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Signs and Symptoms of Envenomation


Many symptoms of envenomation by scorpion is similar in manifestation. Much of the information here is compiled from Simard and Watt chapter from 'The Biology of Scorpion'.
After making the components of venom WITHOUT reading his articles, I regretted. The information I compiled from at least 5 books are nearly all summarised in his article. Reading one book would have been much simpler ........


Most of the scorpions stings (70% in one article) occurs on the hands. The rest mostly occur on the legs and stings on other region is rare.

Possible local effects are :
1) Pain at the site of sting. Some species causes unspeakable pain I heard. (100% victims of Tityus spp experience pain)
2) Itchiness. (usually masked by pain)
3) Slight to medium swelling
4) Slight bleeding (rare and most likely not related to toxin as only Heterometrus scaber seems to have hemolytic components)

As most scorpion venom is of neurotoxin type, systemic effect is more to be expected.

Early systemic effects includes:
1) Sweating
2) Pallor (paleness of skin)
3) Tachypnea ( fast breathing )
4) tachycardia (fast heart beat)
5) hypertension (heightened blood pressure)
6) salivation (uncontrolled saliva production) with frothy sputum
7) respiratory wheezing
8) stridor (high pitch respiration sound)
9) blurred vision
10)roving eye movement
11)oculogyric crisis (cannot control eye movement)
12)slurred speech
13)dysphagia (cannot swallow properly)
14)pharyngeal spasm (cannot control much of the mouth)
15)drowsiness

Many of the symptoms are sometimes due to or aggravated by victim's shock and anxiety. It is known that some victim shows these signs even when there's no venom injected! Such case is not uncommon and is mainly psychological. Nevertheless, medical attention should be given as injury from psychological distress is very REAL and likely. Even injecting just saline and reassurance gives prompt curative effect.

Advanced symptoms are:
1) muscle twitching (myoclonus?)
2) motor hyperactivity
3) incoordination (ataxia?)
4) increased muscle tone
5) Opisthotonos (spasm causing extreme hyperextension of body, bent over backwards)
6) over-sensitive or undersensitive muscle reflex
7) Seizure like symptoms
8) Chest pain
9) vomitting
10)gastric distension (feeling of fullness)
11)diarrhea
12)abdominal cramps
13)temperature dysregulation (abnormally high or low temperature)
14)pulmonary oedema

Though some symptoms can be psychological as well, prompt medical attention must be given at the above signs. The likelihood of serious envenomation is very high with such symptoms. Anaphylaxis may be a likely contributor as well

Late symptoms are:
1) Altered sensorium (changed sensory perception)
2) cyanosis (turns purple)
3) hypotension (low blood pressure)
4) bradycardia (slow heart rate)
5) incontinence (cannot control urine........)
6) seizure
7) respiratory and cardiac failure (dying....)
8) paresis - slight to complete paralysis (cannot move)
9) Altered Electrocardiograph (ECG for heart action potential)
10)coma

One can almost rule out pure pschological effect except in epilepsy prone victims. This definitely requires hospitalisation and may be more suitable for Intensive Care Unit (ICU). Anaphylaxis is still a likely potentiating factor.

Blood testing of envenomated patient gives-
1) increased serum and urine catecholamines (eg. adrenaline) and metabolites.
2) Leukocytosis (high leukoytes count; detoxification?)
3) hyperkalemia (high potassium in blood plasma; Na-K-ATPase pump?)
4) hyponatraemia (low sodium in blood plasma; Na-K ATPase pump?)
5) hyperglycaemia (high glucose; due to increased glucocorticoids?)

Dead victim are shown
1) to have diffuse internal bleeding (haemorrhage)
2) passive congestion
3) fatty necrosis
3) myocarditis.

Very rarely do one reach this stage...... It is avoidable in almost all cases if APPROPRIATE medical help is given.

For more, refer to 'Scorpion Sting Syndrome- A Ten Years Experience' on the net.

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