Sepsis and Infection: Types, Morphology, and Pathogenesis

Sepsis Classification

According to Gates of Sepsis

Morphology of Sepsis

• Inflammatory Focus
• Microorganism Entering Bloodstream
• Systematic Change in Immune System

Bacteremic Toxic Shock

Syndrome induced by an abundant amount of toxins and biologically active substances released into the bloodstream by bacteria and injured tissue cells.

Morphological Features

• Disseminated Intravascular Coagulation
• Hemorrhagic Syndrome
• "Empty Heart"
• "Shock Kidney"
• "Shock Lungs"

Cyclic Infection

• Exoinfection (autonomous disease)
• Etiology: Obligatory Pathogenic
• Specific Immune Response
• Immunity Develops Afterwards
• Contagious

Transmission

• Air
• Alimentary
• Inoculation
• Hematogenous

Stages of Cyclic Infection

• Incubation
• Prodromic Period
• Manifestation Period
• Healing Period (Resolutio)

May develop into long-term immunity.

Morphology of Cyclic Infection

• Tissue Injuries (Different Locations)
• Organ Changes Due to Hypersensitivity Reaction
• Cause of Death: Organ Perforation, Bleeding Necrosis, Thrombosis

Local Infection

• Mostly Endoinfection, May Be from Exoinfection
• Non-cyclic Course
• Non-specific (General) Immune Response Leading to Inflammation
• No Immunity is Developed (Innate)
• May Cause Morphological Changes

Morphological Patterns in Chronic Progressive Hepatitis

Monolobular-Micronodular

• 0.2-0.5 cm Nodules
• Regular CT Bands of Approximately 0.1 cm
• Typical for Alcoholism

Multilobar-Macronodular (Many Scars)

• 0.5-1.5 cm Similar Nodes
• Irregular Proliferation of CT
• Chronic Progressive Hepatitis

Multilobar Macronodular with Scars

• Nodes from Very Small to 7 cm in Diameter
• Connective Tissue Forms Wide, Irregular Scars
• Chronic Progressive Hepatitis

Tuberculosis Pathogenesis

1. M. tuberculosis Invades Alveoli
2. Macrophages with Dormant M. tuberculosis to Lymph Nodes
3. Specific Immune Reaction Starts
4. Macrophages with Bacteria are Surrounded by Langhans-type Giant Cells, Epithelioid Cells, and Lymphocytes
5. T Suppressors Cause Death of Macrophages

Primary Complex = Lymphadenitis, Lymphangitis, and Tuberculosis Granuloma

Course

• Recovery
• Progressing:
  • Local: Cavernas in Lungs, Caseous Pneumonia
  • Lymphogenic Dissemination
  • Early Hematogenic Dissemination
• Primary Chronic Tuberculosis with Hypersensitivity Reactions