IMMEDIATE FIRST AID
for bites by
Forest Cobra
(Naja melanoleuca)
In the event of an actual or probable bite from a Forest Cobra, execute the
following first aid measures without delay.
Snake:
- Make sure that the responsible snake or snakes have been appropriately
and safely contained, and are out of danger of inflicting any additional
bites.
Transportation:
- Immediately call for transportation.
Telephone:
Victim:
- 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. (See attached copy from "First Aid for Snakebite", by Dr.
S.K. Sutherland.)
- 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 South African Institute for Medical Research S.A.I.M.R.)
Polyvalent Antivenom ready for the emergency crew to take with the victim to
the hospital. Give them the following:
- the available antivenom (at least 10 - 20 vials)
- the accompanying instruction (Protocol) packet
- the victim's medical packet (if available)
DO NOT cut or incise the bite site
DO NOT apply ice to the bite site
Summary for Human Bite
by
Forest Cobra
(Naja melanoleuca)
The bite of the Forest Cobra with envenomation can be rapidly fatal
(possibly as early as 30 to 120 minutes). Please read the attached Medical
Management Protocol and respond 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 a medical center emergency or 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 signs or symptoms are present, perform the following:
- Administer Lactated Ringers Solution at 200 to 250 mls per hour.
- Draw samples and collect initial laboratory data.
- Withdraw the contents of 3 vials of South African Institute for Medical
research (S.A.I.M.R.) Polyvalent Antivenom. Administer the antivenom I.V.
piggyback at a rate of 1 vial (10 mls) per minute.
- Remove the splints and crepe bandage slowly over a period of 10
minutes. If symptoms progress rapidly, reapply the bandage, and administer an
additional 3 vials. Again attempt to remove the bandage.
- Allergic or untoward reactions to the antivenom should be treated with
Corticosteroids, Epinephrine, Benadryl, Atarax and/or Antihistamines as
appropriate.
- Monitor Signs, Symptoms, and Laboratory data, and administer additional
antivenom in 1 vial increments at a rate of 1 vial (10 mls) per 5 minutes as
necessary to control the progression of symptoms.
- The required amount of antivenom will vary with the severity of
envenomation. One should anticipate using (including the initial dose):
4-6 vials total for a minor bite with envenomation.
8-10 vials or more may be necessary for moderate or severe bites.
MEDICAL MANAGEMENT
for bites by
Forest Cobra
(Naja melanoleuca)
This person has received a bite and probable envenomation from a Forest
Cobra (Naja melanoleuca). This is a large, thick-bodied, black snake from the
tropical and subtropical rain forests of Western, Central, Eastern and
Southern Africa. Considered by some to be the least dangerous of the African
(Naja) Cobras, the bite of this snake, however, can be rapidly fatal without
prompt intervention. In this particular species, envenomation usually presents
predominately with systemic neurologic manifestations. Drowsiness, neurological
and neuromuscular symptoms may develop early; paralysis, ventilatory failure or
death could ensue rapidly.
Please read and execute the following procedures without delay.
- A crepe bandage and splint have been applied asimmediate 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 10 vials of South African Institute for Medical
Research (S.A.I.M.R) Polyvalent Antivenom are present with the patient. This
antivenom contains the appropriate fractions necessary to neutralize the
components of Forest Cobra venom.
- If the patient has been envenomated, the treatment is 4 to 12 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
- Consultants
- References
Signs and Symptoms of Envenomation:
- Neurological and Neuromuscular: These signs and symptoms may manifest
early, but may be delayed in onset. Not necessarily any or all of these will
develop, even with severe envenomation. Monitor for these carefully from the
outset, they generally develop very quickly and dramatically.
- Respiratory paralysis or Dyspnea Excessive salivation
- Drowsiness
- Restlessness
- Sudden hearing loss (Unilateral and bilateral hearing loss have been
reported)
- Sudden loss of consciousness
- Eyelid drooping (Ptosis)
- Ophthalmoplegia
- Palatal paralysis
- Glossopharyngeal paralysis or Dysphagia
- Vertigo
- Fasciculations
- Limb paralysis
- Stumbling gait(Ataxia)
- Head drooping (Cervical muscle paresis or paralysis) Headache
- Local pain or Numbness around bite site (tends to be only mild)
- General: These symptoms typically manifest within 15 minutes to 4
hours following the bite if envenomation occurred. However, in some cases they
may represent the only indication of clinical envenomation.
- Shock
- Hypotension
- Abdominal Pain
- Nausea and Vomiting
- Regional lymphadenopathy and Lymphadenalgia
- Hyperpyrexia (Fever)
- Epistaxis
- Flushing of the face
- Warm skin
- Increased Sweating
- Pallor
- Nephrotoxicity: Acute Renal Failure has not yet been reported in cases
of Forest Cobra bites in humans. Oliguria or Anuria with possible changes in
urinary composition will herald the development of renal shutdown. Dialysis is
advised.
- Cardiotoxicity: Direct toxic effects on the myocardium or conducting
system have not yet been reported in Forest Cobra envenomation. However,
effects on the nervous or vascular systems may manifest as cardiac
complications. Monitoring of cardiac function and rhythm is advised.
- Local Symptoms: Swelling around the area of the bite site should be
expected especially of involved digits. Local necrosis with tissue slough may
also be possible.
- Fang Marks: 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. The absence of
fang marks does not preclude the possibility of a bite (especially if a
juvenile snake is involved). Larger specimens of the Forest Cobra will leave
large, definitive marks. Multiple bites inflicted by a single snake or by more
than one snake are clearly possible, and should be noted if present (See
Special Considerations below). The presence of fang marks does not always
imply that the injection or deposition of venom into the bite wound
(envenomation) actually occurred.
Medical Management:
- Admit patient to an emergency or trauma service and call the consultant
identified by the Poison Control Center.
- 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:
- Hemoglobin
- Urine Electrolytes and Creatinine
- Free Protein
- Electrocardiogram (Place the patient on continuous monitoring).
- 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.
- 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 parametric values previously
normal or slightly abnorma.
- 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 envenomed 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 ANY SIGN OR SYMPTOM becomes apparent or has been noted during the
course of treatment, begin Antivenom Therapy as follows:
- Each vial of S.A.I.M.R. Polyvalent Antivenom is packaged as a
pepsin-digested purified liquid form, and is ready for immediate use.
- Secure Three vials (30 mls) immediately, and withdraw the contents into
a single syringe.
- Prepare a second syringe with 500 mg of Solumedrol; place on
standby.
- Administer the undiluted Antivenom by direct intravenous injection in
an established I.V. slowly over a period of 2 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
Epinephrine, Steroids and Antihistamines. After the patient is stabilized,
continue injecting the remaining initial dose of antivenom without further
delay.
- After the first three vials (30 mls) of antivenom has been administered,
the splint and the bandages may be removed. This should be done VERY SLOWLY
over a period of FIVE minutes to prevent a bolus release of venom. If the
patient's condition WORSENS:
- Reapply the crepe bandage.
- Prepare an additional three vials of antivenom immediately as directed
above.
- Deliver this dose by direct intravenous injection slowly over 4
minutes.
- Release the bandage again slowly over 10 minutes.
- The patient should have received a total of 6 vials (60 mls) of
antivenom at this point.
- Antivenom Therapy is the mainstay of treatment for African cobra
envenomation. Many of the symptoms are ameliorated or entirely eliminated by
the antivenom alone. Other symptoms will require additional modalities of
therapy to correct. Local symptoms may take several days to weeks to
completely resolve; their progression, however, may be controlled with
antivenom therapy.
- Neurological Symptoms (especially respiratory obstruction or failure)
will tend to predominate the clinical picture in cases of African cobra
envenomation, and are usually the most immediate cause of dangerous problems.
Often, these are improved by the antivenom. If breathing becomes impaired,
provide respiratory assistance. Secretions may become copious, necessitating
suctioning.
- Hematological symptoms may present as a Disseminated Intravascular
Coagulopathy, and are treated as are other DICs. This has not been reported in
Forest Cobra envenomations. However, spontaneous hemorrhage, prolonged clot
lysis with failure of clot retraction secondary to a platelet defect, delayed
rise in fibrin degradation products, and complement (C3) depletion have been
seen following bites from the Spitting Cobra (Naja nigricollis).
- Renal symptoms have not yet been reported in Forest Cobra envenomation,
but may complicate the situation, and if severe (i.e., Acute Renal Failure) may
necessitate Peritoneal Dialysis.
- If severe muscle or respiratory paralysis develops and persists,
administer 0.6 mg of Atropine IV. Follow by giving 0.5 mg of Neostigmine IV
every 30 minutes for a maximum of FIVE doses.
- It is important to keep venom neutralization current and continuous.
The best method to accomplish this is to keep a close watch on the patient's
status. If the present condition does not improve, or should it worsen for any
reason, additional antivenom should be administered. The antivenom should
ideally be diluted (1:10) in Lactated Ringers Solution, and always given by
intravenous infusion at a rate of ONE vial per 10 minutes. Give all additional
antivenom in unit (one vial) doses. One should anticipate using (including the
initial dose):
4-6 vials total for a minor bite with envenomation.
8-10 vials or more 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 symptoms are stabilized.
General Considerations:
- 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
concerns. 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 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.
- 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.
Special Considerations:
- Multiple Bites:
- It is possible for a Forest Cobra to deliver more than one bite in a
single attack, and thus may inject a larger volume of venom. If there is
evidence that such an attack occurred (i.e., history or multiple bite sites),
the INITIAL dose of antivenom should be 6 vials (60 mls) given: by direct
intravenous injection. Give the antivenom slowly over four minutes. WATCH
CLOSELY for signs of allergic response; correct reaction (as described below).
Give all subsequent doses in ONE vial increments at 1 vial per 10 minutes as
necessitated by the presence of continued signs and symptoms.
- Severe Envenomation:
- If the patient shows severe signs of envenomation, particularly if early
after the bite, up to 12 vials (120 mls) can be given as an INITIAL dose. Give
the antivenom by direct intravenous injection in two divided six vial (60 mls)
boluses. Correct any adverse or allergic reactions with Corticosteroids,
Antihistamines and/or Epinephrine as indicated
- 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 Forest
Cobra envenomation are present.
- If there is reason to believe that the patient may be sensitive to
equine protein products (e.g., previous snake bite treated with antivenom in
which a sensitivity reaction was noted, multiple previous snake bites):
- If there is reason to believe that the patient may be sensitive to
equine protein products, the following may be performed:
- Administer 1 gram of Solumedrol I.V. push.
- Wait 10 minutes.
- Administer the antivenom by direct intravenous infusion at a rate of 1
vial (10 mls) per 5 minutes.
- Monitor Pulse and Blood Pressure carefully. Be prepared to treat for
Anaphylaxis with Epinephrine and other vasoactive medications.
- Clinical Experience with Naja melanoleuca:
- The Forest Cobra is one of the least frequent causes of snake bite among
the African Cobras, largely due its forest-dwelling habits and its shy,
retiring demeanor. Although one of the largest of the African Naja Cobras, the
venom is considered less toxic than the others. If the snake becomes cornered
or is agitated, it can quickly attack the aggressor, and if a large amount of
venom is injected, a rapidly fatal outcome is possible. The Forest Cobra does
not normally spit or spray its venom. The Forest Cobra is also felt by many
her- petologists to be one of the most intelligent of the African
elapids.
- Clinical experience with Naja melanoleuca has been very sparse, and few
recorded bites have been documented. Deaths from respiratory failure have been
reported, but most victims will survive, especially if prompt administration of
antivenom is undertaken as soon as clinical signs of envenomation have been
noted. Spontaneous recoveries without the use of specific antivenom have also
been seen, however neglecting the use of antivenom places the patient at
increased risk for major morbidity and mortality.
- Signs and Symptoms are likely to be similar to those seen in the other
African cobras and mambas with ptosis, headache, sudden change in
consciousness, respiratory difficulties predominating the clinical
presentation. Some reports of Naja melanoleuca envenomation have recorded
unilateral or bilateral hearing loss as an early symptom.
References:
The following references are recommended for further indepth reading. This
material includes case histories, guidelines and recent findings in elapid
literature. These should be read only after treatment has begun, and the
patient is in stable status.
- SOUTH AFRICAN INSTITUTE FOR MEDICAL RESEARCH: Anti-Snakebite Serum.
(Package Insert with Antivenom), 1980.
-Recommended reading, although not specifically concerning the Forest
Cobra-
- WARRELL, D.A.,GREENWOOD, B.M., DAVIDSON, N.M., OMEROD,L.D., PRENTICE,
C.R.M.: Necrosis, Hemorrhage and Complement Depletion Following Bites by the
Spitting Cobra (Naja nigricollis). Quart. J. Med., n.s., 45(177):1,
1976.
- STROVER, H.M.: Observations on Two Cases of Snake-bite by Naja
nigricollis ss mossambica. Cent. Afr. J.Med., 19(1):12, 1973.
- BLAYLOCK, R.S., LICHTMAN, A.R.,POTGIETER, P.D.: Clinical Manifestations
of Cape Cobra (Naja nivea) Bites. S. Afr. J. Med., 68:342, 1985.
Click here to return to the top of the page.