Scorpion Bite

Management

I. First Aid:

1. Cuts at sting site and tourniquet are not advisable.

2. Local Pain can be relieved by application of cold or ice over the site of sting.

II. Medical:

1. For Pain: If the pain is intolerable, local anesthesia can be given using 200 lignocaine without adrenaline. Oral or sublingual non-steroid anti-inflammatory agents (NSAID) can also be given. In the past, inj. dihydroemetine 60 mg/ampoule was injected in the local site of the bite.

2. Oral diazepam is useful in relieving anxiety.

3. Correction of Dehydration: Dehydration due to vomiting, salivation and sweating shouldbe corrected bycontinuousvigorous oral rehydration solution. This helps to correct initial hypotension and shock. IV crystalloid solution or hydration by nasal tube may be necessary in a confused, agitated child.

4. Fluid replacementmust be done since hypovolemia is one of the proposed mechanisms of shock syndrome in scorpion sting.

5. Electrolyte imbalance should be corrected.

III. Scorpion Antivenin

This is available in India. It does not prevent or protect the Victim from development of severe cardiovascular manifestations and it may give anaphylaxis. The half life of antivenin is 11102 times longer than venom and takes 45 minutes to reach peak tissue concentration. It does not prevent the autonomic storm. Recently it has been reported that scorpion antivenin is no better than a placebo.

IV. Specific Treatment:

1. Prazosin is a selective alpha-1 adrenergic receptor blocker. Its pharmacological properties can antagonize the hemodynamic, hormonal and metabolic

toxic effects of scorpion venom.

Dose: 125-250 pg in children and 500 ug
in adults; repeated 3 hourly until there are signs ofclinical improvement in tissue perfusion i.e. warming of extremities, increase in urine out put, appearance of severe local pain at sting site which was absent ortolerahle on arrival, disappearance ofparesthesias, reduction or improvement in heart rate, pulmonary edema and reduction in raised blood pressure, and rise ofblood pressure in hypotensives without hypovolemia. The dose should be repeated six hourly till extremities became dry and warm. If the initial dose has been vomited, prazosin dose should be repeated.

In confused, agitated, non-cooperative children, prazosin should be administered by nasal tube after giving IV diazepam. First dose phenomenon is rare with this dose. However due care should be taken to avoid postural fall in blood pressure. Children should not be allowed to be lifted. Postural hypotension should be treated by giving head low position and IV fluids.

V. Treatment of Complications:

1. Pulmonary Edema:

In addition to prazosin, patients should be given I Vaminophylline 5 mg/ kg diluted in dextrose as a slow bolus to counteract the associated bronchospasm.1f available, isosorbide buccal spray is useful or powder of nitroglycerine should be rubbed on the gum. I V frusemide (10-20 mg) should be given to reduce the preload and pulmonary congestion.

IV sodium nitroprusside drip (SNP) 3~5 ug/ kg/min can be started and dose should be raised continuously according to patient’s response. Blood pressure should be closely monitored and maintained at the level of systolic 80-90 mm Hg. SNP has to be prepared from fresh powder every 4 hours. the bottle and IV line should be protected from light. At times a severe case may require 15-36 hours of SNl’ drip to clear pulmonary edema. Oral or injectahle cyanocobalamin can be given to avoid cyanide toxicity whenever SNP is given for long time. IV nitroglycerine can be used if SNP is not available.

Shock/hypotension:

Early administration of IV dobutamine 515 ug/ kg/ minute with simultaneous SNP drip may be life saving.

DIC, subdural haematoma and hemiplegia are known to occur and should be treated

with fresh blood transfusion.

Delirious or comatose patients may benefit

from hyperbaric oxygen.

Non-cardiac pulmonary or secretory pulmonary edema or adult respiratory distress syndrome are rarely seen due to red scorpion envenomation but maynecessnate

tracheal intubation and hyperventilation.