Chemical / Physical Injury

Question 1

Toxic metabolites of ethylene glycol
Which causes AGMA?
Histologic hallmark
Treatment

Answer 1

Oxalate and glycolate
Glycolate causes AGMA
Hallmark is Ca-oxalate crystals in kidney. Polarizable.
Treat w/ ethanol

Question 2

CO brain damage

Answer 2

CO binds cytochrome enzymes in neurons of globus pallidus and pars reticulara of substantia nigra → Parkinsonism.

Question 3

4 metabolites of cocaine

Answer 3

• Most cocaine is metabolized to benzoylecgonine
• Combined w/ ethanol, metabolite is coca-ethylene / ethyl-cocaine. Stronger activity and longer half-life.
• Norcocaine generated in people w/ activated P450 system (alcoholics)
• Smoking cocaine produces methylecgonidine

Question 4

Cocaine toxicity

Answer 4

• Blocks reuptake of NE, DA, 5HT, and blocks Na-channel conductance. Main targets are the CV system and CNS.
• Cocaine accelerates atherosclerosis
• Cardiac arrhythmias, intracranial hemorrhage, aortic dissection, coronary artery spasm, seizure, hypertensive crisis, acute psychosis, chronic schizophrenic psychosis, hyperthermia, coma

Question 5

Cocaine bioavailability
IV
Intranasal
Swallowed
Smoking

Answer 5

IV: 100%
Intranasal: 25-95%
Swallowed: 20%
Smoking: 65%

Question 6

Abrasion vs laceration

Answer 6

Abrasion is from frictional / pressure forces

Laceration is tearing from compression, stretching, or crushing.

Question 7

Clues to laceration (3)

Answer 7

Nerve / vessel bridinging, irregular edges, and adjacent contusion.

Question 8

Burn degrees

Answer 8

• 1st degree – epidermis
• 2nd degree – upper layers w/ blistering +/- scarring
• 3rd degree – dermis, often requires skin transplant
• 4th degree – charring of underlying tissues

Question 9

Causes of death from electrocution

Answer 9

Cardiac, respiratory, CNS, or internal charring.

Internal organs are often congested.

Question 10

Skin / histology appearance of non-lightning electrocution

Answer 10

Brown tough tissue on skin, surrounded by pallor, surrounded by erythema. Histology shows severe denaturation of collagen, elevation of epidermis w/ microblisters, and distortion of nuclei in epidermis.

Question 11

Hyperthermia
Temp
High risk pxs
Malignant hyperthermia

Answer 11

> 106 F
•High risk: elderly, very young, diabetics, cardiopulmonary disease, poor, anti-cholinergic meds, such as benztropine or phenothiazine (lack of sweating and vasodilation).
•Malignant hyperthermia - syndrome of hypermetabolism (tachycardia, tachypnea, muscle spasms) triggered by halogenated anesthetic inhalants and succinylcholine. Some genetic susceptibility.

Question 12

Hypothermia
Temp
High risk
Pathophysiology

Answer 12

Less than 95 F
High risk: elderly, very young, intoxicated, and mentally ill.
Erythema of large joints and hypothermic gastric ulcers

Question 13

2 main clues of asphyxiation

Answer 13

Cyanosis and small conjunctival hemorrhages (petechiae)

Question 14

3 types of mechanical asphyxia

Answer 14

Traumatic (car on chest), positional, and internal (excessive intra-abdominal pressure).

Question 15

Which types of strangulation involve ocular petechiae and fractures of tracheolaryngeal skeleton?

Answer 15

Manual and ligature strangulation do. Hanging does NOT.

Question 16

Tight contact GSW characteristics

Answer 16

Skin splitting +/- muzzle stamp. Soot and powder. Large stellate entry wound from gas.

Question 17

Loose contact GSW characteristics

Answer 17

No skin splitting. +/- muzzle stamp

Question 18

Near contact GSW characteristics

Answer 18

Soot w/o stippling

Question 19

intermediate range GSW characteristics

Answer 19

Stippling

Question 20

Indeterminate range GSW characteristics

Answer 20

No splitting, soot, or stippling