Asphyxia Flashcards
Asphyxia
When the body is deprived of oxygen (<20 mmHg) Pulselessness Clinical triad or asphyxial stigmata: C. Cyanosis P. Petechiae C. Congestion of organs
Tardieu spots
0.1 to 2 mm Bilateral venous congestion Present in neck and chest compression M/C site: conjunctiva Also seen in visceral pleura, skin and mucous membranes
Pressure at which structures around the neck are compressed
Bourdel proposed pressures for obstructing these structures J. Jugular vein - 2 kg C. Carotid artery - 5 kg T. Trachea - 15 kg V. Vertebral artery - 30 kg
Types of suffocation
- Environmental lack of O2
- Choking
- Gagging
- Smothering: both choking and gagging
- Perthes syndrome
- Burking- sitting on top
- Overlaying
- Café coronary
Asphyxia and suffocation
Cause of death in suffocation is always asphyxia ➡️ purest form of asphyxia
Triad of asphyxia is always present
Perthes syndrome
Masque ecchymotique
Traumatic asphyxia
Chest is fixed
Eg., building collapse, stampede
Masque ecchymotique:
Line of demarcation (compression) b/w cyanosis and congestion above and their absence below
Café coronary
By Roger Hougew
Accidental, unexpected, sudden death
Seen in intoxication ➡️ bolus enters pharynx /larynx
➡️ vasovagal reflex
➡️ cyanosis/cough ➡️ death
Mode of death: cardiac arrest or laryngospasm
Wet drowning
Typical drowning Person inhaled water Cardiac arrest M/C mode of death Loss of pulmonary surfactant M/C cause of death Fatal period: 5-8 min
Freshwater drowning
Hemodilution ➡️ hyperkalemia from RBCs ➡️ ventricular fibrillation ➡️ cardiac arrest
So earlier death
Seawater drowning
Hemoconcentration ➡️ hypernatremia ➡️ bradycardia
Delayed death
Examples of atypical drowning
- Dry drowning
- Delayed drowning:
Near drowning/ 2° drowning/ post-immersion syndrome - Hydrocution:
Immersion syndrome/ submersion syndrome
Sudden contact with cold 🥶 water
Dry drowning
Water does not enter lung
Water inside pharynx and larynx causes:
1. Vagal inhibition ➡️ cardiac arrest
2. Laryngospasm; sign of asphyxia may be present
Delayed drowning
Near drowning
2° drowning
Post-immersion syndrome
Person dies 1-2 days after an episode of drowning Causes: 1. Encephalopathy 2. Metabolic acidosis 3. Electrolyte imbalance 4. Pneumonia
Changes seen in antemortem drowning
- Cadaveric spasm
- Water enters nose, mouth and lung:
• Churning effect
• Emphysema aquosum
• Paltauf hemorrhagic
• mud particles in trachea
If unconscious, normal water goes into lung ➡️ edema aquosum
Churning effect
Seen in antemortem drowning due to mixing
Mucoid, tiny leather persistent frothing
Seen from nasal and oral orifices after death
Leads to:
1. Emphysema aquosum: 🫁 become heavy
2. Paltauf haemorrhage: subpleural haemorrhage
Non-mucoid frothing is seen in
- Poisoning
- Snake bite
- Decomposition
- Epilepsy
Features seen in both antemortem and post-mortem drowning
1. Floatation of body: due to gas formation by decomposition In summer: 24 hrs In winter ❄️: 1-2 days 2. Cutis anserina: goose flesh, hair erected 3. Washerwoman hands
Washerwoman hands
Skin is puckered, granular in drowning (AM and PM)
2-3 hrs. Wrinkling
12 hrs. Bleaching
2 days. Soddening
3-4 days: cuticle peeled off like degloving
Tests for drowning
- Gettler’s test: Cl-
- Mg and Sr in LR
- Diatom test: acid digestion technique
- Sehrt sign: stomach
- Svedhnikov sign: sinuses
- Sabinsky sign: spleen
- Wydler ring
Gettler’s test
Cl- content of blood in ventricles
Freshwater drowning: 25% decrease in concentration
Seawater drowning: 25% increase
Entry of diatoms into circulation
- Water
- Lung 🫁
- Pulmonary capillaries (diatoms <60 μ)
- Heart 🫀
- Systemic circulation
Acid digestion technique for diatom test
Best organ: femur M/C used: sternum Sample: dead body + water sample 15,000 species: 1. Oligohalophilic: fresh 2. Polyhalophilic: sea
Sehrt sign
Sveshnikov sign
Sabinsky sign
Sehrt sign: Rupture of gastric mucosa Sveshnikov sign: Water in paranasal sinuses Sabinsky sign: Spleen becomes small and anemic
Wydler ring
Stomach content in drowning Three layers: 1. Foam top 2. Liquid middle 3. Solid bottom
Magnesium and strontium
And drowning
When increased in left ventricle ➡️ seawater drowning
Hanging
Neck compression + body suspension
Asphyxial death with neck compression like strangulation
M/C method of suicide in India
Accidental/ judicial/ homicidal
Suicidal methods
1. Complex suicide: More than 1 suicide methods used 2. Complicated suicide: Death due to 2° unintentional trauma following original suicide method 3. Parasuicide: pseudosuicide Attempted suicide M/C cause: drug ingestion
Types of hanging
- Complete hanging
- Incomplete hanging
- Typical hanging: knot at occiput
- Atypical hanging: any other place
Complete hanging
Complete suspension of the body
Cause of death: asphyxia
Classical triad: cyanosis, petechiae, congestion are present
Incomplete hanging
Partial hanging
If done part of the body is touching the ground
Cause of death: bilateral venous congestion
Hanging
post-mortem changes
- CPC cyanosis, petechiae, congestion
- Tardieu spot
- Protrusion of tongue sometimes
- Semen emission- common findings
- Ligature mark
- Hyoid fracture: in 15-20%
- Thyroid cartilage: less common
- Haemorrhage of strap muscle in neck: 20%
Ligature mark
More specific finding of hanging seen in neck
Mark is V shape, not seen over knot.
Mark is above thyroid
Eg of pressure abrasion/ contusion
On dissecting skin- pale, glistening area is seen
Hyoid fracture in hanging
Seen in 15-20% of hanging cases
Anteroposterior fracture
aka Adduction fracture
Antemortem hanging
Death due to hanging
- Maximum pressure is always on opposite side ➡️ compression of submandibular glands + stimulates pterygopalatine ganglion ➡️ dribbling of saliva
- On the same side of knot, 👁 remains open and pupil dilated ➡️ la facies sympathique (cervical sympathetic ganglion dilation)
Accidental hanging
Eg sexual asphyxia, autoerotic asphyxia, Kotzwarrism
This is accidental hanging
Seen in perversion : M/C is masochism, transvestism
By crime examination, it is differentiated from suicidal hanging
Judicial hanging
61 hanged after independence
• Complete atypical hanging, below left angle of mandible (left aural region)
• Removal of platform
• It causes C2-C3 fracture/dislocation ➡️ leads to brainstem damage
• With sudden loss of support- tear of carotid artery more occur ➡️ Amussat sign
M/C delayed cause of death in hanging
Hypoxic encephalopathy
Simon sign haemorrhage
Haemorrhage of intervertebral disc specially in lumbar/thoracic region
Seen in hanging
Strangulation
Only neck compression is seen without suspension of body
M/C homicidal
Judicial strangulation M/C in Spain/Turkey known as Garotting/ Spanish windlass
Types of strangulation
- Ligature
- Throttling: by hand
- Mugging: elbow
- Bansdola: stick
Post mortem changes in strangulation
- Asphyxial signs: CPC more prominent compared to hanging
- Tardieu spot
- Thyroid fracture: less common than hanging
- Resistance injuries
- Complete/Transverse ligature mark below/at the level of thyroid
- Tissue contusion
- Extensive haemorrhage/bruising
- Periligature injuries, bruising
- Hyoid bone fracture: not common
Prinsloo Gordon effect
Artifacts present in neck when it is not dissected last in a asphyxial death.
Cranium is dissected first and neck the last to achieve a blood-less field.
Manual strangulation
fracture
Always homicidal Thyroid cartilage fracture: common at superior horn Hyoid fracture: 40-50% of cases usually at greater cornua Adduction fracture/inward compression fracture
Signs of manual strangulation other than the fractures
- Six penny bruise:
Multiple oval/circular bruises in the neck - In dissection haemorrhage or hematoma
- Nail marks cause semilunar or crescentic abrasion 🌙
- Intense cyanosis, congestion and petechiae - CPC
