Forensic Pathology

Question 1

what is forensic pathology and what kinds of deaths are they involved?

Answer 1

applies principles and knowledge of medical science to problems of the law; violent (accident, suicide, homicide), suspicious, sudden and unexpected, deaths in an institution (prison, hospital <24 hours)

Question 2

What are the major duties of the forensic pathologist?

Answer 2

cause and manner of death, ID deceased, determine time of death, collect evidence from body to prove/disprove, persons of guilt/innocence, document natural disease, determine contributory factors to death, provide testimony goes to trial.

Question 3

Define cause of death. Examples.

Answer 3

injury/disease that produces physiological derangement resulting in death; gun shot wound, stab, coronary atherosclerosis

Question 4

Define Mechanism of death. Examples.

Answer 4

physiological derangement produced by the cause of death; Hemorrhage, septicemia, cardiac arrhythmia

Question 5

Define the manner of death. Examples.

Answer 5

natural, homicide, suicide, accident or undetermined. (can only be one of these five!)

Question 6

What is a coroner?

Answer 6

elected individual who is not a physician, make ruling on cause and manner, no physician consult required, not required to order autopsy, not required to agree with autopsy findings, no training required

Question 7

What is a medical examiner?

Answer 7

physician designated as medical examiner to determine cause and manner, can preform autopsies in cases that need them, established laboratory for use, 60% of country

Question 8

How accurate is time of death generally? What major factors effect accuracy and ability to determine?

Answer 8

difficult and imprecise, often not possible, can only give a range majority of the time; as interval between time of death and discovery increase so does inaccuracy of estimation

Question 9

what factors are used to estimate time of death?

Answer 9

livor mortis, rigor mortis, body temp, degree of decomposition, chemical changes in vitreous humor, stomach contents, insect activity, and scene markers (broken watch, unopened mail, piled up newspapers)

Question 10

What is livor mortis?

Answer 10

reddish purple coloration due to settling of blood by gravity in dependent areas of body, onset 1/2 to 2 hours after death, max coloration 8-12 hours

Question 11

What are some nuances in livor mortis that effect onset, or determination?

Answer 11

occasionally misinterpret as bruising, on firm surface may appear pale, may occurs prior to death in individuals dying of heart failure

Question 12

what is the difference between shifting livor mortis and fixed livor mortis?

Answer 12

shift: intravascular pooling, can move from one area to another; fixed: blood hemolyzed and begins to diffuse into extravascular spaces, coloration won’t move

Question 13

What is rigor mortis and general features of it?

Answer 13

stiffening of body after death due to postmortem muscle contraction, due to loss of ATP from muscle (stable actin-myosin complex preventing relax), onset 2-4 hours, fully developed 6-12 hours (jaw-> upper extremeties-> lower, order of onset and loss), lost due to decomp

Question 14

what factors accelerate onset on rigor mortis?

Answer 14

violent exercise (deplete ATP), high body temp, hot weather (disappears less than 24 hours)

Question 15

What factors cause rigor to persist?

Answer 15

temperate climate (36-48 hours), cold weather (persist several days)

Question 16

What are the assumptions behind body temperature in determining time of death?

Answer 16

most common used method, based on everyone having a “normal” temp at time of death and body cools at uniform rate (both incorrect)

Question 17

Why is the 1st assumption of temperature determination of time of death wrong (normal temp)?

Answer 17

normal: 96-100.8 F, diurnal variation- low at 6 am, high at 4-6, normal temp slightly higher in women, strenuous exercise and chronic disease can raise temperature

Question 18

Why is the 2nd assumption of temperature determination of time of death wrong (uniform cooling)?

Answer 18

plateau where cooling does not appear to occur post mortem, body habitus influences cooling (fat insulates), infants cool quicker (mass/SA), ambient temperature effects, clothing, surface body is on (marble conducts heat, rug insulates)

Question 19

How accurate is post mortem vitreous potassium levels in determining time of death and reasoning behind their use?

Answer 19

not valid; level of K determined by degree and rapidity of composition, accelerated decomp raises K levels (time only one factor in K levels)

Question 20

Define autolysis. Example.

Answer 20

aseptic breakdown of tissue caused by intracellular enzyymes (pancreas)

Question 21

Define Putrefaction.

Answer 21

breakdown of tissue due to bacteria, main cause of decomp, GI tract main source,

Question 22

What are the visual clues of putrefaction?

Answer 22

green discoloration in abdominal quadrants or face and neck, swelling (gas production), protrusion of eyes and tongue, decomp fluid (red) from mouth and nose, slippage of skin with marbling (discoloration along vessels due to hemoglobin reacting to hydrogen sulfide) and blistering,, hair slip from scalp, internal organs and brains= porridge

Question 23

What factor is a big contributor to putrefaction? Give Timelines for levels of decomposition.

Answer 23

accelerated by hot environment or sepsis; hot climate= 24hours, moderate 1-2 weeks, skeletonization- 1-2 weeks to months to years (climate dependent)

Question 24

what are the features of cardiovascular disease in sudden natural death?

Answer 24

300-400K per year, leading natural cause men 20-65 years, if infarct unrecognized (uncharacteristic presentation) will rupture may occur presenting as sudden death (cardiac tamponade)

Question 25

What are the statistical features of coronary artery disease in sudden natural death?

Answer 25

75% of all sudden deaths handled by MEs, 50% sudden death, 25% w/o preceding history or warning, Mechanism: usually lethal cardiac arrhythmia (80% ventricular, 20% sudden asystole)

Question 26

What are the anatomic findings with coronary artery disease in sudden natural death?

Answer 26

severe coronary atherosclerosis (usually 2 vessels, LAD and or Left main, greater than 75% stenosis), myocardial scarring, infrequent findings: coronary artery thrombosis <15 and acute/sub acute MI

Question 27

What are the features of hypertensive CVD in sudden natural death?

Answer 27

most cases accompanied by coronary artery atherosclerosis, cardiomegaly usually present, mechanism of death- acute cardiac arrhythmia (can be entirely from cardiomegaly)

Question 28

What are the features of cardiomyopathy in sudden natural death?

Answer 28

characterized by myocardial dysfunction of known or unknown etiologies, not due to : arteriosclerosis, HTN, valvular, or infection; 3 categories: congestive or dilated, hypertrophic, or restrictive

Question 29

what are the general features of CNS disorders as cause of sudden natural death? most common?

Answer 29

less common then cardiovascular; epilepsy, intracerebral hemorrhage, no-traumatic subarachnoid hemorrhage, meningitis, and undiagnosed brain tumor

Question 30

What are the features of epilepsy as sudden natural death?

Answer 30

young, often in bed, complete autopsy generally negative, toxicology reveals absent or sub-therapeutic levels of anticonvulsants, bite wounds to tongue only 25% (can be associated with other death), Mechanism: cardiac arrhythmia, gross and microscopic changes in brain usually absent

Question 31

what are the features of intracerebral hemorrhage in sudden natural death?

Answer 31

lead to sudden rapid death, 10-30% of all strokes, 45% caused by hypertension, other causes: amyloid angiopathy, AV malformation, tumors, bleeding diathesis, drug induced, and vasculitis, death= secondary brain stem compression/herniation or intraventricular hemorrhage

Question 32

what are the features of cerebral infraction in sudden natural death?

Answer 32

less frequent cause of sudden death, less often in ME, less likely to cause death <24hours before diagnosis at hospital

Question 33

what are the features of non-traumatic subarachnoid hemorrhage in sudden natural death?

Answer 33

rupture berry aneurysm (#1)- 90% silent til rupture, multiple in 15-20% of causes, 2/3 symptomatic btwn 40-60 yo, 1/3 symptomatic if younger, 80-90% in anterior portion circle of willis, fatal cases- 60% immediate and 80% of those survivors that will die < 24 hours

Question 34

What is the occurrence of respiratory system causing natural sudden death? Main Pulmonary diseases behind it?

Answer 34

relatively infrequent ~10%; mainly: pulmonary thromboembolus, bronchial asthma, acute epiglottitis

Question 35

What are causes of thrombolembolism that results in sudden death?

Answer 35

clot dislodged from lower extremity; blood stasis (immobility, obesity, intrapelvic tumors, and pregnancy), venous injury, and hypercoagulable disorder

Question 36

What are the features of thromboembolism as sudden natural death? Mechanism of death?

Answer 36

usually in left main pulmonary artery, (if 60% blocked heart can't pump); mechanical obstruction (large embolus), vasoconstriction due to vasospasm (multiple smaller emboli), pulmonary infarct <10% (due to dual vasculature)

Question 37

What must be done during autopsy of PE is found?

Answer 37

attempt to locate origin (pelvic veins, incisions to popliteal fossae and posterior calves, usually no residual thrombi found

Question 38

what are the features of bronchial asthma in sudden natural death?

Answer 38

~5% of all cases of chronic asthma, may occur w/o prolonged attack, increased frequency at night or early morning, triggers: allergens, infections, drugs (aspirin), psychological stress, exercise, and cold air

Question 39

what is the mechanism of death with sudden death associated with bronchial asthma?

Answer 39

reduces flow with ventilation/perfusion mismatch resulting in decrease oxygenation of blood and increase CO2 and right ventricle overload, decreased airflow due to allergic release of histamine (vasoactive) causing bronchial contraction, marked intrabronchial mucus secretions

Question 40

what is the mechanism of sudden death with acute epiglottitis?

Answer 40

marked edema of epiglottis and upper airway mucosa leading to mechanical obstruction, death can be rapid, most commonly H. influenza and S pneumonia (can follow pharyngeal exam with tongue depressor)

Question 41

what are the various times of sudden death secondary to pregnancy complications?

Answer 41

uncommon due to prenatal care; 54.9% follow live birth, 7.7% while pregnant, 7.1% following still birth, 10.7% following ectopic pregnancy, 5.6% following abortion

Question 42

What are the most common causes of death secondary to pregnancy complications?

Answer 42

ruptured ectopic (hemorrhage), embolism (PE more common than amniotic fluid embolism), pregnancy induced hypertensive complications (pre-eclampsia, eclampsia) and infection

Question 43

What are the five categories of intraoperative deaths?

Answer 43

due to underlying disease, disruption of vital organ during procedure, air embolism, anesthetic related, can't be ascertained

Question 44

What are some examples of intraoperative death due to disruption of vital organ during procedure?

Answer 44

catheter passed through right atrium, rt. ventricle, or pulm artery perf; coronary artery perf;

Question 45

When is an intraoperative air embolism death commonly seen?

Answer 45

CNS, laminectomy procedure

Question 46

What are common causes of anesthetic related intraoperative deaths?

Answer 46

intubation of esophagus, administration of wrong gas, drug OD (most common), allergic reaction to iodine based dyes (rare), malignant hypertension (halogenated anesthetics and succinylcholine), most locals are cardiotoxic (arrhythmia)

Question 47

what is an abrasion?

Answer 47

removal of superficial epidermis due to friction against rough surface

Question 48

What is a contusion? Hematoma?

Answer 48

hemorrhage into soft tissue due to rupture of BV caused by blunt trauma (skin, lung, brain, heart, muscle); large focal collection of blood

Question 49

How are contusions dated?

Answer 49

histo= not possible, color change= depth, pigment, location influence appearance and time of onset (superficial yellow sooner, eyes bruise immediately), evolution of color (hemoglobin degradation= varies by person and bruise, no standard terms

Question 50

What is a laceration? What do you look for?

Answer 50

tear in tissue by shearing or crushing: internal organs and skin, blunt objects, falls, vehicle impact, skin irregular with abraded contusions, explore for foreign material from weapon or surface

Question 51

What are the characteristics of a stab wound?

Answer 51

pointed instrument, wound tract depth exceeds skin length, sharp skin edges w/ or w/o contusion or laceration, single edge V pattern, secondary tract due to twisted knife or victim movement as knife pulled out

Question 52

What are the characteristics of an incised wound?

Answer 52

cut produced by sharp edge weapon or incision, clean cut straight edge w/o abrasion or contusion, longer than deep, self inflicted= hesitation marks (superficial)

Question 53

What are the characteristics of a chop wound?

Answer 53

heavy instrument with cutting edge, combo of incised and laceration (cutting and crushing) but mostly incised appearance

Question 54

what is asphyxia? What are the non-specific classical signs?

Answer 54

failure of cells to receive or utilize O2; visceral congestion, petechiae, cyanosis

Question 55

What is petechiae?

Answer 55

pinpoint hemorrhage produced by rupture of small vessels, sudden overt distension/rupture of vessels due to abrupt increase intravascular pressure= visceral pleura and epicardium, strangulation= conjunctiva or sclera, also caused by vomiting, coughing, and acute heart failure

Question 56

What are the features of suffocation?

Answer 56

failure of O2 to reach blood (smothering-external airway obstruction, choking-internal airway obstruction, mechanical asphyxia- pressure outside body preventing respiration

Question 57

What are the features of strangulation?

Answer 57

in all forms cerebral hypoxia secondary to compression of vessels supplying blood to brain; carotids- 11lbs pressure, unconscious 10 seconds, direct front pressure; vertebrals- severe lateral flexion or rotation (hanging) 66lbs pressure

Question 58

How does hanging cause death?

Answer 58

asphyxia secondary to compression or constricture of neck structures by constricting band tightened by body weight, virtually all suicide, can obstruct airway but not necessary, rarely fracture neck

Question 59

What are the features of hanging?

Answer 59

furrow in neck (not completely encircle, slants up to point of suspension), face pale, tongue protruding and black, blood pools in dependent areas (punctate hemorrhages or tardieu spots- black)

Question 60

what effect does hanging have on internal structures of the neck? Other markers not always present?

Answer 60

50% no injury, 10-15% fracture of thyroid cartilage or hyoid bone; 25% have petechiae (absence due to complete arterial obstruction)

Question 61

What are the general features of ligature strangulation?

Answer 61

pressure on neck applied by constricting band tightened by force other than body weight, virtually all homicides, mechanism the same as hanging

Question 62

What are the physical features of ligature strangulation?

Answer 62

no complete occlusion of vasculature (vertebral open, veins compressed), face and neck congested, confluent sclera, conjuctival hem, 86% fine petechiae periorbital, horizontal ligature mark, rarely injure internal neck structures

Question 63

How does manual strangulation occur and general features?

Answer 63

pressure from hand, arm, limb, compressing internal structures, virtually all homicide, mechanism of death the same, occlusion of airway minor role

Question 64

what are the physical features of manual strangulation?

Answer 64

face congested and cyanotic, petechiae conjuctiva and sclerae, marks of violence- abrasion, contusion, fingernail marks, internal neck- extensive musculature hemorrhage, fracture hyoid/thyroid in older patients (more force than necessary)

Question 65

What is SIDS?

Answer 65

sudden unexpected death of apparently healthy infant, less than 1 year, diagnosis of exclusion, examine scene, review of history, and complete postmortem fails to reveal cause of death

Question 66

What are the demographics and "causes" of SIDS?

Answer 66

4-5K deaths per year, decreasing incidence, heterogenous group of disease, most 2-4 months and 92% <6 months, under 1 month- inability to adapt, peak- midnight and breakfast

Question 67

what are increased risk factors for SIDS?

Answer 67

premature greater risk, males more than females, race not a factor, no known genetic etiology, temperature decrease (increase in SIDS)

Question 68

what are the demographical features of child homicide?

Answer 68

in 07 322 bwtn 1-4 murdered, infanticide (killing <24 hours, usually mom, young and unmarried, usually smothered), after a few days of life usually blunt trauma, perpetrators more varied

Question 69

What are the different types of child homicide?

Answer 69

classic battered child (neglected or starved), impulse or "Angry" homicide (majority), and "gentle" homicide (smothering or Munchausen by Proxy)

Question 70

What is battered baby syndrome?

Answer 70

repeated intentional acts of trauma at slightest provocation, delay in bringing child to the hospital

Question 71

How does battered baby syndrome present to the physician?

Answer 71

acute injury and old injuries, significant discrepancy between hx and clinical findings, explanation of trauma vague/inconsistent, head injuries from falling, burns, starvation (fussy eater), often severe diaper rash

Question 72

What is seen on autopsy with battered baby syndrome?

Answer 72

multiple bruises various ages, pattern bruises, long incisions down back and buttocks, extremities to reveal soft tissue hemorrhage, most die from head trauma, retinal hemorrhage, punched in abdomen

Question 73

What are the features of angry or impulse homicide?

Answer 73

most cases, sudden violent act brought on by trivial provocation, child picked up and thrown/slammed, may be well cared for

Question 74

What are the features of gentle homicide?

Answer 74

smothering most commonly missed method, minor force necessary therefore no evidence of trauma, autopsy unremarkable, small percentage of SIDS (<10%)

Question 75

What are the demographic features of Munchaussen's by proxy?

Answer 75

usually mom, child brought to physician for induced signs and symptoms of illness, multiple hospital admissions, extensive evaluations or procedures all negative,

Question 76

what are the methods for munchausen's syndrome by proxy?

Answer 76

smothers child and then resuscitates or brings to ER semi-moribund, hx- apnea, cyanosis, loss of consciousness, continues to recur, extensive negative workup

Question 77

What physical damage is seen with shaken baby syndrome?

Answer 77

retinal, subdural/subarachnoid hemorrhage caused by violent shaking (Peds), injuries to scalp and skull (contusions and fractures), impact trauma (

Question 78

What are the actions that lead to shaken baby syndrome?

Answer 78

acceleration-deceleration traction stresses due to head whipping back and forth, original reports- diagnosis made clinically, autopsies not always performed

Question 79

What is the damage seen with wound ballistics?

Answer 79

severity of wound- amount of tissue shredded base in KE lost by bullet in body, bullet enters tissue, imparts radial motion to tissue creating temporary cavity much larger than permanent

Question 80

What happens when a gun goes off?

Answer 80

bullet, flame 1400 F, gas, soot, powder- burning or unbrunt, metal vaporized from bullet and jacket, primer compounds, copper and nickel vaporized from cartridge case

Question 81

What are the features of a wound from a contact gunshot?

Answer 81

muzzle in contact with body, scorching of wound edges, soot deposited on wound margins, soot driven into wound tract, may be muzzle impression and soot on skin adjacent to wound

Question 82

What are the features of a contact gunshot wound over bone?

Answer 82

stellate over entrance, soot deposited around bone entrance, , soot may be deposited on inner surface of skull, clothing may absorb soot and powder

Question 83

What are the features of a near contact gun shot wound?

Answer 83

transition between contact and intermediate, entrance surrounded by wide band of seared blackened skin

Question 84

What are the features of intermediate gun shot wounds?

Answer 84

powder tattooing, punctate abrasion of skin due to impact of unburnt and burning grains of powder in skin, range depends on gunpowder, barrel length caliber, size and density determine range, cant be wiped off

Question 85

What are the features of distant gun shot wounds?

Answer 85

no soot or tattoing, cant determine exact range, entrance wound- abrasion ring, small, circle, or oval (reg. except over bone), can't tell caliber based on entrance wound

Question 86

What are the features of an exit wound?

Answer 86

larger and more irregular than entrance- bullet tumbling and deformation, no abrasion ring

Question 87

What are the features of bullet wounds with a skull?

Answer 87

entrance- punched out with sharp edges, opposite surface beveled; exit- beveled or cratered outward

Question 88

What are the differences in gun shot wounds with a high velocity riffle?

Answer 88

more KE means more wounding, external injuries to torso appear no different from handgun- severe internal injury, temporary cavity may fracture bone, injure vessels and organs far from bullet, micro tears, soft point hunting bullets- shed lead through body

Question 89

What are some facts about suicides by gun?

Answer 89

5-6% rt handed shoot with left, multiple wounds does not rule out suicide, fatal accidental shooting while cleaning gun is usually not suicide, notes only 25%, blood on shooting hand 33-35%, gun in hand 25% hand and 20% long arm, occasionally shoot themselves in back of head