Mechanism of action, clinical features and management of poisoning

1. SCORPION STING
SUBMITTED BY,
Group-1
MBBS
PIMS

2. OBJECTIVES
• Introduction
• Distribution
• Venom property
• Clinical manifestation
• Laboratory evaluation
• Management of envenomation

3. INTRODUCTION
• Scorpion –phylum arthropod have a lobster
like body shape with seven sets of paired
appendages
Chelicerae
Pedi alps (claws)
4 sets of legs
Pectines (a pair of comb like structures on the
ventral surface)

5. SCORPION
• Segmented tail curves upward dorsally ending
in a terminal bulbous segment called telson
(venom glands and stinger)
• Envenomation occurs through stinging ,not
biting

6. SCORPION
• Characteristic physical property-fluorescence
when illuminated by UV light/wood’s lamp
• This property used in
 collecting scorpions for breeding
 venom harvesting and
 providing pest control

7. SCORPION

8. DISTRIBUTION
• Found in all continent except Antartica
• Live in desert areas, semiarid grassland, tropics
• About 1400 scorpion species are found
• Of which 30 species cause potentially fatal
stings
• Dangerous species:
 Centruroides sculpturatus
Parabuthus species

9. Centruroides sculturatus

10. Parabuthus species

11. Indian red scorpion

12. Indian black scorpion

13. VENOM PROPERTIES
• Venoms are complex mixtures containing
mucopolysaccharides,hyaluronidase,phospholi
pase,acetylcholinesterase,serotonin,histamine
,protease inhibitors, histamine releasers and
neurotoxins
• Scorpion alpha toxins are important venom in
human envenomations

14. Alpha toxin
• Neuronal membrane-inhibits the inactivation of
sodium channels which prolongs depolarization
• Causes membrane hyperexcitability and leads to
uncontrolled firing of axons
• Hence release of neurotransmitter at synapse
and the neuromuscular junction is enhanced
• Leads to excessive neuromuscular
activity(Centruroides and parabuthus species)
• Autonomic dysfunction(Androcotonus and
tityus species)

15. TAP TEST:
Little swelling, prominent pain, paresthesia
and hyperesthesia can be accentuated by
tapping on the affected area

16. CLINICAL MANIFESTATION
• SYMPTOMS PROGRESS TO MAXIMAL
SEVERITY WITHIN 5 HOURS.
• SYMPTOMS ARE GRADED BASED ON
SEVERITY
• THERE ARE 4 GRADES

17. GRADE CLINICAL
FINDINGS
TREATMENT
1. Localized pain
or paresthesias
at site
•Pain management (eg,ibuprofen)
•Local wound care
•Tetanus prophylaxis
2. Local and
remote pain or
paresthesias
•As above, regional anesthesia for severe local pain and IV
opioids (eg; fentanyl) for severe remote pain
3. Cranial nerve
dysfunction:
OR
Somatic
skeletal
neuromuscular
dysfunction:
with
Autonomic
dysfunction
•Antivenom , if available*
•Supportive care : Frequent suctioning of oral secretions
•Endotracheal intubation if airway compromise or
pulmonary edema with hypoxemia
•Monitor for and treat myocardial ischemia, heart failure,
and rhabdomyolysis.
•Treat pain with intravenous opioids (eg, fentanylΔ)
•If antivenom is not available, treat muscle activity and
anxiety with short-acting benzodiazepines (eg,
midazolam)
•Provide local wound care as above

18. Cranial nerve dysfunction:
Dysphagia, drooling of saliva, abnormal eye
movement, blurred vision, slurred speech, tongue
fasciculation
or
Somatic skeletal neuromuscular dysfunction:
Restlessness, fasciculations, shaking and jerking of
the extremities, opisthotonus, embrosthotonus
with
Autonomic dysfunction:
Centruroides-salivation, vomiting, diaphoresis,
tachycardia
Parabuthus-salivation, diaphoresis and urinary
retention

19. COMPLICATIONS
a. Hyperthermia
b. Respiratory failure - (most common cause of death)
c. Pulmonary edema
d. Metabolic acidosis
e. Rhabdomyolysis
f. Arrythmia

20. MANAGEMENT

21. LABORATORY EVALUATION
• Grade1 to 2envenomation:
Lab studies are not needed
• Grade3 to 4envenomation:
Serum electrolytes, liver enzymes(AST
&ALT),blood urea nitrogen, serum creatinine,
serum creatine kinase, urinalysis.

22. •Identification of the offending scorpion helps to
determine the course of treatment.
•Stings of non-lethal species atmost require
icepacks, analgesics and antihistamines. Because
they undergo only local discomfort.
•Supportive care and anti venom usage.
•Keeping the patients calm and applying pressure
dressings and icepacks to the sting site.

23. • Proper IV infusuion , medication and other
sedatives or narcotics is necessary for
persons with neuromuscular symptoms
because of the risk of respiratory arrest.
• Hypertension and pulmonary edema respond
to NIFEDIPINE, NITROPRUSSIDE, HYDRALAZINE
or PRAZOSIN.

24. Pain management
• Oral IBUPROFEN other NSAIDs
• Oral OPIOIDS medications
• Short-acting intravenous opioids .eg - FENTANYL
•Continuous IV infusion of MIDAZOLAM controls
agitation, flailing and involuntary muscle movements

25. Wound management
• Cleansing of the sting site
• Tetanus prophylaxis as needed
• These patients should be observed for 4
hours to ensure no further progression of
symptoms.

26. ANTIVENOM
•An FDA approved C.Sculpturatus antivenom in
horse serum is now available.
•IV administration of antivenom rapidly reverses
cranial nerve dysfunctions and muscular symptoms.
•Although antivenom should be reserved for only
the most severe envenomations.
• Initiate therapy as soon as possible after scorpion
sting.

27. •Initial: 3 vials (containing ≤57 mg total protein
and ≥450 LD50 [mouse] neutralizing units); may
administer additional vials in 1-vial increments
every 30 to 60 minutes as needed.
• Typical dosage range: 1 to 5 vials
•Mechanism of Action Contains venom-specific
F(ab’)2 fragments of IgG which bind and neutralize venom
toxins; thereby helping to remove the toxin from the
target tissue and eliminate it from the body.

28. Administration:
• IV - Administer over 10 minutes.
• Monitor for return of symptoms of
envenomation and repeat as needed.
• Medications (eg, epinephrine, corticosteroids,
diphenhydramine) and equipment for
resuscitation should be readily available in
case of hypersensitivity reactions.
• Avoid IM since the time to peak blood
concentration may be prolonged with this
route of administration

29. Adverse Reactions
•Central nervous system: Fatigue, headache,
lethargy
•Dermatologic: Pruritus, skin rashes
•Gastrointestinal: Diarrhea, nausea, vomiting
•Miscellaneous: Fever

30. • Neuromuscular & skeletal: Myalgia
• Respiratory: Cough, rhinorrhea
• Rare but important or life-threatening:
Aspiration, ataxia, chest tightness,
hypersensitivity, hypoxia, ocular edema,
palpitations, pneumonia, respiratory distress,
serum sickness (delayed)
• There is no contraindication.

31. THANK YOU