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