Among the most poisonous substances in the urine are the extractive and coloring materials. Normal urine loses one-half of its toxicity by decoloration; bile acts in the same way. Urea alone represents about one-eighth of the total toxicity of urine. Ammonia is toxic, but present in small amounts. The coloring matters of the urine cause two-thirds of its toxicity, the remainder of which is to be ascribed to its mineral salts, which it contains in the following proportion: A liter of urine ordinarily contains 44 Gm. of solid matter, of which 32 are organic, 12 mineral. Of the latter, potassium salts constitute 3 Gm., sodium salts 7.5 Gm., and other earthy salts constitute the remainder.
In these conditions physicians have relied largely upon purgatives, hoping thereby to remove urea from the blood. But intestinal elimination has no elective affinity for it, and removes it only in its normal proportion with the balance of the blood. Purgatives, however, help, first, by dehydrating the tissues—i. e., removing water with toxic material in solution. But they should be followed by restoring to the tissues pure water. By bleeding more extractives are removed than by any other channel, except by the kidneys. A bleeding of 32 Gm. removes from the body as much toxic matter as would 280 Gm. of a liquid diarrhea or 100 liters of perspiration. This much may be removed by two leeches. It is especially in the subacute nephritis of scarlatina, etc., that bleeding finds its greatest indication. If the kidneys are chronically diseased, the utility of bleeding is doubtful. Between the arterial capillaries of the bowels, however, and the liver is found a mass of blood accumulated in the portal vessels. This may be regarded as a reserve which can be thrown into the general circulation when needed, in order that thereby arterial tension may be augmented and the function of the kidney increased. Cold injections into the bowels will often accomplish this, and serious anuria frequently disappears after their use. It is advisable, also, to make use of urea by subcutaneous administration, as the most powerful diuretic known, surface friction, caffeine, digitalis, etc., being far behind it in efficiency. In the form of intoxication noted in the eclampsia of puerperal patients inhalations of chloroform are valuable. Potassium salts should, under these circumstances, never be employed. An exposure of urine in compressed air will diminish its toxicity, on account of contact with the oxygen; the most toxic bacteria are those which grow without oxygen. Consequently patients inhaling this gas may overcome this kind of auto-intoxication.
The value of an active liver is not appreciated by most surgeons to the full extent. The blood of the portal vein is so much more toxic than that of the hepatic vein that it is evident that the function of the liver is to purify and remove the toxic material from the blood that comes from the intestines. This has been called by Flint and others the depurative action of the liver. The activity of the liver also may be proved by grinding up a freshly removed liver with alkaloids, whereby the latter are chemically changed.
That the facts above stated, or others related thereto, have not been lost sight of by surgeons is shown by such expressions as septic enteritis, enterosepsis, etc., which are used by various writers. In previous publications the writer has made a separate topic of so-called intestinal toxemia, which he has preferred to introduce here as one of the many possible auto-intoxications. It is a condition not always permitting of exact definition, nor, still less, can the exact toxic agency be indicated in a given case. Nevertheless, it has been made plain that there is perhaps no condition which so predisposes to sapremia, septicemia, or even pyemia as this vague condition of intestinal toxemia, which, notwithstanding, is so often present. Many surgical patients present forms of blood poisoning in which the poison has not proceeded from the wound, for which the surgeon is not responsible, except that he may have neglected to avail himself of certain precautions.
The auto-intoxications, then, which have peculiar interest for the surgeon may be conveniently classified as follows:
1. Those caused by failure in the function of particular organs; e. g., myxedema, cretinism, and cachexia strumipriva from thyroidal failure; pancreatic diabetes, where the islands of Langerhans are invaded ([interstitial pancreatitis], q. v.); Addison’s disease from adrenal failure (this being at present the prevailing belief).
2. Those caused by general disturbance of metabolism, where its incomplete or abnormal products reach the general circulation, e. g., oxaluria, gout, diabetes. (See [Diabetic Gangrene].)
3. Those caused by retention in particular organs or tissues of disturbed metabolic products, e. g., the toxemias following serious burns and many septic conditions.
4. Those due to excessive formation of more or less normal products, e. g.:
(a) Hydrothionemia, i. e., the presence of hydrogen sulphide in the blood. This results from one form of gastro-intestinal putrefaction and causes violent symptoms with evidences of hydrogen sulphide poisoning. It is seen in some cases of gastric dilatation, especially those caused by [pyloric obstruction] (q. v.).