Progressive interstitial sclerosis in pneumoconiosis
A classic example of severe sclerotic changes in the lungs is talcosis, a pneumoconiosis developing from the inhalation of magnesium silicate (containing 29.8% to 63.5% silicon dioxide). The chronic and slowly progressive course of the disease triggers a cascade of fibrous alterations.
Pathomorphologically, the process begins with a cellular reaction: lymphocytes, histiocytes, and foreign-body giant multinucleated cells accumulate around insoluble fibers of talc dust. Subsequently, pronounced diffuse interstitial sclerosis develops. Connective tissue proliferates in the form of massive, thick bands that lead to the thickening of interalveolar septa.
Main pulmonary manifestations and complications:
- Development of peribronchial and perivascular sclerosis.
- Critical narrowing of the lumens of compressed alveoli (making them barely visible), leading to severe respiratory failure.
- Formation of miliary and larger sclerotic areas (while lacking the typical structure of classic silicotic nodules).
- Macroscopically, widespread adhesions are determined in the pleural cavity.
Sclerotic processes in chronic brucellosis
In the chronic stage of brucellosis, pathological anatomy is characterized by polymorphism: old and fresh lesions simultaneously coexist in tissues. Following the acute phase, accompanied by the formation of specific granulomas, productive thrombovasculitis, and necrosis foci in organs of the reticuloendothelial system, active fibrogenesis is triggered.
The regular outcome of chronic inflammation is total sclerosis of inflammatory infiltrates, miliary necrosis foci, and the stroma of internal organs. The extent of fibrous tissue proliferation can reach the stage of cirrhosis. The main morphological complication of this process is pronounced atrophy of the specific parenchyma of the affected organs.
Clinically, these very irreversible sclerotic changes become the main cause of permanent loss of working capacity (disability) in patients, despite the low overall mortality rate in brucellosis (about 0.1%).
Ulcer cicatrization and cardiosclerosis in escherichiosis
Escherichiosis (coli infection), affecting predominantly children in their first year of life, is based on an allergic component (the Shwartzman phenomenon) and toxic damage to the small intestine wall. Bacterial toxin disrupts the vascular barrier permeability, causing severe edema, plethora, and diapedetic hemorrhages.
In a protracted and severe course of the disease (from 2 to 6 months), serous inflammation and epithelial desquamation may progress to ulcerative colic-enteritis.
Complications of a protracted course:
- The prolonged presence of intestinal ulcers inevitably leads to the formation of local sclerosis, with dense connective tissue proliferating grossly at their base and edges.
- Atrophic enteritis develops in the intestinal wall, impairing absorption processes.
- Extraintestinal complications: toxinemia leads to the appearance of necrosis foci in the myocardium. Their subsequent replacement by fibrous tissue results in focal cardiosclerosis.
Sclerosis of parenchymal glands
Sclerotic complications are extremely dangerous for reproductive function and exocrine gland activity. Specifically, in severe inflammatory processes in testicular tissue (for example, in generalized infections), morphology reveals pronounced edema, mononuclear infiltration, and microfocal hemorrhages.
This massive edema within the confined space of the capsule leads to severe circulatory impairment and the development of testicular tissue microinfarcts. The predictable outcome of such infarcts is atrophic and sclerotic processes. Functional glandular tissue is replaced by scar tissue, which ultimately causes irreversible male infertility.
Class and exam questions
Why does respiratory failure develop in talcosis?
Due to diffuse interstitial sclerosis: connective tissue forms thick bands that thicken the interalveolar septa and compress alveolar lumens until they are barely visible.
What does tissue sclerosis lead to in chronic brucellosis?
Sclerosis of organ stroma, necrosis foci, and granulomas causes profound parenchymal atrophy (up to cirrhosis). This leads to persistent disability and patient invalidization.
Can $Escherichia\ coli$ cause myocardial sclerosis?
Yes, in severe and protracted E. coli infection, extraintestinal manifestations occur: necrosis foci form in the myocardium, which are subsequently replaced by scar tissue, resulting in cardiosclerosis.
What else to study on this topic
- Productive thrombovasculitis in the microvasculature
- Formation of Brucella granulomas in the nervous system
- Dystrophy of Auerbach's and Meissner's plexuses in $Escherichia\ coli$ infection
- Specific morphology of the talc pneumoconiotic reaction
- Morphogenesis of atrophic enteritis
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