Forensic Exam (2) PDF

23A - Time since death estimation (possibilities in the field practice, accuracy) Time of death terms -​ Time of death (ToD)= Exact moment of death estimation -​ Postmortem interval (PMI) = Time elapsed since death...

23A - Time since death estimation (possibilities in the field practice, accuracy) Time of death terms -​ Time of death (ToD)= Exact moment of death estimation -​ Postmortem interval (PMI) = Time elapsed since death -​ → Shorter PMI = More accurate estimation Crime scene -​ Police estimate times of death using body temp + Stiffness → Forensic pathologist conduct more accurate evaluations -​ Provide police with preliminary idea of time of assault + Verify if time since death matches suspect alibi Methods -​ Premortem changes= Wound age + Gastric content -​ Postmortem = Progressive changes at time scene → more commonly used -​ Algor mortis (cooling of body, normal 1°/h) -​ Livor mortis (pooling of blood to gravity, 30 min-12h) -​ Rigor mortis (stiffening to muscle, lack of ATP, 2-24h) -​ Drying of lips/genitals/Conjunctiva/Extremities -​ Supravital reaction + Putrefaction + Corpse fauna presence (insects) Purpose -​ Criminology = Helps to narrow down time frame related to crimes, to match alibi‘s -​ Civil proceedings = Legal contexts → Inheritance cases -​ Medicine = Organ transplantation viability Algor mortis -​ Body temperature →After death heat production stops → Cools gradually -​ Factors ↑ Cooling -​ ↓ environmental temp + minimal clothing + ↑ humidity + air movement + ↓ s.c fat -​ Estimation -​ Central core temp (Rectum + brain) → Most useful -​ Temp ↓ varies across body parts -​ Skin = Cools quickly + unpredictable -​ Rectum = Drops 0,5°C (first 3h) + 1°C (next 6h) + continues until it matches environment in 20-24h -​ Brain = Drops at consistent intervals → Measured w. Needle probe -​ Henssge Nomogram = based on calculation of Marshall → Calculates time of death based on: -​ Rectal temp + Environmental temp + Body weight + Covering of body -​ Adjustments are needed for non-standard cooling conditions Rigor mortis -​ Stiffening of muscles after death due to persistent actin-myosin attachment due to ↓ ATP -​ Timing -​ Occurs in 30min-2h after death → Lasts 8-36h (>36 h rigor disappears, muscle relax) -​ Nysten rule -​ Starts in mandibular joints and eyelids → Trunk → Lower extremities → Upper extremities -​ Can start in lower extremities in prolonged agony or glycogen depletion -​ Also affects smooth muscles = Visible as gooseflesh due to arrectores pilorum rigidity -​ Limitations = Rigor mortis as evidence diminishes significantly over time Livor mortis -​ Begins in 20-30 min PMI → Fully developed in 6-8h -​ Relocation -​ Occurs within 6h depending on body position -​ Partial relocation (6-12h PMI) + Permanent (12h PMI) -​ Blanching -​ Blanchable by moderate exertion within 20h PMI + by rigid object 36h PMI -​ Supravital reaction -​ refers to certain bodily functions that can continue briefly after death, during the period before all cellular activity stops. These signs are useful in estimating the post-mortem  interval (PMI), which is the time since death. -​ Muscle excitability =Mechanical (1,5-2h PMI) + Electrical (1-5h PMI) -​ Pupillary reaction = Mydriasis (4-6h PMI) + Miosis (2-21h PMI) -​ Motile sperm cells = up to 80h PMI Malach criteria -​ Warm + Flaccid = Death occurred < 3h -​ Warm + Stiff = Death occured 3-8h -​ Cold + Stiff = Death occured 8-36h -​ Cold + Flaccid = Death occurred > 36h Putrification -​ breakdown of tissues, the production of gasses, and a strong odor -​ Development of putrefaction at 21°C → PMI -​ Greening of skin (48h) -​ Marbling of skin/green-gray color/Blisters (1 week) -​ Detachment of hair (2 weeks) -​ Drying of tissues (1-2 m) -​ Complete decomposition of soft tissues (6m) -​ Putrefaction of internal organs -​ Liquefaction of brain (10 days) -​ Loss of renal structure/Gastric + hepatic emphysema (3 weeks) -​ Mold on internal organs (2m) -​ Soft tissue decay/dry leaving skeleton exposed (1y) -​ Rate of decomposition rate = Casper‘s rule → Air:water:earth = 1:2:8 -​ Air is the fastest + Earth is the slowest Stages of -​ Greenish discoloration (lower abd) putrefaction -​ Marbling on skin (due to breakdown of blood vessels) -​ Bloating (swelling of body caused by gas production) -​ Purge fluids (release of body fluid from body opening) -​ Skin loosen and peels Stomach emptying -​ Location of meal in stomach since last eating stages -​ Recent meal (stomach + minimal duodenum) -​ 2-3h post meal (SI + minimal stomach) -​ 6h (LI) + >30h (GIT is completely empty) -​ hægt að nota mat til að sjá tímann -​ Insect activity → Sjá spurningu 10A 23B - Drug dependence: amphetamines, cath Addiction Definition -​ persistent use of drugs despite substantial harm and adverse consequences Drug dependence Definition -​ adaptive state ass. w. withdrawal symptoms upon cessation of repeated exposure to drugs -​ Receptors decrease in number due to adaptation after prolonged exposure CNS stimulant What is it -​ similar effects and risk (vary in usage pattern and cultural significance) -​ amphetamine (speed) -​ methamphetamine (meth) -​ MDMA (ecstasy / molly) -​ Cathinones (khat) Amphetamine MoA -​ ↑ release and ↓ reuptake of neurotransmitters (adrenaline + NE + serotonin + dopamine) → CNS stimulation Effect -​ Central -​ euphoria + ↑ energy + hallucinations + impaired judgment + agitation + confusion  + sleep disturbances + psychosis -​ Peripheral -​ tachycardia + hypertension + arrhythmia + hyperthermia + mydriasis + nausea + weight loss + muscle weakness -​ hugsa allt öfugt við opioids Complications -​ Cardiac arrhythmias + cerebral hemorrhage + rhabdomyolysis + hyperthermia + memory impairment Withdrawal symptoms -​ Dysphoria + fatigue + depression + ↑ appetite + insomnia/hypersomnia + drug cravings + anxiety + aggression -​ Chronic use → psychosis Death -​ Death usually results from overdose → cardiovascular collapse or hyperthermia Management -​ symptoms based → BNZ for seizures or agitation Mechanism of overdose -​ Hypertensive crisis -​ vasoconstriction + SNS stimul.dangerously high BP -​ stroke, MI, aortic dissection -​ Arrhythmia -​ tachycardia and irregular heart beats → sudden cardiac arrest and death -​ Severe hyperthermia -​ can lead to multiorgan failure and can also cause rhabdomyolysis and kidney failure -​ Seizure -​ amphetamine overdose can lead to seizure and status epilepticus -​ Lethal dose -​ 150-500 mg in non tolerant users KHAT What is it -​ lauf af plöntu sem er tuggið (CATHIONINE → the potent stimulant found in the khat leaves) -​ can cause physical and psychological dependence -​ Stimulant and contains amphetamines. -​ Small amounts of khat might feel like drinking a lot of coffee, which opens the blood vessels in the brain to allow more oxygen to pass through and causes the heart to pump faster. Large dose of Khat -​ can lead to several cardiovascular effects effects -​ Positive -​ euphoria + excitement + mild hyperactivity - glaður kall að hoppa í grasinu -​ Negative -​ agitation + hallucination + paranoia + hypertension + tachycardia + mydriasis + constipation - svo kemur pirringur og paranoia -​ Long term -​ liver damage + permanent tooth darkening + ulcers + compromised self control Withdrawal -​ mild depression + irritability (occasional use) + lethargy + tremors (chronic use) Tests -​ blood, urine, saliva -​ Death: cardiovascular í bæði -​ Autopsy: MI, left ventricular hypertrophy, ats -​ Intracerebral hemorrhage and stroke -​ Brain edema -​ Git ulcers -​ Brain edema Comparison -​ commonalities = euphoria + ↑ energy + agitation + psychosis + withdrawal (depression + irritability) -​ differences -​ Amphetamines = stronger + faster onset effects → ↑ risk of severe complications -​ (hypernatremia + cardiovascular events) -​ Khat = more culturally embedded in some regions → more gradual intoxication but similar long term dependance risk