ABPath Forensic Pathology cheat sheet

Atherosclerotic plaque rupture with superimposed thrombosis causes most acute coronary deaths; critical stenosis is typically >75% cross-sectional luminal narrowing.

Acute myocardial infarction histology: coagulative necrosis and wavy fibers at 6-12 h; neutrophilic infiltrate 1-3 days; macrophage resorption and granulation tissue 1-2 weeks; fibrous scar after ~8 weeks.

Pulmonary thromboembolism is confirmed at autopsy by saddle or lobar emboli; deep vein thrombosis of leg veins is the usual source.

Hypertensive intracerebral hemorrhage favors the basal ganglia, thalamus, pons, and cerebellum; amyloid angiopathy favors lobar hemorrhage in the elderly.

Therapeutic complications to document include drug anaphylaxis, heparin-induced thrombocytopenia with thrombosis, contrast nephropathy, and fatal arrhythmia from QT-prolonging drugs.

Traumatic axonal injury shows axonal swellings and retraction balls on silver or beta-amyloid precursor protein stains, often with corpus callosum or dorsolateral brainstem lesions.

Fat embolism syndrome presents 24-72 h after long-bone fracture with petechiae, hypoxemia, and fat globules in pulmonary capillaries.

Distinguish antemortem from postmortem wounds: antemortem wounds show vital reactions such as hemorrhage, leukocyte margination, and fibrin deposition.

Blunt impact produces abrasions, contusions, and lacerations; lacerations show tissue bridging, unlike sharp-force incised wounds.

Sharp-force wounds: incised wounds are longer than deep; stab wounds are deeper than long, and the wound track may exceed blade length with hilt marks.

Exit gunshot wounds are typically larger, everted, and lack soot, tattooing, or a muzzle imprint; abrasion collars occur at entry.

Soot deposition and powder tattooing indicate firing at close range; dense soot without tattooing suggests near-contact, and a muzzle imprint suggests hard contact.

Hanging produces an inverted V ligature mark high on the neck; manual strangulation produces horizontal marks, petechiae, and hyoid or thyroid cartilage fracture.

Drowning lacks a specific diagnostic test; findings include froth in airways and diatoms in bone marrow, but water aspiration can occur postmortem.

Heat injury: charring, pugilistic attitude, heat fractures, and epidural hematoma without brain injury; soot in airways and elevated carboxyhemoglobin indicate antemortem fire exposure.

Child abuse patterns: metaphyseal corner fractures, rib fractures of varying ages, retinal hemorrhage, and injuries inconsistent with the stated mechanism.

Manner of death categories are natural, accident, suicide, homicide, undetermined, and pending; manner is a legal classification distinct from cause.

Cause of death is the disease or injury that initiated the lethal sequence; the mechanism is the physiologic derangement such as arrhythmia or exsanguination.

The autopsy report should document external examination, internal organ weights and findings, toxicology, and a clinicopathologic correlation with cause and manner.

Deaths in custody, deaths during restraint, and deaths following police contact generally require autopsy and often external oversight.

Sudden infant death syndrome is a diagnosis of exclusion requiring scene investigation, complete autopsy, and review of history; unsafe sleep conditions shift classification.

Postmortem changes used to estimate time of death include livor, rigor, algor mortis, decomposition, and vitreous potassium; each has wide individual variability.

Exhumation and second autopsies require chain-of-custody documentation and comparison with the original report and retained specimens.

Skeletal remains require forensic anthropology for biological profile and trauma analysis; perimortem fractures show no healing and match bone color.

Vitreous humor is relatively protected from putrefaction; potassium rises roughly linearly after death and is used with other findings to estimate postmortem interval.

Ethanol interpretation requires testing vitreous or urine to distinguish antemortem ingestion from postmortem fermentation; a urine-to-blood ratio >1.3 suggests recent drinking.

Carboxyhemoglobin >50% is often lethal; cherry-red livor and soot in airways support fire-related death, but CO also forms postmortem.

Cyanide causes bright red livor and bitter-almond odor; it is detected in blood and tissue, and fire victims may have elevated levels.

Opiate deaths show respiratory depression with pulmonary edema; interpret morphine and 6-monoacetylmorphine to establish heroin exposure.

Toxicology specimens include femoral blood, vitreous, urine, bile, liver, and brain; femoral blood avoids postmortem redistribution from the stomach and lungs.

Drugs of forensic importance include tricyclic antidepressants (arrhythmia), insulin (hypoglycemia), and potassium (electrolyte derangement); each requires scene and history correlation.

Postmortem redistribution and putrefactive alcohols can falsely elevate drug and ethanol concentrations; interpret with sampling site and interval.

DNA profiling uses short tandem repeats (STRs) amplified by PCR; a match probability is reported using population allele frequencies and Hardy-Weinberg assumptions.

Mitochondrial DNA is maternally inherited and useful for degraded or hair shaft samples; Y-STR testing targets male lineage.

Forensic odontology uses dental records, restorations, and radiographs for identification; bite mark comparison is limited and increasingly disfavored as evidence.

Anthropology estimates sex from pelvis and skull, age from epiphyseal fusion and dental wear, ancestry from craniometrics, and stature from long-bone regression formulas.

Criminalistics: bloodstain pattern analysis classifies impact spatter, cast-off, transfer, and passive drops; directionality derives from stain shape.

Latent print development uses powders, ninhydrin, cyanoacrylate, and alternate light sources; DNA recovery may be compromised by some methods.

Trace evidence includes hair, fiber, glass, paint, and gunshot residue; gunshot residue particles contain lead, barium, and antimony.

Chain of custody must document every transfer of evidence; breaks can render evidence inadmissible or reduce its weight.

Death certificates require the immediate cause, underlying cause, and manner; the underlying cause is the condition that began the lethal sequence.

The medical examiner system is usually appointed and independent; the coroner system is often elected and may lack medical training.

Jurisdictional authority for medicolegal death investigation derives from statute; reportable deaths include violence, unexpected deaths, and deaths without a physician.

Expert testimony must meet admissibility standards (Daubert or Frye depending on jurisdiction) and be based on reliable methodology.

Occupational safety in the morgue requires universal precautions, sharps handling, adequate ventilation for formalin, and biosafety practices for tuberculosis and prions.

Mass fatality management uses the incident command system, victim identification by DNA, dental, fingerprint, and radiographic methods, and family assistance.

Public health surveillance uses death certificate data and medical examiner reporting for injury and overdose trends; syndromic surveillance complements it.

Quality assurance includes peer review, standardized protocols, proficiency testing, and accreditation of laboratories and offices.

Aortic dissection shows a false lumen with intimal tear; type A involves the ascending aorta and carries higher mortality.

Cardiac contusion and commotio cordis can cause sudden death after blunt chest trauma without structural heart disease.

Pulmonary fat embolism and marrow embolism follow long-bone fractures; microscopic fat globules in pulmonary capillaries support the diagnosis.

Hepatic and splenic lacerations from blunt trauma cause hemoperitoneum; document volume and capsular integrity.

Chronic ethanol use causes hepatic steatosis, alcoholic hepatitis, and cirrhosis with portal hypertension and varices.

Cocaine and methamphetamine cause catecholamine surge with coronary vasospasm, myocardial contraction band necrosis, and arrhythmia.

Anaphylaxis shows laryngeal edema, pulmonary hyperinflation, and eosinophils; serum tryptase elevation supports the diagnosis.

Sepsis shows neutrophilic infiltrates, microabscesses, and DIC with fibrin thrombi; blood cultures and postmortem cultures aid interpretation.

Abrasion patterns can reproduce the shape of the impacting object, such as a patterned tire mark or ligature.

Contusions may be deeper than the surface and require dissection; color changes over time are unreliable for dating.

Defense wounds occur on forearms and hands; hesitation marks are parallel, superficial, and grouped on the wrists or neck.

Dicing injuries from shattered glass produce multiple small angular lacerations; patterned injuries from a weapon should be photographed with scale.

Gunshot entrance wounds show a circular defect with an abrasion ring; atypical entries occur over bone or with tangential fire.

Drowning deaths may show water in the stomach and diatoms in organs; the findings are supportive, not definitive.

Electrical injury produces Joule burns at entry and exit, metallization, and cardiac arrhythmia; lightning causes arborescent burns.

Asphyxia from smothering or neck compression shows petechiae of conjunctivae, face, and palate, with cyanosis and congestion.

The death certificate immediate cause is the final disease or condition; the underlying cause is the initiating condition, and contributing conditions are listed separately.

Manner of death is determined by the medical examiner or coroner and is a legal conclusion, not a pathologic diagnosis.

Autopsy consent and statutory authority differ; medical examiner cases proceed under legal authority, while hospital autopsies require consent.

Retained tissues and specimens require documentation and may be subject to family requests and jurisdictional rules.

Sudden cardiac death in a young person prompts evaluation for cardiomyopathy, channelopathy, and aortic disease, with molecular autopsy considered.

Deaths from chronic disease may still be reportable if unexpected, violent, or unattended; scene and history guide jurisdiction.

Postmortem interval estimation combines body temperature, rigor, livor, decomposition, and entomology; no single method is reliable alone.

Skeletal trauma analysis distinguishes perimortem from postmortem damage by fracture color, sharp edges, and absence of healing.

Vitreous sodium and chloride are stable after death; urea and creatinine reflect antemortem renal function.

Acetone and isopropanol indicate ketoacidosis or isopropanol ingestion; distinguish from ethanol by specific assays.

Carbon monoxide and cyanide co-exposure occurs in fire deaths; test both because each can be lethal independently.

Organophosphate poisoning shows miosis, bronchorrhea, and reduced cholinesterase activity; at autopsy, gastric odor may be noted.

Digoxin, lithium, and theophylline have narrow therapeutic indices; postmortem levels require cautious interpretation.

Blood alcohol concentration interpretation accounts for absorption, distribution, and elimination; a rising versus falling curve affects impairment estimates.

Specimen collection should include femoral blood, vitreous, urine, and liver; document sites and times to address redistribution.

Drug screening uses immunoassay with confirmatory gas chromatography-mass spectrometry; false positives require confirmation.

DNA quantity and degradation affect STR typing; low-template samples require increased cycles and carry stochastic effects.

PCR inhibitors in blood, soil, and fabric can cause allelic dropout; dilution and re-extraction are used to overcome them.

Dental age estimation uses tooth eruption and mineralization; the Demirjian method is commonly applied in children.

Sex estimation from the skull uses the mastoid process, supraorbital ridges, and mandibular angle; the pelvis is more reliable.

Stature estimation uses regression equations derived from reference populations; ancestry-specific formulas improve accuracy.

Bloodstain impact spatter shows small droplets with directionality; cast-off patterns are linear and associated with a swinging weapon.

Fingerprint classification uses arches, loops, and whorls; minutiae matching underlies identification.

Evidence collection must avoid contamination; controls, blanks, and documented packaging are required.

Death certificate completion requires the certifier to state the cause and manner and to sign; errors require an amended certificate.

Medical examiner offices may be county, district, or state based; jurisdiction determines authority and reporting requirements.

Expert witnesses must disclose the basis of opinion; courts assess reliability, testing, error rates, and peer review.

Informed consent and confidentiality apply to autopsy and specimen use; statutes govern release of records and images.

Biosafety in the morgue includes sharps containers, personal protective equipment, and ventilation for formalin and infectious aerosols.

Mass fatality identification integrates antemortem records with postmortem findings using DNA, dental, fingerprint, and radiographic comparison.

Public health reporting of deaths and injuries supports surveillance and prevention; standardized coding uses ICD-10.

Accreditation and peer review improve quality; documentation and chain of custody support legal defensibility.

Chronic obstructive pulmonary disease shows hyperinflation, bullae, and mucous gland hyperplasia; cor pulmonale may be present.

Pulmonary embolism can be missed at autopsy; examine pulmonary arteries after opening the heart and lungs.

Cerebral infarction shows pale softening acutely and cystic cavitation chronically; hemorrhagic transformation may occur.

Subarachnoid hemorrhage from a ruptured berry aneurysm shows basal blood; document aneurysm site and size.

Acute pancreatitis shows fat necrosis and hemorrhage; alcohol and gallstones are common causes.

Drug-induced liver injury and Stevens-Johnson syndrome are therapy-related causes of death requiring medication review.

Traumatic subdural hematoma results from tearing of bridging veins; subarachnoid blood follows trauma or aneurysm rupture.

Rib fractures with flail chest and pulmonary contusion cause hypoxia; document fracture locations and lung injury.