Bites and Stings

Snakebites can cause both local and systemic effects. Non-venomous snakes cause local effects (swelling, redness, laceration) and venomous snakes cause both local and systemic effects due to envenomation. Over 70% of snakes in Uganda are non-venomous and most bites are from non-venomous snakes. Of the venomous snakes, more than 50% of bites are “dry” i.e. no envenomation occurs. In the event that venom is injected, the effect of the venom depends on the type of venom, quantity,
location of the bite and size and general condition of the victim.

Cause
Common venomous snakes in Uganda: Puff adder, Gaboon viper, black mambas, Brown Forest cobra, Egyptian cobra and Boomslang.

Clinical features

 
If cytotoxic venom (Puff adder, Gaboon viper)
Extensive local swelling, pain, lymphadenopathy – starting 10-30 minutes after the bite.

If neurotoxic venom (Jameson’s mamba, Egyptian Cobra, Forest Cobra, Black mamba)
Weakness, paralysis, difficulty in breathing, drooping eye- lids, difficulty in swallowing, double vision, slurred speech – starting 15-30 minutes after the bite
Excessive sweating and salivation.

If hemotoxic venom (Boomslang, Vine/Twig snake)
Excessive swelling and oozing from the site
Skin discoloration
Excessive bleeding, bloody blisters
Haematuria, haematemesis – even after some days
Shock

If combined venom toxicity
Late appearance of signs and symptoms

Investigations
Whole blood clotting test at arrival and every 4-6 hours after the first day:

• Put 2-5 ml of blood in a dry tube and observe after 30 minutes
• If incomplete or no clotting, it indicates coagulation abnormalities

Other useful tests depending on severity, level of care and availability:

• Oxygen Saturation/PR/BP/RR
• Haemoglobin/PCV/Platelet count/PT/APTT/D-Dimer
• Biochemistry for Serum Creatinine/Urea/Potassium
• Urine Tests for Proteinuria/Haemoglobinuria/ Myoglobinuria
• Imaging ECG/X-Ray/Ultrasound

Management

Venom in eyes

• Irrigate eyes with plenty of water
• Cover with eye pads

Criteria for referral for administration of antivenom

• Signs of systemic envenoming (paralysis, respiratory difficulty, bleeding)
• Spreading local damage:

1. Swelling of hand or foot (site of most bites) within 1 hour of bite
2. Swelling of elbow or knee within 3 hours of bite
3. Swelling of groin or chest at any time
4. Significant swelling of head or neck

• Antivenom sera polyvalent (Africa)
  - Check package insert for IV dosage details. Ensure the solution is clear and check that patient has no history of allergy
• Antibiotics
  Indicated only if wound is infected

ICD10 CODE: T63.4

Causes

• Bees, wasps, hornets and ants: venom is usually mild and causes only local reaction but may cause anaphylactic shock in previously sensitized persons
• Spiders and scorpions: Most are non-venomous or only mildly venomous
• Other stinging insects

Clinical features

• Swelling, discolouration, burning sensation, pain at the site of the sting
• There may be signs of anaphylactic shock.

Differential diagnosis

• Allergic reaction

Management

Prevention

• Clear overgrown vegetation/bushes around the home
• Prevent children from playing in the bush
• Cover exposed skin while moving in the bush
• Use pest control methods to clear insect colonies.

ICD10 CODE: W50.3, W54.0

Clinical Features

• Teeth marks or scratches, lacerations
• Puncture wounds (especially cats)
• Complications: bleeding, lesions of deep structures, wound infection (by mixed flora, anaerobes), tissue necrosis, transmission of diseases (tetanus, rabies, others)

Management

Note: Do not use routine antibiotics for small uncomplicated dog bites/wounds

ICD10 CODE: Z20.3, Z23

Management

Post exposure prophylaxis effectively prevents the development of rabies after the contact with saliva of infected animals, through bites, scratches, licks on broken skin or mucous membranes.

For further details refer to Rabies Post-Exposure Treatment Guidelines, Veterinary Public Health Unit, Community Health Dept, Ministry of Health, September 2001.

General Management

Dealing with the animal:

Notes:

• Consumption of properly cooked rabid meat is not harmful
• Animals at risk: dogs, cats, bats, other wild carnivores
• Non-mammals cannot harbour rabies

Dealing with the patient:

• The combination of local wound treatment plus passive immunisation with rabies immunoglobulin (RIG) plus vaccination with rabies vaccine (RV) is recommended for all suspected exposures to rabies
• If the RIG is not available, the patient should still be vaccinated with the Rabies Vaccine alone
• Since prolonged rabies incubation periods are possible, persons who present for evaluation and treatment even months after having been bitten should be treated in the same way as if the contact occurred recently
• Administration of Rabies IG and vaccine depends on the type of exposure and the animal’s condition

Treatment

Recommendations for Rabies Vaccination/Serum

Prevention

Vaccinate all domestic animals against rabies e.g. dogs, cats and others

Administration of Rabies Vaccine (RV)

The following schedules use Purified VERO Cell Culture Rabies Vaccine (PVRV), which contains one intramuscular immunising dose (at least 2.5 IU) in 0.5 ml of reconstituted vaccine.

RV and RIG are both very expensive and should only be used when there is an absolute indication

Post-Exposure Vaccination in Non-Previously Vaccinated Patients

Give RV to all patients unvaccinated against rabies together with local wound treatment. In severe cases, also give rabies immunoglobulin.

The 2-1-1 intramuscular regimen

This induces an early antibody response and may be particularly effective when post-exposure treatment does not include administration of rabies immunoglobulins.

• Day 0: One dose (0.5 ml) in right arm + one dose in left arm
• Day 7: One dose
• Day 21: One dose

Notes on IM doses:

Doses are given into the deltoid muscle of the arm. In young children, the anterolateral thigh may also be used.

Never use the gluteal area (buttock) as fat deposits may interfere with vaccine uptake making it less effective.

Alternative: 2-site intradermal (ID) regimen This uses PVRV intradermal (ID) doses of 0.1 ml (i.e. one fifth of the 0.5 ml IM dose of PVRV).

• Day 0: one dose of 0.1 ml in each arm (deltoid)
• Day 3: one dose of 0.1 ml in each arm
• Day 7: one dose of 0.1 ml in each arm
• Day 28: one dose of 0.1 ml in each arm

Notes on ID regime:

Much cheaper as it requires less vaccine.

Requires special staff training in ID technique using 1 ml syringes and short needles.

Compliance with the Day 28 is vital but may be difficult to achieve.

Patients must be followed up for at least 6-18 months to confirm the outcome of treatment.

If on malaria chemoprophylaxis, do NOT use.

Post-exposure immunisation in previously vaccinated patientsIn persons known to have previously received full pre- or post-exposure rabies vaccination within the last 3 years.

Intramuscular regimen

• Day 0: One booster dose IM
• Day 3: One booster dose IM

Intradermal regimen

• Day 0: One booster dose ID
• Day 3: One booster dose ID

Note: If incompletely vaccinated or immunosuppressed: give full post exposure regimen.

Passive Immunisation with rabies immunoglobulin (RIG)

Give in all high risk rabies cases irrespective of the time between exposure and start of treatment  BUT  within  7 days of first vaccine. DO NOT USE in patient previously immunised.

Human rabies immunoglobulin (HRIG)

HRIG 20 IU/kg (do not exceed)

• Infiltrate as much as possible of this dose around the wound/s (if multiple wounds and insufficient quantity, dilute it 2 to 3 fold with normal saline)
• Give the remainder IM into gluteal muscle
• Follow this with a complete course of rabies vaccine
• The first dose of vaccine should be given at the same time as the immunoglobulin, but at a site as far away as possible from the site where the vaccine was injected. If the bite is at or near the upper arm, do not infiltrate the wound with the immunoglobulin unless the vaccine won’t be injected in the deltoid muscle of that arm. If the wound near the deltoid is infiltrated with the immunoglobulin, use the deltoid muscle of the opposite arm for the vaccine”

Notes: If RIG not available at first visit, its administration can be delayed up to 7 days after the first dose of vaccine.

Pre-exposure immunisation

Offer rabies vaccine to persons at high risk of exposure such as:

• Laboratory staff working with rabies virus
• Veterinarians
• Animal handlers
• Zoologists/wildlife officers
• Any other persons considered to be at high risk
  • Day 0: One dose IM or ID
  • Day 7: One dose IM or ID
  • Day 28: One dose IM or ID

Rabies Vaccine Schedules