forensic pathology Flashcards
what is a forensic pathologist?
medical doctors that preform autopsies on individuals who have died suddenly/unexpectedly
what are the four types of information that can be gained from a forensic pathologist?
(1) identity of the deceased
(2) the medical cause of death
(3) the interpretation of injuries
(4) the manner of death
what is the post-mortum interval? how is it determined?
- the amount of time btwn death and the discovery of a body
- estimated by examining the state of the body
what does post-mortum interval allow forensic pathologists to differentiate?
natural changes that occur to the body following death and evidence of homicide
what characteristics do pathologists use to estimate 3 hours post-mortum?
body feels warm and is flaccid
what characteristics do pathologists use to estimate 8 hours post-mortum?
- body progressively starts to cool and become stiffened - ultimately the body will cpme to room temp and remain stiff for hours
- after this point timeline depends on environmental factors
what characteristics do pathologists use to estimate 36 hours post-mortum?
usually there’s early putrefactive decomposal changes which leads to progressive flaccidity
what characteristics do pathologists use to estimate >36 hours post-mortum?
body feels cold and flaccid
what is the normal range for heart weight and how can this help us during an autopsy?
- normal = 300-350g
- if weighs more or less could be related to the cause of death
what is forward heart failure?
inability of the heart to pump blood forward at a sufficient rate to meet metabolic demands of the body
what is backward heart failure?
- occurs when left ventricle does not fill sufficiently with blood, resulting in reduced stroke colume
- under these condition the heart can only pump enough blood to meet the metabolic demands of the body if cardiac filling pressures are abnormally high
what are the three principle classes of heart failure?
(1) reduced ejection fraction
(2) preserved ejection fraction
(3) right heart failure
describe reduced ejection fraction
- the heart isn’t contracting as well as it normally does
- amount of blood being pumped out of the left ventricle is less than the body needs
- often occurs bc left ventricle is enlarged and cannot pump normally
- heart usually appears dilated or baggy
describe preserved ejection fraction
- heart contracts normally
- but the left ventricle does not relax enough to properly fill with blood
- amount of blood pumped to the body decreases
- usually occurs if the heart is stiff or thick
what is an ejection fraction?
- measurement of how much blood is pumped out of the left ventricle with each contraction
- e.g. 80% ejection fraction = 80% of blood in the left ventricle is pumped out
describe right heart failure
- failure of the right side of the heart to pump deoxygenated blood to lungs
- often occurs as a result og left-sided heart failure
what are primary cardiomyopathies?
- refers to diseases begining in the heart muscle itself
- most have a clear genetic underlying basis (e.g. ion channel deficiencies), while some are acquired (stress-provoked), or both
- recall: cardiomyopathy = hard for heart to pump blood to rest of body
what are secondary cardiomyopathies?
- refers to systemic disease that leads to heart muscle injury
- includes many inflammatory and endocrine origins
- anything that causes damage to the heart can lead to secondary cardiomyopathy if it is severe enough
what are the 3 structural forms of cardiomyopathies?
(1) dilated cardiomyopathy (reduced ejection fraction)
(2) hypertophic cardiomyopathy (preserved ejection fraction)
(3) restrictive cardiomyopathy (stiff muscle)
what is the difference btwn hypertophic cardiomyopathy and myocaridal hypertrophy?
- myocardial hypertrophy = too much heart muscle
- hypertrophic cardiomyopathy = myocardical hypertrophy with a specific underlying genetic cause
what represents the end of the line for almost all types of heart disease? why?
dilated cardiomyopathy - almost all heart disease comes to this
what is a common complicatoin associated with dilated cardiomyopathies? how does this occur?
- mural thrombus - blood clot attached to the wall of a bv or the endocardium, impeeding blood flow
- occurs when blood is not flowing effectively through the heart
can mural thrombi embolize? what is the significance of this?
yes - can become logged in smaller vessels
- kidney = renal failure
- brain = stroke
what are the two levels at which hypertrophic cardiomyopathies are characterized?
macroscopic and microscopic levels
how are hypertrophic cardiomyopathies characterized at the macroscopic level
by unusually thick muscle
what macroscopic feature is the most common pattern of hypertrophy? what is another feature commonly seen?
- asymmetrical septal hypertrophy - septum is very thick relative to the walls
- also see myocardial fibrosis (increased amounts of scar tissue)
what are key features at the microscopic level?
- cardiomyocyte enlargement
- myofiber disarray
what is apical hypertrophy
- less common pattern
- muscle hypertrophy has occured mostly in the apex of the heart
what is concentric hypertrophy?
- less common
- muscle hypertrophy is symmetric either across both ventricles or within one ventrical wall
restrictive cardiomyopathies are the ______ form
rarest
how are restrictive cardiomyopathies characterized?
- stiff heart and in a particular stiff ventricles, caused by infiltration of fibrous tissue into the myocardium
- heart can’t fill woth blood, & overtime cannot sufficiently pump blood, leading to HF
what is the typical cause of restrictive cardiomyopathy?
sarcoidosis - inflammatory disease affecting multiple organs that causes the formation of granulomas (consisting of inflammatory cells) throughout the body
describe alcohol ablation as treatment for hypertrophic cardiomyopathy resulting in a left ventricular outflow obstruction
catheter is inserted into a small branch of the coronary arteries
- releases alcohol, causing local infarction of the muscle lining the left ventricular outflow tract
- leads to tissue necrosis and ultimately healing through fibrous tissue deposition
- leads to tissue retraction, and thus, release of the obstruction caused by hypertrophic cardiomyopathy
describe septal myectomy as treatment for hypertrophic cardiomyopathy resulting in a left ventricular outflow obstruction
- ascending aorta is opened surgically
- protruding muscle is shaved away, releiving the obstruction
what is a cardiac transplant
- donor heart is sown into patient
- patient maintains endogenous major vessels
- for patients that are expected to live less than 6 months
- do not always work
what are heart transplant risks?
infection, bleeding, blood clots, kidney failure, breathing problems, cardiac allograft vasculopathy (long-term rejection leading to scarring of the coronary bvs) and accelerated atherosclerosis
if do an autopsy on a sudden death patient and nothing is showing what is the likely cause
- ion channel deficiency leading to arrythmia and death
- likely from a genetic cause
- could be inherited, must be explained to family
