Local impact of calculi on tissues
The primary link in the development of severe complications from lithogenesis is the direct mechanical impact of the dense concretion on surrounding tissues. Calculi can localize in various anatomical structures: the renal pelvis, the lumen of the ureters, the gallbladder cavity and bile ducts, as well as the appendix.
Prolonged presence of a stone in one place causes continuous pressure on the organ wall, leading to the formation of pressure ulcers. This condition is fraught with a number of dangerous outcomes:
- Perforation: destruction of the organ wall across its entire thickness with the formation of a full-thickness defect.
- Adhesion formation: a pathological process in which the damaged organ fuses with adjacent tissues.
- Fistula formation: the appearance of abnormal tracts as a direct consequence of deep tissue destruction caused by the concretion.
Pathogenesis of inflammatory processes
The presence of calculi is inevitably associated with the development of pronounced inflammation. This process has a clear pathogenetic mechanism consisting of several consecutive stages. First, hard stones constantly traumatize the mucous membrane. Second, the damaged tissue becomes an ideal entry gate for secondary infection. Third, the stone creates an obstruction, causing stasis of secretion or excretion.
Depending on the exact localization of the concretion, specific inflammatory diseases develop:
- Organ involvement: pyelitis and cystitis occur in the urinary system. Cholecystitis and pancreatitis develop in the digestive system. In the maxillofacial region, stones can provoke a salivary gland abscess.
- Duct involvement: obstruction of the pathways leads to the development of cholangitis and cholangiolitis.
Clinical manifestations and treatment approaches
The clinical picture of lithogenesis directly depends on the localization of the pathological process. In clinical practice, three main nosological forms are distinguished: urolithiasis, cholelithiasis, and sialolithiasis.
The pathogenesis of the main symptoms is strictly determined by morphological changes and mechanical impact:
- Hematuria: the appearance of blood in the urine. This symptom occurs because calculi injure the mucous membrane, provoking bleeding.
- Colic (biliary or renal): sudden attacks of acute pain. The basis of this syndrome is a reflex spasm of the smooth muscle layer of the organ in response to the irritant effect of the stone.
Approaches to treating these pathologies are divided into conservative and surgical. A special place is occupied by a modern treatment method for urolithiasis—extracorporeal shock wave lithotripsy, which effectively manages calculi.
Briefly: answers to topical questions
Which specific chemical substances form calculi?
Calculi are formed from various organic and inorganic compounds depending on localization. Stones may consist of:
- Cholesterol (cholesterol monohydrate) and bilirubin (bile pigments).
- Uric acid and its salts (urate).
- Calcium oxalate (oxalates).
- Calcium phosphate, calcium carbonate, and triple phosphates (struvites).
- Cystine and xanthine.
Bronchial stones also contain mucus encrusted with lime.
What types of calculi are distinguished by their chemical composition?
Several types of calculi are distinguished by chemical composition depending on the affected organ. Gallstones are divided into:
- Cholesterol (pure and mixed).
- Pigment.
- Calcareous (calcium).
- Complex (combined cholesterol-pigment-calcareous).
Urinary stones are classified into:
- Urates (uric acid and its salts).
- Phosphates (calcium phosphate).
- Oxalates (calcium oxalate).
- Cystine.
- Xanthine.
What are the macroscopic characteristics of calculi regarding shape and cross-sectional structure?
The macroscopic characteristics of calculi depend on their localization and composition. By shape, they are distinguished into:
- Round or oval — in the urinary bladder and gallbladder.
- Arborescent (staghorn) — in the renal pelvis and calyces.
- Cylindrical — in the ducts of glands.
- Facetted — having faceted surfaces polished against each other.
By cross-sectional structure, stones can be:
- Radiate (crystalloid).
- Layered (colloid).
- Layered-radiate (colloid-crystalloid).
What general (systemic) factors contribute to the process of lithogenesis?
The process of lithogenesis is promoted by:
- Disorders of lipid, carbohydrate, and mineral metabolism.
- Tubulopathies, hyperparathyroidism, and purine metabolism disorders.
- Deficiency of natural crystal formation inhibitors: citrate, pyrophosphate, glycosaminoglycans, and nephrocalcin.
- Hereditary predisposition.
- Dietary patterns.
- Geographical factor — the presence of hardness salts in water.
- Ethylene glycol poisoning.
What local factors and processes contribute to the primary formation of calculi?
Primary calculus formation is promoted by a complex of local pathological changes in organs and ducts. Local factors include:
- Impaired secretion and resorption leads to thickening of the secretion.
- Secretion stasis creates conditions for salt precipitation.
- Inflammatory processes are accompanied by exudation. Desquamated cells, leukocytes, bacteria, and mucus form the organic (colloidal) matrix of the stone.
- Changes in the physicochemical properties of the medium — a shift in pH towards the alkaline side and the appearance of protein substances in the secretion.
What pathological processes and complications develop during bile duct obstruction by a calculus, apart from cholangitis?
Bile duct obstruction by a calculus leads to the following pathological processes and complications:
- Local action (pressure sores) causing perforation, adhesion formation, and fistula formation.
- Inflammatory processes: cholecystitis, pancreatitis, and cholangiolitis.
- Jaundice due to bile duct obturation.
- Biliary colic — attacks of acute pain due to reflex spasm of the smooth muscle layer.
- Secondary biliary liver cirrhosis as an outcome of impaired patency of the biliary tract.
The pathogenesis of inflammation in stone formation is easy to remember using the three-step rule: Tissue injury → Portal of entry for infection → Stasis of secretion or excretion.
Class and exam questions
What is a calculus from the perspective of pathological anatomy?
This is a solid mass (from Latin concrementum — accretion) that forms from components of secretion or excretion and lies freely in hollow organs or excretory ducts of glands.
What is the mechanism of development of renal or biliary colic?
An acute pain attack during colic occurs due to pronounced reflex spasm of the organ's smooth muscle layer, which responds to mechanical irritation by the stone.
Why does the presence of stones lead to the development of inflammation?
Stones constantly traumatize surrounding tissues, creating a gateway for infection, and obstruct the lumen, causing pathological stasis of secretion or excretion.
What outcomes are characteristic of prolonged pressure of a stone on the organ wall?
The local impact of the calculus causes pressure sores, which can subsequently lead to wall perforation, adhesion formation, and fistula development.
What else to study on this topic
- Morphological features of mucosal pressure sores during prolonged presence of calculi.
- Pathogenesis of fistula and perforation formation as an outcome of the local impact of stones.
- Comparative characteristics of inflammatory processes in the ducts: cholangitis and cholangiolitis.
- Mechanisms of salivary gland abscess development against the background of sialolithiasis.
- Principles of extracorporeal shock wave lithotripsy in the treatment of urolithiasis.
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