Strangulation

From Guide to YKHC Medical Practices

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Following Written by: Jennifer Prince, MD

last updated 1/5/2022

Strangulation is A Complexity of Challenges

Medical issues

  • Strangulation is potentially life-threatening
  • Initial patient presentation may be minimal or subtle
  • Under-appreciation of the risk (by all involved)
  • Historically limited medical evaluation and treatment
  • Subsequent deterioration and bad outcomes may occur
  • Historically poor medical documentation and little or no forensic documentation…until the autopsy

Forensic issues

  • Limited/poor forensic documentation
  • Little or no medical testing (objective proof of injury)

Criminal Justice issues

Strangulation is an extremely common and very serious problem in domestic violence

  • Up to 68% of DV victims have been strangled by their male partner in their lifetime
  • Up to 47% of DV victims have been strangled in the last year
  • 18–43% of DV homicide victims had been strangled — Sexual assault and domestic violence are frequently intertwined
  • At least 75% of sexual assault victims know their assailant — The prevalence of strangulation in sexual assault has not been specifically studied, but it is estimated that at least 15% of sexual violence includes strangulation

Basic Physiology

  • The brain needs a continuous supply of oxygen
  • Without oxygen, brain cells quickly malfunction and die
  • Two vital bodily systems must work perfectly and in unison — Respiratory — Cardiovascular
  • Multiple areas of vulnerability exist in both systems
  • Compromise of a single area may rapidly produce a very bad outcome
  • Respiration delivers oxygen into the blood
  • Air must pass through the mouth and nose, the upper air passages, the larynx), the trachea, and into the lungs
  • Air must flow in and out of the lungs
  • The chest and diaphragm muscle work together to create the “bellows” that moves the air
  • The lungs extract oxygen from the air and shift it into the blood (oxygenation)
  • Oxygen-rich blood is pumped by the heart through the carotid arteries in the neck up to the brain
  • After the oxygen is delivered, carbon dioxide and other waste products are transferred from the cells into the blood and returned (by the jugular veins in the neck) to the lungs to be exhaled
  • The next breath begins the cycle of oxygenation again

Mechanisms and Definitions

  • Asphyxia: brain cells deprived of oxygen
    • Lungs deprived of air (failure of respiration)
    • Brain deprived of blood (failure of blood flow)
    • Combination of mechanisms
  • Common clinical features during asphyxia (symptoms and signs)
    • Pain
    • Anxiety
    • Altered consciousness
    • Unconscious in 10–15 seconds
  • Strangulation: external pressure applied to neck until consciousness is altered
    • Manual (most common method in domestic violence and sexual assault)
      • One hand
      • Both hands
      • Other body part (knee, “choke hold,” etc)
    • Ligature (cord-like object used to apply pressure to the neck)
  • Strangulation may impair blood flow, airflow or both
    • Compromised blood flow to the brain - Compression of one or both Carotid Arteries
    • Compromised airflow to the lungs
      • Suffocation: process that halts or impedes respiration
  • Choking: object mechanically blocks the upper airway or windpipe (trachea)…often inappropriately used to describe strangulation!
  • Smothering: mechanical obstruction to airflow into the nose and mouth
  • Compressive Asphyxia: external limitation of chest motion (assailants body weight on victim)

Pathophysiology

  • Damage to larynx and/or hyoid bone
    • Contusion:
      • 22 pounds of pressure
      • Hemorrhage
      • Edema
    • Occlusion (temporary)
      • 33 pounds of pressure
    • Fracture:
      • 35–46 pounds of pressure
    • Combinations
  • Damage to Carotid Arteries (causes compromised blood flow to brain)
    • Immediate (acute) impairment
      • Frontal force (5.5–22 lb) compresses arteries against neck bones
      • Single carotid artery compressed or blocked—may create neurologic findings on opposite side of body
      • Both carotids compressed or blocked—rapid loss of consciousness (as soon as 10 seconds)
    • Slower onset (delayed) findings
      • Bleeding and internal artery damage (intimal tears)
      • Blood clots form inside artery (thrombosis)—blocked blood flow
      • Blood clots break off and travel to brain (embolization)—blocked blood flow
      • Neurologic findings develop because of dysfunction in areas of the brain “down stream” from the area deprived of blood flow
    • Return of blood from the brain may be compromised (venous outflow obstruction)
      • 4.4 pounds of pressure on jugular veins causes back up of blood lacking oxygen (stagnant hypoxia)
      • 5–30 seconds of compression causes altered consciousness
      • Common clinical findings
        • Tiny surface blood vessels rupture from increased internal pressure
        • Petechiae (face, mucous membranes)
        • Sub-conjunctival hematoma (sclera or white part of the eye)
      • Blood vessel ruptures may occur internally (not visible)
    • Less common medical problems after strangulation
      • Compression of the carotid body
        • Problems may begin after 3–4 minutes of sustained pressure
        • Carotid sinus reflex is stimulated
        • Bradycardia
        • Altered consciousness (lightheadedness or loss of consciousness)
        • May progress to cardiac arrest
      • Neck (cervical vertebrae) fractures
        • Rare (except in long—drop hanging)
      • Pulmonary Edema
        • Often delayed development (up to 2 week)

Clinical Symptoms

  • Neck pain and sore throat
    • Very common (60–70%)
    • Usually related to direct trauma (blunt force)
  • Breathing changes or difficulty
    • Very common (up to 85%)
    • Psychogenic (hyperventilation)
    • Laryngeal injury, swelling, bleeding
    • Pulmonary edema—late finding
    • Breathing problems may be delayed (up to 2 weeks)
    • Worsening of other conditions (e.g. asthma)
  • Voice changes
    • Very common (up to 50%)
    • Hoarse or raspy voice
    • Inability to speak
    • Coughing
    • Laryngeal injury, swelling, bleeding, Suggestion: document with voice recording
  • Swallowing abnormalities
    • Very common (up to 44%)
    • Difficulty swallowing (dysphagia)
    • Painful swallowing (odynophagia)
    • Laryngeal injury, swelling, bleeding
    • Esophageal injury, swelling, bleeding
    • May be immediate or delayed (up to 2 weeks)
  • Mental status and consciousness changes
    • Light-headedness and dizziness
    • Loss of memory
    • Loss of consciousness
  • Behavioral changes
    • Early: agitation, restlessness, combativeness
    • Late:
      • Impairments in memory, concentration, sleep
      • Mental health issues (anxiety, depression, dementia
  • Mental status and behavioral changes
    • Main cause: brain cells deprived of oxygen
      • Brief interruption: Findings (symptoms and signs) are temporary and resolve
    • Longer interruption
      • Findings are permanent and do not resolve (may improve partially, but not completely)
      • Anoxic brain damage
    • Other neurologic symptoms and signs
      • Vision changes
      • Tinnitus
      • Facial or eyelid palsies
      • Hemiplegia
      • Incontinence (bladder or bowel)
      • Miscarriage

Clinical Symptoms Caveats

  • Symptoms are subjective (described by patient)
  • Documentation is essential
    • Symptoms may resolve or change
    • Recording patient experience provides a degree of objectivity
    • Objectivity is strengthened by multiple/consistent descriptions
  • Some symptoms may be non-specific or have multiple causes (but must be thoroughly explored and recorded)
    • Light-headedness and dizziness
    • Difficulty breathing
  • Impairment of memory and/or consciousness
    • May compromise accuracy and credibility of the history
    • Must be explored in detail and carefully documented
  • No visible findings
    • Very common (up to 50%)
    • Pain (subjective discomfort)
    • Tenderness (discomfort with palpation)
    • Other symptoms are often present
  • Caution! Lack of visible findings (or minimal injuries) does not exclude a potentially life-threatening condition

Clinical Findings

  • Visible findings: Petechiae
    • Compression impedes venous blood flow (venous return)
    • Venous pressure increases
    • Small blood vessels near skin or mucous membrane surfaces rupture
    • Multiple tiny red spots appear (1–2 mm)
      • Non-palpable (or “flat”—can’t feel them on exam)
      • Non-tender (no discomfort when touched)
      • Do not blanch (temporarily change color when touched)
    • Caution! “petechiae” may be used inappropriately to describe direct blunt trauma findings
  • Visible findings: Sub-conjunctival Hematoma
    • Compression impedes venous blood flow
    • Venous pressure increases
    • Small blood vessels on the surface of the eye (sclera, or white part) rupture
    • Appearance can very disturbing to patient and family
    • Not dangerous; no treatment required; resolves within 2 weeks
    • Does not impair vision
  • Visible findings: Neck Injuries
    • Redness (hyperemia or erythema) - Fades quickly
    • Bruising (contusion or ecchymosis) - Often not visible initially
    • Scratches and abrasions – Common, May be self-defense injuries
  • Ligature marks
    • Abrasions
    • Bruises (contusion or ecchymosis)
    • Redness (erythema)—fades quickly
  • Tips:
    • Look for “patterning” of findings – can give information about cause or mechanism of injury
    • Understand the “mechanism of injury” - Compare and correlate the history of what happened to the physical findings and assess consistency
    • Consider follow-up examination(s) + photos
      • Document emerging or evolving injuries
      • Compare and clarify non-specific findings
        • Redness (erythema)
        • Swelling (edema)

Clinical Manifestations—CAUTION!

  • “Strangulation survivors who appear stable can harbor insidious injuries associated with high morbidity and mortality if not recognized and treated in a timely fashion” (Taliaferro, Hawley, McClane and Strack 2009)”
  • Common pitfalls in caring for strangulation patients:
    • Attempting to predict outcome based on initial condition of the patient
    • Premature discharge of patient who has been strangled within the past 24–36 hours

Clinical Evaluation in the ED

  • ABC’s (airway, breathing, circulation)
  • Cervical spine precautions
  • Structured history and physical exam (Autotext)
  • Imaging Strategies in the ED ( see Strangulation Guideline)
    • Plain neck X-rays rarely helpful
    • CT angiography of carotids/cerebral arteries
      • Intimal tears
      • Thrombosis
    • Non-contrast CT of neck – body and cartilaginous structures

Documentation

  • Documentation should include:
    • Narrative of event
    • History of injury causing events (mechanisms of injury)
    • Patient symptoms (initial and current)
    • Physical exam findings
    • Diagnostic evaluation
    • Clinical assessment
    • Management
    • Follow-up plan
  • Forensic management
    • Consider forensic photography with filters
    • Consider neck swabs (assailant saliva, epithelial cells for touch DNA)
    • Consider follow-up evaluation (exam, imaging studies)
    • Documentation in Forensic Medical Record by Forensic Examiner when requested by Law Enforcement

Important Phone Numbers

  • Tundra Women’s Coalition: 907-543-3444, 1-800-478-7799
  • Emmonak Women's Shelter: 907-949-1443
  • Bay Haven Shelter: 907-754-4711, 1-888-754-4711
  • Alaska’s CARELINE: 877-266-HELP (4357)
  • The National Domestic Violence Hotline: 1-800-799-SAFE (7233)
  • Bethel Police Department: 907-543-5086
  • Alaska State Troopers – Bethel: 907-543-2294 or call your community’s VSPO
  • Alaska State Troopers – Emmonak: 1-866-949-1303
  • Alaska State Troopers – St. Marys: 1-907-438-2019
  • YKHC Behavioral Health Emergency Service: 24-HOUR CRISIS: (907) 543-6499 or 1-844-543-6499

Resources/References


YKHC Clinical Guidelines
Common/Unique Medical Diagnoses

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