1. NEUROLOGICAL
MANIFESTATIONS OF
SCORPION STING

2. Scorpion sting is an acute life threatening , time limiting
medical emergency

3. CASE
A 36 years old male patient non hypertensive, non
diabetic was admitted to our hospital with h/o
scorpion sting 3 days ago on the right little toe on
1/7/2011.
He developed excruciating pain locally followed by
profuse sweating, vomiting, headache, within one
hour of sting
After 2 hours patient became unconscious for 1 hour.
On regaining consciousness patient was irritable
and was unable to move left upper limb and lower
limb and with facial asymmetry.

4. He was referred to our hospital after 3 days. On
examination patient was irritable with GCS of
E3M5V3 -11/15, profuse sweating, peripheries were
cold, pulse rate of 100/minute and blood pressure
of 100/70mm of Hg
Pupils 3mm, bilateral reacting normally with left
hemiperesis (Power in left upper limb and lower
limb 3/5). There were no local signs of sting.
During hospital stay patient had wide fluctuations of
B.P ranging from 100/60mm of Hg to 160/90mm of
Hg
Respiratory system, cardiovascular system
examination was normal

5. INVESTIGATIONS
Hemoglobin – 13.8 gm%
ESR: 20mm/1hr
TLC: 15600/cumm
Differential Leukocyte Count – N-89%, L-7%, M-4%
Platelet Count: 2.82 lakhs/cumm
BT-3 Min 30sec, CT: 7 Mins
PT(T)- 13.6 Secs (Control 12.3)
APTT - 32.9 Secs (Control-31.1)
RBS – 130mg/dl
ECG: Normal sinus rhythm
2D ECHO: No RWMA
Normal LV function
LVEF: 60%

6.  He was treated conservatively (antioedema
measures,adequate hydration, prazosin)
 Patient improved sensorium wise after 3 days and
became conscious, coherent and motor deficit
improved after 1 week

7. CT SCAN BRAIN (PLAIN)
Hematoma in right frontal and left caudate with intraventricular extension

8. CT ANGIO
CT Angio is normal

9. SCORPION STING
INTRODUCTION
Out of 1500 scorpion species, 50 are dangerous to
humans.
Scorpion stings cause a wide range of
conditions, from severe local skin reactions to
neurologic, respiratory, and cardiovascular
collapse.

10. VARIOUS TYPES AROUND WORLD
 Buthus - Mediterranean area, from Spain to the Middle East
 Parabuthus - Western and Southern Africa
 Mesobuthus – Throughout Asia
 Buthotus (ie, Hottentotta) - Across southern Africa to
southeast Asia
 Tityus - Central America, South America, and the Caribbean
 Leiurus - Northern Africa and the Middle East
 Androctonus - Northern Africa to Southeast Asia
 Centruroides - Southern United States, Mexico

11.  Among the 86 species of scorpions in India ,only 2
are of medical importance.
 They are…
 Mesobuthus tamulus ( Indian red scorpion )
 Palamneus swammerdam (Black scorpion)

12.  In general, scorpions are not aggressive. They do
not hunt for prey; they wait for it.
 Scorpions are nocturnal creatures
 They hunt during the night and hide in crevices and
burrows during the day to avoid the light.
 Thus, accidental human stinging occurs when
scorpions are touched while in their hiding
places, with most of the stings occurring on the
hands and feet.

13.  Scorpions use their pincers to grasp their prey;
 then, they arch their tail over their body to drive
their stinger into the prey to inject their
venom, sometimes more than once.
 The scorpion can voluntarily regulate how much
venom to inject with each sting.
 The striated muscles in the stinger allow regulation
of the amount of venom ejected, which is usually
0.1-0.6 mg

14.  If the entire supply of venom is used, several days
must elapse before the supply is replenished.
 The potency of the venom varies with the
species, with some producing only a mild flu and
others producing death within an hour.
 Generally, the venom is distributed rapidly into the
tissue if it is deposited into a venous structure.

15. VENOM
 Scorpion venom is a water-soluble, antigenic,
heterogenous mixture, as demonstrated on
electrophoresis studies.
 This heterogeneity accounts for the variable patient
reactions to the scorpion sting.

16. VENOM
Scorpion venom – toxins are polypeptides . Various
enzymes are…..
 Acetylcholinesterase
 Alkaline phosphatase
 Acid phosphatase
 5’nucleotidase
 Hyaluronidase
 Ribonuclease,deoxyribonuclease……

17. VENOM MECHANISM OF ACTION
The primary targets of scorpion venom are voltage-
dependent ion channels, of which sodium channels are
the best studied.
 The long-chain polypeptide neurotoxin causes
stabilization of voltage-dependent sodium channels in
the open position, leading to
continuous, prolonged, repetitive firing of the
somatic, sympathetic, and parasympathetic neurons.
 This repetitive firing results in autonomic and
neuromuscular overexcitation symptoms, and it prevents
normal nerve impulse transmissions
 Many end-organ effects are secondary to this excessive
excitation.

18. VENOM MECHANISM OF ACTION
 Autonomic excitation leads to cardiopulmonary
effects.
 Somatic and cranial nerve hyperactivity results
from neuromuscular overstimulation.
 Additionally, serotonin may be found in scorpion
venom and is thought to contribute to the pain
associated with scorpion envenomation.

19. VENOM MECHANISM OF ACTION
 Furthermore, it results in release of excessive
neurotransmitters such as
epinephrine, norepinephrine, acetylcholine, glutamate, and
aspartate.
 Meanwhile, the short polypeptide neurotoxin blocks the
potassium channels.
 The binding of these neurotoxins to the host is
reversible, but different neurotoxins have different affinities.
 The stability of the neurotoxin is due to the 4 disulfide
bridges that fold the neurotoxin into a very compact 3-
dimensional structure, thus making it resistant to pH and
temperature changes

20. PATHOPHYSIOLOGY

22. CLINICAL FEATURES

23. NEUROTOXIC LOCAL EFFECTS
 Local evidence of a sting may be minimal or absent in
as many as 50% of cases of neurotoxic scorpion
stings.
 A sharp burning pain sensation at the sting site,
followed by pruritus, erythema, local tissue swelling,
and ascending hyperesthesia, may be reported.
 This paresthesia feels like an electric current, persists
for several weeks, and is the last symptom to resolve
before the victim recovers.

24. AUTONOMIC EFFECTS
SYMPATHETIC PARASYMPATHETIC
 Hyperthermia  Bronchoconstriction
 Tachypnea  Bradycardia
 Tachycardia  Hypotension
 Hypertension  Salivation, lacrimation, urination
 Arrhythmia , diarrhea, and gastric emesis
(SLUDGE)
 Pulmonary edema
 Rhinorrhea and bronchorrhea
 Hyperglycemia
 Goose pimple skin
 Diaphoresis
 Loss of bowel and bladder
 Piloerection control
 Restlessness and  Priapism
apprehension
 Dysphagia
 Hyperexcitability and
convulsions  Miosis
 Generalized weakness

25. CRANIAL NERVE EFFECTS
 Classic roving or rotary eye movements
 Blurred vision
 Tongue fasciculations
 Loss of pharyngeal muscle control
 Difficulty swallowing
 Excessive salivary secretions
 Respiratory difficulty.

26. CENTRAL NERVOUS SYSTEM
Infrequently encountered but invariably fatal.
 Encephalopathy,
 Convulsions within 1-2 hours of sting
 Stroke -both cerebral hemorrhage and thrombosis
 Central respiratory failure
 These manifestations are similar to strychnine like effect and
spurt of BP secondary to catecholomine release occasionally
leads to rupture of intracerebral artery resulting in intracerebral
bleed and also cerebral infarcts due to thrombosis due to
coagulant nature of venom and autonomic storm induced
vasospasm

27. SOMATIC EFFECTS
 Rigidity and spasticity in muscles of the limbs
 Involuntary muscle spasms
 Twitching
 Clonus and contractures
 Alternating opisthotonous from inactivation of
sodium channels, leading to increased sodium and
calcium uptake
 Increased tendon reflexes, especially prolongation
of the relaxation phase
 Piloerection accompanied by goose pimples

28.  The signs of the envenomation are determined by
the scorpion species, venom composition, and the
victim's physiological reaction to the venom.
 The signs occur within a few minutes after the sting
and usually progress to a maximum severity within
5 hours.
 The signs last for 24-72 hours and do not have an
apparent sequence.
 Thus, predicting the evolution of signs over time is
difficult.
 Furthermore, a false recovery followed by a total
relapse is common.

29. CARDIOVASCULAR
 Myocarditis
 Gallop rhythm
 Hypertension or hypotension
 Arrythmias
 Conduction blocks
 Myocardial infarction
 Congestive heart failure
 Shock
 Pulmonary edema
 Develop within 30 min to 3 hours after a sting due to
myocardial dysfunction

30. RESPIRATORY
 Dyspnea
 Cyanosis
 Hemoptysis
 ARDS

31. GASTRO INTESTINAL
 Acute pancreatitis - intra-pancreatic conversion of
trypsinogen to trypsin
 Pseudo pancreatic cyst
 Rise in liver enzymes
 Necrosis of liver

32. RENAL
 Hematuria
 Oliguria
 Acute renal failure

33. METABOLIC
 Acidosis
 Hyperglycemia
 Hyperkalemia
 Raised free fatty acids
 Raised cholesterol & triglycerides

34. SYSTEMIC INFLAMMATORY RESPONSE
SIRS is triggered due to increased levels of
 Interleukin -6
 IL-1a
 IL-1beta
 IFN-gamma
 Alpha 1-antitrypsin

36. GRADING OF SEVERITY
Santhana krishnan grading
 GRADE 1 –peripheral circulatory failure good
 GRADE 2 – GRADE 1 + myocarditis prognosis
 GRADE 3 – GRADE 2 + CNS failures

37. MANAGENENT
SUPPORTIVE
 ABC
 O2 inhalations
 Inj TT
 Benzodiazepines
 NSAIDS
 Local ice packs
 Xylocaine infiltration
 IV fluids

38. MANAGEMENT
 Prazosin–
 A competitive post-synaptic alpha1, adreno-
receptor antagonist–should be the first line of
management
 Suppresses sympathetic outflow
 Activates venom-inhibited potassium channels.
 Decreases the preload, afterload and blood
pressure without increasing the heart rate.
 Reverses the metabolic and hormonal effects of
alpha receptors stimulation

39.  By accumulating c GMP
 counters vasoconstriction induced by endothelins
 prevents further myocardial injury
 Peak concentration is reached in 1-3hours and plasma
half life is about 2-3hours. Clinically, it starts acting in 1
hour and maximum action occurs at the end of three
hours.
 Prazosin is a cellular and pharmacologic antidote to
the actions of scorpion venom and it is also
cardioprotective.

40. DOSAGE
 Available as 1 mg/2.5mg/5mg tablets.
 The dose recommended is 30 microgram/kg/dose
 Sustained release tablets are not recommended in
this condition.
 Prazosin repeated in the same dose at the end of 3
hours according to clinical response
 And later every 6 hours till extremities are
warm, dry and peripheral veins are visible easily
 SVIMS Experience: Oral L-carnitine is useful to
treat patients with scorpion ting
envenomation, myocarditis and shock (Rajasekhar
D, Mohan A. Natl Med J India 2007)

41.  It should not be given as prophylaxis in children
when pain is the only symptom.
 First dose phenomenon
 Can be given irrespective of blood pressure
provided there is no hypovolemia
 The time lapse between the sting and
administration of prazosin for symptoms of
autonomic storm determines the outcome

42. L-CARNITINE
 SVIMS Experience: Oral L-carnitine is useful to
treat patients with scorpion ting envenomation,
myocarditis and shock
(Rajasekhar D, Mohan A. Natl Med J India 2006)

43. SCORPION ANTIVENOM
 Scorpion venoms reach their target too rapidly to be
neutralized and anti-venom within 30 minutes of
sting may reverse their effect
 Antivenom against the toxins of Indian scorpions is
not available for clinical use

44. UNHELPFUL RX
 Lytic Cocktail (Pethidine + Promethazine +
Chlorpromazine )
 Morphine
 Steroids
 Atropine
 Nifidepine
 Ace Inhibitors (Captopril)

45. COMPLICATIONS
 Dilated cardiomyopathy
 Ankylosis of small joints if the sting occurs at a joint
 Rhabdomyolysis
 Persistent paresthesias
 Antivenin anaphylaxis and serum sickness
 Respiratory arrest
 Cardiac arrest
 Shock
 Seizures
 Death

46. PROGNOSIS
 In the pre-prazosin era (1961-1983), 25-30% fatality
due to pulmonary edema was reported in scorpion
victims
 Since the use of prazosin (1984 onwards) the
mortality in these victims is reduced to less than 1%

47. KEY MESSAGES
 Scorpion venom is a potent sympathetic stimulator
 Cardiac manifestations are common in Indian red
scorpion envenomation
 Both hemorrhagic and ischemic strokes are known to
occur
 CNS involvement indicates poor prognosis
 Alpha receptors stimulation plays a major role in
evolution of myocardial dysfunction and acute pulmonary
edema in victims of scorpion sting
 Prazosin–an alpha adrenoreceptor antagonist–is antidote
to venom action
 Time lapse between the sting and administration of
Prazosin for autonomic storm determines the outcome

48. REFERENCES
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