neurological manifestations of scorpion sting


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neurological manifestations of scorpion sting

  2. 2. Scorpion sting is an acute life threatening , time limiting medical emergency
  3. 3. CASEA 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 stingAfter 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. 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 HgPupils 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 HgRespiratory system, cardiovascular system examination was normal
  5. 5. INVESTIGATIONSHemoglobin – 13.8 gm%ESR: 20mm/1hrTLC: 15600/cummDifferential Leukocyte Count – N-89%, L-7%, M-4%Platelet Count: 2.82 lakhs/cummBT-3 Min 30sec, CT: 7 MinsPT(T)- 13.6 Secs (Control 12.3)APTT - 32.9 Secs (Control-31.1)RBS – 130mg/dlECG: Normal sinus rhythm2D ECHO: No RWMA Normal LV function LVEF: 60%
  6. 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. 7. CT SCAN BRAIN (PLAIN)Hematoma in right frontal and left caudate with intraventricular extension
  8. 8. CT ANGIOCT Angio is normal
  9. 9. SCORPION STINGINTRODUCTION 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. 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. 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. 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. 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. 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. 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. 16. VENOM Scorpion venom – toxins are polypeptides . Various enzymes are…..  Acetylcholinesterase  Alkaline phosphatase  Acid phosphatase  5’nucleotidase  Hyaluronidase  Ribonuclease,deoxyribonuclease……
  17. 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. 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. 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
  22. 22. 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.
  23. 23. 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
  24. 24. 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.
  25. 25. CENTRAL NERVOUS SYSTEMInfrequently 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
  26. 26. 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
  27. 27.  The signs of the envenomation are determined by the scorpion species, venom composition, and the victims 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.
  28. 28. 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
  29. 29. RESPIRATORY  Dyspnea  Cyanosis  Hemoptysis  ARDS
  30. 30. GASTRO INTESTINAL Acute pancreatitis - intra-pancreatic conversion of trypsinogen to trypsin Pseudo pancreatic cyst Rise in liver enzymes Necrosis of liver
  31. 31. RENAL Hematuria Oliguria Acute renal failure
  32. 32. METABOLIC Acidosis Hyperglycemia Hyperkalemia Raised free fatty acids Raised cholesterol & triglycerides
  33. 33. SYSTEMIC INFLAMMATORY RESPONSE SIRS is triggered due to increased levels of  Interleukin -6  IL-1a  IL-1beta  IFN-gamma  Alpha 1-antitrypsin
  34. 34. GRADING OF SEVERITYSanthana krishnan grading GRADE 1 –peripheral circulatory failure good GRADE 2 – GRADE 1 + myocarditis prognosis GRADE 3 – GRADE 2 + CNS failures
  35. 35. MANAGENENTSUPPORTIVE ABC O2 inhalations Inj TT Benzodiazepines NSAIDS Local ice packs Xylocaine infiltration IV fluids
  36. 36. 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
  37. 37.  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.
  38. 38. 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)
  39. 39.  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
  40. 40. 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)
  41. 41. 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
  42. 42. UNHELPFUL RX Lytic Cocktail (Pethidine + Promethazine + Chlorpromazine ) Morphine Steroids Atropine Nifidepine Ace Inhibitors (Captopril)
  43. 43. 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
  44. 44. 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%
  45. 45. 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
  46. 46. REFERENCES1) Rai M. Intracerebral hemorrhage following scorpion bite.:Neurology. 1990;40:18012) Udayakumar, N, Rajendiran, C, Srinivasan, AV. Cerebrovascular manifestations in scorpion sting: a case series. Indian J Med Sci 2006; 60: 241–244.3) Raichur, DV, Magar, VS, Wari, PK, Chandragouda, DK. Hemiplegia and motor aphasia following scorpion sting. Indian J Med Sci 2001; 68: 669–6704) Bonilha, L, et al. Epilepsy due to a destructive brain lesion caused by a scorpion sting. Arch Neurol 2004; 61: 1294–1295) Bawaskar HS, Bawaskar PH. Scorpion sting. J Assoc Physicians India. 1998; 46: 388 – 3926) Kavathale, Khan A et al. Scorpion – Stings the limb and stuns the heart? J Assoc Physicians India 1999; 47: 1045 – 10467) Sundararaman T, Olithselvann M et al. Scorpion envenomation as a risk factor for development of dilated cardiomyopathy. J Assoc Physicians India 1999; 47: 1047 – 10508) Elatrous S et al. Dobutamine in severe scorpion envenomation. Effects on standard haemodynamics, right ventricular performance and tissue oxygenation. Chest 1999; 116: 748 – 7539) Bawaskar HS, Bawaskar PH. Prazosin therapy and Scorpion envenomation. J Assoc Physicians India. 2000; 48: 1175 – 118010) Natu VS et al. Efficacy of Species Specific Anti-scorpion Venom Serum (AScVS) against severe serious scorpion stings ( Mesobuthus tamulus concanesis Pocock) – an experience from Rural Hospital in Western Maharashtra. J Assoc. Phys of India 2006; 54: 283 - 287