Forensic Pathology

Question 1

cause of death

Answer 1

disease or injury that initiated the lethal chain of events
o May precede death by seconds or years
o Intermediate illnesses of conditions may connect current fatal condition to initiating condition
o Can stand alone on death certificate

Not: cardiac arrest, respiratory arrest, renal failure, asystole, etc

Question 2

mechanism of death

Answer 2

nonspecific etiology; broad differential; cannot stand alone on a death certificate
o Cardiac arrest, hypoxia, etc

Question 3

manner of death

Answer 3

how/circumstances – natural, accident, suicide, homicide, undetermined

Question 4

rigor mortis

Answer 4

-lactic acid builds up while cells try to stay alive –> this stiffens the muscles

Question 5

marbling

Answer 5

decomposition that occurs initially in the vasculature

Question 6

abrasion

Answer 6

scraping and removal of superficial skin; contact with rough surface, by sliding or pressure
o Scrape (linear), Brush burn/Road Rash (frictional force of rubbing against a rough surface over large area)
o pattern reflects object
o readily form thin scab

Question 7

contusion

Answer 7

area of bleeding (hemorrhage) into the skin or soft tissue as a result of rupture of blood vessels due to blunt force injury or pressure (BRUISE)

o site of contusion isn’t necessarily the point of impact (baseball bat, hand examples)

Question 8

hematoma

Answer 8

o focal collection of blood

Question 9

coup and contre-coup

Answer 9

coup injury is on side of impact and contrecoup is on the opposite side of primary impact (brain moves and hits opposite side of skull)

Question 10

bruising coloration

red/blue/purple/black can occur…

Answer 10

anytime but often are early

Question 11

bruising coloration

a bruise with yellow….

Answer 11

is atleast 18 hours old

but the converse is not true

Question 12

laceration

Answer 12

tearing (not a cut or incision) of the skin or tissue due to stretching, crushing, shearing or avulsing by blunt force injury
o Can have abrasion and/or contusions around edges; rarely patterned
o Soft tissue bridging is the hallmark
o NOT a cut or a stab

Question 13

fracture

Answer 13

lacerations of bone caused by BFI, that occur when the quantity of force overcomes the strength of bone
o Fatal fractures = skull or C-spine
o Long bones fractures are rarely fatal
 Fat embolism syndrome

Question 14

atlanto-occipital dislocation

Answer 14

dens (axis/C2) is horizontally fractured from C1 and occipital condyles of skull base –> severs respiratory centers in the medulla oblongata

Question 15

2 processes of post mortem decomposition

Answer 15

autolysis and putrefaction

Question 16

autolysis

Answer 16

aseptic dissolution of organs by intracellular enzymes

 **organs with enzymes (pancreas) autolyze faster than those without (ex: kidney)

Question 17

putrefaction

Answer 17

tissue breakdown by bacterial action  gas formation and bloated abdomen, green discoloration, marbling, skin slippage, degloving of hands, brain liquefaction and loss of hair/nails

Question 18

marbling in decomposition

Answer 18

due to reaction of hgb and hydrogen sulfide that occurs along the blood vessels resulting in green-purple discoloration of skin

Question 19

green discoloration in decomposition

Answer 19

due to colon bacteria denaturing hemoglobin with hydrogen sulfide to produce green biliverdin

Question 20

stabs/punctures

Answer 20

o Depth > length
o Wound edges are sharp and straight, NO tissue bridging and no margin abrasions
o May have extensive internal bleeding with minimal external blood loss
o Single edged weapon  wound has 1 blunted margin and 1 V shaped margin
o Double edged weapon  2 V shaped margins
o stab wounds with an L or Y shape indicates twisting of weapon or movement of victim
o “Defense wounds” – palms/back of hands, non-fatal, protective position

Question 21

chop wounds

Answer 21

o Caused by heavy sharp objects dramatic, may have fine abrasion and contusion at margin
o Associated with a wedged cut into underlying bone

Question 22

incision

Answer 22

o Sharp edge drawn over tissue; width > depth
o Suicide usually has multiple, superficial groupings; “hesitation marks”
o NO tissue bridging, NO marginal abrasions

Question 23

contact vs immediate range of fire

Answer 23

Contact – muzzle touches body; essentially all the leaves the gun enters the body
 Can be hard, loose, near, angled or partial

Immediate – has stippling (tattooing); bits of gunpowder causing abrasions
 Hard to cause stippling on palms and soles

Question 24

asphyxia

Answer 24

systemic or cerebral hypoxia

Question 25

sign of asphyxia

and how it happens?

Answer 25

conjunctival petechiae
petechiae

d/t increased venous pressure and bursting capillaries

Question 26

choking presents with

Answer 26

swollen epiglottis

Question 27

death by hanging is due to

Answer 27

vessel occlusion, not airway obstruction

Question 28

ionizing vs nonionizing radiation

Answer 28

nonionizing are microwaves, UV waves etc

ionizing is BAD

Question 29

ionizing radiation can cause these chronic sequelae

Answer 29

fibrosis, mutagenesis, carcinogenesis, and teratogenesis

Question 30

immediately after exposure to ionizing radiation, you can see

Answer 30

vascular dilation

Question 31

later changes you see with ionizing radiation are

Answer 31

endothelial cell swelling, vacuolization, necrosis, and thrombosis or vessel rupture

Question 32

least sensitive tissue to radiation is

Answer 32

adult brain

Question 33

most sensitive tissue to radiation is

Answer 33

rapidly diving and proliferating; bone marrow, spleen, LNs, (blood forming tissues), reproductive organs, skin, bone, teeth, and muscle

Question 34

Changes that occur with ionizing radiation

Answer 34

skin dyspigmentation, atrophy, pulmonary interstitial fibrosis, LN fibrosis, and GI fibrosis; followed by scarring, adhesions, keloid formation, and sterility

• ACUTE CHANGES  structure changes in chromosomes, nuclear swelling, condensation, and chromatin clumping, and apoptosis
• DNA DAMAGE = Nuclear morphology changes  giant cells, nuclear pleomorphism, and binuclear changes AND cytoplasmic changes like swelling, mito distortion, and plasma membrane breakage

Question 35

anthrax is caused by

what does it look like

Answer 35

• bacillus anthracis large boxcar shaped gram + rods in chains

Question 36

classic anthrax case

Answer 36

• Case: postal worker presenting with fever, myalgia, malaise, fatigue, retrosternal pain and nonproductive cough
• Papules/vesicles on skin –> characteristic black eschar

Question 37

classic anthrax cxr

Answer 37

• CXR shows widened mediastinum due to hemorrhagic mediastinitis

Question 38

how is anthrax acquired?

Answer 38

• Acquired by contact with spores on infected animals or animal products

Question 39

3 anthrax syndromes

Answer 39

• 3 major syndromes = inhalational (pulmonary), cutaneous, and GI

Question 40

anthrax toxin

Answer 40

a 3 protein exotoxin secreted by bacteria, made of PA (protective antigen cell binding protein) = B subunit, and A subunit made of EF and LF (edema factor and lethal factor)

A subunit causes edema and cell death!

Question 41

staph aureus is

Answer 41

• Gram + cocci in clusters

Question 42

MRSA VRSA MSSA

Answer 42

• MRSA and VRSA are very resistant staph; MSSA = methicillin sensitive (non resistant)

Question 43

staph aureus effects

Answer 43

• Affects skin and soft tissue of kids and adults; commonly causes osteomyelitis and pneumonia associated with empyema
• Presents with focal destructiveness, puss and abscess formation

Question 44

staph aureus causes what in diabetics?

Answer 44

infective endocarditis

Question 45

staph epidermidis

Answer 45

much less virulent than staph aureus and plays a major role in colonizing indwelling medical devices leading to bacteremia (form biofilms); NICU issue

Question 46

with a staph aureus infection, what is elevated in WBC

Answer 46

neutrophils

Question 47

SSSS

Answer 47

(staphylococcal scalded skin syndrome) –

thin walled vessels and desquamation (spares mucous membranes) caused by epidermolytic exotoxins (exfoliatin) A and B which are proteases –>released by staph aureus and cause detachment within the epidermal layer by breaking apart desmosomes