Transcript ARTHROPOD BITES AND STINGS - Cleveland Clinic Hospital

ARTHROPOD
BITES AND
STINGS
Chrisnel Jean, D.O
March 9, 2006
EM Lecture Session
Hymenoptera

(WASPS, BEES, AND ANTS)
Hymenoptera:
•
•
•
Most important venomous
insect known to humans
More fatalities result from
stings by these insects.

Apids are usually docile, stinging
only when provoked.

Female bee is capable of stinging
only once. (Male bees have no
stinger).

Vespid have ability to perform
multiple stings.
Three major subgroups:
•
•
•
•
Apidae  includes honeybee
and bumblebee
Vespidae  includes yellow
jackets, hornets and wasps
Formicidae  ants
Most of all allergic reaction
reported yearly occur from
vespid stings.
Africanized honeybees

Known as killer bees

Now found in Texas, Arizona, California, and
most of the temperate southeastern and
southwestern states.

Attack from these bees  massive stinging
resulting in multisystem damage and death from
severe venom toxicity.
Hymenoptera Venom





Contain several components.
Histamine is only a minor component within
the venom.
50% of the venom consist of Melittin.
Melittin is a known membrane-active
polpeptide that can cause degranulation of
basophils and mast cells.
Yellow jackets venom is perhaps the most
potent sensitizer.
Hymenoptera Venom:
Local Reaction
Toxic Reaction

Urticarial lesion contiguous
with the sting site.

Severe local reaction may
involve one or more
neighboring joints.

If the sting involve the mouth
or throat, it can produce
airway obstruction.

Multiple stings (Africanized bees)
can lead to systemic toxic
reaction.

Symptoms may resemble
anaphylaxis, but these pts can
also develop N/V/D.

They may also have HA, fever,
drowsiness, involuntary muscle
spasms, edema without urticaria,
and convulsions.

Complication Renal / Hepatic
failure, DIC, and Death
Hymenoptera Venom: Anaphylactic
Reaction

Can occur from a single sting or multiple stings.

May range from mild to fatal and death within
minutes.

There is no correlation between the systemic
reaction and the number of stings.
Hymenoptera Venom: Delayed
Reaction

Delayed reaction appearing 5 – 14 days after
the sting consists of serum sickness-like signs
and symptoms.
• Pts can develop fever, malaise, HA, urticaria,
lymphadenopathy, and polyarthritis.

This reaction is believed to be immune
complex-mediated.
Hymenoptera Venom: Treatment

Immediate removal of the
bee stinger from the wound,
is the important principle
rather than the method of
removal.

Wash the sting site with soap
and water to decrease risk of
infection.

Intermittently apply ice to the
site to limit local reaction and
delay absorption of venom.

Oral antihistamines and
analgesic may limit discomfort,
pruritis, and decrease local
reaction.

If pts develop symptoms of
anaphylaxis then most important
agent to give is Epinepherine.
•
Epinepherine 0.3 to 0.5mg (0.3
to 0.5 mL of 1:1000 conc.) in
adults and 0.01 mg/kg in children
(never more than 0.3 mg) given
IM
Hymenoptera Venom: Treatment

Other treatment should include:
•
Diphenhydramine 25 to 50 mg IV, IM or PO
•
H2-receptor antagonists (ranitidine 50 mg IV)
•
Methylprednisolone 125 mg
•
•
•
Use Beta agonist nebulization if pt has evidence of
bronchospasm
IVF, oxygen, cardiac monitor, pulse ox.
Persistent hypotension after multiple IVF bolus may require
Dopamine or Epinepherine drip
Hymenoptera Venom: Disposition

Pts who develop severe systemic reactions
should be admitted monitored for potential
cardiac, bleeding, renal or neurologic
complications.

Skin tests and RASTs (radioallergosorbent
test) are not reliable in determining which
patients are at risk in developing future
systemic reactions.
Hymenoptera Venom: Disposition

Every patient who has had a systemic
reaction should be provided with an
insect sting kit containing premeasured
epinepherine and be carefully instructed
in its use. The physician should stress
that the patient must inject the
epinepherine at the first sign of a
systemic reaction.
Ants (Formicidae)

5 known species of fire ants
(Solenopsis)
•
•
•
(S. aurea, S. geminata, S. xyloni,
S. invicta, and S. richteri)
Fire ants swarm when provoked
and they may attack in numbers.
Fire ants sting simultaneously in
response to an alarm pheromone
released
A Solenopsis xyloni major
worker surrounded by minor
workers
Ants (Formicidae)

Fire ants sting result in a
papule that becomes a sterile
pustule in 6 to 24 hrs.

Pustule can lead to localized
necrosis  scarring 
secondary infection.

Systemic reaction (urticaria /
angioedema) can also occur.

Treatment includes:
•
•
local wound care.
Usual treatment for
anaphylaxis should be initiated
if there is evidence of systemic
reaction.
Spiders (Araneae)



More than 34000 species
of spiders worldwide
Only few dozen produce
medically significant
envenomations in humans
Refer to Table 194 – 3 for
medically important spiders
by geographic location.
Necrotic Arachnidism (Loxosceles)

Three species:
• L. reclusa (true
brown recluse)
• L. laeta (corner
spider)
• L. arizonica (Arizona
brown spider) –
produce majority of
Loxosceles bites in
the US.
• Prefers warm and dry
areas (abandon buildings
/ woodpiles, and cellars)

L. reclusa (true brown
recluse)
•
•
•
One of the most common species
found in the US.
Definitively diagnosing a brown
recluse bite is difficult.
The necrotic wound that develop
can resemble other unrelated
arthropod species and medical
disorder (i.e. Necrotizing Fascitis).
L. reclusa (true brown recluse)

Brown recluse has a dark brown violin shape on the cephalothorax
(the portion of the body to which the legs attach). The neck of the
violin points backward toward the abdomen. However, what you
should look at instead is the eye pattern of 6 eyes in pairs with a
space separating the pairs. Most spiders have 8 eyes in 2 rows of 4.
L. Reclusa (brown recluse)

Venom includes multiple
enzymes such as
•
•
•
•

Hyaluronidase
Alkaline phosphate
5’ –ribonucleotide
phosphohydrolase
Sphingomyelinase D (major
enzyme responsible for
necrosis.)
Necrotic wounds occur by way
of neutrophil activation, platelet
aggregation, and intravascular
thrombosis.

Clinical Features:
1.
Initially pts develop mild to severe pain
several hrs after the bite 
Erythema and blister formation 
Bluish discoloration within the first
24 hrs 
Lesion may become necrotic with
eschar formation in 3 to 4 days.
2.
3.
4.
L. Reclusa (brown recluse): Systemic
reaction




Are rare in adults, however more common in
children
Occur in 24 – 72 hrs after the bite.
Can lead to N/V, Fever/chills, arthralgias,
hemolysis, thrombocytopenia, hemoglobinuria,
and renal failure.
DIC and Death are rare
L. Reclusa (brown recluse)

If a brown recluse bite is
suspected, the following
labs test should be
perform:
• CBC
• Basic Chemistry tests
• BUN / Creatinine
• Coagulation Profile

Treatment:
•
•
•
Supportive measure should
be the initial goal (Analgesic /
clean wound site).
Consider using antibiotics if
any s/sx of infection develop.
Must have close follow – up
with physician for serial
evaluations of the wound.
Hobo Spider (Tegenaria agrestis)




Found in the Pacific northwest
of the US
They are aggressive because
it bite with minor provocation.
Live in moist dark areas
(woodpiles/basements).
They are brown with grey
markings, have 7 – 14mm
body length and 27 – 45mm
leg span
Hobo Spider (Tegenaria agrestis)
Clinical Features:





Present similar to that of brown recluse spider.
Initial bite is painless  delay presentation
Induration may occur with surrounding erythema,
followed by blistering, rupture, and necrosis.
HA is the most common systemic symptom, but N/V
and fatigue can occur.
Aplastic anemia and death are rare complications.
Hobo Spider (Tegenaria agrestis)
Clinical Features:
Hobo Spider (Tegenaria agrestis)
Treatment:

No diagnostic test for hobo spider envenomation.

No proven treatment for local or systemic
complications.

Surgical resection with skin grafting may be
necessary after the necrotizing process is completed.
Widow Spiders (Latrodectus)





Has a worldwide distribution
In the US, the black widow is the most well
known of the 5 Latrodectus species
L. mactans, L. various, and L. hesperus are
black
L. geometricus are brown and L. bishopi are
red.
Found most often in woodpiles, basements,
garages, and sheds.
Widow Spiders (Latrodectus)

L. mactans are the
only species that
have the classic
hour glass-shaped
(orange/red)
marking.
Widow Spiders (Latrodectus)

Female spiders
•
•
•
•
•
Large in size
Body size = 1.5 cm
Leg spans 4 -5 cm
Bites can penetrate
human skin.
Become aggressive
when protecting her web
and eggs.

Male spiders
•
•
•
•
Smaller in size
1/3 the size of female
Liter in color
Bites cannot penetrate
human skin.
Widow Spiders (Latrodectus)



Most bites occur between April and October
and are usually seen on the hands and
forearm.
Inject a highly potent venom – most active
component is latrotoxin.
Through a calcium – mediated mechanism,
latrotoxin cause the release of acetylcholine
and norepinephrine from nerve terminals.
Widow Spiders (Latrodectus)
Clinical Features:


Most bite site, initially feels like a pinprick then
quickly cause increasing local pain that then
involve the entire extremity.
In 1/3 of cases the initial erythema evolves into
a larger “target lesion”.
• The presence of the target lesion, severe pain and muscle
spasm is pathognomonic for widow spider bites.

Pts most commonly c/o muscle cramp like
spasms in large muscle groups.
Widow Spiders (Latrodectus)
Clinical Features:

Other s/sx:
• HA, nausea, diarrhea, diaphoresis, photophobia and
•

dyspnea.
May experience intermittent severe pain for 24+ hours
Laboratory test to confirm Latrodectus bite is
not available.
Widow Spiders (Latrodectus)
Treatment:




Initial Tx: Support ABC.
Clean the bite site.
Use Opioids and benzodiazepines to control
pain and muscle spasms.
The most effective tx for severe envenomation
are parental opioids and Latrodectus
antivenom.
Widow Spiders (Latrodectus)
Treatment:

Latrodectus antivenom:
• Cause rapid resolution of symptoms and significantly
•

Produced in three countries:
•
•
•

shorten the course of illness.
When given properly, pt can often be d/c form ED after
a short period of observation
Anti Latrodectus antivenom available in Argentina
Red-backed spider antivenom available in Australia
Antivenin ( Latrodectus mactans ) available in U.S.A. (1-800-396-6250)
Indications, amount, and route of administration
vary according to product.
Tarantulas

Large hairy spiders

Popular as pets

Family Theraphosidae

Hairs found on the
abdomen and legs
are use defensively
Tarantulas



When threaten, they may
flick some of their hair.
The hair cannot penetrate
human skin however can
cause conjunctiva and
cornea injury.
Pts who are handling
tarantula and present with
red eye must be
evaluated via Slit-Lamp to
identify hairs



Hairs that are identify
must be surgically
removed.
Initiate topical steroid tx
to help control
inflammation.
Initial bite are painful 
local erythema edema
 Local joint stiffness
following nearby bites.
(systemic sx are rare).
Scorpions (Scorpionidae)



World-wide distribution
Highly toxic species are
found in Middle East, India,
North Africa, South
America, Mexico, and
Trinidad.
In the US, only the
Centruroides exilicauda
(bark scorpion) possesses
venom potent enough to
cause systemic toxicity.
Scorpions - Centruroides exilicauda
Clinical features:

Venom can open neuronal sodium channels and
cause prolonged and excessive depolarization.

Immediate onset of pain and parathesias in the
stung extremity is noted and may become
generalized.
Scorpions - Centruroides exilicauda
Clinical features:


Severe Systemic cases after bite can lead to:
•
Abnormal roving eye movements, blurred vision, pharyngeal
muscle incoordination and drooling.
Other s/sx:
• Restlessness, seizure – like activity, N/V, tachycardia, and severe
agitation.


Symptoms can last 24 – 48hrs without anitvenom
treatment.
Cardiac dysfunction, pulmonary edema, pancreatitis,
bleeding d/o, skin necrosis, and occasionally death can
be seen with stings from Asian and African scorpions.
Scorpions - Centruroides exilicauda
Treatment:

Initial treatment is supportive / analgesics.

Centruroides-specific antivenom is only available in
Arizona and is produce from goat serum. (production has
been stop, only used in severe systemic toxicity cases).

Scorpion antivenom directed against different
species is now used and available in 10 other
countries.
Reptile Bites




Approx 3 million bites and 150,000 deaths occur
each year from venomous snakes in the world.
Most bites occur in the warm summer months (snakes
and victims are most active).
In the US, mortality has improve from 25% to only
<0.5% (5 – 10 deaths /year).
Major venomous snakes can be divided into 3
groups:
•
•
•
Viperidae (vipers)
Elapidae
Hydrophiinae (sea snakes)
Crotalinae (Pit Viper) Bites:

Referred to as pit vipers
because of bilateral
depressions or pits located
midway between and below
the level of the eye and the
nostril

With in the pit vipers, the
rattle distinguishes the
rattlesnake from other
crotaline snakes.

Pit is a heat sensor that
guides strikes at warmblooded prey or predators.
Crotalinae (Pit Viper) Bites:
Venom
Causes the following:
•
•
•
Local tissue injury, systemic vascular damage, hemolysis,
fibrinolysis, and neuromuscular dysfunction (CN weakness /
resp. failure / MS∆.
Quickly alters blood vessels permeability leading to loss of
plasma and blood into the surrounding tissue  hypovolemia.
Activates and consumes fibrinogen and platelets, causing a
coagulopathy
Crotalinae (Pit Viper) Bites:
Clinical features

The severity of poisoning following a crotaline
bite depend on these factor:
• The species and size of the snake
• The age and size of the victim
• The time elapsed since the bite
• Characteristics of the bite (location, depth, and
number, the amount of venom injected
•
25% of crotaline snakebites are termed dry :venom effects do
not develop.
Crotalinae (Pit Viper) Bites:
Clinical features

S/Sx of a bite:
• One or more fang mark on the body
• Localized pain with progressive edema.
• N/V, weakness, oral numbness, tachycardia,
•
dizziness, and muscle fasciculation.
Systemic reaction will lead to tachypnea, tachycardia,
hypotension, and MS∆
Crotalinae (Pit Viper) Bites:
Clinical features
Diagnosis is
determined on the presence of fang
marks and a history consistent with
exposure to a snake
Crotalinae (Pit Viper) Bites:
Clinical features

Snake bite injury maybe manifested in three
ways:
1. Local injury (swelling, pain, ecchymosis)
2. Coagulopathy (Thrombocytopenia, elevated PT,
hypofibrinogenemia)
3. Systemic effects (oral swelling / parathesias,
metallic or rubbery taste in the mouth, hypotension,
tachycardia)
Crotalinae (Pit Viper) Bites:
Treatment – Do’s and Don’t



First aid treatment such as suction and incision are
dangerous and should not be used.
Tourniquets are contraindicated because they obstruct
arterial flow and cause ischemia
Constriction bands** may be of some use especially
when immediate medical care is not available.
**An
elastic bandage / Penrose drain, rope, or piece of clothing wrapped
above the bite. It’s applied with enough tension to restrict superficial
venous / lymphatic flow while maintaining distal pulses and cap. refill. It
retard venom absorption, increase local tissue injury but reduce the
severity of systemic effects.
Crotalinae (Pit Viper) Bites:
Treatment – Do’s and Don’t




The Coghlan’s Snake Bite Kit should not be used (the blade
in the kit can injure digital nerves, arteries and tendons).
The use of the Sawyer Extractor suction pump to remove
venom without incision is controversial.
Electric shock to the bite site should be condemned.
Ice water immersion worsens the venom injury
Crotalinae (Pit Viper) Bites:
Treatment

Initial treatment involves:
• Immobilize the limb
• IV access in the contralateral limb
• Establish ABC, oxygen, monitor, IVF
• Previously placed tourniquets and constriction bands
•
•
should not be removed until IV access is established
Clean bite site and update tetanus booster.
Contact Poison control ASAP
Crotalinae (Pit Viper) Bites:
Treatment

Antivenom (FabAV /
CroFab):
•
•
•
Mainstay of treatment for
poisonous snakebites
Composed of heterologous
antibodies derived from the
serum of animal immunized
with the appropriate snake
venoms.
Bind and neutralize the
venom molecules

Indication for antivenom tx:
•
•
•
•
All crotaline bites that show
evidence of progressive signs
and symptoms.
Pts with worsening of local injury
(pain, ecchymosis, swelling)
Pts with lab errors (decr platelet
count, incr coagulation time, decr
fibrinogen)
Pts with systemic sx (unstable
vitals / MS∆)
Crotalinae (Pit Viper) Bites:
Treatment



Observation for progression of edema and
systemic signs of envenomation be continued
during and after antivenom infusion.
Limb circumference serve as an index of
progression as well as a guide for antivenom tx.
Lab results should be repeated every 4h or after
every antivenom tx.
Crotalinae (Pit Viper) Bites:
Other medical Treatment:
• IVF (must be continued)
•
• Vasopressor (maybe
needed for ongoing hypot)
• PRBC / FFP / Platelet
may be needed if
antivenom is not effective
in stopping the bleeding
that can occur.
•
•
Fasciotomy maybe needed if
compartment syndrome occur
secondary to venom spreading
into the compartment.
Cultures / Antibiotics only
needed if signs of infection
develop.
Steroids should only be used
for signs of allergic rxn or
serum sickness (occur in 5% of
pts after FabAV- fever / rash /
arthralgias. Tx with prednisone
60mg/d for 1-2wk)
Crotalinae (Pit Viper) Bites:
Disposition

Indication for discharge:

Pt need close f/u for wound check
Pt should be observed for at least 8hrs.
Pts with severe sx or getting antivenom should
be admitted to the ICU


• Swelling begins to resolve
• Coagulopathy is reversed
• Pt is ambulatory.
Cobra Bite

Large snakes (1 – 1.5m
in length)

Found in most of Africa
and southern Asia.

45% of cobra bites are
dry bites.
Cobra Bite - Venom
Contain multiple toxin that produce different effect:
1. Neurotoxins in the venom bind to postsynaptic acetylcholine
receptors and produce depolarizing neuromuscular blockade.
2. Some toxins from the venom poison cell membrane. Chief effect
is on the heart producing arrhythmias and impaired contractility.
3. Third type of toxins contain enzyme that break down protein and
connective tissue.
Cobra Bite – Clinical Features:

Develop immediate pain at the bite site

Reaction around the bite site may develop over
48hr (local hemorrage, bullae, and necrosis)

Proceed to develop local and progressive soft
tissue swelling, CN dysfunction (ptosis, diplopia,
dysphagia)
Cobra Bite – Clinical Features:




Generalized muscle weakness  Flaccid
paralysis
Parasympathetic stimulation (salivation,
bronchorrhea, N/V)
Venom spit into the eye (spitting cobra) will
produce inflammation, edema, and d/c, but no
systemic s/sx.
Coagulopathy is rare following a cobra bite
(except bites from spitting cobra bites).
Cobra Bite – Diagnosis:

Diagnosing and distinguishing cobra bite from
other snakes is difficult.

If possible, the snake should be caught, killed,
and brought in for identification.

Snake venom assays have been developed to
detect the type of snake from wound aspirate
or urine.
Cobra Bite – Diagnosis:

Standard labs should be obtained:
• CBC
• Serum Electrolytes
• Creatinine
• Coagulation tests
Cobra Bite - Treatment

Bite wound incisions, vacuum extractors, cooling, or ice
are not beneficial

Proximal lymphatic and venous constricting elastic
band approach used in crotalines bites is controversial.

One important first aid that is proven to help is to use
prompt and copious irrigation of the eyes that sustained
a venom exposure (spitting cobra)
Cobra Bite - Antivenom Treatment

The only proven and specific
tx for cobra envenomation.


Some are monovalent, specific
for a single species, but most
are polyvalent, containing
antibodies against several
important or common cobra
species in that country or
region.



Should be considered
experimental and can have
high incidence of allergic rxn.
Should be started before the
constricting band is
loosened.
Should be initiated in pts with
s/sx of systemic toxicity.
Reduces systemic toxicity
but does not reduce local
tissue damage and necrosis.
Cobra Bite – Treatment
Disposition:



Pts without signs of envenomation
should be admitted for at least 24 h obs
Death from cobra bite typically occurs
within 2 – 6 h after the bite.
Survival is possible without antivenom in
pts with good cardio-pulmonary support.
Questions 1:

The edema of snakebite usually does not involve the deep
compartments or cause vascular compromise. Fasciotomy
should therefore be undertaken only when __.
a)
findings of compartment syndrome are present
b)
c)
massive edema is present
the measured intracompartmental pressure is >repeat
doses of antivenom and elevation have failed
30-40 mmHg
Only a, b, d is correct
d)
e)
Questions 2:

Much of the toxicity of coral snake venom is due to its acetylcholine
receptor blocking activity. Absorption and spread of the venom is rapid.
Which one of these statement is false about the treatment or sign /
symptoms of coral snakes bites is incorrect?
a) Delayed: drowsiness, confusion, coma, euphoria, salivation,
vomiting, seizures, paralysis and death in 8-24 hours. Progression
to paralysis can occur rapidly once symptoms begin.
b) Tourniquet application, incision and suction if seen within one hour.
c) Antivenin is available for the eastern coral snake and may be
lifesaving.
d) Early signs: local weakness and paresthesias may begin within 15
minutes or be delayed several hours. Mydriasis, dysphagia, ataxia,
slurred speech and myalgias begin within a few hours.
e) Support respiration and treat seizures.
Questions 3:

a)
b)
c)
d)
Treatment for a brown recluse spider bite does
not includes:
cleaning the wound with soap and water and
administering tetanus prophylaxis.
local cold compresses, elevation of the
affected extremity, and loose immobilization of
the affected part.
with severe ulceration, delayed excision and
grafting may be necessary.
amoxicillin 125-250 mg QID may be as
effective as dapsone.
Questions 4:

a)
b)
c)
d)
e)
f)
Treatment of Hymenoptera stings includes all except:
epinephrine subQ (0.01 mg/kg to a 0.5 mg max) and/or IM or
IV diphenhydramine (1 mg/kg) for systemic reactions. Systemic
corticosteroids.
PO diphenhydramine, 4-5 mg/kg (75 mg max) QID, and
perhaps prednisone 0.5-1.0 mg/kg/day for several days for
severe local inflammation.
washing (to minimize infection), rest, ice, and elevation.
IV crystalloid and vasopressors (dopamine or epinephrine) for
hypotension.
Nebulized albuterol or other beta-2-specific agonist for
bronchospasm; intubation, cricothyroidotomy, or jet ventilation
may be required for severe cases or upper airway edema.
All the above is true
ANSWERS:




1. E
2. B
3. D
4. F