Chemical and Physical Injury

Question 1

toxic products of ethylene glycol

Answer 1

Glycolic acid and glyxolic acid via aldehyde dehydrogenase

Question 2

Secondary metabolites of ethylene glycol

Answer 2

Formate, oxalate

Oxalate is highly toxic in small amounts (nephrotoxicity)

Question 3

Areas of brain damaged by CO inhalation

Answer 3

globus pallidus

Pars reticularis of substantia nigra

Question 4

Biological half life of CO

Answer 4

4-6 hours on room air
40-80 minutes on 100% O2
15-30 minutes on hyperbaric O2

Question 5

Effects of CO on hemoglobin curve

Answer 5

Left shift

hgb remains saturated with O2 even at low pO2 of tissues

Question 6

CO effect on mitochondria

Answer 6

Binds to the hemeochromes in ETC –> impaired respiration

Question 7

LD of CO

Answer 7

Varies.
Very low in children or patients with COPD
Higher in smokers (baseline levels reach 15%)

Question 8

Mechanisms of CO damage to CNS

Answer 8

1. Direct hypoxia
2. Cell death mediated cerebral edema
3. Direct binding to neurons of the SN and gobus pallidus –> parkinsonianism
4. Myelinopathy

Question 9

Relation of cyanide to CO poisoning

Answer 9

CO poisoning occurs primarily in house fires, which also release cyanide from building materials.
Cyanide inhalation can be just as dangerous.

Question 10

Free basing

Answer 10

Extraction of cocaine salt and smoking it

Carries risk of ignition of remaining solvent

Question 11

Crack

Answer 11

Cocaine purified with baking soda

Question 12

Administration routes of cocaine and associated bioavailabilty

Answer 12

IV: 100%
Intranasal: 25-94%, cocaine constricts nasal vessels. People snorting cocaine will also swallow some.
Ingesition: LOW due to first pass metabolism from portal blood
Smoking: RAPID absorption, depends on smoking technique
Rectal: Unknown, but bypasses portal system metabolism

Question 13

Cocaine metabolites that are stimulatory

Answer 13

Ethylcocaine
Norcocaine (p450)
Cocaine
Benzylcocaine is main metabolite and is not active

Question 14

Cocaine metabiolites made by smoking or EtOH ingestion and p450 metabolism

Answer 14

EtOH: Ethylcocaine
Smoking: Methylecgonide
p450: norcocaine

Major metabolite is benzyloegonine

Question 15

Importance of ethylcocaine

Answer 15

Formed with EtOH ingestion, stronger and has longer half live than cocaine

Question 16

Mechanisms of Toxicity for cocaine

Answer 16

1. Monoamine reuptake inhibition
2. Reduced sodium channel conductance
3. Long-term neruophysiological changes–> psychiatric Disease

DEATH IS NOT DOSE DEPENDENT

Question 17

Abrasions concurring when force is perpendicular to the skin

Answer 17

Impact abrasion

Question 18

Pattern abrasion

Answer 18

abrasions showing the pattern of the offending object

Question 19

Clinical used of “contusion”

Answer 19

May be internal or external bruising

Use of word must be accompanied by explanation as it implies blunt force trauma

Question 20

Tearing of tissue

Answer 20

Laceration

Question 21

Characteristics of laceration

Answer 21

Adjacent abrasions
Bridging of tissue, nerves or blood vessels in wound
Adjacent area of contusion
Irregular wound edges

Question 22

Characteristics of an incision

Answer 22

Linear wound edges without bridging

Abrasions or contusions may or may not be present

Question 23

Sharp force injury that is deeper than it is wide

Answer 23

Stab

Question 24

Sharp force injuries that also have characteristics of a blunt trauma, including potential for bone markings

Answer 24

Chop

Question 25

Three types of contact gunshot wounds

Answer 25

Tight Loose Near

Question 26

Differentiation of contact gunshot wounds

Answer 26

Tight: Radiating skin splitting, muzzle imprint (due to gaseous expansion against muzzle) Loose: No splitting, muzzle imprint present Near: Lacks splitting, muzzle, and signs of intermediate GSW (stippling)

Question 27

Characteristics of intermediate GSW

Answer 27

``` Stippling from unburnt powder No soot (See only in contact wounds) ```

Question 28

Characteristics of distant GSW

Answer 28

No signs seen in intermediate or near GSW (no stippling, soot, muzzle imprint, skin splitting)

Question 29

Characteristics of a first degree burn

Answer 29

Damage to epidermis only

Question 30

Characteristics of a second degree burn

Answer 30

Damage to upper skin layers Blistering Dues not penetrate epidermis

Question 31

Characteristics of a third degree burn

Answer 31

Deep damage extending through the dermis and skin structures into the dermis. Requires skin grafts

Question 32

Characteristics of a fourth degree burn

Answer 32

Severe damage penetrating the epidermis and dermis to underlying structures. Requires grafting, debridement, etc.

Question 33

Rule of 9's

Answer 33

``` Head 9% Each arm 9% Front of each leg 9% back of each leg 9% Front of torso 18% back 18% Genitals 1% ``` Does not apply to infants

Question 34

Determining variable in electrocution

Answer 34

Amperage | I= V/R

Question 35

Most damaging amperage

Answer 35

between 40-150Hz | (household wiring is 60Hz

Question 36

Characteristics of electrocution burns

Answer 36

Present only in 50% of all electrocutions White, chalky appearance with raised border and central crater Most typically seen on thick palmar or plantar skin

Question 37

Mechanism of death in most lightning strikes

Answer 37

Cardiac or pulmonary arrest

Question 38

Potential non-environmental causes of hyperthermia

Answer 38

MDMA + dancing Anti-cholinergics (reduce vasodiation) Malignant hyperthermia with anesthesia

Question 39

External signs of asphyxiation

Answer 39

Cyanosis | Conjuntival hemmorhage

Question 40

Pressure exerted outside the body --> impedance of inspiration

Answer 40

Mechanical asphixiation

Question 41

Internal asphyxiation

Answer 41

Suffocation from excess intra-abdominal pressure (seen in gut motility issues, opiate overdoses, CP)

Question 42

Characteristics of manual strangulation

Answer 42

Fracture of tracheo-laryngeal skeleton Conjunctival petechiae Abrasions or fingernail marks on neck

Question 43

Characterisitics of ligature strangulation

Answer 43

Ligature abrasions Petechiae Tracheolaryngeal skeleton fracture Suffocation is VERY RAPID

Question 44

Unique characteristics of hanging asphyxiation

Answer 44

Ligature furrow Absent ocular petechiae or tracheolarygeal fracture