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SCORPIONS, TITYUS SPECIES

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Classification   |    Detailed evidence-based information

Substances Included Synonyms

Therapeutic Toxic Class

    A) Scorpions are members of the order Scorpionida, and are the most primitive and oldest members of the terrestrial arachnids. There are over 100 species of scorpions belonging to the genus Tityus. Of these, T. asthenes, T. discrepans, T. fuehrmanni, T. pachyurus, T. serrulatus, T. stigmurus, T trinitatis, and T trivittatus are known to produce toxic effects in humans. T. bahiensis, T. cambridgei, T. clathratus produce neurotoxic venom but it is not clear that they can cause human envenomation.

Specific Substances

    A) CONSTITUENTS OF THE GROUP
    1) Tityus asthenes
    2) Tityus bahiensis
    3) Tiyus cambridgei
    4) Tityus clathratus
    5) Tityus discrepans
    6) Tityus fuehrmanni
    7) Tityus metuendus
    8) Tityus nematochirus
    9) Tityus obscurus
    10) Tityus pachyurus
    11) Tityus serrulatus
    12) Tityus stigmurus
    13) Tityus tayrona
    14) Tityus trinitatis
    15) Tityus trivittatus dorsomaculatus

Available Forms Sources

    A) SOURCES
    1) Scorpion stings can occur year around in tropical and temperate climates, although stings are more frequent in the warmest months (eg; October-April in Argentina) when scorpions are more active. Stings are most common in children and least common in the elderly. Many patients are stung in the home, reflecting the tendency of some scorpions to enter dwellings and hide in clothing, bedding and shoes. Stings are most common on the hands and feet (de Roodt et al, 2003).

Overview

Life Support

    A) This overview assumes that basic life support measures have been instituted.

Clinical Effects

    0.2.1) SUMMARY OF EXPOSURE
    A) BACKGROUND: Scorpions are members of the order Scorpionida, and are the most primitive and oldest members of the terrestrial arachnids. There are over 100 species of scorpions belonging to the genus Tityus. Of these, T. asthenes, T. discrepans, T. fuehrmanni, T. pachyurus, T. serrulatus, T. stigmurus, T trinitatis, and T trivittatus are known to produce toxic effects in humans. T. bahiensis, T. cambridgei, T. clathratus produce neurotoxic venom but it is not clear that they can cause human envenomation.
    B) LOCATION: Scorpions belonging to the genus Tityus are found in Central and South America and the West Indies. Scorpions are nocturnal.
    C) PHYSICAL CHARACTERISTICS: Scorpions differ in color from straw, yellow or light brown, to black. They have large and often long pedipalps, or claws, which they use to grasp and hold their prey; segmented abdomen, and the post-abdomen is long, slender tail-like structure composed of 5 segments and ends in a sting. Scorpions sting, they do not bite.
    D) TOXICOLOGY: Scorpion venoms contain polypeptides that reversibly bind to sodium (long chain peptides) and potassium channels (short chain peptides). Binding to scorpion toxins causes voltage sensitive sodium channels to be stabilized in the open position, leading to repetitive firing of sympathetic and parasympathetic nerves and release of neurotransmitters (ie, epinephrine, norepinephrine, acetylcholine). There is also evidence that scorpion venom induces a systemic inflammatory response. Increased levels of proinflammatory cytokines have been reported in patients with severe Tityus envenomation. Pulmonary edema that can develop after scorpion envenomation may be caused by both cardiac (LV failure) and neurologic (catecholamine release affecting alveolar capillary membrane permeability) effects. T serrulatus venom contains potent neurotoxins which specifically modify ionic channel functions.
    E) EPIDEMIOLOGY: Children are more likely than adults to develop systemic manifestations, and the majority of published cases of severe or fatal envenomation involve children under the age of 10 years. In Brazil, scorpion stings are not unusual and have become a public health concern. In 2010, there were over 50,000 cases of scorpion stings in Brazil with 88 deaths. Fatalities were due to 3 species: T. serrulatus, T. bahiensis and T. stigmurus with T. serrulatus (commonly known as Brazilian yellow scorpion) being responsible for the most severe envenomations. In 2013, 78,091 cases of scorpion stings were reported in Brazil.
    F) SEASONALITY: In Brazil, the number of scorpion stings varied by regions of the country. In the Amazonas and the Central region of the state, most stings occur between June and July. In the southwest region, more cases occur between February and May (ie, the rainy season). In the South and North regions of the country, seasonality was not observed.
    G) OCCUPATIONAL EXPOSURE: In rural areas of the Amazon, scorpion stings are an important occupational health risk.
    H) WITH POISONING/EXPOSURE
    1) MILD ENVENOMATION: Local manifestations only, including pain at the sting site, localized paresthesias or burning and very mild local edema. Generalized diaphoresis is a common cholinergic manifestation. COMMON: The most common complaints of scorpion stings include pain, edema and paresthesias.
    2) MODERATE ENVENOMATION: Systemic manifestations such as generalized diaphoresis, hyperglycemia, nausea, vomiting, abdominal pain, mild tachycardia and hypertension, tachypnea (especially in children), restlessness, drowsiness, ataxia, in addition to local signs and symptoms. RARE FINDINGS: Hematemesis and pancreatitis develop rarely. Sialorrhea may develop as a result of cholinergic manifestations.
    3) SEVERE ENVENOMATION: In addition, to local manifestations, individuals may develop severe hypertension or hypotension, pulmonary edema, myocardial failure, ECG changes involving ST segments or T waves, dysrhythmias, left ventricular dysfunction, respiratory failure, CNS depression, symptomatic pancreatitis or upper GI bleeding.
    0.2.3) VITAL SIGNS
    A) WITH POISONING/EXPOSURE
    1) Tachycardia, mild hypertension and mild tachypnea may develop with moderate envenomation. Severe hypertension and tachypnea, or hypotension, suggest severe envenomation. Hyperthermia has been reported.

Laboratory Monitoring

    A) Monitor vital signs in symptomatic patients.
    B) Monitor serum glucose and electrolytes, initiate continuous cardiac monitoring and obtain an ECG in patients with moderate or severe manifestations of envenomation.
    C) Monitor serum lipase in patients with abdominal pain or persistent vomiting.
    D) Follow markers of myocardial injury (troponin, CK-MB or myoglobin) in patients with severe envenomation.
    E) Obtain a chest radiograph and monitor pulse oximetry and/or arterial blood gases in patients with respiratory signs or symptoms.

Treatment Overview

    0.4.7) BITES/STINGS
    A) SEVERITY OF ENVENOMATION
    1) Most envenomations are managed with symptomatic and supportive care, particularly pain control. Most local manifestations are limited to pain, edema and paraesthesia. Antivenom should be considered for patients that develop systemic manifestations of envenomation.
    B) MANAGEMENT OF MILD TO MODERATE ENVENOMATION
    1) Treatment is symptomatic and supportive. Oral or parenteral opioids may be required for pain control. Monitor neurologic and respiratory status carefully. Pain control is the only treatment necessary for patients who only have local manifestations of envenomation. Vomiting may develop. Correct any significant fluid and/or electrolyte abnormalities in patients with significant vomiting.
    C) MANAGEMENT OF SEVERE ENVENOMATION
    1) Treatment is symptomatic and supportive. Monitor vital signs and obtain a baseline ECG and institute continuous cardiac monitoring. Severe hypertension or hypotension may develop. Hypotension may be more likely to occur in young children. Initially treat with 10 to 20 mL/kg isotonic fluid. If hypotension persists, administer dopamine (5 to 20 mcg/kg/min), titrate to desired response. Severe hypertension that persists after antivenom administration may require treatment. Short acting, titratable agents are preferred (nitroglycerin, nitroprusside). Labetalol may be useful because of its combined beta and alpha blocking effects. LEFT VENTRICULAR FAILURE: Dobutamine has been used for left ventricular failure secondary to Tityus envenomation. ALLERGIC REACTION SECONDARY TO ANTIVENOM: MILD/MODERATE: Antihistamines with or without inhaled beta agonists, corticosteroids or epinephrine. SEVERE: Oxygen, aggressive airway management, antihistamines, epinephrine, corticosteroids, ECG monitoring, and IV fluids.
    D) DECONTAMINATION
    1) Decontamination is not indicated in this setting.
    E) AIRWAY MANAGEMENT
    1) Administer oxygen and monitor airway carefully in patients with respiratory signs or symptoms. Excessive secretions and tachypnea are common, and pulmonary edema may develop with severe envenomation. Orotracheal intubation and ventilation may be necessary.
    F) ACUTE LUNG INJURY
    1) Maintain ventilation and oxygenation and evaluate with frequent arterial blood gases and/or pulse oximetry monitoring. Early use of PEEP and mechanical ventilation may be needed.
    G) ANTIVENOM
    1) Antivenom should be considered for patients that develop systemic manifestations of envenomation. Several Tityus antivenoms are available: Soro-antiscorpionico genus Tityus and Soro-antiarachnidico. Alacramyn (Instituto Bioclon, Mexico) antivenom also has some activity against Tityus pachyurus venom. Usual dose: 2 to 4 vials diluted in 0.9% saline (50 to 100 mL for children, 100 to 250 mL for adults) infused over 30 to 60 minutes. Monitor for hypersensitivity or an acute allergic reaction.
    H) OTHER NON-INDICATED THERAPIES
    1) There is no role for cryotherapy, heat, tourniquets, incisions, or other local therapies.
    I) PATIENT DISPOSITION
    1) HOME CRITERIA: Healthy adults who are experiencing only local symptoms, can be managed at home.
    2) OBSERVATION CRITERIA: In general, children should be observed for 4 to 6 hours after a scorpion sting. In addition, patients experiencing moderate to severe symptoms, those at the extremes of age or with significant underlying medical illnesses should be referred to a healthcare center.
    3) ADMISSION CRITERIA: Hospitalize patients with severe symptoms not easily controlled with symptomatic and supportive care, or if antivenom has been given. In moderate to severe cases, patients should be monitored for a minimum of 24 hours. The level of care (eg, ICU) is determined by both symptomatology and underlying clinical status. Generally, admission is only required for young children, and rarely for more than 2 to 3 days.
    4) CONSULT CRITERIA: A clinician skilled in the management of scorpion envenomations should be involved in the care of severely envenomated patients. A regional poison center should also be consulted in such cases.

Range Of Toxicity

    A) TOXICITY: In general, a single sting can cause severe, even fatal envenomation; severe envenomation is more common in children less than 10 years of age. In Brazil, the overall mortality is 1% in patients treated with antivenom. Most deaths occur in children stung by T. serrulatus. Overall, T. serrulatus causes the most severe cases of envenomation in Brazil. In Ecuador, an infant died following an envenomation by T. asthenes within 12 hours of being stung.

Clinical Effects

Summary Of Exposure

    A) BACKGROUND: Scorpions are members of the order Scorpionida, and are the most primitive and oldest members of the terrestrial arachnids. There are over 100 species of scorpions belonging to the genus Tityus. Of these, T. asthenes, T. discrepans, T. fuehrmanni, T. pachyurus, T. serrulatus, T. stigmurus, T trinitatis, and T trivittatus are known to produce toxic effects in humans. T. bahiensis, T. cambridgei, T. clathratus produce neurotoxic venom but it is not clear that they can cause human envenomation.
    B) LOCATION: Scorpions belonging to the genus Tityus are found in Central and South America and the West Indies. Scorpions are nocturnal.
    C) PHYSICAL CHARACTERISTICS: Scorpions differ in color from straw, yellow or light brown, to black. They have large and often long pedipalps, or claws, which they use to grasp and hold their prey; segmented abdomen, and the post-abdomen is long, slender tail-like structure composed of 5 segments and ends in a sting. Scorpions sting, they do not bite.
    D) TOXICOLOGY: Scorpion venoms contain polypeptides that reversibly bind to sodium (long chain peptides) and potassium channels (short chain peptides). Binding to scorpion toxins causes voltage sensitive sodium channels to be stabilized in the open position, leading to repetitive firing of sympathetic and parasympathetic nerves and release of neurotransmitters (ie, epinephrine, norepinephrine, acetylcholine). There is also evidence that scorpion venom induces a systemic inflammatory response. Increased levels of proinflammatory cytokines have been reported in patients with severe Tityus envenomation. Pulmonary edema that can develop after scorpion envenomation may be caused by both cardiac (LV failure) and neurologic (catecholamine release affecting alveolar capillary membrane permeability) effects. T serrulatus venom contains potent neurotoxins which specifically modify ionic channel functions.
    E) EPIDEMIOLOGY: Children are more likely than adults to develop systemic manifestations, and the majority of published cases of severe or fatal envenomation involve children under the age of 10 years. In Brazil, scorpion stings are not unusual and have become a public health concern. In 2010, there were over 50,000 cases of scorpion stings in Brazil with 88 deaths. Fatalities were due to 3 species: T. serrulatus, T. bahiensis and T. stigmurus with T. serrulatus (commonly known as Brazilian yellow scorpion) being responsible for the most severe envenomations. In 2013, 78,091 cases of scorpion stings were reported in Brazil.
    F) SEASONALITY: In Brazil, the number of scorpion stings varied by regions of the country. In the Amazonas and the Central region of the state, most stings occur between June and July. In the southwest region, more cases occur between February and May (ie, the rainy season). In the South and North regions of the country, seasonality was not observed.
    G) OCCUPATIONAL EXPOSURE: In rural areas of the Amazon, scorpion stings are an important occupational health risk.
    H) WITH POISONING/EXPOSURE
    1) MILD ENVENOMATION: Local manifestations only, including pain at the sting site, localized paresthesias or burning and very mild local edema. Generalized diaphoresis is a common cholinergic manifestation. COMMON: The most common complaints of scorpion stings include pain, edema and paresthesias.
    2) MODERATE ENVENOMATION: Systemic manifestations such as generalized diaphoresis, hyperglycemia, nausea, vomiting, abdominal pain, mild tachycardia and hypertension, tachypnea (especially in children), restlessness, drowsiness, ataxia, in addition to local signs and symptoms. RARE FINDINGS: Hematemesis and pancreatitis develop rarely. Sialorrhea may develop as a result of cholinergic manifestations.
    3) SEVERE ENVENOMATION: In addition, to local manifestations, individuals may develop severe hypertension or hypotension, pulmonary edema, myocardial failure, ECG changes involving ST segments or T waves, dysrhythmias, left ventricular dysfunction, respiratory failure, CNS depression, symptomatic pancreatitis or upper GI bleeding.

Vital Signs

    3.3.1) SUMMARY
    A) WITH POISONING/EXPOSURE
    1) Tachycardia, mild hypertension and mild tachypnea may develop with moderate envenomation. Severe hypertension and tachypnea, or hypotension, suggest severe envenomation. Hyperthermia has been reported.
    3.3.2) RESPIRATIONS
    A) WITH POISONING/EXPOSURE
    1) TACHYPNEA
    a) Tachypnea was reported in 24.4% (10 of 41) of children who presented for medical care after a scorpion sting (Otero et al, 2004).
    3.3.3) TEMPERATURE
    A) WITH POISONING/EXPOSURE
    1) HYPERTHERMIA
    a) Hyperthermia was reported in 13.1% of 511 patients who presented for medical care after T. trivittatus sting (de Roodt et al, 2003).
    3.3.4) BLOOD PRESSURE
    A) WITH POISONING/EXPOSURE
    1) HYPERTENSIVE EPISODE
    a) Mild hypertension occurs with moderate envenomation. In severe envenomations, severe hypertension may develop.
    b) In a series of 8 children, aged 2 to 9 years, with severe Tityus envenomation, blood pressure ranged from 112/60 to 178/123 mmHg (Cupo & Hering, 2002).
    c) In a series of 41 children who presented to the hospital with scorpion envenomation, 4 (9.8%) developed hypertension (Otero et al, 2004).
    2) HYPOTENSIVE EPISODE
    a) Hypotension and shock can develop in patients with the most severe envenomation, and appears to be more common in children (Daisley et al, 1999).
    3.3.5) PULSE
    A) WITH POISONING/EXPOSURE
    1) TACHYCARDIA
    a) Tachycardia is characteristic of moderate to severe envenomation.
    b) INCIDENCE: Tachycardia developed in about 18% of patients who presented to the hospital in two large case series (n=511 stung by Tityus trivittatus; n=129, 67% with Tityus stings) (de Roodt et al, 2003; Otero et al, 2004).
    2) BRADYCARDIA
    a) Bradycardia has bee reported after Tityus sting, but is not common. It was reported in 2 of 41 children (4.9%) and 2 of 88 adults (2.3%) who presented for medical care in one series(Otero et al, 2004).

Cardiovascular

    3.5.2) CLINICAL EFFECTS
    A) TACHYARRHYTHMIA
    1) WITH POISONING/EXPOSURE
    a) SUMMARY: Tachycardia is characteristic of moderate to severe envenomation.
    b) INCIDENCE: Tachycardia developed in about 18% of patients who presented to the hospital in 2 large case series (n=511 stung by Tityus trivittatus; n=129, 67% with Tityus stings) (de Roodt et al, 2003; Otero et al, 2004).
    c) TITYUS OBSCURUS: In a series of 58 cases of presumed Tityus obscurus envenomations in the Amazon, tachycardia (n=16; 27.6%) was reported frequently (Torrez et al, 2015).
    d) CASE SERIES: In a series of 8 children, aged 2 to 9 years, with severe Tityus envenomation, pulse ranged from 60 to 180 beats/minute. Two children had very variable heart rates, ranging from 60 to 180 beats/minute in a 7-year-old and 88 to 150 beats/minute in the other 7-year-old (Cupo & Hering, 2002).
    B) LEFT VENTRICULAR CARDIAC DYSFUNCTION
    1) WITH POISONING/EXPOSURE
    a) CASE REPORTS: In a series of 8 children with severe Tityus envenomation, echocardiography revealed left ventricular dysfunction (reduced ejection fraction and fractional shortening) in 7 patients (the remaining patient did not have echocardiography performed until 60 hours after being stung). All patients were treated with antivenom and supportive care (including dobutamine in 3 patients) and recovered (Cupo & Hering, 2002).
    1) In all of these patients, specific and non-specific markers of myocardial injury (Troponin I, myoglobin, CK-MB and AST) increased above the normal range with the envenomation and returned to normal within 4 to 5 days.
    b) CASE REPORTS: Twelve children (ages 1 to 12 years) with severe Tityus serrulatus envenomation developed varying degrees of left ventricular dysfunction. Echocardiography revealed marked wall motion abnormalities and reduced ejection fraction (36 +/-16%). Of the 7 patients with an ejection fraction of less than 35%, 6 developed acute pulmonary edema. Myocardial perfusion scintigraphy also demonstrated perfusion defects in all patients. Despite the tests not being performed on the same day, a strong correlation was found between wall motion scores and myocardial perfusion scores (r=0.68, p=0.016). Improvement in both scores was also observed as the children clinically improved. These findings suggest that transient myocardial ischemia is a component of the cardiac dysfunction produced following severe scorpion envenoming (Cupo et al, 2007).
    c) In a series of 10 children with severe Tityus zulianus envenomation with cardiovascular manifestations (including varying degrees of pulmonary edema), 6 of the 8 children who had an echocardiography performed had left ventricular wall motion abnormalities and depressed ejection fractions (20% to 40%). All patients improved with supportive care within 4 to 6 days (Mazzei de Davila et al, 2002).
    C) HEART FAILURE
    1) WITH POISONING/EXPOSURE
    a) TITYUS ASTHENES/CASE REPORT: A 23-month-old boy living in the northern Manabi province of western Ecuador was bit on the foot by T. asthenes scorpion (the scorpion was brought to the hospital for identification) and developed immediate pain and episodes of vomiting. He was brought to a local hospital 2 hours after exposure and treated with IV fluids, analgesia and dexamethasone. He was then transferred to a higher level of care with ongoing emesis, a 20 mmHg decrease in blood pressure, hyperglycemia and crackling rales and bilateral bronchial breathing. The infant was treated supportively. During the same day, his clinical condition continued to worsen with a decrease in oxygen saturation and cyanosis, signs of cerebral decortication and a lack of corneal reflex. He then developed cardiorespiratory arrest that did not respond to resuscitation efforts and died approximately 12 hours after envenomation (Borges et al, 2015).
    D) HYPERTENSIVE EPISODE
    1) WITH POISONING/EXPOSURE
    a) Mild hypertension occurs with moderate envenomation. In severe envenomations, severe hypertension may develop.
    b) In a series of 8 children, aged 2 to 9 years, with severe Tityus envenomation, blood pressure ranged from 112/60 to 178/123 mmHg (Cupo & Hering, 2002).
    c) In a series of 41 children who presented to the hospital with scorpion envenomation, 4 (9.8%) developed hypertension (Otero et al, 2004).
    E) HYPOTENSIVE EPISODE
    1) WITH POISONING/EXPOSURE
    a) Hypotension and shock can develop in patients with the most severe envenomation, and appears to be more common in children (Daisley et al, 1999).
    F) BRADYCARDIA
    1) WITH POISONING/EXPOSURE
    a) Bradycardia has been reported after Tityus sting, but is not common. It was reported in 2 of 41 children (4.9%) and 2 of 88 adults (2.3%) who presented for medical care in one series (Otero et al, 2004).
    G) ELECTROCARDIOGRAM ABNORMAL
    1) WITH POISONING/EXPOSURE
    a) ECG abnormalities are common in patients with severe envenomation. Ventricular extrasystoles and tachycardia are common and bradycardia has been reported. ST segment depression and elevation have also been reported (Cupo & Hering, 2002).
    H) MYOCARDITIS
    1) WITH POISONING/EXPOSURE
    a) Myocarditis with contraction band necrosis has been described in fatal cases (Daisley et al, 1999; Benvenuti et al, 2002).

Respiratory

    3.6.2) CLINICAL EFFECTS
    A) TACHYPNEA
    1) WITH POISONING/EXPOSURE
    a) Tachypnea was reported in 10 of 41 (24.4%) children who presented for medical care after scorpion sting (Otero et al, 2004).
    B) PULMONARY EDEMA
    1) WITH POISONING/EXPOSURE
    a) Pulmonary edema is a manifestation of severe envenomation, and is more common in children than adults. Clinical manifestations include severe tachypnea and respiratory distress, hypoxemia, wheezing and rales, restlessness, cold and clammy skin (Daisley et al, 1999).
    b) ONSET: In a series of 8 children with severe T. serrulatus envenomation, 5 of whom developed pulmonary edema within 24 hours of the sting (Cupo & Hering, 2002).

Neurologic

    3.7.2) CLINICAL EFFECTS
    A) EXCITEMENT
    1) WITH POISONING/EXPOSURE
    a) CNS excitation is a fairly common manifestation; it was reported in 8% of 511 patients presenting to medical care after a Tityus trivittatus sting (de Roodt et al, 2003).
    b) TITYUS OBSCURUS: In a series of 58 cases of presumed Tityus obscurus envenomations in the Amazon, agitation (n=14; 24.1%) was relatively common (Torrez et al, 2015).
    B) ATAXIA
    1) WITH POISONING/EXPOSURE
    a) TITYUS OBSCURUS: In a series of 58 cases of presumed Tityus obscurus envenomation in the Amazon, ataxia (n=42; 72.4%) was reported frequently (Torrez et al, 2015).
    C) NEUROLOGICAL FINDING
    1) WITH POISONING/EXPOSURE
    a) ELECTRIC SHOCK SENSATION
    1) TITYUS OBSCURUS: In a series of 58 cases of presumed Tityus obscurus envenomation in the Amazon, an electric shock sensation (n=55; 94.8%) occurred in almost all patients. Symptoms started within several minutes of exposure and lasted for hours in some cases (Torrez et al, 2015).
    D) MYOKYMIA
    1) WITH POISONING/EXPOSURE
    a) TITYUS OBSCURUS: In a series of 58 cases of presumed Tityus obscurus envenomation in the Amazon, fasciculation (n=27; 46.5%) was reported frequently (Torrez et al, 2015).
    b) Fasciculations at the site of the sting were reported in 3.1% of 129 patients who presented for medical care after scorpion stings (67% Tityus species)(Otero et al, 2004).
    E) MYOCLONUS
    1) WITH POISONING/EXPOSURE
    a) TITYUS OBSCURUS: In a series of 58 cases of presumed Tityus obscurus envenomation in the Amazon, myoclonus (n=44; 75.9%) was reported frequently (Torrez et al, 2015).
    F) DYSARTHRIA
    1) WITH POISONING/EXPOSURE
    a) TITYUS OBSCURUS: In a series of 58 cases of presumed Tityus obscurus envenomation in the Amazon, dysarthria (n=36; 62%) was reported frequently (Torrez et al, 2015).
    G) DROWSINESS
    1) WITH POISONING/EXPOSURE
    a) Drowsiness was reported in 12 of 41 children (29.3%) and 5 of 88 adults (5.7%) who presented for medical care after scorpion sting (67% Tityus species)(Otero et al, 2004). Lethargy and coma are manifestations of severe envenomation.
    b) TITYUS OBSCURUS: In a series of 58 cases of presumed Tityus obscurus envenomation in the Amazon, somnolence (n=12; 20.7%) was a relatively common symptom (Torrez et al, 2015).
    H) PARESTHESIA
    1) WITH POISONING/EXPOSURE
    a) Paresthesias at the sting site are common. In 129 patients who presented for medical care after a scorpion sting (67% Tityus), local paresthesias were reported in 57.4% (Otero et al, 2004). Paresthesias were reported in 9.8%, and localized burning sensation was reported in 24.7% of 511 patients presenting for medical care after a T. trivittatus sting (de Roodt et al, 2003).
    I) HEADACHE
    1) WITH POISONING/EXPOSURE
    a) Headache was reported in 11.4% of 511 patients who presented for medical care after a T. trivittatus sting (de Roodt et al, 2003).
    J) CEREBRAL EDEMA
    1) WITH POISONING/EXPOSURE
    a) Cerebral edema has been reported on autopsy in some, but not all, fatal cases (Daisley et al, 1999).
    K) NEUROPATHY
    1) WITH POISONING/EXPOSURE
    a) CASE REPORT: A 22-year-old woman developed fasciculation of the left eyelid, nasal wing, and upper lip with hypoesthesia of her left face, inside the mouth and left upper maxilla after being stung on the left side of the face by a T. serrulatus scorpion. Physical examination suggested paresis of peripheral branches of the left facial and trigeminal nerves. Symptoms resolved over the next 36 hours (Nishioka et al, 1992).

Gastrointestinal

    3.8.2) CLINICAL EFFECTS
    A) VOMITING
    1) WITH POISONING/EXPOSURE
    a) Vomiting is likely to be an early sign of Tityus envenomation (ie, T. trivittatus, T. trinitatis, T. asthenes) (Borges et al, 2015; de Roodt et al, 2003; Daisley et al, 1999; Otero et al, 2004).
    b) Vomiting developed in 17.8% and 25% of patients presenting to a hospital with Tityus envenomation in 2 large case series (Otero et al, 2004; de Roodt et al, 2003). Hematemesis has been reported rarely with severe envenomation (Daisley et al, 1999).
    B) ABDOMINAL PAIN
    1) WITH POISONING/EXPOSURE
    a) Abdominal pain was reported in 8 (19.5%) of 41 children and 3 of 88 adults (3.4%) presenting to hospital with scorpion stings (67% Tityus species) (Otero et al, 2004).
    C) EXCESSIVE SALIVATION
    1) WITH POISONING/EXPOSURE
    a) Sialorrhea and difficulty swallowing secondary to a foreign body sensation have been reported in 2 of 41 (4.9%) of children and 8 of 88 (9.1%) of adults who presented to hospital after scorpion stings (67% Tityus species) (Otero et al, 2004).
    D) PANCREATITIS
    1) WITH POISONING/EXPOSURE
    a) Acute edematous pancreatitis (documented on CT) was reported in a 3-year-old girl who developed abdominal pain, persistent vomiting, tachypnea, hypoxemia, and hyperamylasemia after a T. asthenes sting. She recovered with supportive care (Otero et al, 2004).
    b) In a series of 51 patients with moderate to severe envenomation after Tityus envenomation, 46% had elevated serum amylase levels, although it is not clear if any of these patients had clinical manifestations of pancreatitis (D'Suze et al, 2003).

Genitourinary

    3.10.2) CLINICAL EFFECTS
    A) INJURY OF KIDNEY
    1) WITH POISONING/EXPOSURE
    a) TITYUS OBSCURUS: In a series of 58 cases of presumed Tityus obscurus envenomations in the Amazon, 2 pediatric patients developed acute renal injury and rhabdomyolysis (Torrez et al, 2015).

Hematologic

    3.13.2) CLINICAL EFFECTS
    A) LEUKOCYTOSIS
    1) WITH POISONING/EXPOSURE
    a) Leukocytosis is a common finding in children after moderate to severe envenomation, likely secondary to catecholamine excess (Borges et al, 2015; Cupo & Hering, 2002).

Dermatologic

    3.14.2) CLINICAL EFFECTS
    A) PAIN
    1) WITH POISONING/EXPOSURE
    a) Pain at the site of the sting is by far the most common manifestation of scorpion envenomation. It develops in 85% to 97% of patients presenting for medical care after a sting (Borges et al, 2015; Otero et al, 2004; de Roodt et al, 2003).
    B) EDEMA
    1) WITH POISONING/EXPOSURE
    a) Mild local edema at the sting site was reported in 26.6% of 511 patients presenting to a hospital after a Tityus trivittatus sting (de Roodt et al, 2003) and 56.6% of 129 patients (67% Tityus stings) in another (Otero et al, 2004).
    C) EXCESSIVE SWEATING
    1) WITH POISONING/EXPOSURE
    a) Generalized sweating is a fairly common cholinergic manifestation, reported in 8% to 29.3% of patients in 3 case series (Torrez et al, 2015; Otero et al, 2004; de Roodt et al, 2003). Localized sweating around the sting site was reported in 24% of 129 patients who presented to hospital after a scorpion sting (67% Tityus species) (Otero et al, 2004).
    D) ERYTHEMA
    1) WITH POISONING/EXPOSURE
    a) Local erythema at the sting site was reported in 20.7% of 511 patients presenting to hospital after Tityus trivittatus sting (de Roodt et al, 2003). Erythema has also been reported following a sting by T. asthenes scorpion (Borges et al, 2015)

Musculoskeletal

    3.15.2) CLINICAL EFFECTS
    A) RHABDOMYOLYSIS
    1) WITH POISONING/EXPOSURE
    a) TITYUS OBSCURUS: In a series of 58 cases of presumed Tityus obscurus envenomations in the Amazon, 2 pediatric patients developed acute renal injury and rhabdomyolysis (Torrez et al, 2015).

Endocrine

    3.16.2) CLINICAL EFFECTS
    A) HYPERGLYCEMIA
    1) WITH POISONING/EXPOSURE
    a) Hyperglycemia is common after moderate to severe envenomation, but generally does not require specific treatment. In a series of 41 patients with moderate to severe envenomation, 49% developed hyperglycemia (D'Suze et al, 2003). Hyperglycemia has also been reported in children following envenomation by a T. asthenes scorpion (Borges et al, 2015).
    B) CATECHOLAMINE
    1) WITH POISONING/EXPOSURE
    a) In a group of 10 children with cardiovascular manifestations after Tityus zulianus scorpion envenomation (all had pulmonary edema and of the 8 who had echocardiography, 6 had left ventricular wall abnormalities and depressed ejection fractions), all had increased plasmal levels of norepinephrine on admission (mean 1279 pg/mL +/- 824) (Mazzei de Davila et al, 2002).

Laboratory Monitoring

Monitoring Parameters Levels

    4.1.1) SUMMARY
    A) Monitor vital signs in symptomatic patients.
    B) Monitor serum glucose and electrolytes, initiate continuous cardiac monitoring and obtain an ECG in patients with moderate or severe manifestations of envenomation.
    C) Monitor serum lipase in patients with abdominal pain or persistent vomiting.
    D) Follow markers of myocardial injury (troponin, CK-MB or myoglobin) in patients with severe envenomation.
    E) Obtain a chest radiograph and monitor pulse oximetry and/or arterial blood gases in patients with respiratory signs or symptoms.
    4.1.2) SERUM/BLOOD
    A) Obtain a serum glucose and electrolytes in patients with moderate to severe manifestations of envenomation. Hyperglycemia and hypokalemia are relatively common (D'Suze et al, 2003; Cupo & Hering, 2002).
    B) Monitor serum lipase in patients with abdominal pain or recurrent vomiting.
    C) Monitor markers of myocardial injury (troponin, myoglobin or CK-MB) in patients with severe envenomation (shock, dysrhythmias, pulmonary edema).
    4.1.4) OTHER
    A) OTHER
    1) ECG
    a) Institute continuous cardiac monitoring and obtain an ECG in patients with moderate to severe envenomation.
    2) ECHOCARDIOGRAM
    a) Echocardiogram may be useful to detect left ventricular dysfunction in patients with severe envenomation (Cupo & Hering, 2002; Mazzei de Davila et al, 2002).

Radiographic Studies

    A) Obtain a chest radiograph in patients with respiratory signs or symptoms.

Methods

    A) ELISA
    1) Venom concentration can be determined in serum using enzyme linked immunosorbent assays; however this is a research method and is not used in clinical practice. There is some correlation between venom levels and the severity of clinical manifestations, although there is considerable overlap (D'Suze et al, 2003).

Treatment

Life Support

    A) Support respiratory and cardiovascular function.

Patient Disposition

    6.3.6) DISPOSITION/BITE-STING EXPOSURE
    6.3.6.1) ADMISSION CRITERIA/BITE-STING
    A) Hospitalize patients with severe symptoms not easily controlled with symptomatic and supportive care, or if antivenom has been given. In moderate to severe cases, patients should be monitored for a minimum of 24 hours (Cologna et al, 2009). The level of care (eg, ICU) is determined by both symptomatology and underlying clinical status. Generally, admission is only required for young children, and rarely for more than 2 to 3 days.
    6.3.6.2) HOME CRITERIA/BITE-STING
    A) Healthy adults who are experiencing only local symptoms, can be managed at home.
    6.3.6.3) CONSULT CRITERIA/BITE-STING
    A) A clinician skilled in the management of scorpion envenomations should be involved in the care of severely envenomated patients. A regional poison center should also be consulted in such cases.
    6.3.6.5) OBSERVATION CRITERIA/BITE-STING
    A) In general, children should be observed for 4 to 6 hours after a scorpion sting (Cologna et al, 2009). In addition, patients experiencing moderate to severe symptoms, those at the extremes of age or with significant underlying medical illnesses should be referred to a healthcare center.

Monitoring

    A) Monitor vital signs in symptomatic patients.
    B) Monitor serum glucose and electrolytes, initiate continuous cardiac monitoring and obtain an ECG in patients with moderate or severe manifestations of envenomation.
    C) Monitor serum lipase in patients with abdominal pain or persistent vomiting.
    D) Follow markers of myocardial injury (troponin, CK-MB or myoglobin) in patients with severe envenomation.
    E) Obtain a chest radiograph and monitor pulse oximetry and/or arterial blood gases in patients with respiratory signs or symptoms.

Range Of Toxicity

Summary

    A) TOXICITY: In general, a single sting can cause severe, even fatal envenomation; severe envenomation is more common in children less than 10 years of age. In Brazil, the overall mortality is 1% in patients treated with antivenom. Most deaths occur in children stung by T. serrulatus. Overall, T. serrulatus causes the most severe cases of envenomation in Brazil. In Ecuador, an infant died following an envenomation by T. asthenes within 12 hours of being stung.

Minimum Lethal Exposure

    A) Fatal envenomation is more common in young children and can develop after a single sting (Daisley et al, 1999; Benvenuti et al, 2002).
    B) TITYUS SERRULATUS: In Brazil, the overall mortality is 1% in patients treated with antivenom. Most deaths occur in children stung by T. serrulatus (De Rezende et al, 1995). Overall, T serrulatus causes the most severe cases of envenomation in Brazil (Pucca et al, 2012).
    C) TITYUS ASTHENES: In the northern Manabi province of western Ecuador, 5 cases of Tityus asthenes envenomation occurred in children ranging in age from 12 months to 16 years of age. The 23-month-old boy developed immediate pain and episodes of vomiting. He was transferred to a higher level of care with ongoing emesis, a 20 mmHg decrease in blood pressure, hyperglycemia and crackling rales and bilateral bronchial breathing. The infant was treated supportively with IV fluids and steroid therapy. During the same day, his clinical condition continued to worsen with a decrease in oxygen saturation and cyanosis, signs of cerebral decortication and a lack of corneal reflex. He then developed cardiorespiratory arrest that did not respond to resuscitation efforts and died approximately 12 hours after envenomation. The other children in this series also developed immediate intense pain, local erythema and edema at the bite site, and multiple episodes of vomiting. Other findings often included hyperglycemia and leukocytosis. Treatment usually consisted of pain control, IV fluids as needed, and corticosteroid therapy in 3 cases. All of these children recovered completely with no permanent sequelae. Of note, antivenom therapy is not currently available in Ecuador (Borges et al, 2015).

Maximum Tolerated Exposure

    A) SUMMARY: A single sting can cause severe envenomation. Severe envenomation is more common in children less than 10 years of age (de Roodt et al, 2003; Cupo & Hering, 2002; Cupo & Hering, 2002).
    B) TITYUS OBSCURUS: In a series of 58 cases of presumed Tityus obscurus envenomation in the Amazon, neurologic adverse reactions were very common. The most common events included myoclonus (n=44; 75.9%), ataxia (n=42; 72.4%), dysarthria (n=36; 62%), dysmetria (n=31; 53.4%), fasciculations (n=27; 46.5%), hyperreflexia (n=16; 27.6%), agitation (n=14; 24.1%), somnolence (n=12; 20.7%) and nystagmus (n=2; 3.4%). Other commonly reported symptoms included pain, sweating, and tachycardia. No deaths were reported (Torrez et al, 2015).

Toxicity Information

    7.7.1) TOXICITY VALUES
    A) TITYUS BAHIENSIS VENOM
    1) LD50- (INTRAMUSCULAR)MOUSE:
    a) 9350 mcg/kg (RTECS, 2005)
    2) LD50- (SUBCUTANEOUS)MOUSE:
    a) 700 mcg/kg (RTECS, 2005)
    B) TITYUS DISCREPANS VENOM
    C) TITYUS SERRULATUS VENOM
    1) LD50- (INTRAMUSCULAR)MOUSE:
    a) 1500 mcg/kg (RTECS, 2005)
    2) LD50- (SUBCUTANEOUS)MOUSE:
    a) 300 mcg/kg (RTECS, 2005)
    D) TITYUS TRINITATIS VENOM
    1) LD50- (SUBCUTANEOUS)MOUSE:
    a) 2 mg/kg (RTECS, 2005)

Pharmacology Toxicology

Toxicologic Mechanism

    A) Scorpion venoms contain polypeptides that reversibly bind to sodium channels (long chain peptides) and potassium channels (short chain peptides). Binding to scorpion toxins causes voltage sensitive sodium channels to be stabilized in the open position, leading to repetitive firing of sympathetic and parasympathetic nerves and release of neurotransmitters (epinephrine, norepinephrine, acetylcholine) (Mazzei de Davila et al, 2002).
    B) There is also evidence that scorpion venom induces a systemic inflammatory response. Increased levels of pro-inflammatory cytokines have been reported in patients with severe Tityus envenomation (Fukuhara et al, 2003).
    C) The pulmonary edema that develops after scorpion envenomation may be caused by both cardiac (LV failure) and neurologic (catecholamine release affecting alveolarcapillary membrane permeability) (Mazzei de Davila et al, 2002).
    D) RENAL EFFECTS - In isolated rat kidneys, Tityus serrulatus venom decreased glomerular filtration rate, urine output and renal blood flow by increasing vascular resistance and inducing an increase in renal and mesenteric perfusion pressure. This is probably by a direct vasoconstrictor action (de Sousa Alves et al, 2005).

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