Sea Urchin InjuryMANAGEMENT

ENVIRONMENTAL AND EXPOSURE PRESENTATIONS · 12 SECTIONS

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674 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/attcp44

Immediate priorities

›Life-threatening presentations

›Systemic envenomation (>15-20 spine penetrations)

›Paresthesias and muscular paralysis

›Hypotension and syncope

›Respiratory distress

›Anaphylaxis

›Urticaria, angioedema, bronchospasm

›Epinephrine 0.3-0.5 mg IM anterolateral thigh immediately

›Necrotizing fasciitis from marine infection

›Rapidly progressive cellulitis with systemic toxicity

›Vibrio vulnificus highest risk in immunocompromised and liver disease patients

›If shock physiology, establish IV access and begin resuscitation

›MAP target > 65 mmHg

›Lactate-guided resuscitation

›Immediate triage triggers

›Spine penetration into joint, nerve, or tendon territory

›Risk of synovitis and neuropathy

›Orthopedic or hand surgery consultation

›Abdominal or thoracic wall penetration

›OR exploration required

›Surgical consultation immediately

›Signs of compartment syndrome in hand or foot

›Pain out of proportion, tense compartment

›Emergent fasciotomy planning

Monitoring and targets

›Hemodynamic monitoring

›Continuous cardiac monitor for systemic envenomation

02History/hx58

Mechanism and exposure

›Injury context

›Mechanism: stepping on, handling, or brushing against a sea urchin

›Diving or snorkeling

›Wading in shallow rocky or coral areas

›Fishing or handling catch

›Water type and geographic location

›Saltwater vs. brackish water affects antibiotic selection

›Tropical or subtropical waters carry higher risk for venomous species

›Species identification if possible

›Over 700 species exist

›Approximately 80 species contain substances toxic to humans

›Timing and prior treatment

›Time from injury to presentation

›Acute vs. delayed granulomatous reaction (latency 1-6 months)

›Field treatment already administered

›Hot water soak performed

›Temperature and duration (target ~45°C for 30-90 minutes)

›Degree of pain relief achieved

›Attempted spine removal

›Self-extraction attempts

›Instrument used

Symptom characterization

›Pain features

›Intense burning pain within minutes of injury

›Often out of proportion to wound size due to toxin release from hollow spines

›Thermolabile venom components

›Number and distribution of puncture sites

03Physical Exam/exam58

Vitals and systemic assessment

›Hemodynamic stability

›Blood pressure

›Hypotension SBP < 90 mmHg suggesting systemic envenomation

›MAP < 65 mmHg requiring resuscitation

›Heart rate

›Tachycardia as systemic envenomation marker

›Bradycardia rare but possible with severe envenomation

›Respiratory rate and oxygen saturation

›Respiratory compromise rare but present in massive envenomation

›SpO2 on room air

›General appearance

›Degree of distress

›Pain out of proportion to wound size suggests envenomation

›Diaphoresis and pallor in systemic reactions

Wound assessment

›Puncture site inspection

›Number and depth of puncture sites

›Superficial vs. deep penetration

›Sole of foot and palm most commonly affected

›Purple or blue-black discoloration at puncture site

›May be dye from spine, not necessarily a retained fragment

›Important not to confuse with retained spine on clinical exam

›Erythema and edema

›Cellulitis spreading from wound margins

›Lymphangitic streaking

›Retained spine assessment

›Palpation for retained spines

04Differential Diagnosis/ddx48

Marine envenomation mimics

›Other marine injuries

›Stingray envenomation

›Larger laceration rather than puncture pattern

›Barb may be retained

›Similar hot water immersion treatment applies

›Scorpionfish, lionfish, or stonefish sting

›Puncture wound with severe pain

›Similar venom mechanism, thermolabile toxins

›Hot water immersion first-line

›Coral cut

›Abrasion or laceration pattern rather than puncture

›Coral particles may be retained

›Dermatitis patterns

›Jellyfish or fire coral sting

›Urticaria and vesicles rather than puncture wounds

›Linear whip-like distribution

›Seabather's eruption

›Pruritic papules in swimsuit distribution

›Larval cnidarian etiology

Infectious complications

›Bacterial marine wound infections

›Vibrio vulnificus cellulitis or septicemia

›Rapidly progressive, hemorrhagic bullae

›Mortality up to 50% in immunocompromised

›ICD-10 A00.9 Vibrio infection

›Mycobacterium marinum infection

›Chronic granulomatous nodules along lymphatic channels

05Laboratory Tests/lt44

Routine labs for minor injuries

›Minor uncomplicated puncture wounds

›Routine labs generally not required

›Healthy immunocompetent host with superficial wound

›No systemic symptoms

›Tetanus status verification

›Clinical documentation only if records available

›Immunization update does not require lab testing

Infection and systemic envenomation labs

›Complete blood count with differential

›Leukocytosis supporting infection

›Neutrophilia as bacterial infection marker

›Leukopenia as severe sepsis marker in fulminant Vibrio

›Platelet count

›Thrombocytopenia in Vibrio septicemia

›Inflammatory markers

›C-reactive protein

›Elevated in osteoarticular spine penetration

›Useful for trending in delayed infections

›Erythrocyte sedimentation rate

›Chronically elevated in granulomatous reactions

›Mildly elevated in joint involvement

›Metabolic panel

›Renal and hepatic function

›Baseline for antibiotic dosing

›Hepatic disease identification for Vibrio risk stratification

›Glucose

›Diabetes identification

06Diagnostic Tests/dt71

Scoring Systems

›Wound severity assessment

›No validated marine envenomation scoring tool exists

›Clinical severity guided by spine count, location, and systemic symptoms

›>15-20 spine penetrations associated with systemic toxicity

›Wound infection risk stratification

›Low risk: minor puncture, immunocompetent, no joint involvement

›High risk: deep puncture, joint or tendon involvement, immunosuppressed, liver disease

›Anaphylaxis severity grading

›Grade 1 skin and mucosal findings only

›Grade 2 moderate systemic symptoms

›Grade 3 life-threatening bronchospasm or cardiovascular collapse

›Grade 4 cardiac or respiratory arrest

MRI

›MRI indications for sea urchin injury

›Spine penetration near tendons, nerves, or joints

›Superior soft-tissue resolution compared to CT

›Identifies tendon sheath involvement and synovitis

›Chronic granulomatous reaction evaluation

›Differentiates granuloma from infection

›Characterizes extent of subcutaneous involvement

›Osteomyelitis suspected

›Sensitivity ~90% and specificity ~80% for osteomyelitis

›Bone marrow edema as earliest finding

›MRI protocol considerations

›Contrast administration for infection or tumor exclusion

›Gadolinium enhancement pattern distinguishes infection from granuloma

›Renal function check before gadolinium

›Limitations

›Calcium carbonate spines may not be well visualized

›CT or plain radiography better for spine fragment localization

›CT indications

›Deep puncture wounds with uncertain spine location

›Can localize fragments prior to surgical exploration

›Three-dimensional reconstruction for operative planning

›Suspected joint or bone involvement when MRI unavailable

›CT arthrogram for joint involvement assessment

›Thoracic or abdominal wall penetration

›Identify intracavitary foreign body or organ injury

›CT characteristics of sea urchin spines

›Calcium carbonate composition makes spines radiopaque

›Density similar to cortical bone

›Readily visualized on standard CT

›Limitations

›Soft-tissue resolution inferior to MRI for tendon or nerve detail

›Radiation consideration in young patients

Ultrasound

›Point-of-care ultrasound for retained foreign body

›Useful adjunct for superficial retained spines not seen on plain radiography

›High-frequency linear probe (7-15 MHz) preferred

›Hyperechoic linear structure with posterior acoustic shadowing

›Sensitivity for foreign body detection

›Approximately 80-90% for superficial soft-tissue foreign bodies

›Operator-dependent limitation

›Guidance for removal

›Real-time ultrasound-guided extraction

›Reduces exploration wound size

›Ultrasound in infection evaluation

›Abscess identification

›Hypoechoic fluid collection with internal echoes

›Posterior acoustic enhancement

›Joint effusion assessment

›Effusion as marker for intra-articular spine

›Aspiration under ultrasound guidance

Plain Radiography

›Plain radiography first-line imaging

›Indicated for all but the most superficial wounds

›Calcium carbonate spines typically radiopaque

›Spines visible on plain radiograph in approximately 8 of 12 cases in osteoarticular series

›Views required

›Anteroposterior and lateral minimum

›Oblique views for hands and feet

›Limitations

›Purple discoloration from spine dye may mimic retained fragment clinically but not radiographically

›Small or fragmented spines may be missed

07Disposition/dispo50

Discharge criteria

›Minor injury discharge criteria

›Hemodynamically stable

›No systemic envenomation symptoms

›Normal vital signs

›Wound manageable outpatient

›Superficial punctures

›No retained spines in joint or tendon

›Adequate pain control achievable at home

›Oral analgesics sufficient

›Hot water immersion instructions provided

›Reliable follow-up arranged

›Return precautions given

›Tetanus updated

›Discharge with antibiotics

›Indications for prophylactic antibiotics at discharge

›Deep puncture wounds

›Joint or tendon involvement

›Retained foreign bodies

›Immunosuppressed patients

›Liver disease patients

Admission indications

›Inpatient admission required

›Systemic envenomation

›Hemodynamic instability

›Neuromuscular compromise

›Established or suspected Vibrio or necrotizing infection

›IV antibiotics required

08Treatment/t114

Hot water immersion

›First-line analgesia and venom neutralization

›Hot water immersion protocol

›Temperature approximately 45°C (113°F)

›Duration 30-90 minutes

›Neutralizes thermolabile venom components

›Monitoring during immersion

›Water temperature check to avoid scalding

›Reassess pain level every 15 minutes

›Repeat immersion if pain recurs

›Additional 30-minute soaks as needed

›No maximum number established

Wound care and spine removal

›Wound management principles

›Wound exploration and cleaning after anesthesia

›Copious irrigation with normal saline

›Removal of accessible superficial spines

›Spine removal technique

›Fine forceps for superficial spines

›Do not crush spines during extraction (releases additional toxin)

›Fragmented spines allowed to resorb if not near joint or nerve

›Do not use folk remedies

›Meat tenderizer and papaya not recommended

›Cryotherapy not recommended

›Tight constriction bands not recommended

›Surgical removal indications

›Joint or tendon involvement

›Operative arthroscopic or open removal

›Orthopedic or hand surgery

›Deep or inaccessible fragments

›Ultrasound or CT-guided localization

›Minimizes tissue trauma

Analgesia

›Pain management ladder

›Hot water immersion first-line analgesic

›Effective for thermolabile venom

›Avoid systemic opioids if manageable without

›Local infiltration with lidocaine 1-2% without epinephrine

›For small wound areas

›Facilitates wound exploration and spine removal

›Regional nerve block with bupivacaine 0.5%

›For larger areas or procedural analgesia

›Digital or wrist or ankle block depending on location

›Oral analgesics at discharge

›Acetaminophen 500-1000 mg PO every 6-8 hours

›Ibuprofen 400-600 mg PO every 6-8 hours with food if no contraindication

›Opioid analgesics if refractory

›Short course only

›Reassess wound in 24-48 hours

Antibiotic therapy

›Antibiotic indications

›Not routine for minor wounds in immunocompetent hosts

›ACEP Level C recommendation

›Prophylaxis reserved for high-risk wounds

›Prophylaxis indications

›Deep punctures

›Joint involvement

›Retained foreign bodies

›Immunosuppressed patients

›Chronic liver disease

›Antibiotic selection for marine wounds

›Saltwater wound antibiotic choices

›Doxycycline 100 mg PO twice daily for 5-7 days

›Alternative: ciprofloxacin 500 mg PO twice daily

›Alternative: levofloxacin 500 mg PO daily

›Ineffective antibiotics for marine infections

›Penicillin not acceptable

›Ampicillin not acceptable

›Erythromycin not acceptable

›First-generation cephalosporins not acceptable

›Severe or established infection requiring IV therapy

›Doxycycline 100 mg IV every 12 hours plus ceftazidime 2 g IV every 8 hours

›Alternative: fluoroquinolone IV monotherapy for mild to moderate infection

›Duration 7-14 days for established infection

›Mycobacterium marinum treatment

›Chronic granulomatous wound

›Clarithromycin 500 mg PO twice daily

›Plus ethambutol 15 mg/kg PO daily

›Duration 3-6 months minimum

›Alternative regimen

›Doxycycline 100 mg PO twice daily

›Plus rifampicin 600 mg PO daily

›Infectious disease consultation recommended

Tetanus prophylaxis

›Tetanus prophylaxis protocol

›Tetanus-prone wound category

›Puncture wounds classified as tetanus-prone

›Update prophylaxis regardless of infection risk

›Immunocompetent with complete primary series

›Tdap or Td booster if last dose > 5 years ago

›Incomplete or unknown immunization history

›Tdap plus tetanus immunoglobulin (TIG) 250 units IM separate site

›Immunocompromised patients

›TIG regardless of vaccination history

Granulomatous reaction treatment

›Delayed granuloma management

›Intralesional corticosteroids first-line

›Triamcinolone acetonide 10-40 mg/mL intralesional injection

›Repeat every 4-6 weeks as needed

›Effective for sarcoid-like granulomas

›Surgical excision for refractory cases

›Persistent or enlarging granuloma

›Send specimen for histopathology and polarized microscopy

›Avoid systemic steroids acutely

›Risk of worsening infection

›Topical steroids not effective for established granuloma

Anaphylaxis management

›Anaphylaxis treatment protocol

›Epinephrine 0.3-0.5 mg (1 mg/mL) IM anterolateral thigh

›Repeat every 5-15 minutes if no improvement

›Class I recommendation

›IV access and fluid resuscitation

›Normal saline 1-2 L bolus for hypotension

›Vasopressors if refractory

›Adjunctive therapy

›Diphenhydramine 25-50 mg IV or IM

›Ranitidine 50 mg IV (H2 blocker adjunct)

›Methylprednisolone 125 mg IV to prevent biphasic reaction

›Observation after epinephrine

›Minimum 4-6 hours in ED

›Prescribe epinephrine auto-injector at discharge

09Special Populations/sp59

Pregnancy

›Pregnancy considerations

›Wound management unchanged

›Hot water immersion safe in pregnancy

›Avoid immersion temperatures that cause maternal hyperthermia >38.9°C

›Analgesia in pregnancy

›Local lidocaine infiltration safe

›Acetaminophen preferred systemic analgesic

›NSAIDs avoid in third trimester (premature ductus arteriosus closure risk)

›Opioids use with caution

›Antibiotic selection in pregnancy

›Ciprofloxacin and other fluoroquinolones generally avoided

›Doxycycline avoided in second and third trimester

›Cephalosporins preferred when coverage required

›Azithromycin as alternative for some marine organisms

›Fetal monitoring

›For viable gestations (>23 weeks) with systemic envenomation

›Obstetric consultation for significant exposures

Geriatric

›Older adult specific considerations

›Increased infection risk

›Impaired immune response

›Higher prevalence of chronic liver disease and diabetes

›Elevated Vibrio infection risk

›Wound healing impairment

›Peripheral vascular disease

›Reduced skin turgor and vascularity

›Lower threshold for prophylactic antibiotics

10Background/b73

Epidemiology

›Incidence and distribution

›Sea urchin injuries are among the most common marine envenomations worldwide

›Predominantly affecting recreational divers, snorkelers, and beachgoers

›Highest incidence in tropical and subtropical coastal regions

›At-risk occupations

›Dive instructors and underwater photographers

›Fishermen and aquaculture workers

›Coastal tourism workers

›Geographic distribution

›Pacific and Indian Ocean reef environments most common

›Mediterranean and Caribbean also significant

›Venomous species concentrated in Indo-Pacific

›Species and venom epidemiology

›Over 700 species of sea urchins exist

›Approximately 80 species contain substances toxic to humans

›Most punctures from non-venomous species (spine injury primary mechanism)

›Spines composed of 94% calcium carbonate

›Radiopaque on plain radiography

›Fragile and fragment easily during removal attempts

Pathophysiology

›Spine injury mechanisms

›Primary mechanical injury

›Calcareous spines penetrate skin with minimal resistance

›Antegrade barbs prevent easy withdrawal

›Spines fragment easily during extraction attempts

›Venom delivery from hollow spines

›Thermolabile toxins including steroid glycosides and serotonin

›Histamine and acetylcholine in some species

›Causes intense burning pain disproportionate to wound size

›Secondary tissue injury

›Venom-induced local vasoconstriction and tissue necrosis

›Foreign body inflammatory reaction to retained fragments

›Granulomatous response

›Chronic foreign body granuloma develops over weeks to months

›Latency period 1-6 months from initial injury

›Sarcoid-like non-caseating granulomas on histopathology

›Birefringent spine fragments detectable on polarized light microscopy

›Confirms retained material even when fragments not grossly visible

›Immune-mediated component

›T-cell mediated delayed hypersensitivity

›Persistent despite apparent clinical wound healing

›Infection pathophysiology

›Vibrio vulnificus virulence

›Iron-dependent growth (elevated serum iron increases risk)

›Polysaccharide capsule resists phagocytosis

›Produces cytotoxic and hemolytic toxins

›Mortality up to 50% in immunocompromised hosts

›Mycobacterium marinum

›Environmental mycobacterium in salt and fresh water

›Optimal growth at 30°C explains superficial skin tropism

›Granulomatous infection along lymphatic channels

Therapeutic Considerations

›Hot water immersion rationale

›Thermolabile venom neutralization is primary mechanism

›Venom proteins denature at temperatures above 43-45°C

›ACEP Level C recommendation for hot water immersion

›Additional benefits

›Vasodilation may accelerate venom dispersal and resorption

›Provides significant analgesia beyond venom neutralization

›Spine retention and observation strategy

›Retained spines may be managed conservatively in selected cases

›Spines composed of calcium carbonate resorb over weeks to months

›Conservative management acceptable if superficial and away from joints, nerves, tendons

›Active removal required when

›Intra-articular location

›Adjacent to nerve or tendon

›Persistent granulomatous reaction

›Antibiotic stewardship

›Routine prophylaxis not recommended for minor wounds in healthy hosts

›Risk of antibiotic-associated adverse effects without clear benefit

›Selective use for high-risk patients and wounds

›Marine wound antibiotic spectrum requirements

›Must cover Vibrio and other gram-negative marine organisms

›Fluoroquinolones and third-generation cephalosporins have adequate coverage

›Standard skin flora antibiotics (penicillin, first-generation cephalosporins) inadequate

11Patient Discharge Instructions/pdi32

copy discharge instructions

›Sea urchin injury home care

›Hot water soaks for pain relief

›Soak the injured area in the hottest water you can safely tolerate (not scalding) for 30-90 minutes

›Repeat soaks as needed if pain returns

›Wound care at home

›Keep puncture sites clean with soap and water twice daily

›Apply antibiotic ointment if prescribed

›Cover with a clean bandage

›Do not try to squeeze or dig out spines yourself

›Spine fragments that remain may dissolve on their own

›Squeezing can push spines deeper or break them

›Pain medications

›Take acetaminophen or ibuprofen as directed for pain

›Take antibiotics exactly as prescribed if given

›Return to emergency department immediately if

›Spreading redness, warmth, or red streaks from the wound

›Increasing swelling or pus

›Fever over 38.3°C (101°F)

›Numbness, tingling, or weakness in the injured limb

›Difficulty moving fingers or toes near the injury

›Dizziness, fainting, or feeling of heart racing

›Difficulty breathing or throat tightening

›Severe pain not relieved by pain medications

›Follow-up instructions

›Wound recheck in 24-48 hours with your doctor or emergency department

›If a spine is still suspected but not found, return for repeat imaging

›If a firm painless nodule develops weeks to months after injury, see a dermatologist

12References/r23

Guidelines and key sources

›Primary evidence sources

›New England Journal of Medicine reviews on marine envenomations and wound management

›Hot water immersion 45°C for 30-90 minutes as standard first-line care

›Antibiotic selection guidance for marine wounds

›JAAOS (Journal of the American Academy of Orthopaedic Surgeons) on musculoskeletal sea urchin injuries

›Antibiotic coverage requirements including fluoroquinolones and ceftazidime

›Cutaneous Pathology journal on granulomatous reactions to sea urchin spines

›Sarcoid-like histopathology pattern

›Birefringent spines on polarized light microscopy

›Joint Bone Spine on osteoarticular sea urchin injuries

›Spine visibility on plain radiograph in 8 of 12 osteoarticular cases

›Septic arthritis and synovitis from intra-articular penetration

›Clinical Orthopaedics and Related Research on nerve and tendon involvement

›Clinical and Experimental Dermatology on intralesional corticosteroid treatment of granulomas

›CDC Yellow Book for travel medicine and marine hazard guidance

Coding standards

›Diagnostic coding

›ICD-10 T63.6 contact with other venomous marine animals

›T63.61 contact with Portuguese Man-o-war (related category)

›T63.691 toxic effect of contact with other venomous marine animals

›ICD-10 W56.31 contact with sea urchin initial encounter

›ICD-10 L92.3 foreign body granuloma of skin and subcutaneous tissue

›ICD-10 M00.9 pyogenic arthritis for septic joint complication

›ICD-10 A31.1 cutaneous mycobacteriosis for Mycobacterium marinum

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

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