Stroke following scorpion stings is rare and potentially fatal. Some case reports have been documented, especially in the Indian subcontinent. There is no published report of stroke as a complication of scorpion envenomation from South East Nigeria. Presented is the profile of an elderly woman with hemorrhagic stroke as a complication of a sting from a scorpion which was killed and thereafter ingested. A review of relevant literature is also made. An 83-year-old woman from a rural community was admitted in August 2011 at the University of Nigeria Teaching Hospital, Enugu with dysphasia, altered sensorium and right hemiparesis occurring 4 h after a scorpion sting to the left leg 2 weeks before presentation. Preceding the neurological deficits she had local pain and restlessness. She was not a known hypertensive or diabetic, but had been stung on two previous occasions by scorpions. It was customary to eat the scorpion if killed which was the case here. Systemic examination was remarkable only for drowsiness with a Glasgow Coma Scale of 11/15, mild right facial nerve palsy with ipsilateral spastic hemiplegia. Brain computed tomography scan done about 4 weeks after the ictus showed features consistent with a left intracerebral hemorrhage. She was managed conservatively and recovered motor functions over 3 weeks necessitating discharge. Since there was no other detectable risk factor, we can conclude that the patient suffered a stroke as a result of the vasculotoxic actions of the scorpion venom. Keywords: Envenomation, Nigeria, scorpion, South East, stroke
Scorpion stings are frequently encountered in much of rural Nigeria. Such envenomation can produce well-recognized local and systemic manifestations. Central nervous system complications comprise about 2% of all. [1] Reports of stroke, both ischemic and hemorrhagic, following scorpion stings are rare with some case reviews well documented from the Indian subcontinent. [1],[2],[3],[4] The scorpion venom is a water-soluble, antigenic, complex toxic mixture widespread effects. [1] It causes the release of several neurotransmitters with sympathetic and parasympathetic effects. Acute rise in blood pressure due to sympathetic stimulation, rupture of unprotected perforating arteries, intracerebral hemorrhage, and cerebral infarction are reported in scorpion stings. [5],[6] Subarachnoid hemorrhage has been reported in cases of acquired vascular defects due to hypertension, age and smoking-related atherosclerosis. [7] Hypotension leading to watershed infarction is most commonly observed in the border zones between the anterior, middle and posterior cerebral artery territories. [8] Agbani is a rural community in South East Nigeria with majority of the populace engaged in subsistence farming. Scorpion stings are said to be frequent, and it is traditional for the victim to ingest the culprit scorpion if it is killed.
An 83-year-old female farmer was admitted into the medical ward of the University of Nigeria Teaching Hospital, Enugu in August 2011 with sudden onset speech difficulty, alteration of sensorium and weakness of her right limbs occurring about 4 h after she ate a scorpion that stung her about 2 weeks prior to presentation. She was seated on a reclining chair outside her home in Agbani in the evening of an uneventful day when she was stung on her left foot by a scorpion. Thereafter, followed an interval of screaming from the local pain and restlessness. The scorpion was rapidly killed by a relation, and the patient was made to ingest part of the crushed scorpion against her will. There was no vomiting, breathlessness, seizure or headache. About 4 h after, when she had been made to retire for the night, she was found unable to move her right limbs and could not utter audible words. She appeared drowsy. She was not known to have hypertension, diabetes mellitus or history of stroke or transient ischemic attack. She had two previous episodes of scorpion stings with unremarkable outcomes though she did not eat the scorpions then. Physical examination disclosed an elderly woman, well hydrated but drowsy with a Glasgow Coma Scale of 11/15. The neck was supple, and she had expressive dysphasia. There was a right facial nerve palsy (upper motor neuron type); right spastic hemiplegia with hyperreflexia and extensor plantar response. Fundoscopy was unremarkable. The sensations and visual fields were unimpaired. Her pulse rate was 80 bpm with a regular rhythm while the supine blood pressure was 110/80 mmHg. The rest of the systemic examination was essentially normal. An admission diagnosis of stroke secondary to scorpion envenomation was made, and relevant investigations including brain computed tomography (CT) scan were requested. The hemogram, serum electrolytes, blood urea nitrogen and serum creatinine, lipid profile, clotting screen, fasting blood sugar were within the normal limits. The CT scan was delayed for another 10 days after admission due to financial constraints. In the interim, she was managed conservatively with cerebral decongestants (intravenous [IV] mannitol and frusemide), IV saline and vitamin C inclusive. Physical therapy was commenced. Brain CT scan obtained 2 weeks into admission showed an acute intracerebral hemorrhage involving the left fronto-temporal region with mild brain shift [Figure 1].
The patient subsequently recovered full sensorium and sufficient motor functions to walk with assistance. She however remained mildly dysphasic. She was discharged after 3 weeks of admission to be followed up in the outpatients’ clinic.
Out of 1000 species of scorpion, only 30 are lethally toxic, accounting for 5000 deaths per annum worldwide. [9] The clinical features of scorpion sting vary with the species. [9] Though local symptoms are the commonest manifestation following a scorpion sting, various systemic complications can ensue. Central nervous system complications are very rare and may present in either of two forms, both of which are associated with high mortality rates: [1]
These include:
Our patient had intracerebral hemorrhage that could have resulted from mechanism (i) above. She is an elderly woman with a risk of background amyloid angiopathy. Also, she ingested the scorpion that probably increased the amount of envenomation and thus the extent of attendant complications. In view of the numerous mechanisms predisposing to stroke in patients with scorpion envenomation, it is possible that the risk for hemorrhagic transformation of an ischemic infarct may be greater than anticipated. This scenario can be contemplated in our patient bearing in mind the acute nature of the bleed in view of the time frame from the ictus (>3 weeks) as a differential of a primary intraparenchymal hemorrhage which may have recurred. Following a scorpion sting, it is important to give prophylactic treatment against its complications. This may include administration of prazosin, a competitive post-synaptic α-1 adrenoreceptor antagonist since α-receptor stimulation plays a major role in the evolution of the clinical spectrum. [14],[15] Prazosin suppresses sympathetic outflow and activates venom-inhibited potassium channels thereby decreasing the preload, afterload and blood pressure without increasing the heart rate. It also counters vasoconstriction induced by endothelins through accumulation of cyclic guanosine monophosphate and thus prevents further myocardial injury. The metabolic and hormonal effects of α-receptors stimulation are reversed by prazosin. Thus, prazosin is a cellular and pharmacologic antidote to the actions of scorpion venom, and it is also cardioprotective. The time lapse between the sting and administration of prazosin for symptoms of autonomic storm determines the outcome. [15],[16],[17] Benzodiazepines (diazepam) are often useful to reduce anxiety after scorpion sting. Benzodiazepines in concert with g-aminobutyric acid open chloride ion channel. This effect of diazepam antagonizes the scorpion toxins’ ability to stimulate specific ion channel. Pain relief is useful since it allays anxiety and avoids myocardial stress. Local ice packs, xylocaine (local anesthetic), the dihydroemetine (counter irritant), nonsteroidal anti-inflammatory drugs, and streptomycin (neuromuscular blockade) have been reported to be useful. [18],[19],[20] The loss of fluid due to profuse sweating and vomiting is usually overlooked. Hence, oral fluids whenever feasible must be encouraged. The use of a combination of insulin and alpha blocker with sodium bicarbonate resulted in a reversal of all electrocardiographic changes (rhythm disturbances, conduction defects, ischemia and infarction like pattern) to sinus rhythm in experimental animals. [21] Bawaskar and Bawaskar reported similar changes with oral prazosin in his patients. [15] Scorpion venoms reach their target too rapidly to be neutralized and antivenom within 30 min of sting may reverse their effect. Usefulness of scorpion antivenom varies between countries. Doctors from Brazil, Mexico, and Saudi Arabia report benefit. [22],[23],[24] Systematic administration of scorpion antivenom did not alter the clinical course of scorpion sting in a matched pair study undertaken at an intensive care unit in Tunisia. [24]
It is safe to conclude that our patient’s stroke was a direct consequence of the scorpion sting. The ingestion of the killed scorpion could have exposed the patient to larger envenomation than would be otherwise. She nevertheless showed a favorable outcome. There is a need for more public health education on the possible dangers of unhealthy cultural practices in relation to scorpion stings especially in Nigeria.
Source of Support: None, Conflict of Interest: None
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