forensic pathology - lecture notes - julia

Question 1

what are the five possible manners of death?

Answer 1

• natural
• accidental
• suicide
• homicide
• undetermined

Question 2

what proportion of people who die are investigated by the ME’s office? how many recieve an autopsy?

Answer 2

• about 12,000 people die in NH in a calendar year
• 1500 to 1800 of these deaths will be reported to the ME’s office
• only 500 will require an autopsy - the others will have enough information in their patient records and external examination to deterimine cause and manner of death

Question 3

what are the 25 things that are reportable to the ME’s office in NH? (i don’t think we have to memorize this - i’m bolding the ones he talked about)

Answer 3

1. Death resulting from a criminal act, regardless of time interval between incident and death
2. Suicide, regardless of time interval between incident and death
3. Death resulting from accidental injury, regardless of time interval between incident and death
4. Deaths associated with fire or explosion
5. Deaths associated with firearms or other mortal weapons
6. Death in associated with any public or private conveyance
7. Illegal abortion or complications thereof
8. Death due to poison, illicit drug use or overdose
9. Exposure to toxic agent during course of employment
10. Deaths resulting from agents which constitute a public health or environmental hazard
11. Sudden, unexpected death of a person under 60 in apparent good health
12. Death unattended by a practicing physician
13. Death in legal custody – dying while incarcerated, in police car, under arrest, handcuffs, when police were on the scene
14. Deaths associated (not caused by!) with diagnostic or therapeutic procedures, including intra- and perioperative deaths – even if died during some benign appearing imaging study, must be reported to ME
15. Death in which a body is to be cremated – about 5000 people per year – more or less a clerical check than anything else
16. Deaths occurring less than 24 hours after admission to health care facility, save for those known to be terminally ill from natural disease and death is imminent and expected – unless clinician comfortable with certifying death (ie in a case where, even though he’s come into the ER and only been there for a bit, it’s clear why he died)
17. Death of a child under 18 save for criteria above
18. Death of a child from any cause when death occurs in day care, foster care or child is in custody of or being investigated by DCYF
19. Fetal death resulting from trauma after 20 weeks or 350 gm - not every spontaneous fetal loss presumably due to natural causes is reportable – only if its traumatic such as a traffic accident, drug use, assault
20. Death known to have been improperly certified
21. Death of any unidentified person regardless of cause or manner
22. Discovered buried remains, known or thought to be human
23. Decomposed and skeletonized remains
24. Suspicious or unusual circumstances surrounding a presumed natural death
25. Death of a prominent or controversial person

Question 4

what is rigor mortis? why does it occur (mechanism)? how can it be used to establish time of death?

Answer 4

• stiffening of muscles
• because ATP spontaneously breaks down to ADP and the actin and myosin filaments lock together
• involves the smallest muscles first, so within 45 minutes of death will be detectable in the neck and jaw
• body is completely stiff by 18-24 hours after death
• body will remain stiff for another 24-36 hours depending on environmental conditions
• as body decomposes and muscles break down, body will become flaccid again

Question 5

what is livor? how can it be used to establish time of death?

Answer 5

• color
• blood will settle to the most dependent (bottom/closest to gravity) region of body
• solid elements will settle out and coagulate, fluid will become less and less fluid
• the early stages will blanche
• after 8-10 hours, no longer blanches
• can also tell you whether the body was moved

Question 6

what is algor mortis? what can it tell you about time of death?

Answer 6

• temperature change in the body
• declines at steady rate (depending on environment) so can calculate how long the body’s been dead

Question 7

what ocular changes occur after death? how can they help you establish time of death?

Answer 7

• filming, drying, clouding
• he said the only one he finds helpful is clouding:
• if the cornea is completely opacified and that wasn’t known to be due to some sort of disease process, than the body’s been dead for at least 72 hours

Question 8

what is the difference between putrefaction and mummification?

Answer 8

• putrefaction requires bacteria and a high humidity environment, will smell
• mummification occurs in a low humidity environment and doesn’t involve bacteria, won’t smell as much, like tanning leather

Question 9

what late post-mortem changes can be used to establish time of death? (6)

Answer 9

• putrefaction
• mummification
• infestation (different insects have developmental rates and these are consistent)
• skeletonization
• adipocere (development of wax-like substance by bacterial hydrolysis of fat)
• anthropophagy (eating of the body by animals)

Question 10

what happens during the initial decay stage? what bugs would you expect to see and what is the timing of their development

Answer 10

• enzymatic release and autolysis
• blowflies and house flies will lay eggs around wounds and mucosal surfaces
• eggs hatch and move into the body within 24 hours
• takes 2-3 weeks for the egg to develop into a maggot and then into a fly - considerably longer at low temperatures (rate depends on species - consult entymologist)

Question 11

what is the process of putrefaction (what’s happening during this process?) where will this process first be observable?

Answer 11

• bacteria break down the tissues, releasing fluids into body cavities
• anaerobic species produce gases including hydrogen sulfide, methane, cadaverine, and putrescine (he said he didn’t care about the specific gases, so i’m assuming we don’t need to know them…)
• gas “infiltrates” teh body and forces fluids into body cavities and out of the orifices
• since there’s lots of bacteria in the GI tract, particuarly the cecum, will see greening of the belly over the cecum first - apparently the skin is thinner here at least

Question 12

what occurs during infestation of the body?

Answer 12

• maggots move throughout the body, spreading bacteria, secreting digestive enzymes adn tearing tissues with their mouth hooks
• move as a mass benefiting from communal heat and shared digestive secretions

Question 13

what does skeletonization depend on? how long can it take in summer?

Answer 13

• time taken for a body to decompose depends on temperature and moisture and accessibility to insects
• in summer, in an exposed location, human body can be reduced to bones in just 9 days

Question 14

what is the chain of custody? why is it important?

Answer 14

• chain of people through which evidence is transfered
• must be proper paperwork and such filled out at every step of the chain
• evidence won’t be admissible in court if the chain is not properly followed
• properly packaged and labled evidence is securely maintained

Question 15

what are the three layers of the external autopsy?

Answer 15

1. inspected first as it arrives at the morgue - should be exactly as it was found at the scene
2. body is disrobed and examined again
3. if there’s any external findings, these are cleaned and detailed images and sketches are taken of them
4. only after these three external autopsy steps are taken is the body cut open

Question 16

what is the normal distribution of manner of death (NASHU) in urban settings? how is it different in rural settings

Answer 16

• 55% natural
• 23% accident
• 17% homicide
• 10% suicide
• rest undetermined (about 1 %)
• (these numbers are all approximations from the graph given)
• in rural settings, the homicide and suicide amounts are switched (so about 17% suicide and 9% homicide

Question 17

how many suicides and homicides are usually seen in a year?

Answer 17

• 150 suicides
• 15-20 homicides

Question 18

what must you do to a knife wound in order to determine the true shape of the blade?

Answer 18

• must cut the skin out of the body
• at least in young people, skin has a lot of elastic properties, and so unless you remove all of the tension on the skin, you can’t see the natural shape it would assume

Question 19

how would you determine if someone was hanged or strangled?

Answer 19

• someone strangled will likely have a ligature mark directly across the throat (where it is on this patient)
• someone hanged or how hanged themselves would have a more diagonal ligature mark from mandibular bone to mandibular bone (more along the black line)

Question 20

what do human bite marks look like?

Answer 20

• area of central clearing and then a circular bruise around it
• often tears in the skin (lower central incisors in this image)

Question 21

what can the location of bruising from being hit by a bumper tell you?

Answer 21

• patterns can help you identify the bumper
• height of the bruising can help you identify the type of car, since bumper height varies
• when you apply the breaks, your bumper goes down, so can hypothetically tell if someone was trying to stop themselves from hitting the person (cool!)

Question 22

what kinds of damage would you expect to see in accidents where pedestrians were hit by cars? at what speeds?

Answer 22

• at speeds less than 25 mph, fractures
• at speeds greater than 25 mph and avulsive lower extremity damage

Question 23

what natural deaths are most commonly seen in infants?

Answer 23

• SIDS is most common cause
• undiagnosed congenital defect (should have been diagnosed)
  *

Question 24

what will naturally kill young adults/adolescents?

Answer 24

• very few things
• a few cases of viral endocarditis
• asthma
• very rarely, substnace abuse related deaths (people don’t really use IVs as much anymore becasue the purity of the drug is so high now it doesn’t really add anything…)

Question 25

what are some examples of natural deaths of pateints over 40?

Answer 25

* ruptured abdominal aortic aneurysm * spontaneous intracerebral hemorrhage (stroke)

Question 26

what are the different classes of findings upon autopsy? (5)

Answer 26

1. class I = pathologic findings inconsistent with life - so you can find something like a ruptured MI, pulmonary embolism, hole in the head, etc that indicates that the body could no longer support life 2. class II = pathologic findings explain death, but not to level of class I - example = 70 yo patient with a very enlarged heart - he's therefore prone to spontaneoius ventricular arythnia at any time - but can't say what exactly the cause of death was 3. class III = minimal pathologic findings, compelling history, exclusion of other causes - example= coronary ostial anomalies 4. class IV = traceless lethal disorders with no demonstrabe morphologic abnormalities, well-documented history, exclusion of other causes - example = epilepsy 5. class V = undetermine

Question 27

what is the role of the expert witness in court? how do you become an expert witness? what is the difference between being an expert witness and a factual witness?

Answer 27

* ideally, your role will be to corroborate the theory * may offer opinions as an expert witness * to become one, the judge is presented with your credentials and decides whether they qualify you to be a witness in that area * as an expert witness, you can offer opinion (such as, "in my opinion, this was a homicide") whereas fact witnesses can only offer facts (such as, "he came into the room holding a knife") * must approach it as a scientist - your testimony should be impartial and should be the same no matter whos calling you to the stand (ie prosecution or defense)