3. Mechanical Trauma
•It produce variety of tissue damage
•Injury depends:
• Shape of the object
•Amount of energy discharged at impact
•Tissues or organs that bear the impact
5. Morphology
• Abrasion : Wound produced by scraping or rubbing the skin
surface, damaging the superficial layer
• Contusion: Wound usually produced by a blunt trauma
characterized by damage to vessel and extravasation of blood
into tissues
• Laceration: Tear or disruptive stretching of tissue caused by the
application of force
• Intact bridging blood vessels and jagged, irregular edges
6. • Incised wound: Bridging blood vessels are severely damaged
• Puncture wound: Caused by a long, narrow instrument
• Most common causes of mechanical injury is vehicular accident
• Trauma to the head (windshield impact)
• Chest (steering column impact)
• Knees (dashboard impact)
7. Thermal Burns
• Types : Hyperthermia, Hypothermia
• Burns ,Hot liquids
• Clinical severity of burns depends
1.Depth
2.Percentage of body surface involved
• Full-thickness: Burn produces total destruction of the epidermis and dermis, including
the dermal appendages
• Partial-thickness : Dermal appendages are spared.
8. Morphology
• Full-thickness :Burns are white or charred, dry, and anesthetic (as a result of
destruction of nerve endings)
• Partial-thickness: Burns, depending on the depth, are pink, blistered & painful
• Burn exceeding 50% of the total body surface, whether superficial or deep, is grave
and potentially fatal
• More than 20% of the body surface, there is a rapid shift of body fluids into the
interstitial compartments, both at the burn site and systemically, which can result in
hypovolemic shock
• Protein lost - Edema
9. • Inhalation injury: injury to airway & lungs
• Persons trapped in burning buildings
• Organ system failure resulting from sepsis continues to be the leading cause
of death
• Ideal site for growing micro organisms
• Serum & debris provide nutrients & the burn injury compromises blood flow,
blocking effective inflammatory responses
• Pseudomonas aeruginosa most common opportunist infection
• Pneumonia or septic shock accompanied by renal failure most common
complications
10. Hyperthermia
• Prolonged exposure to elevated temperatures result in
• Heat cramps, Heat exhaustion, or Heat stroke
• Heat cramps: Result from loss of electrolytes through sweating
( voluntary muscles)
• Heat exhaustion: Sudden onset produce hypovolemia
• Heat stroke: Thermoregulatory mechanisms fail, sweating ceases,
and core body temperature rises
11. Malignant hyperthermia
•Not caused by exposure to high temperature
•Genetic condition resulting from mutations in genes such
as RYR1 that control calcium levels in skeletal muscle cells
•Exposure to certain anesthetics during surgery may
trigger a rapid rise in calcium levels in skeletal muscle,
which in turn leads to muscle rigidity and increased heat
production.
12. Hypothermia
• Prolonged exposure to low temperature
• Seen in homeless alcoholic due to wet or inadequate clothing and
dilation of superficial blood vessels
• Loss of consciousness, bradycardia and atrial fibrillation
• Direct effects: Crystallization of the intra- and extracellular water.
• Indirect effects : Vasoconstriction and increased permeability,
leading to edema
13. Electrical Injury
•May be fatal, can arise from low voltage currents (i.e., in
the home and workplace) or
•From high-voltage currents carried in power lines or by
lightning
• Two types: (1) burns (2) ventricular Fibrillation or cardiac and
respiratory center failure
• Resulting from disruption of normal electrical impulses
14. • (120 or 220 V) is high enough to cause serious injury, including
ventricular fibrillation
• Alternating current induces tetanic muscle spasm, spasm of the
chest wall muscles, producing death from asphyxia
• Lightning: Large current flows generated, these injuries are more
likely to produce paralysis of medullary centers and extensive
burns
15. IonizingRadiation• Radiation is energy that travels in the form of waves or high-
speed particles
• Divided into nonionizing and ionizing radiation
• Nonionizing radiation: Such as ultraviolet (UV), infrared light, microwaves,
and sound waves
• Not sufficient to displace electrons from atoms
• Ionizing radiation : x-rays and gamma rays, alpha particles, beta particles
• Two-edged sword: Treatment of cancer & mutagenic, carcinogenic, and
teratogenic
16. Morphology
• Structural changes in chromosomes, including deletions, breaks, translocations,
and fragmentation.
• Nuclear swelling & condensation
• Apoptosis may occur
• Cytoplasmic changes, including cytoplasmic swelling, mitochondrial distortion,
and degeneration of the ER
• Vascular changes and interstitial fibrosis are prominent in irradiated tissues
