4. Adult Medical Autopsy & Natural Disease

Connolly (Atlas): Ch. 12 (Sudden Natural Death), Ch. 13 (Sepsis/MODS) Di Maio (Handbook): Ch. 5 (Natural Disease – adult sections)

What is sudden natural death?

An unexpected death resulting from an intrinsic (non-traumatic, non-toxic) disease, typically occurring within minutes to hours after symptom onset.

Why is sudden natural death considered medicolegally important?

Because trauma, toxic exposure, and other unnatural causes must be actively excluded before concluding that the death is natural.

What is the leading cause of sudden natural death in adults?

Cardiovascular disease.

Does a known history of disease automatically establish the cause of death?

No. The clinical history must be correlated with the autopsy findings before determining the cause of death.

What are the normal reference values for the adult heart?

• Male heart weight: 300–350 g
• Female heart weight: 250–300 g
• Left ventricular wall thickness: 1.3–1.5 cm
• Right ventricular wall thickness: 0.3–0.5 cm

What is the general investigative approach to a suspected sudden natural death?

1. Review the scene and circumstances of death.

2. Obtain the decedent's medical history.

3. Perform a complete external and internal examination.

4. Retain tissue for histology and collect toxicology specimens.

5. Correlate the history, scene, gross findings, histology, and toxicology before determining the final cause of death.

What coronary artery finding is most commonly associated with sudden natural death?

Severe coronary atherosclerosis with greater than 75% luminal stenosis, often involving multiple vessels.

What acute coronary findings may be present in sudden cardiac death?

Plaque rupture or erosion, coronary thrombosis, and acute myocardial infarction.

Why are old myocardial infarctions important even if they did not directly cause death?

Fibrous scars from prior infarctions create a substrate for fatal cardiac arrhythmias.

Can severe coronary artery stenosis cause sudden death without an acute myocardial infarction?

Yes. Severe coronary stenosis alone may trigger a fatal arrhythmia even when no acute infarct is present histologically.

What cardiac abnormalities, other than coronary artery disease, can cause sudden natural death?

• Hypertensive heart disease
• Cardiomyopathies (dilated, hypertrophic, ARVC)
• Valvular disease
• Conduction system abnormalities
• Myocarditis
• Congenital coronary anomalies

Which cardiac disease is characterized by left ventricular hypertrophy and increased heart weight?

Hypertensive heart disease.

Why are conduction system abnormalities difficult to diagnose at autopsy?

They often require specialized histologic sectioning because gross examination may appear normal.

Why can myocarditis be missed on gross examination?

Gross findings are often subtle or absent, so the diagnosis is usually confirmed microscopically.

What vascular diseases should always be considered in sudden natural death?

• Aortic dissection
• Ruptured abdominal aortic aneurysm
• Ruptured berry aneurysm
• Pulmonary thromboembolism

What two classic autopsy findings identify an aortic dissection?

An intimal tear and a false lumen.

Which disease is most commonly associated with aortic dissection?

Chronic hypertension (and connective tissue disorders such as Marfan syndrome).

What is the typical hemorrhage associated with rupture of an abdominal aortic aneurysm?

Massive retroperitoneal hemorrhage.

What type of hemorrhage results from rupture of a berry aneurysm?

Subarachnoid hemorrhage.

During an autopsy for pulmonary thromboembolism, where should the embolic source be sought?

The deep veins of the legs and pelvis.

What is a saddle pulmonary embolus?

A pulmonary embolus lodged at the bifurcation of the main pulmonary artery.

What pulmonary diseases may cause sudden natural death?

• Massive pulmonary thromboembolism
• Severe asthma
• Pneumonia
• COPD exacerbation

What gross findings are characteristic of fatal severe asthma?

Hyperinflated lungs, mucus plugging, and bronchial wall eosinophilia.

What central nervous system diseases may cause sudden natural death?

• Hypertensive intracerebral hemorrhage
• Subarachnoid hemorrhage
• SUDEP (Sudden Unexpected Death in Epilepsy)

What is SUDEP?

Sudden Unexpected Death in Epilepsy—a diagnosis of exclusion when no anatomic cause of death is identified.

What gastrointestinal diseases may cause sudden natural death?

• Peptic ulcer hemorrhage
• Esophageal variceal hemorrhage
• Mallory-Weiss tear
• Acute pancreatitis
• Ruptured bowel
• Mesenteric ischemia/infarction

Which postmortem specimens are most useful when diabetic ketoacidosis is suspected?

Vitreous humor for glucose and ketone analysis.

Which uncommon endocrine disorders should still be considered in sudden natural death?

Adrenal hemorrhage and acute adrenal insufficiency (Addisonian crisis).

What is SIRS (Systemic Inflammatory Response Syndrome)?

A systemic inflammatory response defined by clinical criteria including abnormalities in temperature, heart rate, respiratory rate, and white blood cell count.

What is sepsis?

SIRS occurring in the setting of a documented or strongly suspected infection.

What is severe sepsis?

Sepsis accompanied by evidence of organ dysfunction or tissue hypoperfusion.

What is septic shock?

Sepsis with hypotension that persists despite adequate fluid resuscitation.

What is MODS (Multi-Organ Dysfunction Syndrome)?

Progressive dysfunction of two or more organ systems resulting from severe systemic illness.

What is the progression from infection to MODS?

Infection → SIRS → Sepsis → Severe Sepsis → Septic Shock → MODS.

Which pathogens commonly trigger sepsis?

Bacterial (endotoxin- or exotoxin-producing), fungal, and viral pathogens.

Which inflammatory cytokines play a major role in the pathophysiology of sepsis?

TNF-α, IL-1, and IL-6.

What is the sequence of events in the pathophysiology of sepsis?

1. Infection triggers cytokine release. 2. Cytokines cause systemic inflammation. 3. Endothelial injury increases vascular permeability. 4. Microvascular thrombosis (DIC) develops. 5. Tissue hypoperfusion causes ischemia. 6. Progressive organ failure leads to MODS.

Why does endothelial injury contribute to MODS?

It increases vascular permeability and promotes microvascular thrombosis, resulting in tissue hypoperfusion and ischemia.

Can MODS continue to progress even after the infection has been treated?

Yes. MODS may continue despite control of the original infection.

What are the most common pulmonary sources of sepsis?

Bronchopneumonia, lobar pneumonia, and aspiration pneumonia.

What are the most common genitourinary sources of sepsis?

Pyelonephritis and urosepsis.

What abdominal conditions commonly lead to sepsis?

Peritonitis, cholangitis, intra-abdominal abscesses, and bowel perforation.

Which skin and soft tissue infections commonly cause sepsis?

Cellulitis, necrotizing fasciitis, and decubitus (pressure) ulcers.

Which medical devices commonly serve as sources of sepsis?

Vascular catheters, surgical lines, and prosthetic material.

Why can infective endocarditis produce sepsis involving multiple organs?

Septic emboli can spread infection throughout the body.

What are the characteristic gross autopsy findings in sepsis?

• Enlarged, soft, hyperemic spleen ("septic spleen") • Pulmonary consolidation, abscesses, or diffuse alveolar damage (ARDS) • Pale, swollen kidneys consistent with ATN • Centrilobular liver necrosis and cholestasis ("sepsis liver") • Petechial hemorrhages suggesting DIC

What gross appearance characterizes the spleen in sepsis?

Enlarged with soft, hyperemic ("septic") pulp.

What pulmonary findings are commonly seen at autopsy in sepsis?

Consolidation, abscess formation, or diffuse alveolar damage consistent with ARDS.

What renal findings are characteristic of sepsis?

Pale, swollen cortices consistent with acute tubular necrosis (ATN).

What liver findings are characteristic of sepsis?

Centrilobular necrosis and cholestasis ("sepsis liver").

What do petechial hemorrhages on the skin or serosal surfaces suggest in sepsis?

Disseminated intravascular coagulation (DIC).

What is the most important principle during autopsy of a septic patient?

Always identify, sample, and document the primary infectious source.

What are the characteristic microscopic findings of sepsis in the lungs?

Diffuse alveolar damage, hyaline membrane formation, and neutrophilic infiltrates.

What microscopic kidney finding is characteristic of sepsis?

Acute tubular necrosis with tubular epithelial sloughing.

What microscopic liver findings are characteristic of sepsis?

Centrilobular hepatocyte necrosis, cholestasis, and Kupffer cell hyperplasia.

What microscopic cardiac findings may be seen in sepsis?

Contraction band necrosis and microabscesses (when septic emboli are present).

What microscopic vascular finding is characteristic of DIC?

Fibrin (hyaline) microthrombi.

Why should blood and tissue cultures be collected promptly during autopsy?

To minimize postmortem contamination.

Which organ system usually fails first in MODS?

The lungs, resulting in acute respiratory distress syndrome (ARDS).

What renal manifestation is characteristic of MODS?

Acute kidney injury due to acute tubular necrosis.

What hepatic manifestation is characteristic of MODS?

Shock liver with impaired clotting factor synthesis and coagulopathy.

What cardiovascular abnormalities occur in MODS?

Myocardial depression and distributive (vasodilatory) shock.

What hematologic abnormality commonly develops in MODS?

Disseminated intravascular coagulation (DIC) with consumptive coagulopathy and thrombocytopenia.

What gastrointestinal abnormalities occur in MODS?

Mucosal ischemia, stress ulceration, and bacterial translocation.

What is the most important principle when certifying a death due to sepsis?

Identify and document the underlying infectious or anatomic source whenever possible.

How should the cause of death be written in sepsis?

As a sequential chain (e.g., Septic shock → Bronchopneumonia → Underlying disease).

Which contributing conditions should be documented in septic deaths?

Diabetes mellitus, malnutrition, immunosuppression, and malignancy.

Why must postmortem cultures be interpreted cautiously?

Because agonal bacterial translocation and postmortem contamination are common.

What is the primary goal of evaluating natural disease during an autopsy?

To determine whether the identified disease process adequately explains the death.

What must the forensic pathologist determine when evaluating natural disease?

Whether the natural disease alone is sufficient to account for the death.

Can pre-existing disease be present without causing death?

Yes. Pre-existing disease may be an incidental finding and not the actual cause of death.

Why must every significant disease process be documented during an autopsy?

Because its severity, distribution, and relevance may contribute to the interpretation of the death, even if it is not the direct cause.

What should be done when autopsy findings are equivocal?

Perform additional ancillary studies, such as special stains or additional histologic sectioning, before finalizing the diagnosis.

How should coronary atherosclerosis be documented at autopsy?

By grading the degree of coronary artery stenosis.

What gross cardiac finding is characteristic of hypertensive cardiovascular disease?

Left ventricular hypertrophy.

How should cardiomegaly be evaluated at autopsy?

Compare the heart weight with the decedent's body habitus and assess for underlying causes.

What additional cardiac abnormalities should be assessed during evaluation of natural disease?

• Valvular calcification and degenerative changes
• Cardiomyopathies

What are the most common causes of cirrhosis?

Alcohol use, chronic viral hepatitis, and non-alcoholic steatohepatitis (NASH).

What are the major complications of cirrhosis?

• Esophageal or gastric varices
• Ascites
• Hepatic encephalopathy

What are the major life-threatening complications of peptic ulcer disease?

Perforation and hemorrhage.

What two major forms of pancreatitis should be distinguished at autopsy?

Acute hemorrhagic pancreatitis and chronic pancreatitis.

What gross findings are characteristic of chronic kidney disease?

Contracted kidneys with cortical thinning.

What additional renal abnormalities should be documented during an autopsy?

• Renal cysts
• Pyelonephritis
• Nephrolithiasis

Which organ systems are commonly affected by the macrovascular and microvascular complications of diabetes mellitus?

The heart, kidneys, eyes, and peripheral nerves.

Which postmortem specimens best support the diagnosis of diabetic ketoacidosis?

Vitreous humor glucose and ketone levels.

Which thyroid conditions should be considered during evaluation of natural disease?

• Goiter
• Thyrotoxic states
• Myxedema (severe hypothyroidism)

Which adrenal diseases should be considered during autopsy?

• Adrenal hemorrhage
• Adrenal atrophy
• Acute adrenal (Addisonian) crisis

Why are obesity-related comorbidities important at autopsy?

They contribute significantly to cardiovascular disease and metabolic disease burden.

Should significant findings that did not directly cause death be documented?

Yes. All significant findings should be documented, even if they are incidental.

Why is it important to distinguish incidental disease from the actual cause of death?

Because not every abnormality identified at autopsy explains the death.

How can natural disease influence traumatic or toxic deaths?

Natural disease may contribute to death or reduce physiologic reserve, making relatively minor trauma or intoxication fatal.

What information must be integrated when determining the cause and manner of death?

• Medical history
• Scene investigation
• Autopsy findings
• Toxicology
• Histology

What should be done if the cause or manner of death remains uncertain after the autopsy?

Obtain additional testing before finalizing the cause and manner of death.

What is the forensic pathologist's responsibility when evaluating natural disease at autopsy?

1. Determine whether the disease is sufficient to explain the death.

2. Distinguish the true cause of death from incidental findings.

3. Document all significant disease.

4. Correlate the history, scene, autopsy findings, toxicology, and histology before certifying the death.