Bites and Stings

INTRODUCTION

Bites and stings from animals, spiders, marine stingers and insects in Australia are commonplace but fatal bites are uncommon.

BITE WOUNDS

Snake bites

Most bites do not result in envenomation (i.e. ‘dry bites’), which tends to occur in snake handlers or in circumstances where the snake has a clear bite of the skin. Follow the regional/country guidelines.

First aid

• Keep the patient as still as possible.

• Do not wash, cut or manipulate the wound, or apply ice or use a tourniquet.

• Immediately bandage the bite site firmly (not too tightly). A wide crepe bandage is ideal: it should extend above the bite site for as high as possible, at least 15 cm (e.g. if bitten around the ankle, the bandage should cover the leg to above the knee).

• Splint the limb to immobilise it: a firm stick or slab of wood would be ideal.

• Transport to a medical facility for definite treatment. Do not give alcoholic beverages or stimulants.

Note: A venom detection kit can be used to examine a swab of the bitten area or a fresh urine specimen (the best) or blood.

The bandage can be cautiously removed when the patient is safely under medical observation. Observe for symptoms and signs of envenomation.

Envenomation

Important early symptoms of snake bite envenomation include:

• nausea and vomiting (a reliable early symptom)

• abdominal pain

• excessive perspiration

• severe headache

• blurred vision

• difficulty speaking or swallowing

• coagulation defects (e.g. haematuria)

• tender lymphadenopathy

Note: The greatest danger is respiratory obstruction and failure or catastrophic bleeding. Do not give antivenom unless clinical signs of envenomation or biochemical signs (e.g. positive urine, or abnormal clotting profile).

Treatment of envenomation

• Set up a slow IV infusion of N saline.

• Have adrenaline on standby.

• Dilute the specific antivenom (1 in 10 in N saline) and infuse slowly over 30 mins via the tubing of the saline solution (may need 2 or more ampoules of antivenom). Preferable to use specific rather than polyvalent antivenom.

• Have adrenaline, antihistamines, oxygen and steroids on standby.

• Monitor vital signs and blood issues, e.g. coagulation, platelets.

• Provide basic life support as necessary.

Note: A test dose of antivenom is not recommended.

Be careful of prophylactic adrenaline in some situations (e.g. avoid with brown snakes and with coagulopathy).

Spider bites

The toxin of most species of spider causes only localised pain (requiring analgesia only), redness and swelling, but the toxin of some, notably the deadly Sydney funnel-web spider (Atrax robustus), can be rapidly fatal.

First aid

• Sydney funnel-web: as for snake bites

• Other spiders: apply an ice pack, ...