General patterns of complication development
Pathomorphological changes in infectious diseases develop depending on the clinical course of the pathology. The entry portal of infection and subsequent generalization of the process determine internal organ damage. In bacterial and rickettsial infections, toxin production, pathogen reproduction features, and the host immune response play a key role.
- Localized forms tend to progress to generalized forms upon an unfavorable clinical course.
- Persistence of microorganisms supports the chronization of processes.
- Vascular disorders underlie many severe manifestations.
Features in rickettsioses and epidemic typhus
The obligate intracellular parasitism of the causative agents of epidemic typhus and Brill-Zinsser disease determines their tropism for endothelial cells. During rickettsial reproduction, incomplete phagocytosis and their persistence in endotheliocytes are observed, which ensures lifelong chronization and the possibility of late manifestation in the form of relapses.
- Lesion of endothelial cells of the vascular bed.
- Development of specific changes in organs during acute and recurrent forms.
- Risk of severe systemic disorders in the absence of adequate etiotropic therapy.
Lesions in leptospirosis
Hematogenous and lymphogenous dissemination of leptospires causes parenchymal diffusion, leading to systemic damage. In clinical practice and pathomorphology, the formation of critical syndromes is distinguished:
- Infectious-toxic and hemorrhagic syndromes.
- Hemolytic-uremic syndrome.
- Meningeal and encephalitic manifestations.
- Acute kidney injury (AKI) and acute liver failure (ALF).
TOP-ORG: Toxins, Edema, Parenchyma — the main targets for vascular and organ complications.
Class and exam questions
What main syndromes develop in severe leptospirosis?
Infectious-toxic, hemorrhagic, hemolytic-uremic, meningeal, and encephalitic syndromes develop, as well as acute renal and hepatic failure.
What underlies the pathogenesis of Mediterranean spotted fever and rickettsioses?
The key link in the pathogenesis is the development of acute universal vasculitis in the patient, caused by the tropism of rickettsias for endothelial cells.
What are the causes of chronization and relapses in epidemic typhus?
Chronization is associated with incomplete phagocytosis and the persistence of rickettsias in endotheliocytes, which allows the infection to manifest again in the form of Brill-Zinsser disease.
What else to study on this topic
- Etiological properties of Bacillus anthracis and their toxin production
- Features of the primary affect and regional lymphadenitis in Mediterranean spotted fever
- Differential diagnosis of icteric and anicteric variants of leptospirosis
- Pathomorphological changes in the heart, kidneys, and liver in various infections
- Methods of laboratory and bacteriological diagnosis of rickettsioses
Master the complete topic in the «Infectious Diseases» course
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Other topics in the section "Zoonotic infections — 2024 study guide"
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