30. Metastatic calcification: definition, causes, mechanisms of development. Macro- and microscopic changes in organs, clinical significance. Disease examples.

The mechanism of metabolic calcification (calcareous gout, interstitial calcification) has not been clarified: there are no general (hypercalcemia) and local (dystrophy, necrosis, sclerosis) prerequisites. In the development of metabolic calcification, the main importance is attached to the instability of buffer systems (pH and protein colloids), in connection with which calcium is not retained in the blood and tissue fluid even at low concentrations, as well as the hereditarily caused hypersensitivity of tissues to calcium - calcergia, or calcifylaxis.

Etiology of metabolic calcification (interstitial calcification, calcareous gout): instability of buffer systems that retain calcium in a dissolved state + calcifylaxis (increased sensitivity of tissues to calcium).

Morphology of metabolic calcification:

a. systemic interstitial calcification - calcium salts in the skin, subcutaneous tissue, along the tendons, fascia, muscles, blood vessels.

b. limited interstitial calcification is the deposition of lime in the form of plates in the skin of the fingers (calcareous gout).

Issue. Unfavorable: fallen lime usually does not dissolve or resolves with difficulty. With lung damage, respiratory failure is possible; with massive nephrocalcinosis, renal failure is possible; with myocardial damage, the formation of chronic heart failure is possible.

Meaning. The prevalence, localization and nature of calcifications are important. Thus, lime deposition in the vessel wall leads to functional disorders and can cause a number of complications (for example, thrombosis). Along with this, the deposition of lime in a caseous tuberculous focus indicates its healing, i.e. it has a reparative character.

31. Formation of stones: definition of the concept, causes, mechanisms of development. Forms and chemical composition of urinary and biliary tract stones, complications, clinical significance.

Stones (concretions) are dense formations lying freely in the abdominal organs or excretory ducts of the glands.

Reasons for education:

a) common factors: metabolic disorders - hereditary, acquired (cholesterol, nucleoproteins, carbohydrates, minerals)

b) local factors: 1. violation of secretion and stagnation of secretions 2. inflammatory processes in the places of localization of stones.

Types of stones:

a) in size: macrolites and microliths

b) in shape: round and oval in the MP and LC, process in the pelvis and cups of the kidneys, cylindrical in the ducts of the glands

c) by quantity at the location: single and multiple

d) surface structure: smooth (faceted - lapped surfaces of stones to each other) and rough (oxalates - a kind of mulberry)

e) by color (determined by their chemistry. composition): white - phosphates, yellow - urates, dark green - pigments

f) according to the structure on the saw: crystalloid - radial structure, colloidal - layered structure, colloidal-crystalloid.

Localization of stones: more often - bile and urinary tract, also: excretory ducts of the pancreas and salivary glands, bronchi, crypts of the tonsils, veins (phlebolitis - petrified thrombi separated from the vessel wall), intestines (coprolites-compacted intestinal contents)

Mechanism of development: inflammation (→ the appearance of a protein that forms an organic matrix for stones) + impaired secretion and stagnation of secretions (→ increased concentration of salts - the "building" material of stones) → deposition of salts on the matrix (crystallization of salts) → stone.

Types of gemstones: a) cholesterol b) pigment c) calcareous d) complex (combined). The cause of gallstone disease.

Complications:

1. perforation of the wall of the gastrointestinal tract with a stone → biliary peritonitis

2. obturation of the common bile or hepatic ducts → subhepatic jaundice

Types of MP stones: a) urates - from uric acid and its salts b) phosphates - from calcium phosphate c) oxalates - from calcium oxalate d) cystine e) xanthine. The cause of urolithiasis.

Complications, clinical significance:

1. pelvic obturation → pyeloectasia and hydronephrosis with atrophy of the entire renal parenchyma

2. obturation of the calyx → hydrocalcosis and atrophy of a part of the renal parenchyma

3. ureteral obstruction → hydroureteronephrosis, ureteritis, possible formation of ureteral strictures

4. attachment of infection → pyelonephritis, pyonephrosis and purulent melting of the kidney, sepsis

5. long-term course, atrophy, fibrosis, fatty kidney replacement → CRF