Scorpion envenomation

Scorpion envenomation
Antonio Souto
acasouto@bol.com.br
Médico coordenador
Unidade de Medicina Intensiva Pediátrica
Unidade de Medicina Intensiva Neonatal
Hospital Padre Albino
Professor de Pediatria nível II
Faculdades Integradas Padre Albino
Catanduva / SP

UTI Pediátrica & Neonatal


Important public health hazard in tropical and
sub-tropical regions
The annual number of scorpion stings cases exceeds 1.23
million, of which over 32250 may be fatal

Brazil:
•8.000 /year
•3 /100.000 habitants
•50% Minas Gerais e São Paulo

Dr. Antonio Souto

acasouto@terra.com.br

2013


Dr. Antonio Souto



2013



•60s and 70s, cases fatality rate of up to 30%
•Since the advent of vasodilators prazosin, captopril,
nifedipine, sodium nitroprusside, hydrazine, scorpion
antivenom and intensive care management the fatality is
dropped to
<2-4%.

Dr. Antonio Souto


2013



•Tityus serrulatus scorpion venom has shown to be
more deleterious to children than to adults
•This effect is suggested to be body weight dependent.
•The children would have higher venom concentration in
their body liquids.
•More severe systemic symptoms, including higher
lethality.
•Buthidae species can result a life threatening systemic
effects

Dr. Antonio Souto


2013



T. serrulatus

T. stigmurus

Dr. Antonio Souto

T. bahiensis

T. metuendus


T. obscurus

2013



Familia Buthidae (Hemiscorpius Lepturus)
Genero
•Buthus (Mediterranean Spain to the Middle East)
•Parabuthus (western and southern Africa)
•Hottentotta (South Africa to south east Asia)
•Leiurus (northern Africa and middle East)
•Androctonus (northern Africa to southeast Asia)
•Centruroides (southern united states, Mexico, central
America and Caribbean)
•Mesobuthus (through out the Asia)

Tityus (central America, south America
and the Caribbean)
Dr. Antonio Souto


2013



•Arthropods in the class Arachnid
•Viviparous and cannibalistic

Scorpion have been able to survive in heat, drought,
freezing conditions for weeks, desert condition and
starvation for months and total immersion of water for
days.

Survival independent of ecological
condition
Dr. Antonio Souto


2013



Scorpion Venom

Dr. Antonio Souto


2013



Scorpion Venom
Cocktail
•Low molecular weight basic proteins, neurotoxins,
nucleotides, aminoacids, oligopeptides, cardipotoxins,
nephrotoxin, hemolytic toxins, phosphodiesterase,
phospholipase A, hyaluroinidase.
•Acetylcholineesterase, glycosaminoglycans, histamine,
serotonin. 5-hydroxyptamine and proteins that inhibit
protease, angiotensinase and succinate –dehydrogenese,
ribonuclease, 5- nucleotidase.

Dr. Antonio Souto


2013



Scorpion Venom
The lethality varies with species
•Venom almost complete absorption would occur in 7-8
hours
•70% of maximum concentration in the blood within 15
minutes
•Half life of intravenously injected venom is between 4 to 7
minutes
•Takes 4.2 to 13.4 hours for elimination from blood.

Dr. Antonio Souto


2013



Regulating venom ejections
This ability explains the variation of
intensity of symptoms and existence of
“dry” sting without envenoming.

Dr. Antonio Souto


2013



Scorpion Venom
Neurotoxins
Highly lethal than neurotoxin of snake venom.
The LD50 of some neurotoxins 10 fold more potent than
cyanide
Act mainly on excitable cells of nerves and muscles
Intense and persistent depolarization of autonomic nerves
with massive release of autonomic neuromuscular
neurotransmitter.

Dr. Antonio Souto


2013



“autonomic storm”
Clinical laboratory data reporting
increased catecholamine metabolite excretion
and elevated plasma renin and aldosterone
are consistent with the stimulatory effects
of the venom on the autonomic nervous system.

Dr. Antonio Souto


2013



Clinical effects
•depends upon the species of scorpion
•dose of venom injected
Severity
•Age
•Time between sting and hospitalization
•Children with 3.9-10% fatality irrespective of
intensive care management from Israel, Turkey
and India
Clinically “autonomic storm”
releasing massive amounts of catecholamines
Dr. Antonio Souto


2013



Transient parasympathetic stimulation
vomiting, profuse sweating, ropy salivation, bradycardia,
ventricular pre mature contraction, priapism in male,
hypotension

Prolonged sympathetic stimulation
cold extremities, hypertension, tachycardia, pulmonary
edema and shock

Dr. Antonio Souto


2013



Clinical manifestations/ severity
4 grades
Grade 1: severe excruciating local pain radiating along with corresponding
dermatomes, mild local oedema, without systemic involvement.
Grade 2: signs and symptoms of autonomic storm characterized by acetyl
choline excess or parasympathetic stimulation and sympathetic stimulation
Grade 3: cold extremities, tachycardia, hypotension or hypertension with
pulmonary edema (Respiratory rate > 24 per minute, basal rales or
crackles in lungs).
Grade 4: tachycardia, hypotension with or without pulmonary
edema with warm extremities (warm shock).
Dr. Antonio Souto


2013



Sixteen scientists (Algeria, Argentina, Bolivia,

Egypt,

India, Israel, Mexico, Morocco, Saudi Arabia, Tunisia and Turkey).

2009 consensus was reached
Class I : Local manifestations
Class II : Systemic involvement
Class III : Cardiogenic failure, hypotension, ventricular
arrhythmia, bradycardia, cardiovascular collapse,
Respiratory failure- cyanosis, dyspnoea, pulmonary
edema, neurological failure
Glasgow score < 6 (in absence of sedation), paralysis.
Dr. Antonio Souto


2013



Local Manifestations
•Soon after sting
•Severe radiating pain
•Inconsolable, incessant crying in a child due to pain
there is transient tachycardia, rise in blood pressure,
mild sweating but extremities are warm.

Severe pain without systemic involvement
suggestive of benign or dry sting by
venomous species.

Dr. Antonio Souto


2013



Systemic Manifestations
Vomiting : due to autonomic storm often is due to
serotonic content of venom
Profuse sweating : sweat literally flows all over body
Clinically it is called “skin diarrhea”, persist for 3-17 hours.
Salivation : Thick ropy salivation due to stimulation
of bronchial mucus glands, contributing factors for
respiratory failure, occurs soon after sting and
it persists for 2-4 hours.

Dr. Antonio Souto


2013



Priapism : seen in almost all victims of pediatric age
Priapism is diagnostic of venomous envenoming
but its absence or disappearance did not correlate the
outcome.
It persists for 5-16 hours.

Dr. Antonio Souto


2013



Vomiting, sweating, salivation, priapism a
diagnostic cardiac signs and symptoms of
scorpion sting suggestive of free circulating
venom in the blood,

can be accessible to antivenin
therapy.

Dr. Antonio Souto


2013



Cardiovascular system mostly affected by venomous
sting.
Clinical manifestations depends upon the duration
of envenoming.

Hypertension, cardiac arrhythmias,
tachybradycardia, pulmonary edema,
hypotension and shock are not the
different syndromes but of one process
of ongoing autonomic storm.

Dr. Antonio Souto


2013



Tityus serrulatus
The cardiovascular manifestations
Arterial hypertension or hypotension, heart failure,
pulmonary edema, shock and electrocardiographic
changes.

“acute myocardial infarction-like
pattern.”

The American Journal of Cardiology, 67:7; 655-657
Dr. Antonio Souto


2013



Tityus serrulatus
The cardiovascular manifestations
Myocardial damage and depressed left ventricular
systolic function.
Pulmonary edema attributed to left ventricular failure
or to increased pulmonary vascular permeability.

Dr. Antonio Souto


2013



Hypertension :
Hyper-renemia and sympathetic stimulation
rapid and significant increase level of epinephrine,
norepinephrine, endothelin, atrial nitriuretic peptide.
Accumulation of angiotensin II accelerate the myocardial
injury and oxygen demand.
Alpha receptors stimulation.

Dr. Antonio Souto


2013



Hypertension :
45-70% within 30 minutes to 8 hours with Bradycardia
Main complaints are headache, chest discomfort,
suffocation and per oral parasthesia.
Children look agitated confused and have propped up
eyes, oculogyric phenomenon, puffy face, decreased level
of consciousness and convulsions;
If untreated the hypertensive effect is long lasting and
result in development of myocardial failure and pulmonary
dema
Dr. Antonio Souto


2013



Tachycardia :
Raised level of circulating catecholamines by toxin on beta
adrenergic receptors
5-20% after 6-7 hours supraventricular tachycardia (heart
rate 110-240 per minute)
Sudden onset of tachycardia occurs in a recovering
hospitalized patient
Impaired left ventricular filling, reduction in cardiac out put
due to mark tachycardia particularly in children result in
delirium and convulsion due to anoxia to the brain
Dr. Antonio Souto


2013



Hypotension :
Hypovolemia and cardiac arrhythmias.
Reduction in systemic vascular resistance a hypokinetic
phase accompanied by raised heart rate, hypotension
with shock reflecting an alter left ventricular contractility.
Depletion of catecholamines from nerve terminals
because of autonomic storm.
Venom inhibits kinase II enzyme and lead to accumulation
of bradykinin a neuromuscular agent incriminated for
development of pulmonary edema and hypotension
Dr. Antonio Souto


2013



Pulmonary edema
Develop within 30 minutes with severe hypertension and
may develop after 36 hours of sting with hypotension
and tachycardia.
Acute onset of tachydyspnoea, tachycardia, summation
gallop, systolic murmur, cold extremities, sudden onset of
intractable cough, bilateral moist rales and low volume fast
thready pulse.

Dr. Antonio Souto


2013



Management
Fluid loss
vomiting, sweating and salivation
correct the fluid balance

Dr. Antonio Souto


2013



Management
Scorpion antivenom (SAV) :
Without skin test,
Administered as early as possible and through venous
route
•SAV is specific treatment of scorpion sting’s therapy
•Randomized controlled trials
•Antivenom resolved the neurological manifestations
within four hours.
•SAV reduced the levels of circulating unbound venom.

Dr. Antonio Souto


2013



Management
Prazosin
Alpha receptors stimulation plays an important role in the
pathogenesis of scorpion sting.
Phosphodisterase inhibitor, it reduces preload and left
ventricular impedance without raising heart rate.
Prazosin is a physiological antidote to scorpion venom
actions

Dr. Antonio Souto


2013



Management
Angiotensin converting enzyme inhibitor captopril
improves the pulmonary edema and cardiogenic shock
due to scorpion sting.
Victims who presented in hypokinetic phase due to both
ventricular dysfunction, clinically characterized by
hypotension, shock, tachycardia, delirium with or without
pulmonary edema and warm extremities,
Dobutamine infusion 5-20 microgram /kg/min.

Dr. Antonio Souto


2013



Management
Nitroglycerine (NTG) drip 0.5 to 5 microgram /kg/min by
improving heart dysfunction and reduction in pulmonary
congestion.
Venodilator action of NTG reduces the preload of the
heart and it improves the intrapulmonary shunting and
also relaxes the epicardial coronary arteries and its
collaterals.
Amiodarone improves the survival by reduction of
serum nor-epinephrine level in four children with scorpion
sting
Dr. Antonio Souto


2013



antivenin therapy
antivenin therapy
4-5 ampoules (moderate)
8-10 ampoules (severe)

Dr. Antonio Souto


2013



•Tityus species of scorpions are endemic to South
America, particularly Brazil. An F(ab)2 for Tityus
serrulatus antivenom is available from Fundação
Ezequiel Dias (FUNED), in Belo Horizonte,
Brazil.
•T. serrulatus envenomation treated with antivenom,
vomiting and local pain decreased within 1 hour, and
cardiorespiratory manifestations disappeared within 6 to
24 hours in all patients except the 2/18 who presented
with acute lung injury. 16/18 patients recovered
completely by 24 hours.

Dr. Antonio Souto


2013



Antivenom therapy must be applied as soon as possible
after envenoming.
Antivenom preparations
•higher purity, greater potency and minimal (or absent)
side-efects
•widely shared among clinicians in charge of scorpion
envenoming, that antivenom therapy is the most efective
specific treatment of severe cases.
Its use is still justified on the basis of observations both
empiric clinical and in experimental models.

Dr. Antonio Souto


2013



Keep in your mind: when in a endemic
region, we must allways think about
scorpion envenomation when we have a
child crying, vomiting, with profuse
sweating,
salivation
and
arterial
hypertension without a cause.

Dr. Antonio Souto


2013



Thank you!
Dr. Antonio Souto


2013

Scorpion envenomation

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