Scorpion stings and bites
Omar Al-Qudsi
Abdullah Al-Shorman
17/11/2011
Scorpion Stings
One of the major public health problems. In the summer people come to the
hospital almost daily due to scorpion stings. People that live in the desert or
straw houses are at a higher risk of getting stung by scorpions, and people that
move rocks and farmers are at a high risk. However, this doesn’t mean that
someone on the 5th floor can’t be stung.
“For every person killed by a poisonous snake, 10 are killed by a poisonous
scorpion.”
We are always scared of snakes and spiders, but scorpions are deadly as well.
So ten times as many people are killed by scorpions than by snakes, and ten
times as many are killed by bees than scorpions.
Snakes: Scorpions: Bees
1:10:100
This is because bees are found everywhere, whereas scorpions and snakes
aren’t as widespread.
Characteristics of Scorpions:
1)
2)
3)
4)
Flat, elongated body
Easily hides in cracks
Has 4 pairs of legs and a pair of claws
Has a segmental tail that is topped by a gland and on top of that a
stinger is found
5) They vary in size from 1-20 cm in length
6) Out of 1,500 scorpion species, 50 are dangerous to humans
There are usually two colors of scorpions, black and yellow. The yellow kind
usually lives in the desert and is more dangerous. This is because it is dehydrated
and its venom is more concentrated.
Most scorpion species are neurotoxic, but less than 5% of stings require medical
attention. Mainly children between 0 and 5 years of age require medical
attention. After 5 years, there is toxicity but the distribution of the venom
according to the surface area is increased so it is not as dangerous. So since
small children have a smaller surface area, they are in more danger from
scorpion stings. So we usually see the stings in smaller age groups.
Last year, we had a baby whose family lives in a tent and during the night the
baby started crying (He was wrapped in a blanket), so his mom took him (stil
wrapped) to the NICU in Rahma. When the baby was unwrapped the Dr. found
him dead (the Dr. was from Sweden and doesn’t know what a scorpion looks
like…) but he saw something and tried moving it. It turned out to be a scorpion
and it stung him.
You should know that the sting of a scorpion is very very painful, so the Dr.
started screaming. The baby ended up dying, but the Dr. was fine.
In the rural areas, families usually wrap their children very tightly in
blankets since they think this will make them stronger. However, when
they wrap them, they keep their feet straight and if the baby has
Developmental Dysplasia of the Hip (DDH) it will move the head of the
femur away from the acetabulum and it will become worse. So if the DDH
were to have disappeared naturally, it won’t because of the blanket and
they usually will require osteotomy in the future.
Scorpions are mostly nocturnal; they appear at dusk and during the day they
hide under rocks to avoid light. However, some species hunt in the daytime.
There are many types, but we don’t really need to know them.
Scorpions are not aggressive, and they don’t hunt for their prey. However, they
wait for their prey and when someone moves a rock they will sting him. Usually
humans are stung when they touch the scorpions in their hiding places.
Pathophysiology:
Scorpions use their pincers to grasp the prey, and then with their tail they will
inject the venom. The amount of venom in the tail/stinger is usually between 0.10.6 mg, but this is more than enough to be lethal.
The gland is lateral to the tip of the stinger and is composed of two types of
columnar cells (A & B), with one producing mucus and the other producing the
venom. The exact components of the venom have been discovered through
electrophoresis, and the venom is toxic in different ways, but mainly it affects
Acetylcholine and the Neuromuscular Junctions.
Most deaths occur during the first 24 hours after the sting and are secondary to
respiratory and cardiovascular failure.
Clinical Presentation:
History:
For patients presenting with scorpion stings, asking about the following is essential
1)
2)
3)
4)
Time of being stung
Nature of the incident
Description of the scorpion
Local and systemic symptoms (if found)
The toxicity and severity of the sting depends on certain factors.
Factors related to the scorpion:
1)
2)
3)
4)
The scorpion’s species
The scorpion’s age and size
Nutritional status of the scorpion
Health of the scorpion’s stinger, since if the needle is injured it is less
dangerous
5) The number of stings
6) Depth and site of the sting; a sting in the neck is more dangerous than in
the foot since there is higher absorption in the neck
Factors related to the victim:
1)
2)
3)
4)
Age of the victim (worse in younger age groups)
Health of the victim
Weight of the victim relative to the amount of venom
Effectiveness of treatment
Physical Exam:
Signs of toxicity depend on the venom and species, but we should know:
1) Pain
2) No local swelling, except in some species. But just remember that there
are no changes in the sight of injection, such as edema around the
injection.
Scorpion Sting: More Pain Less Swelling
Snake Sting: Less Pain More Swelling
The grading of scorpion stings depends on the presence of neurological
symptoms and is divided into:
1) Non-Neurological Predominance:
 Mild: Local Signs Only. Paleness and Parasthesia around the
sting
 Moderate: Ascending local signs or mild systemic
manifestations
 Severe: Life-Threatening systemic signs
2) Neurological Predominance:
 Grade I: Local Pain (85% of scorpion stings
 Grade II: Pain or Parasthesia away from the site of the sting
 Grade III: Either Cranial Nerve or somatic neuromuscular
dysfunction
 Grade IV: Both Cranial Nerve and somatic neuromuscular
dysfunction
It may be true that the most common type found is Grade I; however, there are
still 3% that present with Grade IV neurological symptoms.
Other manifestations
Sympathetic signs: Hyperthermia, Hypertension, Tachypnea, Tachycardia,
Arrhythmia, Hyperkinetic Pulmonary Edema, Diapheresis, Restlessness,
Hyperglycemia, Apprehension, Hyperexcitability and Convulsions.
Parasympathetic signs: Bronchoconstriction, Bradycardia, Hypotension and
others.
Priapism is important to note in patients, because if there is priapism with pain
then this usually means that it is a more deadly scorpion.
Other somatic signs:
Cranial Nerve Palsies, Cardiovascular collapse, vascular collapse, and death
from respiratory and cardiovascular failure like we said.
Differential Diagnosis:
Botulism, Tetanus and Organophosphate poisoning.
Anybody that comes with a scorpion sting we need to do the following:
1)
2)
3)
4)
5)
ABC (Airway, Breathing, Circulation): Just like any other case
CBC
KFT (Kidney Function Test)
Glucose levels
Creatinine Kinase levels. This is in case of muscle abnormalities such as
Rhabdomyolysis which leads to increased Creatinine Kinase levels in the
blood.
6) Complete Examination including CNS exam in order to see Cranial and
neuromuscular dysfunction
7) ECG in cases of cardio-pulmonary symptoms
8) Ventilator in case of respiratory failure
Afterwards we give painkillers but make sure to stay away from opiates! This is
because some books say that the use of opiates as painkillers increases the
toxicity of spider and scorpion stings. Instead we should stick to the use of
paracetamol and its relatives.
The cornerstone for treatment of any scorpion sting is anti-venin.
Anyone with systemic manifestations (cardiopulmonary abnormalities), or Grade
III or IV neuro-exam then we have to give them anti-venin. However, in cases of
Grade I or Grade II cases then there is no need for anti-venin and we only give
them painkillers.
Now in cases where you have to give the anti-venin, there is something known
as “The Rule of Five”.
This means that we give 5 ampules administered IV slowly one at a time, then
we observe after 20-30 minutes. If there is no development of new
manifestations then we can stop here. However, if there are any new
manifestations we can repeat the rule of Five.
Some people say that the anti-venin can cause allergy, and while this is true, we
must balance between the allergy and the systemic manifestations. So if you
decide to give anti-venin, in one line give Dexamethasone/Corticosteroids and
Anti-Histamine. This isn’t because of the scorpion sting manifestations but as
prevention of anaphylaxis in response to the antivenom.
Now as far as the anti-venin, every country should have the specific anti-venin
for the scorpions that are found in their country. This is because every country
has its own specific species of scorpions. For example, the scorpions found in
Arizona are different than those found in Saudi Arabia, and those are different
from the ones found in Jordan. This is why we need to use the specific antivenom for each country.
Unfortunately, this isn’t found all over the world and in Jordan they are currently
trying to achieve this in Jordan University. They collected all the species of
scorpions found in Jordan and they did certain antigenicity tests on them and
Inshallah we will soon have anti-venom for the Jordanian scorpion species.
For the time being we use Saudi Arabian and Iranian anti-venom because we
live in the same region and the scorpions are more or less the same.
Of course, the response isn’t as effective as the specific anti-venom, but we
have to use what we have.
Side Effects of Anti-Venom:
1) Allergy: like we said, we give corticosteroids to combat the allergic
reactions.
2) Serum Sickness: can occur in the long run
Snake Bites
Most snake bites are delivered by non-poisonous species. Around 15% of over
3,000 species worldwide are dangerous. The most dangerous and worst species
is the Viperidae which is also the largest family of venomous snakes.
Its subfamilies include Pit Vipers, Rattlesnakes, Cottonmouths, Copperheads.
They have a triangular shaped head, with two eyes that move all around and it
has no ears so it can’t hear.
Most common snake species in Jordan:
Just know that the Vipera palaestinae is the most common snake in Northern
Jordan and is extremely poisonous.
Pathophysiology:
Snake venom is produced from a paired gland below the eye. It is discharged
from hollow fangs that are connected to the gland. This is why snakes that only
have teeth without fangs are not poisonous. They also have a huge muscle
around the jaw and when the fangs bite the skin, the muscles will squeeze the
gland and the venom will enter the prey’s body.
Comparison of bite marks left
by poisonous (fanged) and
non-poisonous (non-fanged)
snakes. The teeth help
increase toxicity by allowing
more entry points for the
venom in poisonous snakes
Around 100 fatalities occur per year in the Middle East due to snake bites
Clinical Presentation:
During the physical exam it is important for us to look for local swelling and pain
because like we said, in scorpion stings the pain is more whereas in snake bites
the swelling is more.
If we see systemic manifestations in the first 5-15 minutes after the bite, this is not
due to the venom but it is due to the vasovagal attacks from fear of the snakes.
However, if the manifestations appear after 15 minutes then this is usually as a
result of the venom.
Physical Exam:
First thing is the vital signs, then we see if there are any injuries to the soft tissue or
area of the sting and we see if there are marks from two fangs. Of course, we
don’t necessarily have to see both fangs in order for the snake to be poisonous,
because if the patient is bitten in the finger then only one mark will show. So if
we see a sting with only 1 mark, we will think of either a scorpion sting or a snake
bite. Now if it is associated with swelling then this is likely a snake bite, and if it is
associated with pain it is likely a scorpion sting.
Now we can also see signs of systemic toxicity such as hypotension, petechiae,
epistaxis and this is because the snake bite is neurotoxic and hematotoxic so we
may even have DIC. One of the major causes of DIC in children is sepsis, but the
2nd is snake bites.
We may also see Parasthesia, Neuromuscular Blockade and Respiratory Distress
Any patient that comes with a suspected snake bite we need to do:
1) CBC
2) Clotting Factors, Prothrombin, Fibrinogen
3) Cross-Matching (cause they may need blood transfusions)
4)
5)
6)
7)
Blood Chemistry
Electrolyte
Creatinine
Follow-up for hemoglobin, platelets and kidney function
This is because snake venom is hematotoxic, and it may cause hemolysis, kidney
failure and can cause diaphragm paralysis due to its neurotoxic effect.
We admit them to the NICU or PICU and the medical care is very important.
Secure the ABC most importantly, and some hunters actually have kits with antivenin just in case they get bitten by a snake.
Q. Do we band the area of the bite?
A. No, we just restrict activity and immobilization. There is also no need for a
tourniquet, because some of them may cause toxicity and necrosis of the
muscle.
So basically we monitor the ABC’s and offer supportive therapy while looking for
signs of shock. Then we have to grade the severity of the envenomation in order
to find out exactly which anti-venin we will give.
Grading:
1) Mild envenomation: Characterized by local pain, edema but with no signs
of systemic toxicity and normal lab values
2) Moderate envenomation: severe local pain; edema larger than 12 inches
surrounding the wound; and systemic toxicity including nausea, vomiting,
and alterations in lab values (eg, fallen hematocrit or platelet values).
3) Severe envenomation: generalized petechiae, ecchymosis, blood-tinged
sputum, hypotension, hypoperfusion, renal dysfunction, changes in
prothrombin time and activated partial thromboplastin time, and other
abnormal tests defining consumptive coagulopathy.
The grading is important in order to know whether we will give the anti-venin or
not. However, we still have to give every grade anti-venin because we don’t
know how the evolution of symptoms will be.
Dosing:
Mild: 5 vials
Moderate: 10 vials
Severe: 10 vial
Unlike the scorpion anti-venin, each vial contains 10 cc and we dilute this in
normal saline and give it to the patient. However, just like in scorpion stings, we
give the patient corticosteroids in order to prevent anaphylaxis.
There are two indications for the repetition of the dose:
1) Extension of the swelling
2) Persistent coagulapthy (Prolonged PTT that doesn’t change after giving
the first dose)
There are currently two types of Anti-Venin available:
The first is the Wyeth Anti-Venin, and it is polyvalent but contains some proteins
that can cause an immune reaction. (This is the most popular anti-venin)
The second is the savage, which is a monovalent immunoglobulin approved by
FDA
Just like scorpions, each area has its own species and its own types of anti-venin.
In 2009 there was the highest incidence of snake bites in Jordan and this is
because that year was the hottest year in Jordan in a long time.
Bee Stings




The problem that we have with bee stings is the anaphylactic allergic
reaction and the rare toxic venom effect.
In the US there are 25 deaths per year, with the majority of them due to
honeybees.
0.4% of the population is at a risk of serious allergic reaction.
50% of 2006 sting patients experiencing allergic reaction had no previous
warning symptoms
Local reactions



Sharp, burning pain
Itching
Edema
–
Extensive reactions may involve entire extremity, the sting may be in
the finger and the edema can be in all the extremities
–
We’re especially afraid of stings around the mouth and tongue,
because this may cause closure of the airways.
Systemic reactions
–
–
Immediate
•
Mild: Diffuse itching, urticaria, swelling distant from sting site,
flushing
•
Severe: Laryngeal edema, severe bronchospasms, profound
hypotension
Delayed
•
1 to 48 hours after sting, so we are afraid of bee stings up till
48 hours of the sting since the symptoms may take time to
appear
•
May be life threatening
Treatment
1. Immediate
•
Remove stinger (scrape). So you want to try and scrape out
the stinger, rather than using tweezers to take it out. Using
tweezers is dangerous because it may squeeze more venom
out and cause an even worse reaction.
•
Manage airway (ABC)
•
Oxygen
•
Support BP with fluid
•
Epinephrine
•
Antihistamines
•
Steroids
The last 3 are needed depending on the severity of the allergic reaction.
2. Prevent subsequent sting
•
Avoid exposure
•
No bright clothing
•
Avoid sweet fragrances
•
Avoid eating sweets outdoors
3. Self-treatment
•
Medic Alert Tags
•
Anaphylaxis kit
4. Hyposensitization therapy
Spiders





37,000 species of spiders
All are venomous
50 species can bite humans
15 species will produce symptoms
Only two species are dangerous, the Black Widow and the Brown Recluse
The Black Widow: Black and characterized by a red spot on its belly



Makes irregular webs in wood piles, under rocks,
in trash dumps and in outdoor structures
Occasionally in houses
Females rarely leave web
Only females can bite humans



Neurotoxic venom
More potent than pit viper venom
Binds to nerve-ending calcium channels

Venom:
–
Triggers neurotransmitter release
–
Produces low serum calcium
A Black Widow’s sting is followed by an immediate sharp, stinging pain and
muscle cramping that occurs within 15 minutes to 2 hours. It causes:

Upper extremity: pleuritic chest pain (differential diagnosis of
acute abdomen)

Lower extremity/genitalia: abdominal pain, rigidity

Symptoms peak in a few hours, then diminish

Usually last < 24 hours

Some symptomatic up to 4 days

5% have delayed hypersensitivity 2 to 3 days post-bite

Mortality rate unknown but most recover completely
Treatment






Local cold application
Relieve muscle cramping
Calcium gluconate
Methocarbamol (Robaxin)
Diazepam
Narcotics
Antivenin indications:

Very young

Very old

Hypertensive reactions

Acute respiratory distress
These are the 4 groups that we give anti-venin and this anti-venin is available
and FDA approved.
Indications for Admission:

Treated with antivenin

Very young

Very old

Persistent symptoms develop
Done by: Omar Al-Qudsi