CIRCUMSTANCES UNDER WHICH OXALATE OF LIME IS DEPOSITED.
The development of this salt appears to depend more upon the lime present in the urine than upon the oxalic acid.
" Given an excess of lime in the urine, oxalic acid, come it from whence it may, is seldom wanting. If the secretion be normally acid, much of the lime will appear as oxalates ; if it be slightly acid or neutral, as acid or crystalline phosphate; if alkaline, as amorphous or basic phosphate. If, then, this deposit is formed persistently in copious, clear, and pale urine, it may generally be regarded as the result of secretion, and as a sign of a constitutional state. When it is found in high-colored or uratic urine it may possibly have re sulted from a decomposition of urates and be without clinical signi ficance" (Dickinson).
The conditions under which oxalate of lime appears in the urine may be noticed under four headings (Jaksch) : 1. Oxalates appearing as a physiological product; 2. Oxalates of accidental origin, or symptomatic; 3. Oxalates appearing vicariously; 4. True oxaluria, the so-called oxaluria nervosa.
A few remarks upon the first three headings will be sufficient.
1. Oxalates Appearing as a Physiological Product.—As has been stated, the normal urine contains oxalate of lime in minute quantities. Much greater, then, will be the product when oxalic acid is taken either with the food or with drugs.
Lime Tfater.—It is supposed that the frequency of lime oxalate calculi in districts supplied with lime-stone water is due to the pres sence of this mineral in the water.
Drugs and Diet.—Oxalic acid and its compounds, even the insolu ble oxalate of lime, when introduced into the stomach pass into the urine. Thus Wohler (Roberts, " Urinary Diseases," 4th ed., p. 84) found that oxalic acid given to dogs caused oxalate of lime to appear in the urine.
Piotrowsky confirmed these results by experiments on himself.
He took in divided doses from 80 to 100 grains of oxalic acid in the course of six hours and found that from 8 to 14 per cent. appeared in the urine as oxalate of lime mixed with a little alkaline oxalate.
In slight cases of poisoning by oxalic acid much oxalate of lime appears in the urine. Many fruits, vegetables, and other articles of diet contain this substance; such are turnips, onions, cauliflower, tomatoes, spinach, sorrel, endive, purslain, carrots, parsnips, parsley, celery, asparagus, apples, pears, pomegranates, grapes; also drinks that contain carbonic acid gas, as seltzer water and champagne. The excessive use of sweetmeats leads to an excretion of oxalic acid, also the exhibition of some drugs, such as rhubarb, squills, gentian, val erian, and cinnamon. The ingestion of any of these by persons pre disposed to the formation of oxalates causes the appearance of oxalate of lime crystals in the urine.
2. Oxalates Appearing Symptomatically or in the Course of Acute or Chronic Disease.—The appearance of oxalates as the result of increased tissue metabolism in the course of acute or chronic disease is usually transitory and without special pathological significance, for any in terference with the digestive processes or with free respiration will cause a copious deposit of oxalates in the urine.
It has been noted in pulmonary and cardiac affections, in icterus (Schulzer and Fiirbringer), and in the convalescence of acute rheuma tism. In cases of intestinal and gastric catarrh it has been found to follow as a result of a superabundance of amylaceous or saccharine food. It has also been found in cases of cyclic albuminuria.
3. Oxalates Appearing Vicariously.—V. Jaksch states that oxal uria may appear vicariously in diabetes mellitus.