1. Physical Injuries
Dr. Asmaa Fady
Ph D., MSC., M.B, B.Ch

2. Learning objectives: By the end of the lecturer, the students should
Define & classify of different types of burns.
Know Differences between ante-mortem & postmortem burn.
Understand Types of burns, under each one we have to know, the causative agent, mechanism of infliction, characters, mechanism of death & postmortem appearance.
Recognize Types, mechanism, clinical picture & treatment of heat diseases.
Understand mechanism, signs and cause of death in electrocution cases.
اسم ورقم المقرر – Course Name and No.
6/2/2019

3. Classification of Physical agents
I- Thermal: heat (dry & wet) and cold(frost bites).
II- Electrical.
III- Chemicals as corrosives.
IV- Radiations.
V- Lightning.
اسم ورقم المقرر – Course Name and No.
6/2/2019

4. Thermal Injuries Definition:
Tissue injuries result from application of heat or cold to the surface of the body.
Heat injuries results from:
a- Dry heat as flame or solid heated objects  dry burn.
b- Moist heat as hot liquids or steam  moist burn (scalds).
اسم ورقم المقرر – Course Name and No.
6/2/2019

5. Wilson’s classification of burns:
1st degree:
- Superficial destruction of the epidermis, without loss of dermis (as Sun burn).
- It is presented by:
a- Erythema.
b- Pain (due to stimulation of nerve endings).
c- Healing within 10 days without scaring.
2nd degree:
- Destruction of partial thickness of the skin. (including epidermis and dermis)
a- Erythema and blisters.
b- It is very painful (due to exposure of nerve endings)
Risk of scarring depends on the extension (mild to great disfigurement)
3rd degree:
Destruction of full thickness of the skin and deeper tissues below the skin.
The lesion may be white, red or black & sensation is absent.

6. Rule of nines: Anatomical description of the burned areas.
Used to estimate the area of damage
اسم ورقم المقرر – Course Name and No.
6/2/2019

7. Mechanism of death in burn:
Immediate:
1- Neurogenic shock:
2- Asphyxia: due to inhalation of toxic gases as CO or CO2, or inhalation of irritant gases & fumes.
3- Traumatic asphyxia: due to falling objects or by the feet of running persons.
4- Fatal head injury: due to falling objects.
5- Massive and rapidly developed edema of the glottis: due to inhalation of irritant gases & fumes.
6-48 hours
1. Slowly developed edema of the glottis.
2. Dehydration & Hemconcentration
3. Hematogenic shock: due to absorption of histamine like substance from burnt area.
4. Fat embolism
اسم ورقم المقرر – Course Name and No.
6/2/2019

8. Mechanism of death in burn:
2-7 days:
1. Infection: septic absorption  septicemia  septic shock.
2. Bronchopneumonia: especially in extremes of age.
3. Supra renal hemorrhage: as a result of burn stress.
4. Inflammation of vital organs: hepatitis, nephritis or serous membranes (pleurisy, meningitis or peritonitis): due to toxins absorbed from burnt area.
More than 7 days:
1. Rupture of curling ulcer: toxins absorbed from burnt area  excreted by liver in the bile  duodenum  devitalization and ulceration of duodenum.
2. Liver and kidney failure: due to toxins absorbed from devitalized tissue
اسم ورقم المقرر – Course Name and No.
6/2/2019

9. D.D of ante-mortem and post-mortem burnAM PM
1. Erythema
Present
No erythema (not sure)
2. Vesicles
Tense, filled with fluid rich in albumin and chloride.
Absent. If present they are not tense, contain gases & fluid poor in albumin and chloride.
3.Soot in the air passage
Present in distal air passages and embedded in bronchial mucosa.
Absent, if present it will be proximal & not embedded in mucosa.
4. Level of carboxy Hb
More than 10 %
Less than 10%
5. Hemconcentration
Absent
6. Vital reaction (signs of cellular infiltration, sepsis and healing)
8. Cause of death
Due to burn
Presence of other possible causes of death

10. D.D of burn, scalds & corrosion
Burn
Scald
Corrosion
1. Agent
Dry heat, flame, heated object
Hot liquid or steam
Strong acids or alkalis
2. Extension
Usually from below upwards
From above downwards
3. Hair
Charred, clubbed signed (comma shaped) or absent
Wetted, may be discolored
Wetted & eaten up
4. Clothes
Burnt
Wet, may be discolored
Discolored & eaten up
5. Soot (carbon particles)
Present in air passages
Absent
7. Level of CO Hb
More than 10%
Ranged from 1-6%, may reach 10% in heavy smoker
8. Scar
May cause disfigurement
No or mild disfigurement
Much disfigurement
6/2/2019

11. HEAT DISEASES Types of Heat diseases: 1- Heat cramps.
2- Heat exhaustion (Heat Collapse).
3- Heat stroke
اسم ورقم المقرر – Course Name and No.
6/2/2019

12. 1- Heat cramps Mechanism: Excessive loss of salt and water in sweating
Clinical Picture:
- Painful cramps of voluntary muscles especially calf.
- Sweating: increased
- Temperature: Normal
Treatment: It is reversible. Salt and water may be needed.
اسم ورقم المقرر – Course Name and No.
6/2/2019

13. 2- Heat exhaustion (Heat Collapse or heat syncope)
Mechanism: Exposure to excessive heat during muscular exercise   heat production  Activation of heat regulating system 1- Peripheral vasodilatation   peripheral blood flow 2-  Sweating &  ventilation   water loss  Venous return &cardiac output (patients suffering from cardiovascular disease are predisposed to syncope as heart can't normalize blood pressure)
اسم ورقم المقرر – Course Name and No.
6/2/2019

14. 2- Heat exhaustion (Heat Collapse or heat syncope)
Clinical Picture: 1- Onset: sudden with symptoms of peripheral vascular collapse. 2- Headache, weakness, may be fainting 3- Skin: Pale. 4- Blood pressure: low, pulse: rapid & weak. 5- Temperature: Normal or subnormal. 6- Sweating: Increased (patient bathed in perspiration). 7- Decreased urinary output Treatment: 1- Put patient supine with legs up 2- Rest in cool atmosphere. 3- Intravenous saline.
اسم ورقم المقرر – Course Name and No.
6/2/2019

15. 3- Heat stroke or (Heat hyperpyrexia)
Mechanism:
Exposure to excessive heat   heat production denature proteins (enzymes, hormones) & liquefies membrane lipids in the CNS  neuronal degeneration  disturbance in heat regulating mechanism  heat loss is less than heat gain.
Clinical Picture:
1- Onset may be:
Sudden: collapse, coma and convulsion
Gradual: headache, dizziness, nausea, vomiting, mental confusion delirium and convulsions.
2- Skin: hot, flushed & dry.
3- low Blood pressure, rapid pulse, & rapid breathing.
4- Temperature: High (40- 43°C).
5- Sweating: mild or no
Treatment:
1- Remove the patient to cool place.
2- Application of cold compresses to the skin, ice bag to the head and ice cold rectal enema.
3- Fluid and electrolyte therapy.
6/2/2019

16. ELECTRICAL INJURIES (electrocution)
Mechanism of electrical injury:
The passage of electric current involves flow of energy (electrons) through the body while the victim is earthed (body in contact with earth)  complete electrical circuit is formed  biological damage in the form of coagulative necrosis.
The highest resistance is found in Skin & bones so; they are more susceptible to heating during an electrical injury.
Once electric current overcomes skin resistance, it flows easily through body tissues  different electrical injuries
اسم ورقم المقرر – Course Name and No.
6/2/2019

17. Signs of Electrocution
1- Electric burns: due to electro thermal heating.
a- Entry mark:
The point where the current enters the body.
It is a thermal burn results from heating epidermis and dermis  raised blister.
When the current ceases the blister cools and collapses.
The collapsed blister is annular with raised, grey or white edges with an umbilicated center.
b- Exit mark (Earthling lesion):
It is not often seen, but should be looked for on the contralateral hand or feet.
It is similar to entry mark but less severe
اسم ورقم المقرر – Course Name and No.
6/2/2019

18. اسم ورقم المقرر – Course Name and No.
6/2/2019

19. Signs of Electrocution
2- Effect on muscles "Hold on” effect":
When the entry point is in the hand, the stronger flexor muscles of the arm go into spasm and cause a "hold- on effect".
3- Metallization:
Due to transfer of metals from metallic conductor to the skin and subcutaneous tissues.
اسم ورقم المقرر – Course Name and No.
6/2/2019

20. Mechanism of death from electric current
I- Immediate:
1) Ventricular fibrillation:
It is reversible so, it is necessary to continue artificial respiration until death is certain (the victim is in a state of suspended animation).
2) Respiratory Failure:
a- Central: When the current passes through the head.
b- Peripheral: When the current passes through the thorax due to tetanic contractions of the intercostal muscles & diaphragm  peripheral asphyxia.
3) Neurogenic shock:
Most commonly parasympathetic due to fear.
4) Non electrical trauma:
Due to throwing the victim from a height especially in high tension voltage.
II- Delayed:
1) Hemorrhage: particularly from labial artery in children sucks on the end of a wire.
3) Renal failure: due to rhabdomyolysis  damage of renal tubules by myoglobin
4) Transverse myelitis (poor prognosis).
6/2/2019