Severe Forms of Plague
The postmortem picture of severe (likely pneumonic) plague is characterized by a fulminant course (2–3 days) and 100% mortality. The main findings at autopsy include:
- Lungs: consolidated, showing a mottled grey-red appearance on cross-section, containing foci of necrosis and suppurative inflammation.
- Respiratory tract: serous-hemorrhagic inflammation in the trachea and bronchi, with fibrinous deposits on the pleura.
- Internal organs: parenchymal fatty change and reactive inflammation of the stroma.
The primary septicemic form progresses even more rapidly, with death occurring in 24–36 hours. Due to this extreme velocity, specific morphological changes do not have time to form, and the diagnosis is confirmed primarily by bacteriological methods.
Smallpox (*Variola vera*)
Although officially eradicated, the cessation of universal vaccination leaves the population vulnerable to a potential pandemic. The causative agent is a large DNA virus transmitted via airborne droplets and direct contact.
Pathogenesis and Skin Rash Morphology: The infection goes through minor and major viremia stages. The skin, sensitized in early stages, bears the brunt of the disease. The rash evolves sequentially:
- Papule: the epidermis thickens due to proliferation of the Malpighian layer.
- Pustule (multilocular vesicle): ballooning and reticular degeneration of the epidermis occur. The cavity fills with seropurulent exudate, forming a central depression (umbilication).
- Crust/Scab: by days 12–14, the exudate is reabsorbed, and the pustule dries out.
The most dangerous form is black smallpox (pustular-hemorrhagic). It features massive diapedetic hemorrhages in the dermis. The exudate becomes bloody, and hemoglobin transforms into iron sulfide, turning the pustules a black-grey color. Mortality for this form is 100%.
Yellow Fever (*Febris flava*)
A zoonotic quarantine infection endemic to Latin America and Africa, transmitted by mosquito vectors. The virus initially replicates in lymph nodes before causing massive viremia.
Target Organs and Alterations:
- Liver: widespread focal parenchymal necrosis leading to hepatic jaundice (yellow discoloration of sclerae, skin, and internal organs).
- Kidneys: development of icteric nephrosis and fatty degeneration, leading to oliguria and anuria in severe cases.
- Vessels: generalized vasculitis triggers widespread hemorrhages in the stomach, intestines, brain, and lungs.
- Heart: interstitial myocarditis and fatty change.
Death most frequently occurs on days 7–8 from uremic coma secondary to toxic encephalopathy.
Autopsy Protocols for Quarantine Infections
Performing autopsies on individuals who died of high-consequence infectious diseases requires strict safety measures to prevent pathogen dissemination and personnel contamination.
- Prosector Protection: A biological hazard suit is mandatory (or two closed gowns with sleeve protectors, cap, mask, goggles, and two pairs of gloves). Afterward, the gear is incinerated in a secure facility.
- Facility: The morgue drainage system must be completely shut off. Fluids are collected into dedicated containers.
- Autopsy Technique: Organs are examined in situ (without being removed from the body cavities).
- Corpse Disposal: Organs are covered with quicklime and treated with lysol. The body is wrapped in sheets soaked in disinfectant. Burial must be at a depth of at least 3 meters, with layers of soil interspersed with quicklime.
Sepsis and SIRS
Sepsis differs fundamentally from other infections: it lacks a specific causative agent, is non-contagious, and does not confer post-infection immunity. It is a host-centered pathological process rooted in hyperergy—a distorted, hyper-intense systemic immune response to infection.
According to the ACCP/SCCM consensus criteria, the underlying pathogenesis involves SIRS (Systemic Inflammatory Response Syndrome). Diagnosis requires meeting criteria involving abnormal temperature (>38°C or <36°C), heart rate (>90 bpm), respiratory rate (>20 breaths/min), or leukocyte count (<4,000 or >12,000/µL).
Morphologically, sepsis manifests as microcirculatory disorders (stasis, sludging), diapedetic hemorrhages, degenerative changes, and multiple microabscesses across internal organs. The primary cause of death in sepsis is Multiple Organ Dysfunction Syndrome (MODS).