Suprarenal by the mouth seems to me to have the power of raising low pressures to the normal—a most valuable property in the asthenia of pneumonia and diphtheria—but there comes in some check action which prevents its causing hypertension.
Dr. Sajous, the well-known scientific physician of America, at the annual meeting of the American Therapeutic Society in May 1920, said: “With regard to the adrenals, in his opinion, clinical experience with the human subject did not bear out the statements of physiologists that therapeutic doses of adrenalin had any inhibitory effects on the functions of the gastro-intestinal canal; in fact, the effect was quite the opposite. The supposed blood-pressure raising power of adrenalin also proved misleading; indeed, one of his workers found that, if there was one thing that adrenalin did not do, it was to raise blood pressure.”
In this direction we must realize the wonderful selective action of adrenalin, that of dilating the coronary arteries, contracting the arteries and arterioles of the skin and of the great splanchnic area and of dilating the deep arteries of the limbs. These selective actions explain the great relief it gives in asthma and acute respiratory distress, such as œdema of the lungs, where it bleeds a man into his own distal vessels.
The absence of raised pressure in the brachial and radial arteries may be thus explained also. Again we must not forget that there may be, and probably is, something in the extract of the whole gland besides adrenalin. Administered by stomach the extract has, I think, far more effect than pure adrenalin given in the same way, and more lasting. Given by rectum, adrenalin acts quickly and powerfully. In France thyroid treatment is sometimes carried out by injections of an extract of the whole gland subcutaneously, but it is difficult to get an extract that is stable.
In persons of middle age it is far more common to get the unpleasant heart effects of thyroid than in really old people, but it is not by any means an absolute rule. I know of two women well over ninety who cannot on this account take thyroid by itself for long. After sixty, thyroid in combination with pitglandin (the dried extract of the pars-anterior of the hypophysis) becomes very useful. At this time of life the internal secretion of the sexual glands begins to fail, and pitglandin, I think, compensates for their deficiency. When one thinks of the extraordinary influence that the pars-anterior has in youth on growth, and non-growth, causing gigantism and infantilism, one cannot be surprised at its having some powerful influence at the other end of life. It can be given in large doses, 1 or 2 grains, and seems to have no poisonous effects. Unlike pituitrin (pars-posterior), it does not raise blood pressure, but, I believe, has the opposite effect. The secretions of testis and ovary are probably mild pressure raisers, and as they enter into the formation of nearly all the pluri-glandular preparations that are on the market, this should be recognized. What may be of great value in neurasthenia, where the pressure is generally sub-normal, may be harmful in sclerosis. Most of these preparations contain also whole pituitary, and this again is harmful in plus pressure. It always strikes me as unscientific to give whole pituitary in any case, for the two parts are largely antagonistic in their action. The extracts of the sexual glands have been given, with the object of restoring sexual power (except for its side effects a thing of doubtful value), but if they prove to be pressure raisers, sclerosis will do better without them. In all probability pitglandin has a stimulating effect on the gonads, as it has on sexual development in childhood, but it does not raise pressure.
We must regard it as a clinical fact that the thyroid reduces pressure. The original experiments of Oliver and Schäfer seem conclusive. Brunton said: “Thyroid gland, when taken by the mouth, dilates the peripheral vessels, making the skin warm and moist, and quickens the pulse. In this respect it antagonizes the suprarenal secretion. Besides this effect on blood pressure, it has other effects on metabolism which are important.” Biedl says: “If thyroid or iodothyrin be given continuously for two or three weeks, the amount of CO-excretion will be increased by 15 to 16 per cent. The nitrogenous interchanges are invariably disturbed by thyroid; the increased decomposition of albumen is expressed by an increased excretion of nitrogen. Thyroidism also brings about a considerable increase in the amount of calcium excreted in the fæces, the calcium carrying off with it a large proportion of phosphorus.” This phosphorus loss may explain some of the feeling of weakness and exhaustion that thyroid feeding often causes; this a good phosphate food such as Bynogen will help to remove.
It is thus evident that we have in thyroid medication something much more than a mere tension depressor. Its other properties, influencing excretion, explain to some extent its sphere of usefulness and its drawbacks. The increased excretion of calcium may be very beneficial in atheroma, but is probably not an advantage in other ways. An observant man, who did not need it, was taking thyroid rather freely; he cut his finger and could not get it to heal. Thinking that this might be the result of calcium loss, he stopped the thyroid, and his wound healed, as he said, in a few hours. To the increased general metabolism that thyroid produces is due its striking effects in myxœdema: the new tissues, abnormal in quantity if not in essence, are absorbed, and the face and limbs resume their natural appearance. Senility and myxœdema are so closely related that one would naturally expect the same results to ensue. A fair steady trial will prove that such is the case, but all such clinical experiments need to be carried out in each individual case with thoroughness, faith and intelligent observation. Failure may at first be the verdict, but it is in most cases due to some defect in method. A thoughtful review of our physiological knowledge of endocrine actions will often show where lies the fault. A carping critic may say, What is your physiological knowledge of the action of these glands? And one must humbly answer, Not very much. But we are going to find our way through the twilight of our ignorance, partly by physiological experiment, but chiefly by clinical results. We must also be encouraged by the thought that all these clinical trials are without risk. What matters it if we produce temporary symptoms of hyperthyroidism? We can always correct them or retrace our steps. Russell Lowell’s proverb was, “A man who never makes a mistake never makes anything.” In such therapeutics we shall discover the pathways of natural curative medicine. It is not the introduction into human bodies of vegetable and mineral remedies or poisons; it is simply the introduction of correlated gland extracts from other mammals. As far as we know, the glands of the herbivora answer as well as the glands of the omnivora, but we may have to correct this view.
In treating hyperpiesis, we shall come across some cases that seem to yield to thyroid treatment hardly at all, and here the trouble is often found to be chiefly, if not entirely, in intestinal absorption of deleterious products of faulty digestion; there may or may not be signs of colitis; but, as I have said before, duodenal extract freely given alters the condition rapidly in most cases. In these cases probably the absorption of these residues of defective digestion produces hyperadrenia, and the adrenal-thyroid balance is disturbed. Dr. Sajous (in his paper previously mentioned) claims that calomel in very small doses, not exceeding gr. 1/12, is a powerful activator of the thyroid secretion; he claims that so given it has been effective in checking epidemics of diphtheria. It probably acts partly as an intestinal bactericide and partly by its action on the thyroid, increasing the defensive anti-bodies in the blood.
There is one other medicine that has a very decided action on some forms of raised pressure, and that is hippuric acid. This again is a natural or endogenous cure. It was introduced by the late Dr. George Oliver of Harrogate, and is chiefly used as sodium or lithium hippurate. For some time before his death Dr. Oliver was seeking for a reasonable explanation of its action, but his death unfortunately came before he had carried this through. I can give no theory, but of its effects in many cases I feel convinced, though I cannot say beforehand in which class of case it will answer. In the pre-sclerotic cases of middle life it often acts quickly and well, even better than thyroid. Again, in old age, in cases where one would expect thyroid to give the better results, it answers equally well.
Two of my patients—old ladies well over seventy—have had hyperpiesis for twelve years or more; they were condemned by good men many years ago. They have lived on hippurate almost without breaks all these years, and it has kept their pressure down to a reasonable working-point. With both I have tried thyroid treatment with very slight success; they always come back to their hippurate as the well-tried friend. I have another patient aged ninety-four, who has had periods of high pressure for twenty years, and if she misses her daily dose the pressure goes up and her head gets giddy and confused. It is a very wholesome medicine, causes no gastric disturbance, and is easily soluble; from 5 to 15 grains a day are generally needed. If there are gouty symptoms I give the lithia salt; if not, the sodium. The benzoates have, I believe, much the same action, but they are not easily digested and large doses are required. In bad and obstinate cases the hippurate and thyroid treatment sometimes act well together.