Venomous Bites and Stings

Venomous Bites and StingsSnake bite and poisoning:

– In 50% of cases no venom is inoculated at a snake bite. If venom inoculation, the severity of the poisoning depends on the species, the amount injected, location (bites the head and neck are the most dangerous), weight, general health and age of the subject (most serious in children).

– It is rare to identify the snake in question. The observation of the patient, however, can guide the diagnosis and what to do. There are 2 major syndromes of poisoning:

• neurological disorders, progressing to respiratory muscle paralysis and coma, moving towards a elapid envenomation (cobra, mamba, etc.);

• extensive local lesions (severe pain, inflammatory syndrome with edema and necrosis) and clotting disorders moving towards a viperid envenomation or a pit viper (rattlesnake).

– Early diagnosis and monitoring of coagulation disorders based on measuring the dry tube clotting time (to the patient’s arrival and then every 4-6 hours the first day).

Collect 2-5 ml of blood, wait 30 minutes and examine the tube:

• Comprehensive Coagulation: no haemorrhagic syndrome

• Incomplete or lack of coagulation Coagulation: hemorrhagic syndrome 1

If there are coagulation disorders, continue monitoring once / day until normalization.

– The etiological treatment based on the administration of antivenom, only if there are clinical envenomation orcoagulation abnormality signs.

Sera are effective (verify local availability) but difficult to keep. Their administration is done as early as possible by infusion (in sodium chloride 0.9%) for low or purified by slow IV push serums in severe envenomation, provided you use a properly purified serum. Renew serum 4-6 hours if the symptoms of envenomation persist.

In all cases, include the possibility of an anaphylactic reaction which, despite its potential severity (impact), is generally easier to control a bleeding disorder or serious neurological damage.

– In an asymptomatic patient (bite without signs of envenomation and without coagulation disorders), medical surveillance lasts at least 12 hours (at best 24 hours).

1 * There is sometimes a wide gap between the collapse of the clotting factors (<30 min after the bite) and the first bleeding (bleeding outside the site of bite and / or the appearance of sero-bloody blisters) that can occur up to 3 days after the bite. Conversely, stopping bleeding precedes the biological standardization of coagulation.

– In case of overt infection only: drainage in cases of abscess; Amoxicillin / clavulanic acid (co-amoxiclav) for 7 to 10 days in case of cellulite.

The infections are relatively rare and mostly related to traditional treatments or nosocomial infection after surgery unnecessary or premature.

2* Tourniquets, incision-suction and cauterization are useless or even dangerous.

3* Do not use acetylsalicylic acid (aspirin).

Sting scorpions and poisoning:

– Envenomation results in most cases by local signs: pain, edema, erythema. Treatment is limited to a complete rest, cleaning the wound, administering a PO analgesic and tetanus prophylaxis. In case of severe pain, local anesthesia with lidocaine 1% in infiltration around the puncture site. Observation for 12 hours.

– General signs appear in severe envenomation: hypertension, sweating, salivation, hyperthermia, vomiting, diarrhea, muscle aches, difficulty breathing, convulsions; rarely, shock.

– Etiological treatment:

The use of antivenom is controversial (low effectiveness of most of them poor tolerance due to insufficient purification).

In practice, in countries where scorpion envenomation are severe (Maghreb, Middle East, Central America and the Amazon), to learn about the local availability of sera and follow national recommendations.

For information, administrative criteria are the severity of the poisoning, the patient’s age (increased severity in children) and the time since the bite. Thereof does not exceed 2 to 3 hours. Beyond this time (unlike envenomation by snakes), the benefit of antivenom serum is insufficient compared with the risk of anaphylaxis.

– Symptomatic treatment :

• If vomiting, diarrhea, sweating prevention of dehydration (oral rehydration salts), especially in children.

• In case of muscle pain: 10% calcium gluconate by slow IV (children: 5 ml / injection, adults: 10 ml / injection, to be administered 10 to 20 minutes).

• If convulsions diazepam should be used with caution, the risk of respiratory depression is increased in patients envenomed.

Bite of spiders and envenomation:

– The treatment is usually limited to a complete rest, cleaning the wound, administering a PO analgesic and tetanus prophylaxis.

– Severe envenomation is rare. mainly there are two major syndromes:

• Neurological Syndrome (Black Widow): intense muscle pain, tachycardia, hypertension, nausea, vomiting, headache, sweating. The signs develop for 24 hours and then spontaneously disappear in a few days.

• necrotic syndrome (recluse spider): local tissue lesions, possible necrosis and ulceration; mild general symptoms (fever, chills, malaise and vomiting) usually disappear within days. Sometimes hemolytic jaundice can be life-threatening.

In addition to general measures above, use calcium gluconate 10% slow IV (children: 5 ml / injection, adults: 10 ml / injection, to be administered 10 to 20 minutes) for muscle spasms.

Debridement or incision necrosis are not recommended (useless, decaying).

Hymenoptera (bees, wasps, hornets):

– Local treatment: removal of the sting (bee), cleaning with water and soap, lotion

calamine important pruritus.

– Analgesics PO if required (paracetamol PO).

– In case of anaphylactic reaction:

epinephrine (adrenaline) IM

Use undiluted epinephrine solution (1 mg / ml) and 1 ml syringe graduated in 100th in children:

Children from 6 months to 6 years: 0.12 ml

Children 6 to 12 years: 0.25 ml

Children over 12 and adults: 0.5 ml

In children, in the absence of 1 ml syringe, use a dilute solution of 0.1 mg of epinephrine per mL (1 mg epinephrine in 9 ml of sodium chloride 0.9%):

Children from 6 months to 6 years: 1.2 ml

Children 6 to 12 years: 2.5 ml

If no improvement, repeat the injection after 5 minutes.

Insert an IV line and use IV epinephrine in case of circulatory collapse or non-response to treatment IM.