Scorpion stings and venoms
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The term scorpionism is the medical term used to describe the syndrome of
scorpion stings. We focus here on the thick-tailed scorpions in the family Buthidae,
which are the most dangerous scorpions in South Africa (See Dangerous
scorpions: how to identify them). Find out here about how
to prevent being stung, the signs
and symptoms of scorpionism, and scorpionism
In South Africa we are fortunate
to have a fascinating and diverse scorpion fauna and yet a low incidence of
scorpionism, unlike areas in the south-western U.S.A., Mexico, east-central
South America, north Africa, the Middle East and India where the incidence of
serious scorpion envenomation is high. Worldwide, there are about 100,000 cases of scorpion
envenomation resulting in approximately 800 deaths per year. Locally more than
95% of cases of scorpionism results in no more than local pain lasting from
several minutes to about 4 hours with most of the Ischnurid stings resulting in
no more than a pin prick. In South Africa there are only 1
to 4 deaths a year resulting from Parabuthus envenomation (nothing in
comparison to car, crime, sport or health related deaths).
A case study of 42 serious
scorpion envenomations, occurring in western Cape over 5 summers (1986/7 to
1991/2), recorded 4 fatalities of children. Parabuthus granulatus was
found to be the main culprit, responsible for 3 deaths. Parabuthus capensis
was the alleged culprit of the fourth death but as the specimen was lost it
cannot be verified. Parabuthus transvaalicus is the major cause of
serious scorpion envenomation in Zimbabwe with recorded cases of death. Parabuthus
mossambicensis has also been implicated in cases of serious envenomation.
All Parabuthus and especially P. kalaharicus, P. schlechteri and
villosus must be regarded as potentially lethal.
The reason for the high number of
envenomations by Parabuthus granulatus is probably due to its habit of
actively foraging unlike most scorpions' sedentary ambush strategy. October to
March is the period when most stings occur, with a peak in January / February,
with about 75% of stings occurring at night. The victims are usually stung on
the foot due to open footwear or no footwear. Scorpions are a greater problem in
the north-western Cape than snakes.
All scorpions posses a neurotoxic
venom that affects the central nervous system but there are some exotic species
with cytotoxic venom. Less than
5% of stings result in signs and symptoms requiring medical attention. The non-Buthidae
families normally result in no more than a mild to intense pain at the sting
site with possible mild local inflammation (swelling and redness). The family
Ischnuridae with its thin tail and small stinger can hardly penetrate the skin
although some of the larger species can execute a mild to painful sting.
Scorpions, as with spiders and
snakes, voluntarily deliver venom that is expelled by 2 muscles surrounding the
venom gland in the vesicle. Sometimes, the animal can deliver a dry sting and
the victim, due to sheer hysteria, can show false signs and symptoms. The depth of the sting will
the severity of the envenomation as will the health and size of the victim. The
effects of a sting can be reduced if delivered into a bony area or thick clothing can prevent venom entering
tissue below the skin. A deep sting into a fleshy area will result in more
Scorpions, like spiders and
snakes, do not make good pets and invariably succumb to neglect. The scorpion
becomes stressed with continual handling and prodding and may end up stinging
its keeper when he picks it up to impress his friends. If they are to be
kept, only those who know and understand them should keep them.
- Wear protective footwear especially at night.
- Exercise caution when lifting rocks, logs and
when collecting firewood.
- Do not handle scorpions with bare hands.
- When camping try not to sleep directly on the
- Shake out footwear, clothing and bedding to
expel unwanted creepy crawlies.
- Learn how to distinguish a highly venomous
scorpion from a harmless one and the area they occur in.
The severity of envenomation
depends on various factors such as the health and age of the victim, the sting
site and species, size and degree of agitation of
the scorpion. A person with
heart or respiratory problems will be at greater risk. Some or all of the
following sings and symptoms may result.
- Immediate and intense, burning pain at the
sting site that lasts about 30 minutes. Mild inflammation may be present,
with the sting mark not always visible.
- Signs and symptoms only develop after 30
minutes and sometimes only after 4 to 12 hours, increasing in severity over
the following 24 hours. The pain can be local as well as distal with
- Paraesthesia, an abnormal sensitivity,
includes a burning sensation and pins and needles usually in the hands,
feet, face and scalp.
- Hyperaesthesia, an excessive sensitivity of
the skin to clothing and bedding with the patient even sensitive to noise.
- Ataxia, a lack of muscle coordination with a
stiff legged or drunken walking action. Involuntary movements, tremors and
- Tachycardia, an increased pulse rate of 100 to
150 bpm for Parabuthus granulatus and below 55 bpm for Parabuthus
- Raised blood pressure in Parabuthus
Normal in children but raised in some adults in Parabuthus transvaalicus
- Dysphagia, a difficulty in swallowing
especially with Parabuthus transvaalicus and excessive salivation.
- Dysarthia, a speech difficulty.
- Excessive perspiration in Parabuthus
- Headaches, nausea, vomiting and diarrhea.
- Ptosis, patient has droopy eyelids.
- Restlessness and anxiety is a prominent
feature seen in children with Parabuthus granulatus. Hyperactivity and
infants crying for unexplained reason.
- Urine retention.
- Respiratory distress is a major complication
and can result in death.
The following possibilities must
be considered when making a diagnosis: Alcohol withdrawal, Botulism, Diphtheria,
Drug overdose, Encephalitis, Guillain-Barré syndrome, Hysteria, Meningitis,
Myasthenia gravis, Myocardial infarction, Organophosphate poisoning,
Poliomyelitis, Subdural haematoma, Tetanus.
- First aid treatment is the application of a
cold compress, if the hyperaesthesia will allow and an analgesic (Asprin,
Paracetamol) to relieve pain and transport to a hospital.
- Monitor cardiac and respiratory functions and
treat as required.
- Patient with systemic symptoms, especially
children and the elderly must be hospitalized for 24 to 48 hours.
- Immobilize and clean wound.
- Antivenom must only be administered in the
case of severe systemic envenomation.
- Antihistamine and steroids only to be
administered in cases of allergic reaction to antivenom. In the event of
anaphylactic reaction, which must always be anticipated, administer
- Atropine may be administered in cases of
confirmed Parabuthus transvaalicus envenomation to control excessive
- Intravenous administration of 10 ml of 10%
calcium gluconate IV over 10 to 20 minutes may provide relief from pain and
cramp, but is only effective for 20 to 30 minutes.
- Administer a tetanus toxoid to prevent
- Envenomation of the eyes must be flushed with
water or any bland fluid (milk, urine). In severe cases antivenom can be
diluted 1 to 5 or 1 to 10 with water.
- Do not use traditional remedies such as
incisions, suction, tornique or the application of ointments.
- Do not use alcohol as it will only mask any
- Do not administer antivenom if no signs or
symptoms of severe envenomation presents itself.
- Do not administer spider or snake antivenom.
- Do not administer atropine to reduce
salivation in the case of Parabuthus granulatus stings as it may lead to
unopposed adrenergic reaction.
- Do not administer barbiturates, opiates,
morphine or morphine derivatives as this could greatly increase convulsions
and cause respiratory distress.
Research on local venomous species
Research in the Western Cape was done to
improve the treatment for victims stung by Buthidae scorpions as it was felt that the
treatment previously administered was not very effective. Eventually
scorpions responsible for the stings were obtained when patients were stung and
it was established
that in the majority of cases it was Parabuthus granulatus that was
responsible. Once this had been established, a more
specific anti-venom was developed. This proved very
successful and patients thereafter recovered rapidly from stings. In just about
all the cases that were researched, patients were stung under very similar
conditions - at night, not wearing shoes on gravel roads. Similar research in
Zimbabwe isolated Parabuthus transvaalicus as the main culprit.
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Norman Larsen ©.