Strangulation Injury

Aka: Strangulation Injury, Strangulation, Asphyxia by Strangulation, Suffocation by Strangulation

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II. Definitions

  1. Strangulation
    1. External neck compression affecting underlying large vessel perfusion or tracheal airflow
    2. Types of Strangulation include hanging, manual Strangulation (Choking), ligature Strangulation
  2. Suffocation or Asphyxiation
    1. Impeded respiration with tissue Hypoxia
    2. In addition to Strangulation, other causes include Drowning, obstruction of mouth and nose
  3. Choking
    1. Internal tracheal obstruction

III. Epidemiology

  1. Strangulation contributes to 10% of violent deaths
  2. Nonfatal Strangulation is a common presentation in Intimate Partner Violence and Sexual Assault
    1. Reported by 7 to 22% of Sexual Assault victims
    2. Nonfatal Strangulation is reported by women in 24 to 68% of Intimate Partner Violence cases
      1. High risk for future homicide by the same assailant (RR 7.5)
      2. Up to 90% of Intimate Partner Violence victims are uncomfortable disclosing assault
    3. Risk Factors
      1. See Intimate Partner Violence
      2. Single, young black women
      3. Unplanned Pregnancy
      4. Lower socioeconomic status
  3. Voluntary Strangulation causes (high risk activities)
    1. Choking Game
      1. Self-Strangulation or that by a partner to achieve brief euphoria
      2. (2008) MMWR Morb Mortal Wkly Rep 57(6):141-4
    2. Autoerotic asphyxia
      1. Used to enhance sexual stimulation

IV. Pathophysiology

  1. Suffocation or Asphyxiation resulting from neck compression
    1. Vascular Occlusion
      1. Jugular Veins are first to obstruct even with superficial compression (2 kg force)
        1. Results in vascular engorgement and Petechiae
      2. Carotid arteries obstruct with anterior neck compression (3.5 kg force)
        1. Loss of consciousness occurs within 5-15 seconds due to rapid drop in brain perfusion
        2. Carotid Artery intima injury may lead to thrombosis and Cerebral Infarction
        3. Carotid Artery Dissection (with direct compression, neck hyperextension, violent movement)
    2. Airway obstruction (e.g. trachea)
      1. Trachea obstruction (10 kg of force)
      2. Obstruction due to Compression from Hemorrhage and edema mass effect
        1. Thyroid cartilage or Hyoid BoneTrauma
    3. Carotid Sinus baroreceptor stimulation
      1. Prolonged stimulation may cause severe Bradycardia degenerating into Cardiac Arrest
  2. Injury may be compounded by other Traumatic injuries
    1. Violent head or neck movements
    2. Recurrent neck injury (cummulative effects of repeated neck Trauma)

V. Types: Strangulation

  1. Manual Strangulation (Throttling, 83% of Strangulation cases)
    1. Direct neck pressure by assailant's hands or feet, elbows or knees
  2. Ligature Strangulation
    1. Tightening of rope, cord, wire, clothing, or jewelry to constrict the neck
    2. Avoid cutting knots if possible when removing (to preserve evidence)
    3. Common accidental asphyxia cause in young children due to entanglement
  3. Postural Strangulation
    1. Weight is applied to a victims neck, preventing respiration (e.g. knee held against posterior c-spine)
  4. Hanging
    1. Combines ligature Strangulation and postural Strangulation (patient's own body weight)

VI. Precautions

  1. Strangulation delayed presentation even up to 4 days after injury may require emergent airway management
  2. Altered Mental Status is a red flag for anoxic brain injury related to Strangulation
    1. Exercise caution in attributing Altered Mental Status to Intoxication
  3. Exam findings of Strangulation may be subtle
    1. No visible external neck injuries in up to 50% of nonfatal Strangulation (and 20% of fatal Strangulation)
    2. Only 15% of survivors will have photographic evidence of Strangulation
  4. Careful documentation is important (and may avert need for physician Testimony)
    1. Careful history in patient's own words
    2. Number of assailants
    3. Intoxicants (e.g. Alcohol)
    4. Method of Strangulation and details of the attack
    5. Body maps and images of injuries
    6. Assign appropriate serious associated diagnosis (e.g. Strangulation, Traumatic asphyxia)

VII. Symptoms

  1. Severe pain from neck compression
  2. Loss of consciousness may occur even within 5-15 seconds of severe neck compression
  3. Other symptoms
    1. Dizziness or Syncope
    2. Headache
    3. Tinnitus
    4. Neck Pain
    5. Shortness of Breath
    6. Loss of bowel or blader function with episode
    7. Focal neurologic deficits
  4. Psychiatric
    1. Anxiety
    2. Depressed mood with Suicidality
    3. Insomnia or Nightmares

VIII. Signs

  1. See Intimate Partner Violence
  2. Head and Face
    1. Scalp bald patches (related to hair pulling)
    2. Facial Petechiae
  3. Eyes
    1. Subconjunctival Hemorrhage or Scleral Hemorrhage
    2. Conjunctival Petechiae
    3. Chemosis
  4. Ears
    1. Hemotympanum
    2. Blood in ear canal
    3. Post-auricular Bruising
  5. Mouth
    1. Tongue swelling
    2. Buccal mucosaPetechiae
    3. Peri-oral Bruising
    4. Drooling
  6. Neck
    1. Dysphonia or muffled voice (50% of manual Strangulation cases)
    2. Dysphagia
    3. Subcutaneous Emphysema (crepitation)
    4. Skin findings (Ligature marks, Bruising, Petechiae, scratches)
    5. Thyroid Storm (has been reported with Strangulation Injury)
    6. Carotid Bruit
    7. Neck Hematoma
  7. Cardiopulmonary (including airway and respiratory tract)
    1. Pharyngeal, supraglottic or laryngeal edema (presentation may be delayed >36 hours)
    2. Pulmonary Edema (may be delayed onset up to 48 hours)
    3. Pneumothorax
    4. Tachycardia
    5. Stridor
    6. Respiratory Distress (Tachypnea, accessory Muscle use)
  8. Neurologic
    1. Altered Level of Consciousness
    2. Seizures
    3. Encephalopathy
    4. Traumatic Horner Syndrome (Ptosis, myosis, Anhidrosis)
    5. Carotid Artery Dissection
      1. Evaluate for CVA Symptoms or Signs (Ptosis, facial palsy, Anisocoria, extremity weakness)
  9. Skin Findings
    1. Scratches
      1. Found on chest, neck, face (often related to attempts to break free)
    2. Bruises
      1. Found post-auricular (sternocleidomastoid Muscle), mouth, neck, chest
      2. Ligature mark may also be present on neck
    3. Petechiae
      1. Found on Conjunctiva, scalp, face, Buccal mucosa
  10. Pregnancy
    1. Fetal Hypoxia

IX. Labs: If Indicated

  1. Complete Blood Count (CBC)
  2. Serum basic chemistry panel (chem8)
  3. Pregnancy Test (urine or blood bHCG)

X. Imaging

  1. Soft-Tissue Neck XRay Findings (if CTA Neck not performed)
    1. Subcutaneous air
    2. Tracheal deviation
    3. Hyoid Fracture
  2. Chest XRay Findings
    1. Pulmonary Edema
    2. Aspiration Pneumonia
  3. CT Angiogram Neck (CTA neck) Indications (for Carotid Artery Dissection, Laryngeal Fracture, Cervical Spine Fracture, Hemorrhage)
    1. See Denver Screening Criteria for Blunt Cerebrovascular Injury
    2. Visible neck Trauma related to attack
    3. Dyspnea
    4. Dysphonia
    5. Neurologic changes with the attack
      1. Loss of consciousness
      2. GCS <15
      3. Incontinence
      4. Vision changes
    6. References
      1. Matusz (2020) Ann Emerg Med 75(3): 329-38 [PubMed]
      2. Zuberi (2019) Emerg Radiol 26(5): 485-92 [PubMed]
  4. MRA Neck
    1. Consider as alternative to CTA Neck (e.g. pregnancy)
    2. Less Test Sensitivity than CT angiogram for vascular injury, but more sensitive for Soft Tissue Injury
  5. MRI/MRA Brain and Neck
    1. Anoxic brain injury
    2. Stroke Symptoms

XI. Management

  1. See ABC Management
  2. See Blunt Neck Injury
  3. See Neck Vascular Injury in Blunt Force Trauma (BCVI)
  4. See Post-Cardiac Arrest Care
  5. See Traumatic Brain Injury
  6. Consultation
    1. Consult Forensic Nurse Examiner
      1. Documents history and exam and assists with disposition planning
    2. Consult Domestic Violence advocate
    3. Consult resources related to children who witnessed or may have been injured in the attack
    4. Social Work
    5. Law enforcement (if indicated)
  7. Disposition: Observation Indications (for 12 to 24 hours)
    1. Loss of consciousness
    2. Visible signs of Trauma (e.g. Petechiae)
    3. Intoxication
    4. Unreliable for outpatient monitoring
    5. Pregnancy monitoring for Gestational age >20 weeks (6 hours of cardiotocographic monitoring)
  8. Disposition: Home
    1. Specific symptom and sign precautions for return (delayed, Strangulation-related red flags)
    2. Discharge to environment safe from perpetrator
    3. Follow-up with primary care within 48 to 72 hours

XII. Complications

  1. Airway compromise (e.g. Laryngeal Fracture)
  2. Carotid Artery Dissection
  3. Hypoxic brain injury
  4. Pulmonary Edema
  5. Acute Stress Disorder or Post-Traumatic Stress Disorder
  6. Mood Disorder (Major Depression, anxiety)

XIII. Prevention

  1. See Intimate Partner Violence Screening

XIV. References

  1. Riviello and Rozzi (2020) Crit Dec Emerg Med 34(12): 17-23
  2. Stapczynski (2010) Emergency Med Rep 31(17): 193-204

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