Scorpion EnvenomationMANAGEMENT

ENVIRONMENTAL AND EXPOSURE PRESENTATIONS · 12 SECTIONS

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488 items

☷ Legend

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Cardiovascular Presentations71▾

Respiratory Presentations52▾

Neurological Presentations83▾

Gastrointestinal Presentations74▾

Genitourinary and Reproductive Presentations48▾

Infectious Disease Presentations148▾

Trauma Presentations89▾

Toxicologic Presentations80▾

Psychiatric Presentations26▾

Musculoskeletal and Rheumatologic Presentations96▾

Dermatology Presentations23▾

Environmental and Exposure Presentations27▾

Acute Mountain Sickness Arterial Gas Embolism Bee-Wasp Sting (Anaphylaxis)Chilblains Ciguatera Fish Poisoning Coral Cut Decompression Sickness Electrical Burn Injury Envenomation (snake, spider, insect)High Altitude Cerebral Edema (HACE)High Altitude Pulmonary Edema (HAPE)High-altitude illness Hypothermia Hypothermia (Mild)Hypothermia (Severe)Immersion Foot Lightning Strike Injury Scombroid Fish Poisoning Scorpion Envenomation Sea Urchin Injury Shark Bite Snake Envenomation Spider Bite (Black Widow)Spider Bite (Brown Recluse)Stingray Spine Injury Tick paralysis White Phosphorus Burn

Hematologic and Oncologic Presentations36▾

Pediatric-Specific Presentations19▾

Endocrine and Metabolic Presentations45▾

ENT and Maxillofacial Presentations27▾

Ophthalmologic Presentations19▾

Obstetric Presentations23▾

Systemic and Miscellaneous Presentations17▾

01Approach to the Critical Patient/attcp39

Airway and breathing

›Airway threats from envenomation

›Hypersalivation and excessive secretions causing obstruction

›Stridor or gurgling — immediate intervention

›Tongue fasciculations impairing airway patency

›Respiratory failure mechanisms

›Neuromuscular dysfunction impairing ventilatory effort

›Noncardiogenic pulmonary edema from catecholamine surge

›Cardiogenic pulmonary edema from scorpion cardiomyopathy

›If airway compromise present, proceed to definitive airway management

›Rapid sequence intubation preparation

›Suction immediately available

Hemodynamic stabilization

›Hemodynamic instability patterns

›Hypertensive emergency — early sympathetic phase

›SBP > 180 mmHg with end-organ signs

›Nitroglycerin or prazosin first-line

›Cardiogenic shock — late severe envenomation

›SBP < 90 mmHg with signs of low output

›Dobutamine preferred over norepinephrine in cardiomyopathy

›Avoid beta-blockers — unopposed alpha stimulation worsens hypertension and shock

›Class IIb contraindication in autonomic storm

Severity grading and escalation triggers

›Envenomation grade classification

›Grade 1: local pain and paresthesias only — observation

›Grade 2: remote paresthesias, agitation, mild tachycardia/hypertension — monitoring

›Grade 3: neuromuscular dysfunction, cranial nerve findings, severe hemodynamic instability — ICU

›Grade 4: combined cranial nerve plus neuromuscular OR multi-organ failure — ICU with full support

02History/hx41

Sting circumstances

›Exposure context

›Geographic location — southwestern US (Arizona), Mexico, Middle East, North Africa, India, Brazil

›Time of day — 78% of pediatric stings are nocturnal

›Activity at time of sting — reaching into shoes, crevices, woodpiles

›Indoor vs outdoor setting

›Scorpion description

›Size and color — bark scorpion (Centruroides sculpturatus) is small and tan/yellow

›Witnesses who can identify the species

Symptom characterization

›Local symptoms

›Immediate sharp pain at sting site

›Paresthesias: tingling and numbness at sting site

›Tap test — tapping the site reproduces severe pain (pathognomonic)

›Systemic progression

›Onset of systemic symptoms typically within 30 minutes to 4 hours

›Agitation, restlessness, drooling, difficulty swallowing, slurred speech

›Visual changes, roving eye movements

›Muscle twitching or uncoordinated limb movements

›Vomiting and nausea

›Autonomic symptoms

›Diaphoresis, lacrimation, salivation

›Urinary incontinence

›Priapism in males

Risk factors

›Patient-level risk factors

›Age less than 5 years — strongest risk factor for severe envenomation and mortality

›Low body mass relative to venom load

03Physical Exam/exam33

Vital signs

›Hemodynamic pattern

›Tachycardia — early sympathetic phase marker

›Hypertension — common in Grade 2 to 4 envenomation

›Hypotension — late finding suggesting cardiogenic or distributive shock

›Tachypnea with hypoxia — pulmonary edema or secretion-related obstruction

›Hyperthermia from autonomic storm

Sting site examination

›Local findings

›Sting site often difficult to visualize — no obvious wound

›Local erythema and edema when present

›Fasciculations at sting site

›Tap test: tapping site reproduces exquisite pain — supports diagnosis

Neurologic and cranial nerve exam

›Cranial nerve findings (Grade 3 hallmarks)

›Opsoclonus — roving, conjugate eye movements, pathognomonic for severe Centruroides envenomation

›Nystagmus

›Dysarthria and slurred speech

›Dysphagia — cranial nerve IX and X dysfunction

›Motor and neuromuscular findings

›Uncoordinated limb movements and ataxia

›Muscle spasms and twitching

›Hyperreflexia

›Opisthotonus in severe cases

Oropharyngeal and airway exam

›Airway assessment

›Hypersalivation and frothing — secretion burden

›Tongue fasciculations

04Differential Diagnosis/ddx27

Envenomation and toxidrome mimics

›Arthropod envenomation

›Black widow spider bite — ICD-10 T63.311

›Severe crampy diffuse muscle pain, rigidity, diaphoresis, hypertension

›No opsoclonus or cranial nerve findings

›Latrodectism has diffuse muscle cramping without neuromuscular excitation pattern

›Other arthropod envenomation

›Hymenoptera — primarily anaphylaxis pattern

›Brown recluse — local necrosis without systemic neuromuscular toxicity

›Toxic syndromes

›Organophosphate poisoning — ICD-10 T60.0

›Cholinergic toxidrome: SLUDGE — salivation, lacrimation, urination, defecation, GI, emesis

›Miosis and bradycardia — differentiates from scorpion mixed autonomic picture

›Serotonin syndrome — ICD-10 T43.9

›Agitation, clonus, hyperthermia — medication history distinguishes

›Strychnine poisoning

›Opisthotonus and muscle spasms without autonomic storm

Neurologic mimics

›Central nervous system causes

›Status epilepticus — ICD-10 G41.9

›Rhythmic clonic activity versus the continuous neuromuscular excitation of envenomation

›Consider in seizure without clear sting history

›Tetanus — ICD-10 A35

›Muscle rigidity and spasms with trismus characteristic

›No sting history, no autonomic storm pattern

Anaphylaxis

›Allergic reaction spectrum — ICD-10 T78.2

›Urticaria, angioedema, bronchospasm, hypotension

05Laboratory Tests/lt29

Initial labs for Grade 2 and above

›Electrolytes and renal function

›Hypokalemia common and correlates with severity — aggressive correction required

›Potassium target > 3.5 mmol/l

›Renal function for rhabdomyolysis monitoring

›Cardiac biomarkers

›Troponin — myocarditis or catecholamine-induced ischemia

›Elevation in scorpion-associated myocarditis

›Repeat at 3 and 6 hours in Grade 3 to 4

›BNP or NT-proBNP — cardiomyopathy screening

›Lipase

›Pancreatitis — recognized complication of severe envenomation

›Liver function tests

›Hepatic involvement in severe systemic envenomation

Hematologic and coagulation

›Complete blood count

›Leukocytosis as inflammatory marker

›Hemolysis screen with Old World species

›Coagulation studies

›PT/INR and fibrinogen — coagulopathy with Hemiscorpius and certain Old World species

›DIC screen in severe envenomation

Muscle and perfusion markers

›Creatine kinase

›Rhabdomyolysis screening in severe neuromuscular dysfunction

›Urinalysis

›Myoglobinuria — tea-colored urine

›Lactate

›>= 2 mmol/l as organ hypoperfusion marker

06Diagnostic Tests/dt44

Scoring Systems

›Envenomation severity grading

›Grade 1: local pain and paresthesias only

›Management: observation 4 hours, oral analgesia, wound care, tetanus prophylaxis

›Grade 2: remote paresthesias, agitation, mild hypertension and tachycardia

›Management: observation or hospitalization, benzodiazepines, consider prazosin

›Grade 3: neuromuscular dysfunction, cranial nerve findings, severe hypertension, cardiogenic shock, pulmonary edema

›Management: ICU, antivenom, IV sedation, vasodilators, inotropes, airway management

›Grade 4: combined neuromuscular plus cranial nerve dysfunction OR shock and multi-organ failure

›Management: Grade 3 protocol plus full ICU support

MRI

›Brain MRI indications

›Not routinely indicated for confirmed scorpion envenomation

›Opsoclonus in envenomation is toxin-mediated, not structural

›Consider if neurologic findings persist after antivenom and supportive care

›Alternative diagnosis: opsoclonus-myoclonus syndrome, brainstem lesion

›Cardiac MRI

›Late assessment of myocarditis or cardiomyopathy extent

›Not appropriate in acute phase

›CT head

›Indicated only when alternative diagnosis suspected

›Seizures or altered mental status without clear envenomation history

›Focal neurologic deficit not explained by envenomation

›Not indicated for typical envenomation presentation

›CT chest

›Consider if pulmonary edema etiology unclear

›Differentiate cardiogenic from noncardiogenic pattern

07Disposition/dispo30

Grade-based disposition

›Grade 1 disposition

›Discharge after minimum 4 hours of observation

›No progression of symptoms

›Adequate pain control on oral medications

›Reliable follow-up available

›Grade 2 disposition

›Observation unit or admitted ward

›Until symptoms improving and controlled on oral agents

›Minimum 12 to 24 hour observation recommended

›Discharge criteria

›Symptoms resolved or controlled on oral medications

›No new systemic features during observation

Admission and ICU criteria

›ICU admission indications for Grade 3 to 4

›Neuromuscular dysfunction — opsoclonus, uncoordinated movements

›Cranial nerve findings — dysphagia, dysarthria, abnormal eye movements

›Hemodynamic instability — hypertensive emergency or cardiogenic shock

›Respiratory compromise — hypoxia, secretion burden

›Antivenom administration

›Airway management

›Pediatric ICU for all children with systemic symptoms (Grade 2+)

Transfer criteria

›Transfer indications

›Grade 3 to 4 envenomation at a facility without antivenom

›Antivenom administration should not be delayed for transfer if available

›Pediatric intensive care requirements exceeding local capacity

›Cardiac surgery availability if severe Takotsubo cardiomyopathy with hemodynamic compromise

08Treatment/t81

Initial stabilization (all grades)

›Universal initial management

›Airway patency assessment with secretion suction if needed

›IV access establishment

›Continuous cardiac monitoring

›Continuous pulse oximetry

›Tetanus prophylaxis

›Tdap if not current within 5 years for contaminated wounds

›Local wound care

›Gentle cleansing of sting site

›Ice pack for local pain relief

Grade 1 treatment

›Analgesia for local pain

›Acetaminophen 650 to 1000 mg orally every 6 hours

›Ibuprofen 400 to 600 mg orally every 6 to 8 hours

›Opioids for refractory local pain

›Oral oxycodone 5 to 10 mg every 4 to 6 hours as needed

›Topical 5% lidocaine gel to sting site

›Evidence level: Class IIb, symptom relief

›Ice application to sting site

Grade 2 treatment

›Parenteral analgesia

›IV fentanyl 1 to 2 mcg/kg for pain

›Titrate to comfort every 30 to 60 minutes

›Benzodiazepines for agitation and muscle spasm

›IV or IM midazolam 0.05 to 0.1 mg/kg

›Preferred over diazepam for muscle spasm control

›Repeat every 5 to 10 minutes as needed

›IV lorazepam 0.05 mg/kg as alternative

›Maximum 4 mg per dose in adults

›Antihypertensive therapy

›Prazosin for hypertension — alpha-1 blocker blunting catecholamine effect

›Adult dose: 0.5 to 1 mg orally every 6 hours

›Pediatric dose: 5 mcg/kg orally every 6 hours (Rajasthan protocol)

›Avoid beta-blockers — risk of unopposed alpha-stimulation crisis

Grade 3 to 4 antivenom therapy

›Anascorp (centruroides immune F(ab')2) — FDA-approved antivenom

›Initial dose: 3 vials reconstituted in normal saline, diluted to 50 mL

›Infuse IV over 10 minutes

›Same dose for adults and children

›Additional doses: 1 vial every 30 to 60 minutes as needed until symptoms resolve

›Reassess after each additional vial

›Efficacy: 100% symptom resolution within 4 hours in pivotal RCT vs 14.3% with placebo

›Mean time to symptom resolution: approximately 1.4 hours

›Pediatric mean: 1.3 hours

›Adult mean: 1.9 hours

›Anaphylaxis precautions for Anascorp

›Equine-derived product — 0.2% acute reaction rate

›Epinephrine, corticosteroids, and diphenhydramine at bedside before infusion

›Epinephrine 0.3 mg IM (1:1000) for anaphylaxis

›Serum sickness risk: 0.5% — rash, fever, myalgia, arthralgia at 7 to 21 days

›Antivenom use with benzodiazepines caution

›Benzodiazepines may mask symptom progression after antivenom

›Reassess neurologic status once benzodiazepines metabolized

Cardiovascular management in severe envenomation

›Cardiogenic shock treatment

›Dobutamine for inotropic support

›Initial dose: 2.5 mcg/kg/minute IV infusion

›Titrate by 2.5 mcg/kg/minute every 10 minutes

›Usual range: 5 to 20 mcg/kg/minute

›Target MAP > 65 mmHg with improved perfusion markers

›Avoid norepinephrine as first agent if cardiomyopathy confirmed

›Afterload increase worsens cardiac output in Takotsubo pattern

›Pulmonary edema management

›IV nitroglycerin for hypertensive pulmonary edema

›Initial dose: 10 to 20 mcg/minute IV infusion

›Titrate by 10 mcg/minute every 5 minutes

›Target SBP reduction of 20 to 25%

›Furosemide 40 to 80 mg IV if volume overload confirmed

›Electrolyte management

›Aggressive potassium replacement for hypokalemia

›IV potassium chloride 10 to 20 mmol per hour with cardiac monitoring

›Target serum potassium > 3.5 mmol/l

Airway management

›Intubation indications

›Inability to protect airway from secretion burden

›Respiratory failure unresponsive to supplemental oxygen

›GCS decline with loss of airway reflexes

›Rapid sequence intubation

›Succinylcholine 1.5 mg/kg IV — preferred if no contraindication

›Rocuronium 1.2 mg/kg IV as alternative

›Ketamine 1 to 2 mg/kg IV as induction agent

›Caution: may exacerbate hypertension in autonomic storm

›Etomidate 0.3 mg/kg IV as alternative induction

›Post-intubation management

›Suction secretions frequently

›Propofol sedation for ventilated patients

09Special Populations/sp49

Pregnancy

›Maternal and fetal considerations

›Severe envenomation with catecholamine surge risks placental insufficiency

›Uteroplacental vasoconstriction from sympathetic activation

›Fetal distress monitoring required in Grade 3 to 4

›Antivenom use in pregnancy

›Anascorp: Category C — benefit outweighs risk in severe envenomation

›Anaphylaxis from antivenom poses greater fetal risk than the envenomation in most cases

›Analgesia considerations

›Acetaminophen preferred for mild to moderate pain

›Opioids acceptable short-term for severe pain with monitoring

›NSAIDs avoid in third trimester — premature ductus arteriosus closure

›Benzodiazepines

›Midazolam acceptable short-term for severe muscle spasm/agitation

›Neonatal respiratory depression risk with repeated high doses

›Prazosin — limited data in pregnancy; use only if hypertension severe and refractory

›Obstetric consultation for all Grade 2+ envenomation in pregnancy

Geriatric

›Age-related physiologic vulnerabilities

›Reduced cardiac reserve — higher risk of decompensation from catecholamine surge

›Pre-existing cardiomyopathy increases mortality risk

›Lower threshold for echocardiography

›Medication interactions

›Beta-blockers (pre-existing use) — do not use to treat envenomation hypertension

›ACE inhibitors and ARBs — monitor renal function during hemodynamic instability

›Neurologic changes

›Baseline cognitive impairment complicates neurologic assessment

›Delirium from envenomation overlaps with dementia

10Background/b63

Epidemiology

›Global burden

›Approximately 1.5 million scorpion stings per year worldwide

›Estimated 2,600 deaths per year globally — primarily in developing countries

›Highest mortality regions: Middle East, North Africa, Latin America, India

›Mexico reports more than 250,000 stings per year — highest burden globally

›United States epidemiology

›Arizona is the epicenter of US scorpion envenomation — Centruroides sculpturatus

›Approximately 10,000 to 15,000 stings per year in Arizona

›US fatalities are rare with access to antivenom

›Severity distribution

›Greater than 95% of stings result in Grade 1 local symptoms only

›Severe systemic envenomation (Grade 3 to 4) occurs in less than 5% of cases

›Severe envenomation far more common in children than adults

›Mortality from scorpion myocarditis

›Mortality in confirmed scorpion-associated myocarditis: approximately 7.3%

›Independent predictors of mortality in children: diarrhea, skin marbling, respiratory distress, GCS 3 to 9

Pathophysiology

›Venom composition and ion channel toxicity

›Scorpion venom contains peptide toxins targeting sodium and potassium channels

›Alpha-toxins slow inactivation of voltage-gated sodium channels — prolonged depolarization

›Beta-toxins shift activation threshold — spontaneous neuronal firing

›Ion channel dysfunction leads to massive catecholamine release

›Simultaneous sympathetic and parasympathetic excitation — mixed autonomic toxidrome

›Not a pure cholinergic or adrenergic syndrome

›Cardiovascular pathophysiology

›Catecholamine surge causes Takotsubo-like cardiomyopathy

›Apical ballooning pattern on echocardiography in some cases

›Direct catecholamine myocardial toxicity

›Coronary vasospasm contributing to ischemia

›Pulmonary edema — dual mechanism

›Cardiogenic: reduced LV function from catecholamine cardiomyopathy

›Noncardiogenic: increased pulmonary capillary permeability from toxin and catecholamine effect

›Neuromuscular pathophysiology (Centruroides)

›Neuromuscular junction dysfunction from sodium channel toxins

›Uncontrolled acetylcholine release at motor end plates

›Cranial nerve nuclei particularly vulnerable

›Opsoclonus from cerebellar and brainstem ion channel effects

›Respiratory failure mechanisms

›Excessive secretion production from parasympathetic excitation

›Neuromuscular ventilatory pump dysfunction

›Cardiac conduction effects

›Hypokalemia aggravates QT prolongation — arrhythmia risk

›Direct catecholamine-induced dysrhythmia

›ST elevation mimicking STEMI from coronary vasospasm

Therapeutic Considerations

›Antivenom mechanism and evidence

›Anascorp: equine F(ab')2 fragments binding free venom toxins

›FDA approved 2011 for Centruroides envenomation in the US

›Pivotal RCT: 100% symptom resolution within 4 hours vs 14.3% placebo

›1534-patient safety dataset — 0.2% acute hypersensitivity reactions

›Antivenom reduces symptom burden but does not guarantee complete resolution

›Antivenom availability varies by institution — coordinate with toxicology early

›Benzodiazepine rationale

›Primary pharmacologic agent for neuromuscular excitation symptom control

›GABA-A agonism reduces neuronal firing in the excitatory toxidrome

›Midazolam preferred for faster onset and shorter duration

›Do not use as sole therapy in Grade 3 to 4 — antivenom required

›Prazosin for cardiovascular management

›Alpha-1 adrenergic blockade blunts catecholamine-mediated vasoconstriction

›Used extensively in North Africa, Middle East, and India where antivenom unavailable

›Rajasthan protocol evidence supporting mortality reduction with prazosin

›Hemodynamic agent selection rationale

›Dobutamine over norepinephrine when cardiomyopathy confirmed

›Inotropic support without increased afterload

›Avoid beta-blockers — worsen unopposed alpha stimulation and may precipitate crisis

11Patient Discharge Instructions/pdi30

copy discharge instructions

›Scorpion sting discharge instructions

›You were seen for a scorpion sting. Your symptoms have been assessed and are mild enough to be managed at home.

›What to expect at home

›Local pain, tingling, and numbness at the sting site may persist for 12 to 24 hours

›Mild swelling and redness are expected

›Symptoms should gradually improve over the next 24 to 48 hours

›Pain management at home

›Acetaminophen (Tylenol) 650 to 1000 mg every 6 hours as needed for pain

›Ibuprofen 400 mg every 6 to 8 hours with food as needed

›Ice pack wrapped in cloth applied to the sting site for 10 to 15 minutes at a time

›Do not place ice directly on skin

›Prevention — how to avoid future stings

›Shake out shoes and clothing before wearing in endemic areas

›Use a UV (black) flashlight at night — scorpions fluoresce under ultraviolet light

›Wear gloves when moving rocks, logs, or woodpiles

›Seal cracks and gaps in your home foundation and doorways

›Check bedding and towels before use in high-risk areas

›Follow-up

›If you received antivenom (Anascorp), follow up with your doctor in 1 to 2 weeks

›Watch for delayed serum sickness: rash, joint pain, muscle aches, fever starting 7 to 21 days after treatment

›Return to the emergency department immediately if any of the following occur

›Return to emergency department red flags

›Difficulty breathing, choking, or excessive drooling

›Abnormal eye movements — eyes moving on their own

›Muscle twitching or inability to control limb movements

›Difficulty swallowing or speaking

›Chest pain or rapid or irregular heartbeat

12References/r22

Guidelines and key sources

›Herness J, Snyder MJ, Newman RS. Arthropod Bites and Stings. American Family Physician. 2022. PMID 35977137

›Primary clinical guideline source for US scorpion management and grading

›Boyer LV, Theodorou AA, Berg RA, et al. Antivenom for Critically Ill Children with Neurotoxicity from Scorpion Stings. NEJM. 2009

›Pivotal RCT establishing efficacy and dosing of Anascorp antivenom

›Isbister GK, Bawaskar HS. Scorpion Envenomation. New England Journal of Medicine. 2014

›Comprehensive review of global scorpion envenomation and Old World species management

›Abroug F, Ouanes-Besbes L, Tilouche N, Elatrous S. Scorpion Envenomation: State of the Art. Intensive Care Medicine. 2020. PMID 32125457

›ICU management, autonomic storm pathophysiology, prazosin evidence

›Boyer L, Degan J, Ruha AM, et al. Safety of Intravenous Equine F(ab')2: Insights Following Clinical Trials Involving 1534 Recipients of Scorpion Antivenom. Toxicon. 2013. PMID 23916602

›Largest antivenom safety dataset — 0.2% acute reaction rate, 0.5% serum sickness

›Fereidooni R, Shirzadi S, Ayatizadeh SH, et al. Scorpion Envenomation-Associated Myocarditis: A Systematic Review. PLoS Neglected Tropical Diseases. 2023. PMID 37018229

›7.3% mortality in scorpion myocarditis, ECG and echo characteristics

›Rebahi H, Ba-M'hamed S, Still ME, et al. Clinical Features and Prognosis of Severe Scorpion Envenomation in Children. Pediatrics International. 2022. PMID 33682212

›Pediatric mortality predictors: diarrhea, skin marbling, respiratory distress, GCS 3-9

›Almeida ACC, Carvalho FM, Mise YF. Risk Factors for Fatal Scorpion Envenoming Among Brazilian Children. Transactions of the Royal Society of Tropical Medicine and Hygiene. 2021. PMID 34352889

›Brazilian pediatric risk factor analysis and mortality data

›Osnaya-Romero N, et al. Serum Level of Scorpion Toxins, Electrolytes and ECG Alterations in Mexican Children. Toxicon. 2016. PMID 27693586

›Hypokalemia severity correlation and QT prolongation data

›Hewett Brumberg EK, Douma MJ, et al. 2024 American Heart Association and American Red Cross Guidelines for First Aid. Circulation. 2024

›First aid management of envenomation including scorpion stings

›FDA Drug Label: Anascorp (Centruroides Immune F(ab')2). DailyMed. Updated 2013

›Official prescribing information: dosing, reconstitution, safety data

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Reviewed by SymptomDx Medical Team · Last reviewed August 18, 2026

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