Physical Injuries

PHYSICAL INJURIES

This form of tissue injury is produced by the application of heat or hot liquids or gases or solid heated substances to the surface of the body. It is also produced by the action of concentrated acids or alkalis and through contact with electrically charged conductors and exposure to sun rays, X-rays and radiation.

BURNS

Burns are the commonest form of thermal injuries and are due to. the local effect of dry heat as a result of contact with a flame, heated objects or commonly follow the ignition of clothing which has come in contact with a coal gas or an electric fire.

Pathophysiology of burns:

Local effects:

The local effects are produced in part by accelerated metabolism of the cells, in part by inactivation of temperature critical enzymes and in part by inducing vascular injury.

The severity of burn depends on the length of exposure and the temperature of the heat source.

• Several classifications are put to describe these local effects:

A. Dupuytren’s classification:

It depends on the depth to which the tissue has been destroyed and the nature of the changes that have occurred in the burned tissue. It includes six degrees:

First degree burn:

It consists of erythema of the skin and it heals without scar.

Second degree burn:

It results in detachment of the epidermis from the dermis with the formation of vesicles.

Third degree burn:

It results in the destruction of the full thickness of the epidermis and the epj4ia1 lands and hair follicles. It is a shock degree due to stimulation of sensory nerve endings, it heals with elastic epithelial scar.

Fourth degree burn:

There is destruction of all the dermis down to the subcutaneous tissue.

Fifth degree burn:

it consists of total necrosis of soft tissue (including muscle) and bone.

Sixth degree burn:

There is complete carbonization of the burned part with charring of bones. It follows exposure to temperature of 300°C.

B. Another classification of burns is based on the skin thickness and entails only two degrees:

Partial thickness and full thickness bums.

l- Full thickness burn:

It denotes an open wound. It is not capable of self repair and must be

grafted since there has been destruction of the dermal appendages from which re-epithelialization occurs.

2. Partial thickness burn:

it is produced by low intensity of heat. It comprises only erythema and vesicle formation. Some dermal epithelial elements have survived, so potential regenerative capacity is retained.

This classification is important in skin grafting.

Factors affecting prognosis of burns:

I. Extent: .

Involvement of a third or one half of the body surface will prove fatal due to associated hypovolaemicshock, hence fluid therapy isessential. To. assess the surface area affected we rely on (rule of nines”:

head and neck and upper extremities each constitute 9% of the total body surface area, anterior trunk, posterior trunk and lower extremities each constitute 18% and the perineum makes .up the remaining 1%.

2- Degree of burns:

The third degree (Dupuytren) is the serious one due to associated neurogenic shock, so pain killer is indicated.

3. Position of burns:

When the bums involve the head and neck, trunk or the anterior abdominal wall, the patient’s condition is always grave. Deep burn of an arm or leg, although it may result in grave disability, is unlikely to he-fatal.

4. Age of burned patient:

In extremes of age the prognosis is guarded. In children, having thin skin, wide body surface area in relation to their body weight and increased oxygen need, all these factors endanger their lives. Burning among elderly persons are fatal due to pre-existing diseases which aggravate burns .and they are more vulnerable to infection and serious systemic effects of bums.

Causes of death from burns:

Early causes:

1. Primary neurogenic shock.

2. l-lypovolaemic shock due to fluid loss from the burnt area.

3. Acute myocardial insufficiency and cardiac arrest (secondary to

hyperkalaemia from hydrolyzed erythrocytes).

4. Biochemical disturbance secondary to the electrolyte loss and

destruction of red blood cells and tissues.

5. Toxemia following absorption of various metabolites and burn

toxins.

6. Poisoning by inhaling smoke and irritating gasses e.g. carbon

monoxide, carbon dioxide, sulphur dioxide, nitrogen dioxide and

hydrocyanic acid, following burning of organic matters, silky and wooly

materials as well as artificial leatherette and .plastic materials..

7. Glottic or pulmonary edema caused by smoke or flame in burning of

Pace and neck regions.

8. Pulmonary fat embolism if burns affect fatty area.

9. Associated trauma e.g. head injury or traumatic asphyxia following

collapse of a building.

Delayed causes:

I. Infection: local and systemic especially of the respiratory system.

2. Acute renal failure.

3. Gastrointestinal hemorrhage by perforating 9jjn’sjgcers (in the duodenum)Jt is due to tissue hypoxia, elevated catecholamines and acid peptic mucosal digestion.

4. Suprarenal hemorrhage and failure.

5. Brain herniation due to edema and increased intracranial pressure.

Healing of burns:

First & second degrees burn:

The erythema will disappear withinJ.3 days. Vesicles may resolve by absorption of fluid but the raised epidermis is later shed and replaced by new epithelial growth from the periphery of the bum and from the hair follicles within two weeks. Repair is normally complete without scar formation.

Third & fourth degrees burn:

Third degree burn heals with epithelial elastic scar within a month. Fourth degree burns always heal with scar formation because the true skin is damaged and the repair is by growth of new tissue, Within a week the necrotic tissue separates to leave an ulcer which in turns, heals slowly with a disfiguring scar and often requires correction by plastic surgery. Ungrafted burn may be seen still unhealed, for years.

Fifth & sixth degrees burn:

These are deep burns and devitaliation of tissues in the burnt area renders them prone to infection and slow to repair.

The age of burn scar depends on the extent and depth of the burn. If not extensive it may remain red and sensitive for about two months, then it

attains a coppery colour up to six months then the colour fades away.

Post mortem artifacts caused by heat:

In addition to burns, damage may be produced by the action of heat on the body and must be distinguished from injuries caused by other means due to violence.

1. Heat ruptures:

They are produced by a splitting of the soft parts. They may resemble lacerations or incised wounds.

A distinction between heat rupture and incised wound is by the absence of bleeding in heat rupture as heat coagulates the blood in the vessels. Also the demonstration of nerves in the floor of the heat rupture is an important differentiating point.

A distinction from lacerations is made by the absence of bruising orother signs of vital reaction in the margins of heat rupture.

2. Heat contractures or pugilistic attitude:

The posture of a body which has been exposed to fire is often characteristic and the so-called “pugilistic attitude” or heat rigor is a well known feature of the effects of heat. Coagulation and contraction of the mus often occur, thus the limbs, the arms in particular, are fixed in an attitude commonly adopted by boxers. This position may give a false impression that the victim was engaged in a fight at the moment of death.

3. Heat hematoma:

It follows the exposure of the head to intense heat sufficient to cause charring of the skull. The blood in the hematoma is converted into a soft friable clot of light chocolatecolor, may be pinkish if the victim’s blood

contains carbon monoxide. Heat haematoma may be mistaken with an

extradural hemorrhage, but it is unaccompanied by any signs of injury by blunt force and it follows the distribution of the charring of the outer table of the skull.

4. Thermal fractures:

Fractures of the skull are often found in charred bodies. They are of two types: The first one results from rapid increase in intracranial pressure and he fragments are displaced outwards. In the other type the fracture is produced by rapid desiccation of the bone and only involves the outer table of the skull. There is no displacement and the lines of the fracture are frequently stellate.Thermal fractures may simulate ante-mortem fractures due to violence.

Differentiation between both could be done by the following table:

NB: Thermal fractures should be differentiated also from postmortem fracture following rough handling of the dead body.

Antemortem and postmortem burns:

The differentiation between antemortem and postmortem burns is very important to confirm that the victim was alive at the time. the fire reached him, as it frequently happens that bodies are burnt after death in order to conceal the presence of other crimes.

An antemortem burn is characterized by:

1. Redness of the parts.

2. Vesicles are surrounded by a thin bright red area of inflammation. They are filled with fluid rich in albumin and chloride. After removal of the vesicle, they may be present and it indicates a survival of at least 36 hours.

3. lea! examination of an antemortem burn is reliable evidence. It will reveal tissue reaction.

4. Fine carbon particles in the ha and bronchi are often mixed with mucous following inhalation of smoke .

5. The blood contains carboxyhaemoglobin in a significant amounti.e.

60.70%. I is an evidence of antemortem burns, as carbon monoxide is not absorbed by a body after death. The increased amount of carboxyhaemoglobin in the blood may explain why the victim was unable to escape.

Postmortem examination of a case of burn:

Examination is directed to ascertaining the position and depth of burns whether they were sustained in life or not, and whether their situation

gives any indication of the position of the body when the fire started.

Externally:

1-The clothes are burnt.

2-The hairs are singed (in burns of hairy area).

3. Soot is present in the nostrils, face and clothes.

4. Any degree of burn could befound.

5. The rate of cooling is diminished as the body temperature is raised at

the moment of death,

6. In aseptic burns putrefactive changes are delayed.

7. Heat rigor or pugilistic attitude is present.

Internally:

The internal signs depend on the site of burns, the time passed since

bums, the systemic effects of burns and the cause, of death.’

in rapid death, there will be:

1-Congestion of internal organs which may be cherry red in colour

(carboxyhacmoglobin).

2-The blood in the blood vessels and heart may be viscidand coagulated (hypovolaemia and haemoconcentration) or dark and fluid (asphyxia )

3-The tongue, larynx or trachea are inflamed and coated by a layer of soot adherent to the mucous.

4-The larynx may be blistered and edematous (in burns of the neck).

5-Fat embolism (in bums of fatty areas).

6. Thermal fracture (in severe burns of the head).

In delayed death the internal signs may reveal:

1- infection, local and systemic.

2- Suprarenal hemorrhage.

3-Rupture of Curling’s ulcers.

4- Renal and hepatic necrosis.

Circumstances of burns:

Accidental:

it is the commonest form of burns and are seen most frequently in infants, children and old persons. Also in persons who are unable to escape when a fire breaks out, being under the influence of drugs or alcohol. Accidental bums may also associate motor car and aeroplane accidents.

Suicidal:

It is also common especially among

kerosene then fire is set to them.

Homicidal:

It is uncommon where kerosene or other inflammable material is thrown over the victim and his clothing, and then a fire is lit. Another form. of a deliberately inflicted burn may be encountered among children in the course of the “battered baby syndrome”. Patterned burns are found, which correspond to a particular hot object which was applied to the skin.

Postmortem burns:

They are quite common to conceal the real crime as throttling, strangulation, firearm injuries, stab wounds, etc... The signs of antemortem burns will be absent.

SCALDS

These are tissue damage produced by the application of moist at as

Boiling water or oils or steam. The injuries do not penetrate deeply. They consist of erythema and vesicles. They may be dangerous because of the extent of the bodysurface affected, or when affecting the upper air passages. They heal without leaving a scar. Scalds are usually caused by accidents, as. when steam-pipes burst, or a child is dropped into a hot bath or overturns a tea-pot. Very rarely the damage is produced deliberately as a mean of killing a child.

The scald may show the course taken by the hot liquid trickling over the skin, and so indicate the position of the body at the time of injury.

CORROSIVE BURNS

These are burns produced by concentrated acj4..and alkalis. They are seen in industrial, laboratory, and domestic accidents. Deliberate criminal assaults also occur. The injury is due to both thermal and chemicalchanges in the tissues and clothes.

Due to corrosive nature of these chemicals, there is no vesicationof the affected skin and damage may be deep. Injuries produced by corrosive acids may be recognized by certain colour changes. Sulphuric acid: being hygroscopic acid will produce brownish, later black discoloration. Nitric agj: it combines with organic material, whether skin or fabric, to produce yellow discoloration due to the production of xanthoproteic or picric acid. hydrochloric acid: produces brownish red discoloration due to production of acid hematin.

Corrosive alkali burn will colour the skin white with a soapy feel to the touch. Due to the penetrating nature of corrosive burns they heal by a disfiguring scar.

The following table differentiates between burns due to dry heat, moist heat and corrosives:

ELETRIC TRAUMA

The passage of electrical current through the tissue can cause skin lesions, organ damage and death. This injury is called Electrocution. Fatalities are usually accidental but suicides from electricity have increased in recent years.

Electrocution

Symptoms

At the moment, of contact, there may be generalized muscular spasm which may cause the victim to grip the conductor firmly or may throw the individual some distance away. Sudden death may occur. If death does not occur and recovery takes place, the patient may. suffer from late effects of the electric injury.

Causes of death:

I. Immediate or electric death due to:

1-Ventricular fibrillation.

2-Tetanic asphyxia due to titanic contraction of the extrinsic muscles of respiration.

3-Respiratory arrest due to paralysis of the respiratory centre,

4- Cerebral anoxia: prolonged ventricular fibrillation may cause brain damage due to an inadequate blood supply.

5- Neurological damage by the passage of the current through the head.

II. Delayed death: from complications of electrical injury e.g. renal failure.

III. Associated mechanical injury e.g. skull injury following fall from a height.

Treatment:

Although the victim may appear to be dead, immediate and energetic treatment may revive the individual. The victim should not be pulled away with bare hands. The current should be disconnected or the victim should be removed from the sour of contact by means of a wooden stick or by hands using rubber gloves or wrapped in several thickness of dry cloth. Artificial respiration should be continued till recovery oi the appearance of rigor mortis. Cardiac and res irato stimulants should be given. In thehospital defibrillator and mechanical respirator could be used.

Effects of electrical injury:

I. Skin:

The skin is a relatively thin layer but highly resistant to the passage of electric current. If this tissue resistance is diminished, the current can penetrate the skin and gives rise to the following effects:

a. Current marks:

They vary from superficial circumscribed lesions to severe burns with full thickness tissue necrosis. Current marks are found at the site ofentrance and exit of the electric current. At the entrance the mark appearsas a grayish white ulcer like opening with everted and corrugated exploded margins and necroses tissue. At the exit, the tissues are frequently split in the form of punctured or lacerated wounds. These marks are caused by theexplosive electric force. Current mark is of the same size and sha e as the conductor with which the victim comes in contact. It gives useful information on the path of the current inside the body and it resists putrefaction.