Calcium Deposits

Calcium deposits, metastases and diet therapy. Season from May 20 to September 20. Routes of communication: 1) by steamer along the Kama River to the "Ik mouth" landing, and then 8 versts by horseback or - during high water - by motorboat; after the water subsides (from the second half of June) to the "Izhevsk spring" landing; 2) by railway to the "Suchinskaya" station and then 60 km by horseback.

Calcium Deposits, METASTASES (in pathology). Calcium deposits are the name for dense concretions that appear under certain conditions in various soft tissues of the body (living and dead), in some inflammatory products, secretions, foreign bodies (for example, parasites), fibrinous and blood clots, etc., due to the impregnation of these elements with calcium and magnesium salts precipitating from tissue and blood plasma. The process itself is designated as petrification or calcification. The chemical composition of such deposits (wherever they appear) with very rare exceptions quite accurately corresponds both qualitatively and quantitatively to the composition of salts that normally impregnate the bones of the skeleton. Free fatty acids that sometimes form in tissues under pathological conditions (for example, in fatty tissue necrosis or in so-called oleogranulomas) can also bind Ca, forming calcium soaps; however, over time, these soaps decompose, with the fatty acids being replaced by phosphoric and carbonic acids in the usual proportion.-The origin of calcium deposits can only be clarified by studying the normal calcium metabolism in the body. In this respect, the following has been established: 1. Calcium salts are contained in blood and tissue plasma in quantities significantly exceeding what can be dissolved in the corresponding volume of water. 2. This is made possible by the presence of CO₂ in the blood and tissue fluids, which greatly increases the solubility of calcium salts, as well as by the physicochemical (adsorption) binding of Ca ions with the protein colloids of these fluids. 3. Ca salts are easily and in large quantities adsorbed from solutions by some normal as well as pathologically altered tissues (for example, osteoid tissue, cartilage, especially epiphyseal), elastic fibers, various hyaline substances, tissues in a state of coagulation necrosis, etc., apparently due to the special physicochemical properties of the colloids that make up their composition. 4. The excretory organs for Ca are mainly the large intestines, through which about 70% of all excreted Ca is removed (including that excreted with bile), to a lesser extent - the kidneys (about 30% or less), and to a negligible degree - the salivary and some other glands. As conclusions from these premises, the factors that can be considered as causes of the appearance of calcium deposits emerge. These are precisely: depletion of blood and tissue fluids of CO₂ (local or general alkalosis), decrease in their protein content, certain changes in tissues (mainly degenerative-necrotic in nature), making them avid adsorbents of Ca, and finally an increase in the calcium salt content in the body fluids to the limits of solubility (due to either delayed excretion of Ca or its increased entry into the blood). Experience shows that each of these causes separately very rarely causes the precipitation of calcium salts; usually, the basis of petrification processes is some combination of favorable factors. Because of this, it is often extremely difficult to draw a line between individual types of calcification. Nevertheless, in accordance with the nature of the main causes creating conditions for pathological lime deposits, the latter can be divided into two groups: 1) those that arise with undisturbed general calcium metabolism of the body on the basis of purely local tissue nutrition disorders: these are so-called dystrophic calcifications; 2) those in which some general change in calcium metabolism is the basis: these are so-called dyscrasic calcifications. Part of the latter is united under the name of calcium metastases, another part - under the name of calcium gout.-Dystrophic calcifications represent the most extensive and frequently occurring group of calcium deposits. As classic examples of this kind, one can cite: impregnation with lime of tuberculous and syphilitic caseous masses, coagulated pus, inflammatory deposits on the pleura, pericardium and heart valves, thrombi, contents of atheromatous foci, hyalinized areas of the vascular wall [see separate table (vol. X, p. 475-476), fig. 6], hyalinized scars, foci of necrosis and hyalinosis in some tumors, dead muscle trichinae, echinococcus, etc. Calcium deposits that often appear in large quantities, mainly in the kidneys [see separate table (vol. X, p. 475-476), fig. 5] and myocardium (in poisoning with mercuric chloride), have a mixed origin, since here along with the toxic necrotizing effect of mercuric chloride on tissues, the influence of delayed excretion of Ca and its accumulation in blood, caused by the characteristic lesion of the large intestines and kidneys by mercuric chloride, also plays a role.-Dyscrasic calcifications are caused by a disturbance of calcium metabolism, in which either increased entry of calcium into the blood or its delayed excretion may occur. An example of the first can be the 'calcium metastases' described by Virchow, i.e., those lime deposits that sometimes appear in large quantities in apparently healthy tissues of various organs with widespread destructive or dystrophic lesions of bones, leading to resorption of bone tissue and consequently to accumulation of Ca in the blood (osteomalacia, fibrous osteitis, senile osteoporosis, multiple osteomyelitis, multiple bone tumors, etc.). How easily the amount of Ca in the blood can increase in this case is clear from the fact that 99% of all lime in the body accounts for the bony skeleton and only 1% for all other tissues and body fluids. The favorite sites of calcium deposits in such cases are the lungs, stomach, kidneys, and walls of the large circle of arteries and pulmonary veins, i.e., precisely the organs where the greatest accumulation of PO₄ ions (an indispensable condition for the formation of calcium deposits) occurs. The phosphates, in turn, accumulate in organs either in the order of their main function (kidneys, heart) or in the order of 'concentration', i.e., when organs give off water (stomach, lungs). The relative alkalosis of these organs that excrete acidic products must necessarily be taken into account as a factor contributing to the precipitation of Ca from solution. Not always, however, does widespread destructive process in the bones precede 'calcium metastases'. Experimentally, it has been shown that similar pictures can be reproduced in animals (mice, rats, guinea pigs, rabbits, cats, etc.), for example by poisoning them with vitamin D. Due to the increased acidity of the blood that develops with this intoxication, there is a gradual leaching of lime from the bones, which on the one hand causes osteoporosis, and on the other - deposition of lime in organs in the type of calcium metastases. Rarely, cases are observed where multiple foci of calcification in undamaged tissues (mainly the same favorite organs) occur also with a normal state of the bony skeleton, but with simultaneous kidney damage. It was assumed that these calcifications arise on the basis of disturbed excretion, and they were given the name 'calcium gout' (M. V. Schmidt). At present, however, kidney disease is not given special importance in this respect, since the main mass of lime is excreted by the large intestine. It is believed that deposition of lime in these cases is observed because kidney disease causes strong fluctuations in the acid-base balance in the body fluids, due to which the ability of the blood to hold lime in solution in the usual amount is disturbed. The dependence of lime deposition on the body's shifts of 'acidosis' and 'alkalosis' is best illustrated by experiments in which such fluctuations are artificially induced: the animal is given both lime and oxidizing or alkalizing substances simultaneously, and a typical picture of calcification in the above-mentioned organs is obtained.-As for the calcium deposits themselves, once formed, they can remain in the body unchanged for a long time. In other cases, a proliferative reaction develops around them from the connective tissue elements, leading either to the formation of a fibrous capsule or to the resorption of lime and its replacement with bone tissue. The latter process proceeds according to the type of endochondral ossification. Most elements that tend to be impregnated with lime also easily fix iron compounds on themselves, so that both types of impregnation are often found together. Both lime and iron, impregnating tissues, give them the ability to be sharply stained with hematoxylin. For more precise determination of lime, either the tissues are acted upon with sulfuric acid, whereby crystals of gypsum precipitate at the site of calcium deposits, or the sections are treated according to Kossa with a 2-5% solution of AgN0₃, which well reveals calcium phosphate, converting it into rapidly blackening in light silver phosphate.