GenPath Week 13

Questions and Answers

What is a major risk associated with thermal injuries in terms of tissue health?

Formation of eschar (correct)

Loss of body temperature regulation

Development of scar tissue

Decreased blood oxygen levels

Which condition is characterized by painful muscle spasms due to water and electrolyte loss?

Heat cramps (correct)

Heat stroke

Heat exhaustion

Hyperthermia

What is defined as a life-threatening condition resulting from heat exposure and marked by the failure of heat regulation?

Hyperthermia

Heat exhaustion

Heat stroke (correct)

Heat cramps

What complication can arise from generalized edema in burn patients?

Respiratory insufficiency Signup and view all the answers

Which syndrome is most commonly characterized by weakness, headache, nausea, and vertigo?

Heat exhaustion Signup and view all the answers

In managing hypovolemia due to burn injuries, what is critical to prevent tissue necrosis?

Maintaining proper fluid levels Signup and view all the answers

What can result from the high quantities of corticosteroids used in burn treatment?

Curling's ulcers Signup and view all the answers

What is one characteristic feature of heat stroke that differentiates it from other heat-related conditions?

Confusion and loss of consciousness Signup and view all the answers

Which of the following best describes the management strategy for heat cramps?

Fluid and salt replacement Signup and view all the answers

The development of which condition can lead to a significant risk of infection after thermal injuries?

Formation of eschar Signup and view all the answers

What is a significant consequence of the formation of eschar following a thermal injury?

Increased healing time Signup and view all the answers

What is a distinguishing factor of heat exhaustion compared to heat stroke?

Vasodilation leading to blood pooling Signup and view all the answers

Which mechanism primarily contributes to the development of Curling's ulcers in burn patients?

High levels of corticosteroids Signup and view all the answers

What physiological response occurs in the body when encountering hyperthermia?

Failure of heat regulation mechanisms Signup and view all the answers

Which of the following accurately describes generalized edema in the context of thermal injuries?

Potential to cause respiratory insufficiency Signup and view all the answers

What triggers the increased body temperature observed in fever, distinct from hyperthermia?

Elevated hypothalamic temperature set-point Signup and view all the answers

In the context of fluid loss, which statement is correct regarding the state of the patient during heat exhaustion?

Skin appears gray and wet with low blood pressure Signup and view all the answers

What is the primary issue associated with hypovolemia in burn victims?

Inadequate oxygen delivery to tissues Signup and view all the answers

Which term describes the leathery and stiff necrotic tissue formed after a burn injury?

Eschar Signup and view all the answers

Generalized edema in burn patients can lead to respiratory insufficiency.

True Signup and view all the answers

Heat cramps are characterized by increased body temperature over 40 C without sweat cessation.

False Signup and view all the answers

Formation of eschar is a sign of necrotic tissue that can lead to compression complications.

True Signup and view all the answers

Heat exhaustion is more severe than heat stroke and often leads to mortality.

False Signup and view all the answers

Malignant hyperthermia is a condition resulting from exposure to certain drugs and is inherited.

True Signup and view all the answers

Match the following heat-related conditions with their characteristics:

Heat Cramps = Painful spasms of voluntary muscles due to loss of water and electrolytes Heat Exhaustion = Characterized by weakness, headache, nausea, and vertigo followed by collapse Heat Stroke = Severe and life-threatening condition caused by heat exposure, usually with a body temperature > 40°C Fever = Defined as a temperature increase due to an increased body's temperature set-point Signup and view all the answers

Match the following complications of thermal injuries with their descriptions:

Hypovolemia = Shock due to fluid loss Generalized Edema = Leading to pulmonary insufficiency and respiratory insufficiency Infection = Virtually all burns are colonized Necrosis = Of surrounding tissue, leading to further complications Signup and view all the answers

Match the following terms with their definitions:

Eschar = Leathery and stiff necrotic tissue, leading to compression complications Malignant Hyperthermia = An inherited disease of skeletal muscle, triggered by certain drugs Curling's Ulcers = Peptic ulcers caused by high quantities of corticosteroids Hyperthermia = Increased body temperature > 37.5°C Signup and view all the answers

Match the following heat-related conditions with their management strategies:

Heat Cramps = Fluid and electrolyte replacement Heat Exhaustion = Fluid and electrolyte replacement, and moving to a cool place Heat Stroke = No exposure to a hot environment, and no antipyretics Fever = No specific management strategy mentioned Signup and view all the answers

Match the following physiological responses with their characteristics:

Vasodilation = Leading to peripheral circulatory failure and shock Hemoconcentration = Due to loss of water, leading to decreased effective blood volume Peripheral Vasodilation = Causes peripheral circulatory failure and shock Hypoperfusion = Leading to tissue necrosis Signup and view all the answers

What is a common effect of ionizing radiation on cells?

Production of congenital abnormalities Signup and view all the answers

What is a factor that influences the severity of tissue damage from ionizing radiation?

Dose Signup and view all the answers

What type of radiation is classified as potentially carcinogenic by the International Agency for Research on Cancer?

Radiofrequency radiation Signup and view all the answers

What is a common effect of nonionizing radiation on cells?

Alteration of 'free' moving ions and electrons Signup and view all the answers

What is a type of skin cancer associated with ultraviolet radiation exposure?

Malignant melanoma Signup and view all the answers

What is a sign that a mole may be turning into a malignant melanoma?

Asymmetry Signup and view all the answers

What is a effect of ionizing radiation on blood vessels?

Thrombosis Signup and view all the answers

What is a neurological effect of ionizing radiation?

Neuropathy Signup and view all the answers

What is a effect of ionizing radiation on cells?

Plasma membrane breaks Signup and view all the answers

Which of the following is a characteristic feature of nonionizing radiation?

Can alter 'free' moving ions and electrons Signup and view all the answers

What is a common effect of ionizing radiation on cells?

Production of cancer in irradiated cells Signup and view all the answers

Which of the following factors influences the severity of tissue damage from ionizing radiation?

All of the above Signup and view all the answers

What is a type of skin cancer associated with ultraviolet radiation exposure?

All of the above Signup and view all the answers

What is a sign that a mole may be turning into a malignant melanoma?

All of the above Signup and view all the answers

What is a effect of ionizing radiation on blood vessels?

All of the above Signup and view all the answers

What is a neurological effect of ionizing radiation?

Neurological effects are shown in exposure to cosmic radiation and radiotherapy Signup and view all the answers

What is a characteristic feature of chromosomal and nuclear changes caused by ionizing radiation?

Breaks in the plasma membrane Signup and view all the answers

What is a type of radiation classified as potentially carcinogenic by the International Agency for Research on Cancer?

Microwave radiation Signup and view all the answers

What is a common effect of nonionizing radiation on cells?

Disruption of electric and mechanical homeostasis Signup and view all the answers

Nonionizing radiation has sufficient energy to displace bound electrons from atoms.

False Signup and view all the answers

Total body irradiation can have long-term effects such as the production of cancer.

True Signup and view all the answers

Vascular anomalies caused by tissue damage from ionizing radiation may include thickening of the intima.

True Signup and view all the answers

One of the factors that influence the severity of tissue damage from radiation is the duration of exposure.

True Signup and view all the answers

Skin cancer caused by ultraviolet radiation only includes malignant melanoma.

False Signup and view all the answers

Match the following types of radiation with their characteristics:

Ionizing radiation = Can displace electrons and produce cancer Nonionizing radiation = Does not displace electrons but can alter ions Ultraviolet radiation = Associated with skin cancer and sunburn Microwave radiation = Classified as a category 2B carcinogen Signup and view all the answers

Match the following types of skin cancer with their descriptions:

Basal cell carcinoma = Most common skin cancer, rarely metastasizes Squamous cell carcinoma = Can spread to other parts of the body Malignant melanoma = Often characterized by changes in moles Actinic keratosis = Precursor to squamous cell carcinoma Signup and view all the answers

Match the following factors influencing tissue damage with their descriptions:

Dose = Amount of radiation exposure Tissue sensitivity = Varies by type of tissue exposed Duration of exposure = Length of time cells are exposed Penetration of tissues = Ability of radiation to affect deeper cells Signup and view all the answers

Match the following possible effects of ionizing radiation with their outcomes:

Cellular damage = Chromosomal and nuclear changes Vascular anomalies = Thickening of the intima and thrombosis Neurological effects = Effects from exposure to cosmic radiation Congenital abnormalities = Affecting the germ cell line Signup and view all the answers

Match the following signs indicating a mole turning malignant with their descriptions:

Asymmetry = One half doesn't match the other Border = Irregular edges Color = Variations in pigmentation Diameter = Larger than 6mm typically Signup and view all the answers

Match the type of burn to its description.

First degree layer = Epidermis Superficial second degree = Severe pain Deep second degree = Minimal pain Second degree layer = Dermis Signup and view all the answers

Match the type of mechanism of radiation injury to its description.

Direct action - Mode = Changes molecules in the cells Indirect action - Mode = Causes formation of free radicals Direct action - Target = Membrane, DNA Indirect action - Target = Bone marrow, endothelial cells Signup and view all the answers

Study Notes

Injury Due to Physical Agents

Physical injuries arise from mechanical, thermal, electrical, and nuclear energy sources.

Temperature Injuries

Cold Injuries
- Localized: Includes frostnip (cold sensation without freezing) and frostbite (frozen tissue).
- Generalized: Hypothermia occurs when body temperature drops below 35°C (95°F).
Localized Cold Injury
- Frostnip: Skin appears cold, but no freezing damage.
- Trench foot/Immersion foot: Occurs from prolonged exposure to cold water.
- Frostbite: Superficial types may recover in weeks; deep types can cause necrosis and risk of reperfusion injury.
Generalized Cold Injury
- Hypothermia is especially risky for children and the elderly.
- Mild hypothermia (36-35°C): Peripheral vasoconstriction and shivering occur.
- Moderate hypothermia (<32°C): Symptoms include drowsiness and confusion.
- Severe hypothermia (<28°C): Can lead to coma and death.
Heat Injuries
- Localized heat injuries primarily manifest as burns.
Incidence of Burns
- About 450,000 burn cases treated yearly in medical facilities, with 40,000 hospitalizations and 3,500 fatalities.
- Roughly 30% of burns occur in children, commonly from scalds.
Causes of Burns
- Fire/flame (43%), scalds (34%), contact with hot objects (9%), electricity (4%), chemicals (3%).

Burn Classification

First Degree: Involves only the epidermis; appears pink, dry, heals in 5-10 days without scarring.
Second Degree:
- Superficial partial-thickness: Red, blistered, wet, and painful; heals in approximately 3 weeks.
- Deep partial-thickness: Yellow/white, dry, and less painful; healing occurs in 3-8 weeks with scarring.
Third Degree: White or charred, leathery, minimal pain; heals over 8 weeks, often needing grafting.
Fourth to Sixth Degree: Involve deeper tissue damage with varying degrees of charred skin and exposed bone.

Mechanisms of Burn Injury

Local acute changes: Protein denaturation and damage to cells.
Surrounding tissues experience edema and release inflammatory substances.
Affected areas include zones of coagulation, stasis, and hyperemia.
Complications include hypovolemia, infections, necrosis, and scarring.

Generalized Heat Injury

Hyperthermia: Defined as body temperatures exceeding 37.5°C, not related to a change in the hypothalamic set-point.
Heat Cramps: Result from electrolyte loss; cause painful muscle spasms and require fluid and salt intake for prevention.
Heat Exhaustion: Common hyperthermic condition featuring weakness, nausea, and low blood pressure; usually treated by cooling and electrolyte replacement.
Heat Stroke: Severe condition with potential for mortality; marked by high body temperatures (>40°C), neurological symptoms, and circulatory shock.

Other Conditions

Fever: Increase in body temperature due to a higher set-point.
Malignant Hyperthermia: Inherited condition triggered by certain anesthetic drugs, causing a severe reaction in skeletal muscle when exposed to specific triggers.

Injury Due to Physical Agents

Physical injuries arise from mechanical, thermal, electrical, and nuclear energy sources.

Temperature Injuries

Cold Injuries
- Localized: Includes frostnip (cold sensation without freezing) and frostbite (frozen tissue).
- Generalized: Hypothermia occurs when body temperature drops below 35°C (95°F).
Localized Cold Injury
- Frostnip: Skin appears cold, but no freezing damage.
- Trench foot/Immersion foot: Occurs from prolonged exposure to cold water.
- Frostbite: Superficial types may recover in weeks; deep types can cause necrosis and risk of reperfusion injury.
Generalized Cold Injury
- Hypothermia is especially risky for children and the elderly.
- Mild hypothermia (36-35°C): Peripheral vasoconstriction and shivering occur.
- Moderate hypothermia (<32°C): Symptoms include drowsiness and confusion.
- Severe hypothermia (<28°C): Can lead to coma and death.
Heat Injuries
- Localized heat injuries primarily manifest as burns.
Incidence of Burns
- About 450,000 burn cases treated yearly in medical facilities, with 40,000 hospitalizations and 3,500 fatalities.
- Roughly 30% of burns occur in children, commonly from scalds.
Causes of Burns
- Fire/flame (43%), scalds (34%), contact with hot objects (9%), electricity (4%), chemicals (3%).

Burn Classification

First Degree: Involves only the epidermis; appears pink, dry, heals in 5-10 days without scarring.
Second Degree:
- Superficial partial-thickness: Red, blistered, wet, and painful; heals in approximately 3 weeks.
- Deep partial-thickness: Yellow/white, dry, and less painful; healing occurs in 3-8 weeks with scarring.
Third Degree: White or charred, leathery, minimal pain; heals over 8 weeks, often needing grafting.
Fourth to Sixth Degree: Involve deeper tissue damage with varying degrees of charred skin and exposed bone.

Mechanisms of Burn Injury

Local acute changes: Protein denaturation and damage to cells.
Surrounding tissues experience edema and release inflammatory substances.
Affected areas include zones of coagulation, stasis, and hyperemia.
Complications include hypovolemia, infections, necrosis, and scarring.

Generalized Heat Injury

Hyperthermia: Defined as body temperatures exceeding 37.5°C, not related to a change in the hypothalamic set-point.
Heat Cramps: Result from electrolyte loss; cause painful muscle spasms and require fluid and salt intake for prevention.
Heat Exhaustion: Common hyperthermic condition featuring weakness, nausea, and low blood pressure; usually treated by cooling and electrolyte replacement.
Heat Stroke: Severe condition with potential for mortality; marked by high body temperatures (>40°C), neurological symptoms, and circulatory shock.

Other Conditions

Fever: Increase in body temperature due to a higher set-point.
Malignant Hyperthermia: Inherited condition triggered by certain anesthetic drugs, causing a severe reaction in skeletal muscle when exposed to specific triggers.

Injury Due to Physical Agents

Physical injuries arise from mechanical, thermal, electrical, and nuclear energy sources.

Temperature Injuries

Cold Injuries
- Localized: Includes frostnip (cold sensation without freezing) and frostbite (frozen tissue).
- Generalized: Hypothermia occurs when body temperature drops below 35°C (95°F).
Localized Cold Injury
- Frostnip: Skin appears cold, but no freezing damage.
- Trench foot/Immersion foot: Occurs from prolonged exposure to cold water.
- Frostbite: Superficial types may recover in weeks; deep types can cause necrosis and risk of reperfusion injury.
Generalized Cold Injury
- Hypothermia is especially risky for children and the elderly.
- Mild hypothermia (36-35°C): Peripheral vasoconstriction and shivering occur.
- Moderate hypothermia (<32°C): Symptoms include drowsiness and confusion.
- Severe hypothermia (<28°C): Can lead to coma and death.
Heat Injuries
- Localized heat injuries primarily manifest as burns.
Incidence of Burns
- About 450,000 burn cases treated yearly in medical facilities, with 40,000 hospitalizations and 3,500 fatalities.
- Roughly 30% of burns occur in children, commonly from scalds.
Causes of Burns
- Fire/flame (43%), scalds (34%), contact with hot objects (9%), electricity (4%), chemicals (3%).

Burn Classification

First Degree: Involves only the epidermis; appears pink, dry, heals in 5-10 days without scarring.
Second Degree:
- Superficial partial-thickness: Red, blistered, wet, and painful; heals in approximately 3 weeks.
- Deep partial-thickness: Yellow/white, dry, and less painful; healing occurs in 3-8 weeks with scarring.
Third Degree: White or charred, leathery, minimal pain; heals over 8 weeks, often needing grafting.
Fourth to Sixth Degree: Involve deeper tissue damage with varying degrees of charred skin and exposed bone.

Mechanisms of Burn Injury

Local acute changes: Protein denaturation and damage to cells.
Surrounding tissues experience edema and release inflammatory substances.
Affected areas include zones of coagulation, stasis, and hyperemia.
Complications include hypovolemia, infections, necrosis, and scarring.

Generalized Heat Injury

Hyperthermia: Defined as body temperatures exceeding 37.5°C, not related to a change in the hypothalamic set-point.
Heat Cramps: Result from electrolyte loss; cause painful muscle spasms and require fluid and salt intake for prevention.
Heat Exhaustion: Common hyperthermic condition featuring weakness, nausea, and low blood pressure; usually treated by cooling and electrolyte replacement.
Heat Stroke: Severe condition with potential for mortality; marked by high body temperatures (>40°C), neurological symptoms, and circulatory shock.

Other Conditions

Fever: Increase in body temperature due to a higher set-point.
Malignant Hyperthermia: Inherited condition triggered by certain anesthetic drugs, causing a severe reaction in skeletal muscle when exposed to specific triggers.

Injury Due to Physical Agents

Physical injuries arise from mechanical, thermal, electrical, and nuclear energy sources.

Temperature Injuries

Cold Injuries
- Localized: Includes frostnip (cold sensation without freezing) and frostbite (frozen tissue).
- Generalized: Hypothermia occurs when body temperature drops below 35°C (95°F).
Localized Cold Injury
- Frostnip: Skin appears cold, but no freezing damage.
- Trench foot/Immersion foot: Occurs from prolonged exposure to cold water.
- Frostbite: Superficial types may recover in weeks; deep types can cause necrosis and risk of reperfusion injury.
Generalized Cold Injury
- Hypothermia is especially risky for children and the elderly.
- Mild hypothermia (36-35°C): Peripheral vasoconstriction and shivering occur.
- Moderate hypothermia (<32°C): Symptoms include drowsiness and confusion.
- Severe hypothermia (<28°C): Can lead to coma and death.
Heat Injuries
- Localized heat injuries primarily manifest as burns.
Incidence of Burns
- About 450,000 burn cases treated yearly in medical facilities, with 40,000 hospitalizations and 3,500 fatalities.
- Roughly 30% of burns occur in children, commonly from scalds.
Causes of Burns
- Fire/flame (43%), scalds (34%), contact with hot objects (9%), electricity (4%), chemicals (3%).

Burn Classification

First Degree: Involves only the epidermis; appears pink, dry, heals in 5-10 days without scarring.
Second Degree:
- Superficial partial-thickness: Red, blistered, wet, and painful; heals in approximately 3 weeks.
- Deep partial-thickness: Yellow/white, dry, and less painful; healing occurs in 3-8 weeks with scarring.
Third Degree: White or charred, leathery, minimal pain; heals over 8 weeks, often needing grafting.
Fourth to Sixth Degree: Involve deeper tissue damage with varying degrees of charred skin and exposed bone.

Mechanisms of Burn Injury

Local acute changes: Protein denaturation and damage to cells.
Surrounding tissues experience edema and release inflammatory substances.
Affected areas include zones of coagulation, stasis, and hyperemia.
Complications include hypovolemia, infections, necrosis, and scarring.

Generalized Heat Injury

Hyperthermia: Defined as body temperatures exceeding 37.5°C, not related to a change in the hypothalamic set-point.
Heat Cramps: Result from electrolyte loss; cause painful muscle spasms and require fluid and salt intake for prevention.
Heat Exhaustion: Common hyperthermic condition featuring weakness, nausea, and low blood pressure; usually treated by cooling and electrolyte replacement.
Heat Stroke: Severe condition with potential for mortality; marked by high body temperatures (>40°C), neurological symptoms, and circulatory shock.

Other Conditions

Fever: Increase in body temperature due to a higher set-point.
Malignant Hyperthermia: Inherited condition triggered by certain anesthetic drugs, causing a severe reaction in skeletal muscle when exposed to specific triggers.

Mechanical Injury

Causes of deaths from trauma: approximately 160,000/year
Breakdown of causes:
- Motor vehicle accident: 44,000
- Firearms: 30,000 (55% suicide, 40% homicide, 5% accidental or law enforcement related)
- Acute toxic exposure: 26,000
- Falls: 17,000
- Suffocation including drowning: 13,000
- All other: 31,000
Types of injuries:
- Abrasion: scraping the skin surface, damaging superficial layer of skin
- Contusion or bruise: blunt force, causing hemorrhages under intact skin
- Laceration and incision: tearing (blunt force) and cutting (sharp object)
- Avulsions and fracture: tendon insertions and bones
- Extended compression: ulcers
- Gravity alteration: accelerated aging
Mechanical energy (E) is transferred into the tissue due to action of forces (F) or force fields, causing displacement (∆x) and change in velocity (v)
E = F∆x = ∆mv2/2

Pressure Ulcer

Ischemia with compression or shear forces
Stages of pressure ulcer: 1-4, depending on depth
Preceding stage 1 changes:
- Sensation
- Temperature
- Tissue firmness
Early detection methods:
- Subepidermal micro-edema, micro-vascularisation, micro-hemorrhages
- High-frequency ultrasound
- Thermography IR with adjacent skin comparison
- Spectroscopy (Hb)
- Skin electric conductance (most reliable)

Electrical Injuries

Causes: electrocution and lightning strike
Physics of electrical injuries:
- Current flows in a closed circuit from high energy to low energy of electrical charges
- Amount of current (I) is related to:
  - Voltage exposed to
  - Resistance of the body tissues and of skin at the point of entry and exit
  - Available moving electrical charges (electrons and ions)
Severity of tissue damage is dependent on the amount of energy transferred into the tissue: E = I2Rt = VIt = V2t/R
Two major effects:
- Passage of current producing heat
- Interfering with the function of electrical tissues: alteration of electrons and ions flow across membranes

Ionizing Radiation Injury

Sources of exposure:
- Natural radiation (cosmic, earth, inside living organisms)
- Nuclear bombs
- Nuclear reactor
- Diagnostic and therapeutic purposes
Radiation terminology:
- Rad: a measure of the energy absorbed per unit mass of the tissue
- Gray: the SI unit that replaced the rad
- Roentogen (R): a unit of radiation exposure
- Sievert (Si) and rem (radiation equivalent man): biological equivalent dose
Types of ionizing radiation:
- Mechanism of radiation injury:
  - Direct action: changes molecules in the cells themselves
  - Indirect action: causes formation of free radicals
Effects of radiation injury:
- Cellular injury, necrosis, or apoptosis
- Mostly fibrosis
- Vascular anomalies
- Neurological effects
- Production of cancer in irradiated cell
- Production of congenital abnormalities in germ cell line

Nonionizing Radiation

Energy of nonionizing radiation can move atoms in a molecule or cause them to vibrate, but it is not sufficient to displace bound electrons from atoms
Cells have mechanosensitive and electrosensitive structure interconnected to all cellular functions
Disruption of electric and mechanical homeostasis needs to be investigated

Ultraviolet Radiation

Effects:
- Sun burn
- Accelerated aging of the skin
- Skin cancer
  - Basal cell carcinoma
  - Squamous cell carcinoma
  - Malignant melanoma
Signs that a mole may be turning into a malignant melanoma:
- Asymmetry
- Border
- Color
- Diameter
- Evolution

Visible, Infrared, Microwave, and Radio

Classified as a category 2B agent = potentially carcinogenic by International Agency for Research on Cancer (IARC)--Agenda of World Health Organization (WHO)

Mechanical Injury

Approximately 160,000 deaths/year from trauma
Causes of deaths from trauma: • Motor vehicle accident: 44,000 • Firearms: 30,000 (55% suicide, 40% homicide, 5% accidental or law enforcement related) • Acute toxic exposure: 26,000 • Falls: 17,000 • Suffocation including drowning: 13,000 • All other: 31,000
Types of injuries: • Abrasion: scraping the skin surface, damaging the superficial layer of skin • Contusion or bruise: blunt force causing hemorrhages under intact skin • Laceration and incision: tearing (blunt force) and cutting (sharp object) • Avulsions and fracture: tendon insertions and bones • Extended compression: ulcers • Gravity alteration: accelerated aging
Mechanical energy (E): transferred into the tissue due to action of forces (F) or force fields, causing displacement (∆x) and change in velocity (v) • E = F∆x = ∆mv²/2

Pressure Ulcer

Caused by ischemia with compression or shear forces
1-4 stages, depending on depth
Preceding stage 1 are changes significant for detection: • Sensation • Temperature • Tissue firmness
Early detection possible based on: • Subepidermal micro-edema • Micro-vascularisation • Micro-hemorrhages
- Using high-frequency ultrasound
- Thermography IR with adjacent skin comparison
- Spectroscopy (Hb)
- Skin electric conductance (most reliable)

Abnormal Gravity Effects

Microgravity in space flight: accelerated aging documented on: • Musculoskeletal • Cardiovascular • Respiratory • Neurologic • Blood and CSF redistribution • Metabolic • Endocrine • Eyes
Mostly reversible with appropriate intervention after returning to Earth gravity

Electrical Injuries

Causes: electrocution and lightning strike
Physics of electrical injuries: • Current flows in a closed circuit from high energy to low energy of electrical charges • Amount of current (I) is related to:
- Voltage exposed to
- Resistance of the body tissues and of skin at the point of entry and exit
- Available moving electrical charges (electrons and ions) • Severity of tissue damage is dependent on the amount of energy transferred into the tissue: E = I²Rt = VIt = V²t/R
Two major effects: • Passage of current producing heat – happens in any tissue or object • Interfering with the function of electrical tissues: alteration of electrons and ions flow across membranes
- Effects on: • Muscles: spasm, mostly for AC • Cardiac conduction tissue: ventricular fibrillation • Depression of respiratory centers
Low energy electric and electromagnetic fields or radiation may not be life-threatening but still pathological • Alteration of electrons and ions flow across membranes = classical view of electric current effects • Alteration of voltage-gated ion channels
- Most sensitive appears to be voltage-gated calcium channel (VGCC) – multiple effects due to increased intracellular Ca
Electric (and magnetic) fields can also be beneficial by: • Restoring electromagnetic “homeostasis”: muscle rehab, tissue growth, and repair • Resetting activity of electrical dependant tissue: e.g. defibrillator in cardiac arrest

Ionizing Radiation Injury

Sources of exposure: • Natural radiation (cosmic, earth, inside living organisms) • Nuclear bombs • Nuclear reactor • Diagnostic and therapeutic purposes
Radiation terminology: • Rad: measure of the energy absorbed per unit mass of the tissue (1 rad = 100 ergs per gram of tissue) • Gray (Gy): SI unit that replaced the rad (1 Gy = 1J/kg = 100 rads) • Roentgen (R): unit of radiation exposure (For X-ray, 1R ~ 1 rad) • Sievert (Si) and rem (radiation equivalent man): biological equivalent dose (BED)
- BED (in Si) = D (in Gy) x Q (“quality” factor) • Q: how effective is radiation in damaging tissue compared with X-ray or high-energy electrons
Types of ionizing radiation: • Direct action: changes molecules in the cells themselves
- “Direct hit”: Membrane, DNA • Indirect action: causes formation of free radicals
- Damage to cells and especially rapid dividing cells (bone marrow, epithelial, endothelial cells)
Effects of radiation injury: • Cellular injury, necrosis, or apoptosis
- Cytoplasmic swelling
- Mitochondrial distortion
- Degeneration of the endoplasmic reticulum
- Plasma membrane breaks/focal defects may be seen
- Chromosomal and nuclear changes • Mostly fibrosis, like after chronic inflammation • Vascular anomalies, with fibrosis, collagenous hyalinization, thickening of the intima, thrombosis, scaring • Neurological effects: shown in exposure to cosmic radiation and radiotherapy • Production of cancer in irradiated cells • Production of congenital abnormalities in germ cell line
Factors that influence the severity of tissue damage: • Dose • Penetration of tissues • Sensitivity of tissues • Duration of exposure
Effects of total body irradiation

Nonionizing Radiation

Energy of nonionizing radiation (UV and infrared light, microwave, and sound waves) can: • Move atoms in a molecule • Cause them to vibrate • Alter “free” moving ions and electrons (ion channels and ETS)
Cells have mechanosensitive and electrosensitive structures interconnected to all cellular functions, so disruption of electric and mechanical homeostasis needs to be investigated

Ultraviolet Radiation

Causes: • Sunburn • Accelerated aging of the skin • Skin cancer
- Basal cell carcinoma
- Squamous cell carcinoma
- Malignant melanoma
Signs that a mole may be turning into a malignant melanoma: • Asymmetry • Border • Color • Diameter • Evolution

Visible, Infrared, Microwave, and Radio

Classified as a category 2B agent = potentially carcinogenic by International Agency for Research on Cancer (IARC)--Agncy of World Health Organization (WHO)

Mechanical Injury

Trauma accounts for approximately 160,000 deaths annually.
Leading causes include:
- Motor vehicle accidents: 44,000 deaths
- Firearms: 30,000 deaths (55% suicide, 40% homicide, 5% accidental/law enforcement)
- Acute toxic exposures: 26,000 deaths
- Falls: 17,000 deaths
- Suffocation (including drowning): 13,000 deaths
- Other causes: 31,000 deaths
Types of mechanical injuries:
- Abrasion: Scraping of the skin's surface, affecting the superficial layer.
- Contusion: Bruise from blunt force, with hemorrhage beneath intact skin.
- Laceration and Incision: Result from tearing (blunt force) or cutting (sharp object).
- Avulsions and Fractures: Involvement of tendon insertions and bones.
- Extended Compression: Can lead to ulcers.
- Gravity Alteration: Linked to accelerated aging.
Mechanical energy (E) is calculated as (E = F \Delta x = \Delta \frac{mv^2}{2}), indicating the transfer of energy into tissue from forces.

Pressure Ulcers

Develop from ischemia due to compression or shear forces.
Classified into 1 to 4 stages based on tissue depth.
Early indicators include changes in sensation, temperature, and tissue firmness.
Early detection methods involve:
- Subepidermal micro-edema
- Micro-vascularization
- Micro-hemorrhages
- Techniques like high-frequency ultrasound and thermography
- Skin electric conductance is the most reliable method.
Microgravity effects in space contribute to accelerated aging across various bodily systems but are mostly reversible upon return to Earth.

Electrical Injuries

Caused by electrocution and lightning strikes.
Current flows in a closed circuit from high to low energy; severity relies on current amount, voltage, and tissue resistance.
Tissue damage severity is determined by energy transfer, computed as (E = I^2Rt = VIt = \frac{V^2t}{R}).
Major effects include:
- Heat production during current passage impacting all tissues.
- Disruption of electrical tissue function, causing muscle spasms and potential cardiac issues.
Low-energy electric fields may cause pathological effects but can also provide therapeutic benefits, aiding in muscle rehab and tissue repair.

Ionizing Radiation Injury

Sources of Exposure:
- Natural radiation (cosmic, terrestrial, biological)
- Nuclear bombs and reactors
- Medical diagnostics and treatments
Radiation Terminology:
- Rad: Measure of energy absorption (1 rad = 100 ergs/g tissue)
- Gray (Gy): SI unit replacing rad; 1 Gy = 1 J/kg = 100 rads
- Sievert (Sv): Biological equivalent dose for radiation effects in humans.
Mechanisms of Radiation Injury:
- Direct action: Damages cellular molecules (membrane, DNA).
- Indirect action: Creates free radicals that harm rapidly dividing cells.
Effects of Radiation Injury:
- Cellular damage can lead to necrosis or apoptosis.
- Common consequences include fibrosis, vascular anomalies, and neurological effects from cosmic radiation.
- Increases risk of cancer and congenital abnormalities.
Severity of damage influenced by dose, tissue penetration, tissue sensitivity, and exposure duration.

Nonionizing Radiation

Includes UV, infrared, microwaves, and sound waves; sufficient energy to move atoms but not to displace bound electrons.
Alters free ions and electrons, impacting cellular functions through mechanosensitive and electrosensitive structures.

Ultraviolet Radiation

Causes sunburn, accelerates skin aging, and increases skin cancer risks, including:
- Basal cell carcinoma
- Squamous cell carcinoma
- Malignant melanoma
Signs of potential malignant melanoma transformation include changes in asymmetry, border, color, diameter, and evolution of moles.

Visible, Infrared, Microwave, and Radio

Classified as potential carcinogens (Category 2B) by the International Agency for Research on Cancer (IARC).

Mechanical Injury

Trauma causes approximately 160,000 deaths annually.
Motor vehicle accidents contribute 44,000 deaths; firearms account for 30,000 with 55% attributed to suicide, 40% to homicide, and 5% to accidental or law enforcement-related incidents.
Other contributors include acute toxic exposure (26,000), falls (17,000), suffocation (including drowning, 13,000), and remaining causes (31,000).

Types of Mechanical Injuries

Abrasion: Scraping of skin leading to superficial damage.
Contusion: Bruising due to blunt force trauma, resulting in hemorrhage under intact skin.
Laceration and incision: Tearing from blunt force and cutting from sharp objects.
Avulsions and fractures: Involves detaching tendon insertions and breaking of bones.
Extended compression: Leads to ulcers due to sustained pressure.
Gravity alteration can accelerate aging.

Mechanical Energy Fundamentals

Energy (E) is transferred to tissues through force (F) action, causing displacement (Δx) and a change in velocity (v).
Energy equation: E = FΔx = Δ(1/2 mv²).

Pressure Ulcers

Pressure ulcers develop from ischemia caused by compression or shear forces, categorized into stages 1 to 4 based on depth.
Early detection signs include changes in sensation, temperature, and tissue firmness.
Detection techniques: high-frequency ultrasound, IR thermography, spectroscopy, and skin electric conductance are useful for early identification.

Microgravity Effects

Microgravity from space flight accelerates aging in multiple systems including musculoskeletal and cardiovascular, often reversible with interventions post-return to Earth.

Electrical Injuries

Common causes include electrocution and lightning strikes.
Current flows from high to low energy through a closed circuit, calculated using I = V/R, where I is current, V is voltage, and R is resistance.
Severity of damage depends on energy transferred: E = I²Rt = VIt = V²t/R.

Effects of Electrical Currents

Current passage creates heat and can disrupt the function of electrically active tissues, leading to muscle spasms, cardiac arrhythmias, and respiratory depression.
Low energy electric fields can have pathological effects by altering ion flows and voltage-gated ion channels, particularly affecting calcium channels.

Ionizing Radiation Injury

Sources include natural radiation, nuclear activities, and medical procedures.
Radiation exposure measured in rads (1 rad = 100 ergs/g), with the Gray (Gy) as the SI unit replacing rad (1 Gy = 100 rads).
Biological equivalent dose is expressed in Sieverts (Si), factoring in quality (Q) of radiation.

Mechanism of Radiation Injury

Direct action involves changes in cell molecules leading to membrane and DNA damage.
Indirect action results in free radical formation damaging rapidly dividing cells, notably in bone marrow and epithelial cells.

Effects of Radiation Injury

Cellular necrosis or apoptosis, resulting in cellular swelling and mitochondrial distortion.
Potential for chronic fibrosis, vascular anomalies, neurological effects from cosmic radiation, cancer development, and congenital abnormalities in germ cells.

Factors Influencing Radiation Damage

Severity influenced by dose, tissue penetration, tissue sensitivity, and duration of exposure.

Nonionizing Radiation

Nonionizing radiation includes UV, infrared, microwaves, and sound waves; it can alter moving ions but doesn’t have sufficient energy to displace bound electrons.
Disruption of cellular electric and mechanical homeostasis can affect overall cellular function.

Ultraviolet Radiation Effects

Causes sunburn, accelerates skin aging, and is linked to skin cancers: basal cell carcinoma, squamous cell carcinoma, and malignant melanoma.
Malignant melanoma assessment involves evaluating asymmetry, border irregularity, color variation, diameter, and evolution of moles.

Classification of Nonionizing Radiation

UV, visible light, infrared, microwave, and radio classified as potential carcinogens per the International Agency for Research on Cancer (IARC).

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Description

This quiz examines injuries caused by physical agents, including temperature effects, mechanical trauma, electrical current, and radiation. Topics include frostbite, hypothermia, burns, and hyperthermia. Test your understanding of various thermal injuries and their classifications.