for signs and symptoms of envenomation which usually manifest between 15 minutes and two hours after the bite occurred.
- If NONE of the signs or symptoms have been noted after TWO hours, there is the possibility that the patient received a dry bite (no venom injected).
- VERY SLOWLY begin to remove the bandages and splint watching carefully for any changes in the patient's status. If any changes occur, assume the patient has been envenomated and prepare to give antivenom immediately (as directed below).
- If signs and symptoms still fail to manifest, continue CLOSE observation of the patient for an additional 12 to 24 hours.
- IF SIGNIFICANT SYSTEMIC SIGNS OR SYMPTOMS become apparent, begin antivenom therapy as follows:
- Dilute the contents of 1 vial (18,000 units) of Commonwealth Serum Laboratories Black Snake Antivenom in Lactated Ringers Solution to a total of 250 mls. Give the antivenom I.V. piggyback at the following initial doses and rates:
Administer 250ml diluted antivenom over approximately 30 minutes at the rate of 500ml/hour (i.e. one vial or 18,000 units over 30 minutes).
- Should any signs of ALLERGY/ANAPHYLAXIS (e.g., coughing, dyspnea, urticaria, itching, increased oral secretions, etc.) develop, immediately discontinue the administration of antivenom, and treat symptoms with Corticosteroids, Epinephrine, Benadryl, Atarax and/or Antihistamines. As soon as the patient is stabilized, continue the antivenom infusion at a slower rate.
- After 15 minutes of antivenom administration, the splint and the bandages may be removed. This should be done VERY SLOWLY over a period of 10 minutes to prevent a bolus release of venom. If the patient's condition worsens, reapply the crepe bandage, wait 10 minutes and release the bandage again slowly over 10 minutes while antivenom administration is continuing.
The combined rate of diluted antivenom and Lactated Ringers Solution may now approach 750ml/hour. The rate of Lactated Ringers Solution may be adjusted accordingly to avoid fluid overload, however a brisk urine output should be a goal of treatment.
- Antivenom therapy is the mainstay of treatment for Black Snake envenomation. Many of the signs and symptoms are ameliorated or entirely eliminated by the antivenom alone. Other symptoms will require additional modalities of therapy to be corrected.
- Neurological signs and symptoms are generally less severe than other Australian Elapid snakes. Rarely does an envenomation result in respiratory muscle paralysis. Cranial nerve and limb paralysis are much more common occurrences. However, if breathing becomes impaired, provide respiratory assistance. Secretions may become copious, necessitating suction. Timely administration of antivenom improves neurological signs and symptoms.
- Rhabdomyolysis: Black Snake venom is strongly myolytic and may lead to rhabdomyolysis. If not treated adequately, a bite victim may develop massive myoglobinuria which may subsequently result in oliguria or acute renal failure. If severe, the patient may require dialysis. A brisk diuresis should thus be a goal of treatment.
- Hematological signs include thrombocytopenia, decreased fibrinogen levels, as well as prolonged PT, PTT, and bleeding times. Black Snake venom has also been shown in vitro to cause hemolysis and platelet aggregation. However, bite victims rarely require the administration of blood products to correct a coagulation defect.
- It is important to keep venom neutralization current and continuous. The best method to accomplish this is to monitor the patient's status. If the present condition does not improve, or should it worsen for any reason, additional antivenom should be administered. Give all additional antivenom in 1/2 vial increments. Dilute the antivenom in Lactated Ringers as before and administer the antivenom I.V. piggyback over approximately 15 minutes. One should anticipate using the following amounts of antivenom (including initial dose):
0-1 vials for a minor bite with envenomation.
1-5 vials may be necessary for moderate or severe bites.
- It is advisable to perform periodic serum and urine analyses during therapy (as outlined above).
- It is always best to keep the patient in an Intensive Care setting until free of major symptoms for 24 hours. The patient should be observed in the hospital for at least 24 hours after all symptoms abate.
- It is important that the patient be placed at rest, kept warm, and avoid unnecessary movement.
- The onset of dangerous Neurotoxic symptoms can be rapid and subtle. In addition, they are more rapidly reversed in their early stages than when fully developed. It may be necessary to wake the patient and perform a brief neurologic check every hour or so to assure that breathing and other vital functions are not impaired. Carefully note the progress of any paralysis which may be present.
- Respiratory obstruction and failure are the greatest immediate concern. Should the patient develop difficulties in breathing or airway impairment, respiratory support will be required. If the tongue, jaw or pharynx become paralyzed, insert an oral airway. Make sure adequate suction equipment is available and operative.
- Fluid management is very important in snake bite cases. The patient should be well hydrated, and a brisk urine output maintained. Blood replacement SHOULD NOT be started (as it would be ineffective) until the circulating venom anticoagulants have been fully neutralized.
- If any signs of Oropharyngeal paralysis or impaired swallowing exist, give NOTHING BY MOUTH, and keep patient on his side with head down. Watch for airway compromise and aspiration.
- Morphine is CONTRAINDICATED because of its tendency to suppress respiration. Alcohol should also be avoided. Diazepam (Valium) may be given, but not in large quantities.
- In cases in which Circulatory Shock remains uncorrected by antivenom therapy, Plasma volume expanders and/or vasopressor agents may be given with appropriate considerations.
- Tetanus prophylaxis should be current.
- Antibiotics are NOT recommended prophylactically.
- Multiple Bites:
- It is possible for a Black Snake to deliver more than
one bite in a single attack. If there is evidence that such an attack occurred (i.e., history or multiple bite sites), twice (2X) the INITIAL dose of antivenom should be given.
TWO vials (36,000 units) diluted in Lactated Ringers Solution to a total volume of 500 mls, and delivered over 30 minutes (i.e. 2 vials over 30 minutes)
- Severe Envenomation:
- If the patient shows severe signs of envenomation, particularly if early after the bite, increase the INITIAL dose of antivenom 2X or 3X. Administer over a period of 30 minutes. If the patient is in extreme fluid load, antivenom may be delivered at more concentrated volumes until the patient is in appropriate fluid balance.
- Testing for Equine Protein Sensitivity:
- It is NOT ADVISABLE to utilize subcutaneous or intradermal testing for sensitivity to equine products in that such testing may be unreliable, and may unnecessarily delay antivenom therapy which must be used if any signs of Black Snake envenomation are present.
- If there is reason to believe that the patient may be sensitive to equine protein products:
- Premedicate the patient with 1 gm Solumedrol, administered I.V. push. Assuming the patient's condition is stable, wait 15-30 minutes before administering the antivenom.
- Administer the antivenom at a rate as tolerated by the patient beginning at a rate of 250ml/hour (as opposed to the normal 500ml/hour rate). If the patient tolerates this, increase the rate to 500ml/hour.
- Monitor Pulse and Blood Pressure carefully. Be prepared to treat for Anaphylaxis.
- Clinical Experience with Black Snake:
- Although, the venom of the Black Snake is relatively less toxic than many other venomous snakes, it has large venom stores and has been known to inflict multiple bites. If provoked the snake can be very aggressive. Pseudechis australis and P. papuanus are considered to be more dangerous than other species of Black Snakes.
- The Black Snake is unique among other Australian elapids in that its venom is less neurotoxic and thus neurological symptoms, when present, are generally less pronounced. However, Black Snake venom is considered strongly myolytic and as described previously may cause rhabdomyolysis. In addition the venom is prone to cause significant local swelling and tissue necrosis. Although rare, a fatal outcome is possible after envenomation by a Black Snake, especially from Pseudechis australis or P. papuanus.
The following references are recommended for further reading. This material includes case histories, guidelines and recent findings in the treatment of Black Snake bites. These should be read only after treatment has begun, and the patient is stable.
- Australian Aniamal Toxins, Sutherland, S.K., Oxford University Press, Melbourne, 1983.
- Rowlands, J.B., Mastaglia, F.L., Kakulas, B.A., and Hainsworth, D., "Clinical and pathological aspects of a fatal case of Mulga (Pseudechis australis) snakebite." Medical Journal Australia. 1, 226-230.
- COMMONWEALTH SERUM LABORATORIES: Treatment of Snake Bite in Australia and Papua New Guinea using Antivenom (Package Insert with Antivenom). CSL, September 1985.