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Scorpionism causing severe acute flaccid paralysis. Case report

How to cite this article: Villa-Manzano AI, Vázquez-Solís MG, Zamora-López XX, Arias-Corona F, Palomera-Ávila FM, Pulido-Galaviz C, Pacifuentes-Orozco A. [Scorpionism causing severe acute flaccid paralysis. Case report]. Reporte de caso. Rev Med Inst Mex Seguro Soc. 2016;54(2):268-8.



Received: October 19th 2014

Accepted: October 21th 2015

Scorpionism causing severe acute flaccid paralysis. Case report

Alberto I. Villa-Manzano,a,b Ma. Guadalupe Vázquez-Solís,c Xochitl Xitlalli Zamora-López,a,d Fernando Arias-Corona,a Francisco Miguel Palomera-Ávila,a,c Carlos Pulido-Galaviz,c Adán Pacifuentes-Orozcoc

aCentro Regional de Información y Atención Toxicológica, Cruz Verde de Guadalajara

bUnidad Medicina Ambulatoria 52, Instituto Mexicano del Seguro Social

cCentro Universitario de Ciencias de la Salud, Universidad de Guadalajara

dPosgrado en Ciencias Médicas, Universidad de Colima, Colima, Colima, México

Guadalajara, Jalisco, México

Communication with: Alberto I. Villa-Manzano

Telephone: (333) 629 5079


Background: Scorpionism is a public health problem in various regions of the world, being Mexico the country with the highest number of cases. Clinical manifestations range from local symptoms to severe disease with an impact on cardiovascular, respiratory and neurological level, and even death. There are no reports of acute flaccid paralysis as a manifestation of the clinical picture of the scorpion sting of the Centruroides gender, Family Buthidae, highly toxic, causes high rates of morbidity and mortality in our region.

Case report: We documented a case of scorpionism, caused by a scorpion gender Buthidae, Centruroides family, which caused acute flaccid paralysis, after resolution of other severe manifestations. There is only one case report of scorpionism that produces acute flaccid paralysis in the literature, but it is related to the Parabuthus scorpion, endemic of South Africa.

Conclusions: The knowledge of this complication, new for our region, will maximize efforts to diagnose and appropriately manage this symptoms, with the adequate application of the specific fabotherapy and advanced life support for proper survival in the patients with compromise of vital functions and imminent risk of death mainly by respiratory failure.

Keywords: Scorpion stings; Arachnid control; Paralysis

The epidemiology of scorpion stings worldwide is little known.1 Mexico is a country of high risk due to its increasing incidence and high mortality;2 about 300,000 cases of scorpion stings are recorded annually.3

Several families of scorpions have been identified in our country; poisonous species include the genus Centruriodes in the Buthidae family, responsible for the signs of poisoning with the worst morbidity and mortality.4,5 This genus has 30 species, and the medically important ones are: Centruroides noxius, C. limpidus, C. tecomanus, C. suffusus, C. infamatus, C. elegans, C. sculpturatus, C. balsasensis, and C. meisei. The states with the highest poisoning mortality from scorpion stings are: Guerrero, Jalisco, Michoacan, Morelos, Nayarit, Sinaloa, and Zacatecas, while the highest morbidity is registered in the states of Jalisco, Guanajuato, Guerrero, Michoacan, Morelos, and Nayarit.6

Jalisco is one of the states with the highest number of reported cases, ranking second nationally after Guerrero; for 2014 47,261 cases were reported7 and the mortality rate exceeds the national average with 31/100,000 inhabitants,8 ranking third in the nation with an average of 8 deaths per year.9

Poisoning by scorpion sting is diagnosed by: a history of the presence of scorpion species in the area, certain or suspected scorpion sting, clinical characteristics, and response to treatment with Fab-based antivenin. The clinical signs and evolution are related to the age, weight, and health conditions of the patient at the time of the sting, the amount of venom injected, and the time between the sting and access to health care. The signs and symptoms are: local (mild clinical symptoms) and systemic (moderate and severe clinical symptoms), and they are classified as grade I, II, and III, according to the severity of the symptoms presented:10-12


  • Grade I: Local pain, local paresthesia, pruritus, mild restlessness.
  • Grade II: Mild symptoms plus: persistent crying in children under 5 years old, anxiety, headache, epiphora, eye redness, itching nose, mouth, and throat, sneezing, runny nose, drooling, sensation of a foreign body in the throat, dysphagia, tongue twitches, feeling of dry mouth, tachycardia, dyspnea, abdominal distention, abdominal and muscle pain, priapism, vulvar itching.
  • Grade III: Moderate symptoms plus: hypertension or hypotension, fever or hypothermia, pinpoint pupils, mydriasis, photophobia, nystagmus, dyslalia, cyanosis around the mouth, convulsions, amaurosis, bradycardia, arrhythmias, chest pain, oliguria, unconsciousness, multiple organ failure, coma, death. The most common complications include heart failure, respiratory distress, pulmonary edema, cerebral edema, and pancreatitis.

The identified symptoms range from local events to severe symptoms, with an impact on respiratory, cardiovascular, and neurological levels,13 with cardiovascular collapse and pulmonary edema being the complications that cause mortality from this posoning.14

There is only one case report in medical literature of a scorpion sting producing acute flaccid paralysis, related to the scorpion family Parabuthus endemic to South Africa. 

Acute flaccid paralysis is a common disorder in pediatrics and is mainly due to causes related to neuromuscular diseases with acute presentation. Semiologically it can affect one, two, or four limbs in  a special or particular distribution (crural or brachial paraplegia); it manifests as an acute or hyperacute motor disorder- as defined by PAHO/WHO, acute is up to five days-, with a progressive or rapidly progressive course that is mainly due to causes related to neuromuscular diseases of acute presentation and multiple etiology: disease of the anterior horn of the spinal cord (acute anterior poliomyelitis, enterovirus); disease from a spinal marrow disorder (transverse myelitis, epidural abscess, neoplasm); disease of the plexus, roots, and peripheral nerves (S. Guillain-Barré, enterovirus, toxicity); diseases of the neuromuscular junction (myasthenia gravis, botulism, organophosphate poisoning, neurotoxins); muscle diseases (inflammatory myopathy, polymyositis, myoglobinuria). Successful management depends on knowing how to make a quick and accurate differential diagnosis, for which the main diagnostic weapon will be the patient’s history of muscle weakness.15,16

Case report

Female patient 1 year 8 months of age presented at the Centro Regional de Información y Atención Toxicológica (CRIAT) diagnosed with severe scorpion sting (failure of vital functions with imminent risk of death)17 with one hour of evolution. Patient with a history of hypersensitivity to insect bites, family atopy, and poor breast-feeding. Prior to admission she received initial management with 1 vial of specific Fab-based antivenin, but given the severity of symptoms characterized by severe respiratory failure, seizures, and Glasgow 3, she was sent by ambulance to CRIAT. The patient was admitted in poor general condition with respiratory rate of 10/min, heart rate 70/min, hypothermic, diaphoretic, with distal cyanosis, horizontal nystagmus, drooling, salmon-colored expectoration, reduced reflexes, no response to painful stimuli, relaxed sphincters, and Glasgow 3. Secretions were suctioned and endotracheal intubation performed, requiring a cycle of positive pressure ventilation, achieving O2 saturation of 91%, connected to mechanical ventilation with average parameters. There was no permeable venous access, and she was perforated in multiple places, so a Fab-based antivenin was administered intramuscularly. With intraosseous access obtained, two vials of Fab-based antivenin (third and fourth dose) and a dose of atropine were administered. Electrolyte deficit and requirement therapy was initiated; subsequently peripheral access was gained and the fifth Fab-based antivenin intravenous dose was applied.    

Her evolution was towards slow improvement, lung function was stabilized and she was conscious after 3 hours, with automatic respiration, lung fields with minimal bilateral crackles, HR 180/min, RR 40/min, O2 saturation 98%. No signs of bulbar dysfunction. The patient continued to have peripheral muscle paralysis, unresponsive to painful stimuli, reduced tendon reflexes, she did not move limbs or head, only followed a light source with eyes and presents nystagmus; these symptoms lasted 8 hours after the resolution of symptoms of the scorpion sting. Laboratory control of blood count, blood chemistry, and serum electrolytes is reported in normal parameters. After 8 hours she began to have free movement of upper and lower extremities simultaneously, from distal to proximal region and at 10 hours after extubation: the patient had a freely chosen position, sat unaided, and had present and normal tendon reflexes. New laboratory control of blood count, electrolytes, and blood chemistry normal. At 22 hours of hospitalization in the CRIAT the patient was in good general condition, without cardio-respiratory or abdominal disorders, full neurological examination normal. The chest x-ray showed no infiltrates or atelectasis. She was discharged home asymptomatic after 36 hours in the hospital.  


Scorpionism is a public health problem, Mexico is the country with the highest incidence of scorpion stings.18,19 Approximately 300,000 people are reported with scorpion stings in our country each year; the World Health Organization estimates that between 700 and 1400 deaths occur each year in Mexico, mostly in children under ten years of age.20

The clinical presentation of poisoning by scorpion sting is similar in different parts of the world and includes profuse sweating, agitation, vomiting, tachycardia, and hypertension;21,22 in severe cases arrhythmia, pulmonary edema, coma, and death can occur in the first 24 hours after the sting.

The signs and symptoms have been widely described and classified into mild, moderate, and severe; however, acute flaccid paralysis has not been described as part of the clinical manifestations to consider in poisoning by the Centruroides scorpion.

In assessing the signs and symptoms presented by our patient, the next state would have been death if the symptoms had not been stabilized with advanced life support and use of Fab-based antivenin. Stabilizing the patient allowed the gradual recovery and observation of this symptom (flaccid paralysis) that has not been reported previously in the genus Centruroides, probably because in such severe symptoms of scorpion stings patients do not survive in most cases, and on the other hand, there is no culture among health personnel to publish cases of this nature.

There is one report of flaccid paralysis in a patient stung by scorpion of the family Parabuthus endemic to South Africa23 (a case is reported of poisoning by the Parabuthus species scorpion causing severe respiratory failure, systemic effects including muscle weakness and bulbar dysfunction, developed in the 8 hours after poisoning).   

Muscle weakness has not been reported in our region as a complication of scorpion stings by the Buthidae genus of the Centruroides family; in this case report, the scorpion was identified by association because it is endemic to the area, the mother saw the scorpion, the clinical sign was distinctive, and there was a favorable response to treatment with specific Fab-based antivenin.

The poison has the potential to cause paralysis by the massive release of neurotransmitters in the somatic sensory and parasympathetic nervous systems. A similar sign to that observed in organophosphate poisoning has been reported where flaccid paralysis is an expected effect and one to be monitored.24 Despite the theoretical foundation, this complication has not been reported although Mexico is a country with high morbidity and mortality from scorpion stings.

Knowledge of this complication will maximize efforts to diagnose and appropriately handle this entity with early application of specific Fab-based antivenin and advanced life support, to achieve adequate survival in these patients with compromised vital functions and imminent risk of death.

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Conflict of interest statement: The authors have completed and submitted the form translated into Spanish for the declaration of potential conflicts of interest of the International Committee of Medical Journal Editors, and none were reported in relation to this article.

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