The insect that is responsible for the majority of serious sting related reactions belong to the order hymenoptera. This include bees, wasps, spiders, scorpions, ants and centipedes.
Diagnostic Criteria
- Pain, swelling, redness, and itching to the affected area
Non-Pharmacological Treatment
- Clean the area with soap and water to remove contaminated particles left behind by some insects
- Refrain from scratching because this may cause the skin to break down and results to an infection
Pharmacological Treatment
A: Ibuprofen
Adults: 400–800mg (PO) 8 hourly for 3 days
Children: 10mg/kg 8hourly maximum 400mg per day for three days
B: Prednisolone, 2 mg/kg/day (PO) in single daily not to exceed 80 mg/day for 5 days
Where there is an anaphylactic reaction treat according to guideline.
C: Diphenhydramine
Adults: 50 mg (PO) 6 hourly not exceeding 300mg/day for 5days. In severe reaction 50mg IV 6 hourly not exceed 400mg/day for 5 days
Children: 2–6 years: 6.25mg (PO) 6 hourly; not to exceed 37.5 mg/day for 5 days
6-12 years: 25mg (PO) 6hr; not to exceed 150 mg/day for 5 days
>12 years: 25–50mg (PO) 6 hourly ; not to exceed 300 mg/day for 5 days
D: Cimetidine/Ranitidine
Adults :5–10 mg/kg IV 6hourly for 5days
Neonates: (<28 days old): 1–5 mg/kg IV 8 hourly for 5days
Infants: 2–5 mg/kg IV 6 hourly for 5 days
25.7.1 Management of Specific Bites/Stings
25.7.1.1 Bee and Wasps Sting
Bee Venom contains many toxins including: Haemolytic enzyme, a neurotoxic factor, histamine and lytic peptide. Wasp Venom contains Hyaluronidase and 5hydroxytryptamine.
Diagnostic Criteria:
- Locally: Itching, pain, erythema, and swelling, cellulites
- Systemic: Oedema, fatigue, nausea, vomiting, fever, unconsciousness, Anaphylaxis, diarrhea or stool incontinence, dizziness, hypotension, haemolysis, rhabdomyosid, haemoglobinuria and myoglobinuria
Non-Pharmacological Treatment:
- Airway and breathing
- Remove stingers by forceps or scrap with care
- Elevation of the affected limb
- Clean wound
Pharmacological treatment
A: Adrenaline IV 0.5mg (0.1Ml) of 1;1000 solution diluted in 10ml of 0.9% sodium chloride slowly over 2min23 Give Ranitidine IV
A: IV 0.9% sodium chloride 10–20mls/kg as a bolus
A: Paracetamol 1g for adult or 15mg/kg for children 8hourly for 48hours
D: IV Methylprednisolone 125mg stat in patient with respiratory and cardiovascular compromised
Note:
- Patient with multiple stings: observe for 24 hours
- Healthy adults >50stings,
- Children 1 sting
25.7.1.2 Scorpion Sting (Envenoming)
Scorpion stings can be very painful for days. Systemic effects of venom are much more common in children than adults.
Diagnostic Criteria
- Local pain and/or paresthesia at the site of envenomation,
- Pain and/or paresthesia remote from the site of sting,
- Blurred vision, roving eye movement, hypersalivation, tongue fasculation, dysphagia, dysphonia, restless,
- Severe involuntary shaking or jerking extremities
Non-Pharmacological Treatment
- Provide adequate airway, ventilation and perfusion
- Calm the patient to lower the heart rate and blood pressure, thus limiting the spread of the venom
- Give oxygen
- Monitor vitals: oxygen saturation, heart rate respiratory rate and blood pressure
Pharmacological Treatment
S: Centruroides scorpion immune F(ab)2 injection
Initial dose: infuse 1vial of the 3vials over 10minutes, observe for 60minutes
If symptoms persist you may repeat the remaining 2 vials, one vial at a 30 minutes interval.
A: Paracetamol (PO) or IV
OR
C: Morphine (PO) or IM according to severity
If very severe, infiltrate site with
A: 1% lignocaine.
25.7.1.3 Snake Bite
Less than 10% of 3500 snake species are poisonous and they include cobras and mambas (Elapidac), sea snakes (hydrophidac) and the boom slang and vine snakes (columbidac). Clinical ccondition depends on the type of snake bite and amount of poison (venom) injected. Hence envenomation (poisoning) will be:
- Neurotoxin in cobra, mambas and sea snakes
- Haemotoxic in vipers and boom slang.
Snake bites should be considered in any severe pain or swelling of a limb or in any unexplained illness presenting with bleeding or abnormal neurological signs. Some cobras spit venom into the eyes of victims causing pain and inflammation.
Diagnostic Criteria:
- General signs include shock, vomiting and headache
- Bite for local necrosis, bleeding or tender local lymph node enlargement
- Specific signs depend on the venom and its effects. These include:
- Shock
- Local swelling that may gradually extend up the bitten limb o Bleeding: external from gums, wounds or sores; internal especially intracranial
- Signs of neurotoxicity: respiratory arrest or paralysis, ptosis, bulbar palsy (difficulty swallowing and talking), limb weakness
- Signs of muscle breakdown: muscle pains and black urine
Investigations:
- Haemoglobin
- Bleeding indices
Non-Pharmacological Treatment:
- Reassure the patient;
- Splint the limb to reduce movement and absorption of venom.
- If the bite was likely to have come from a snake with neurotoxin venom,
- Clean the site with clean water to remove any poison and remove any fangs;
- If any of the above signs, transport to hospital which has antivenom as soon as possible.
- Paralysis of respiratory muscles can last for days and requires intubation and mechanical ventilation or manual ventilation (with a mask or endotracheal tube and bag) by relays of staff and/or relatives until respiratory function returns.
- Do endotracheal intubation +/- elective tracheotomy.
- Elevate limb if swollen
- Give
A: Anti-Tetanus prophylaxis - Monitor very closely immediately after admission, then hourly for at least 24 hours as envenoming can develop rapidly.
Pharmacological Treatment:
- Treat shock, if present.
- A: 0.9% sodium chloride 10–20mls/kg bolus, repeat after 30min if still in shock
- Give fluids orally or by NG tube according to daily requirements. Keep a close record of fluid intake and output fluid daily requirements to be inserted
- If there are systemic signs or severe local signs (swelling of more than half of the limb or severe necrosis), give
A: Antivenom (polyvalent). Follow the directions given on the antivenom preparation.- Dilute antivenom in 2–3 volumes of 0.9% saline and give intravenously over 1 hour
- Give more slowly initially and monitor closely for anaphylaxis or other serious adverse reactions.
- A: Epinephrine (adrenalin), IM dose of 1:1000 (Repeat after 5 min if no improvement)
- Children > 12 years and Adults 500 µg (0.5ml)
- Children 6-12 years 300 µg (0.3ml)
- Children < 6 years 150 µg IM (0.15ml)
AND
B: IV Chlorpheniramine and be ready if allergic reaction occurs. Dosage as below
- Children under 6 years: 4mg 8hourly needed
- 6–12 years: 8mg (PO) 12 hours as needed
- >12 years and older 12mg 12hourly needed
NOTE
- If itching/urticarial rash, restlessness, fever, cough or difficult breathing develop, then stop antivenom and give Epinephrine 0.01 ml/kg of 1/1000 or 0.1 ml/kg of 1/10,000 solution subcutaneously and IM or IV/SC Chlorpheniramine 250 micrograms/kg.
- When the patient is stable, re-start antivenom infusion slowly.
- More antivenom should be given after 6 hours if there is recurrence of blood incoagulability or after 1–2 hr if the patient is continuing to bleed briskly or has deteriorating neurotoxin or cardiovascular signs.
- Blood transfusion should not be required if antivenom is given.
- Response of abnormal neurological signs to antivenom is more variable and depends on type of venom.
Surgical Intervention
- Excision of dead tissue from wound
- Incision of facial membranes to relieve pressure in limb compartments, if necessary
- Skin grafting, if extensive necrosis
- Tracheotomy if paralysis of muscles involved in swallowing occurs
