The present study is an attempt to evaluate the clinical manifestations of severe scorpion sting in children and their management at a rural setting. Twelve patients with severe scorpion sting referred from primary health center are presented in this report. Eight children had pulmonary edema and hypotension; two had pulmonary edema and hypertension while one each presented with hypertension and tachycardia in isolation. Oral prazosin, dobutamine infusion and sodium nitroprusside drip (SNP) were used as therapeutic options based on the symptomatology. Two children died of massive pulmonary edema despite use of SNP and dopamine drip. Anti scorpion venom did not prevent the cardiovascular manifestations of severe scorpion sting. Early administration of prazosin alleviated the severity of scorpion envenomation

Key words: Pulmonary edema, Scorpion sting

Scorpion sting is a frequent event in tropical and sub-tropical countries(l). Mesobuthus tamulus or Indian red scorpion is the most lethal of all scorpion species. These are found abundantly in Western Maharashtra, parts of Karnataka, Andhra Pradesh, Saurashtra, Pondicherry and Tamil Nadu(2). Children are at greater risk of developing severe envenomation. Clinical manifestations of scorpion envenomation are vomiting, profuse sweating, pulmonary edema and death(3,4). Primary health centers in villages are often the places where medical aid is first sought(5).

In this report, we describe the clinical features and our experience with the management of children who presented to our center with severe scorpion envenomation.

Subjects and Methods

This study included 12 consecutive children £15 years of age admitted between January 2002 to January 2003 to general Hospital, Mahad with the diagnosis of scorpion envenomation. The diagnosis was based on positive history of scorpion sting, with scorpion being seen or killed by relatives or bystander. All children developed severe clinical manifestations. Eleven cases reported to nearby primary health center (PHC) at median of 1.5 hours (Range 0.5-12 hours). These children were later referred (11 from PHC and one from spiritual healer) to our center within 1-36 hours of sting. The details of the clinical features and treatment given at PHC were noted from reference letter and in doubtful cases one of the author (HSB) visited the PHC to obtain such information. All clinical details including blood pressure, heart rate, chest findings and temperature of extremities were recorded on arrival and thereafter at one hourly interval. Electro-cardiogram (ECG) was done on arrival and thereafter every 6 hourly. Other tests performed were hemoglobin and creatine phosphokinase(CPK) which could be done in 11 cases. Pulmonary edema was diagnosed on basis of clinical findings of tachypnea with basal crepitations in chest, transient systolic apical murmur and proto-diastolic gallop. Massive pulmonary edema was defined if the child had orthopnea, cyanosis, extensive bilateral crepitations and irritable cough with redish frothy sputum. Details of the treatment administered and outcome were recorded.

Results

The age of the children (6 males and 6 females) ranged from 3.5 years to 15 years. Eleven children were referred to our center from PHCs. The median time interval elapsed between envenomation and presentation was 13.5 hours with range 1-36 hours. Eleven children presented with vomiting, sweating, and cold extremities at PHCs. One child initially shown to a Spiritual healer (tantrik) also had vomiting, sweating and cold extremities.. Blood pressure was recorded in six children out of whom two were hypertensive. One child had convulsions and one had priapism. Steroids were used in all eleven cases at PHCs while antihistaminic (Pheniramine) was used in eight cases. Antiscorpion venom (ASV) and prazosin was used in four patients each while five were given furosemide.

Two children (aged 6 years and 10 years) died of massive pulmonary edema and hypotension despite use of dopamine and nitroprusside infusion. Both othese children first presented to PHC within 1.5 hours and were administered steroids, antiscorpion venom (ASV) and furosemide. Prazosin was not used in these children at PHC. Out of the four cases where prazosin was administered at PHC, three developed pulmonary edema while one presented with only tachycardia. None of these children had massive pulmonary edema (Table I). Six out of seven children where prazosin was not used initially had pulmonary edema with three having massive pulmonary edema. One child who was not initially given prazosin reported within 1 hour of sting to our hospital. She was in inotropic phase having hypertension and recovered without development of tachycardia with oral prazosin therapy at our hospital.

TABLE I

Relationship of Initial Prazosin Use to Various Complications

Use of Prazosin at PHC	Total cases	Pulmonary edema	Massive pulmonary edema	Hypotension	Hypertension	Death
Prazosin used	4	3	0	3	0	0
Prazosin not used	8	7	5	3	3	2

 

The child who was initially taken to spiritual healer presented to us at 36 hours when she became breathless. She was having pulmonary edema and hypotension but responded well to oral prazosin and oxygen.

Hemoglobin levels were more than 10 g/dL in all but one child where it was 9.5 g/dL. Creatine phosphokinase (CPK) was elevated in all the nine cases of scorpion envenomation where this test was performed. ECG findings of the cases included ST segment depression (4 out of 12), acute infarction like pattern (5/12), tented T waves (3/12) and left anterior hemiblock (2/12).

Discussion

The present report shows that prazosin, a post synaptic alpha blocker, helps to alleviate the severity of clinical manifestations of scorpion sting. Steroids might enhance the necrotizing effects of circulating catechol-amines on myocardium resulting in clinical deterioration(6). One of the child who was initial shown to spiritual healer and thus did not receive any steroids recovered with only prazosin despite presenting very late (36 hours). Massive pulmonary edema may require sodium nitrioprusside(7) or inotropic support if the patient presents late with hypotension and marked tachycardia(8).

Indian red scorpion (Mesobuthus tamulus) venom delays the inactivation of sodium channels of autonomic nervous system resulting in autonomic storm. The clinical manifestations due to scorpion sting are believed to be primari1y due to complex interaction between sympathetic and para-sympathetic stimulation, characterized by transient cholinergic (vomiting, sweating, bradycardia, priapism in males, ventricular premature contraction, salivation and hypo-tension) and prolonged sympathetic stimula-tion (hypertension, tachycardia, pulmonary edema, cool extremities and shock)(4). Initial transient hypotension is due to excessive fluid loss as a result of sweating and vomiting and subsequent hypertension and tachycardia is due to sudden liberation of endogenous catecholamines into the circulation. The pro-longed hypertensive crisis can be explained on the basis that the scorpion venom sensitizes the pre-synaptic membrane in such a way as to render the neuron very susceptible to subsequent stimulation(9). If these phases are not rectified in time, these cases subsequently land into tacycardia, hypotension and pulmonary edema due to depletion of catecholamines from nerve terminals and myocardium and also because of activation of kinin/prostaglandin pathway(10). Myocardial ischemia is due to coronary spasm as a result of circulating catecholamines(11). ECG findings of tented T waves, myocardial infarction pattern and injury to conducting system in our cases were suggestive of myocardial damage. Raised cardiac enzymes further suggested that pulmonary edema due to scorpion envenomation in our cases was cardiogenic.

Scorpion antivenom is considered as the specific treatment of scorpion envenomation. However, the benefit of scorpion antvenom has been seriously challenged by recent randomized placebo controlled trial(12). In our series of cases, antiscorpion venom administered within 1.5 hours of sting in four cases did not prevent the development of severe cardiovascular manifestations. Two out of these four children died of massive pulmonary edema.

Insulin glucose potassium drip and lytic cocktail also do not reduce the cardiovascular morbidity and mortality in scorpion sting victims(13,14). As scorpion venom acts indirectly through the release of auto-pharmacological agents, the aim of the treatment should be to counteract the effects of these agents.

Alpha receptor stimulation plays important role in the pathogenesis of pulmonary edema. Prazosin, a post synaptic alpha blocker, reverses both inotropic and hypokinetic phases and reverses the metabolic effects caused by depressed insulin secretion(15). Oral prazosin is fast acting, easily available, relatively cheap, free from any anaphylaxis and highly effective. Early intervention with oral prazosin and appropriate use of dobutamine with avoidance of atropine, excessive diuretics, steroids and antihistamines might help to hasten the recovery in severe scorpion sting victim.

Contributors: Both authors were involved in the management and work up of the patients. HSB reviewed the literature and drafted the manuscript. HSB shall act as the guarantor.

Funding: None

Competing interests: None stated.

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