|Clinical Guidelines and Treatment Manual (Médecins Sans Frontières, 1993)|
|Chapter 10 - Medical and minor surgical procedures|
Trauma caused by venomous animals; bites are inflicted by the mouth-parts (e.g. snakes, spiders), stings by the hindparts (e.g. bees, scorpions).
ENVENOMATION BY INSECTS, SCORPIONS AND SPIDERS
- Stings by bees, wasps...
Usually benign, but in susceptible individuals may provoke either laryngeal edema or anaphylactic shock:
adrenaline (epinephrine) (SC):
Adult : 1 mg
Child : 0.01 mg/kg
dexamethazone (IV): 4 mg stat. Repeat if required
plus a perfusion of ringer´s lactate or volume expander.
- Spider bites and scorpion stings
Gravity depends upon the particular species, however the majority of such envenomations are either benign or else cause local tissue damage only. If a truly toxic species is thought to be responsible apply first aid and supportive measures as for snakebite (see below). Otherwise, therapy is limited to analgesia, local wound toilet and reassurance.
Clean and disinfect wound:
noramidopyrine (IM) (or any other analgesic): 500 mg in 1 injection IM
If pain very severe:
pentazocine (IM): 30 mg in injection IM
or lidocaine 1% (without adrenaline) infiltrated around the wound gives good relief for very painful scorpion stings.
It is most often not possible to identify the snake reponsible. In any case, the principles of management are the same: first aid and supportive therapy as indicated from close monitoring of the victim's clinical condition. Antivenenes are costly, difflcult to store, difficult to use, sometimes dangerous (anaphylaxis), and moreover of arguable efficacy.
- First aid: the "pressure-immobilization method". The object is
to confine the venom to the site of the bite, thus allowing time for the body to
metabolize it and for attendants to transport the victim to a health care
facility. Venom diffuses mainly via the lymphatics, not via blood, tourniquets
are thus of little use.
· Apply firm constant pressure to the site of the bite.
· Apply a crepe bandage (or substitute) firmly to the entire limb.
· Immobilize the limb with a splint.
· Immobilize the patient.
- Supportive therapy: see table.