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DIAGNOSIS OF URÆMIA, ABSOLUTE AND DIFFERENTIAL.
The symptoms of uræmia are so closely allied to those presented in other forms of disease, that it would lead me into an almost impossible task to attempt a differential diagnosis applicable to every case. I shall therefore endeavour first to establish, as near as can be, an absolute diagnosis. Such differences as may exist between uræmia and certain other allied diseases may then be noticed with rapidity, and with a certain degree of precision.
Absolute Diagnosis. I should include in the following symptoms the nearest verbal description of simple uræmia.
There are almost invariably some premonitory signs. These consist of sleepfulness—an irresistible desire to sleep at almost any time and place. With this there may be paralysis of sensation in extreme parts, as in the hands, lips, or feet. In one case with which I was acquainted, this sign frequently occurred long before the decided and final attack : the patient said he felt as if he were treading on wool, and his feet seemed to give way, although he could stand on them steadily and use them as well as ever, when he made an effort to that effect. Or, again, there is a confusion of the mind, transitory in its character, and conveying the impression that objects near at hand on which the sight is fixed are receding or dissolving: There is no vertigo, and no oppression with this peculiarity, but a feebleness and listlessness. There may also be vomiting, sometimes very severe; and in one example I knew the ejected matter to be charged with blood, the hæmatemesis occurring at least twice as a premonitory sign. There may be occasional relaxation of the bowels, which relaxation gives relief and renders the mind clearer for a time, if it be not too profuse and too continuous. Lastly, there is very commonly a peculiar fætid condition of the breath, a sickening odour more like that caused by sulphide of ammonium than aught else. The breath in this condition yields ammonia largely
Persons affected with a tendency to uræmia suffer exceedingly from cold; they feel the influence of a fall in the thermometer acutely, and the symptoms of the uræmic coma have often their date from such a declination of temperature. The action of cold in this case is evidently upon the skin and pulmonary membrane primarily, and by reflection on the kid neys, leading to congestion and obstruction. Again, these sufferers, more than others, feel the effects of a hearty meal, especially if that consist largely of nitrogenous foods. I believe that in many cases the so-called apoplexy occurring after a meal, and remaining for many hours before ending either in death or recovery, is uræmic in character.
Patients disposed to uræmia are further dangerously susceptible to the action of certain medicines. The smallest mercurial dose seems sufficient in them to shut off the renal secretion and excite the acute uræmic paroxysm. Mercury, however, is not the only drug productive of this evil. I have seen, with exception of the ptyalism, exactly the same effects
follow the administration of an ordinary dose of opium. I cannot conceal my belief, indeed, that in many cases where opium has seemed to destroy life when given in very small doses, the “ idiosyncrasy assumed to have been present has consisted in a condition of kidney, during the existence of which uræmia in its acute form might have stood prognosticated, had the earlier symptoms been known,
The acute symptoms of uræmia come on either with coma or convulsion, or both combined. They are usually sudden in their intensity, and are preceded by suppression of urine, or by constipation, or by a chill by which the eliminating function of the skin is suppressed. There is often active convulsion ; but I have seen death occur from uræmia without much convulsive movement. Nay, I have seen an animal die from artificial uræmia without active convulsion, though this is an exception. There occasionally will be squinting in the course of the acute paroxysm, but this is not the rule. The state of the pupil varies; but it usually is largely dilated, and is insensible to light, and fixed; the countenance is dusky; the skin is unimpressionable and cool, with short exacerbations of heat.
If the coma be profound, the pulse is slow and intermittent, or irregular in periods. When I say that the pulse is irregular in periods, I mean that, counted over two spaces of time of equal duration, it shows a difference in those two periods. We find the pulse during one minute at 60; we wait a minute and take it again, and although the relation of beat to beat seems the same, we find that in the course of the second observation five, ten, or even fifteen pulsations have been gained or lost. This form of irregularity of pulse is not peculiar to uræmia, but is common in it, and is inevitably a bad sign. Traced to its cause, it is found to depend on a corresponding irregularity of the respiration, for in nearly all forms of slow narcotic poisoning the heart is obedient to the respiration. The respiration is, from the beginning to the end, irregular and imperfect; there is not dyspnea, but uncertainty; no obstruction to air, but a destroyed balance in the respiratory movements.
Much has been argued as to the condition of the expired air in uræmia ; Frerichs has stated that the breath is largely ammoniacal in this state. Other observers have denied the position. In fact, both are right and both are wrong. The true position is simple. In all persons there is an exhalation of ammonia by the breath, varying in amount. In uræmic persons, in their ordinary health, there is, I believe, always an excess of ammonia in the breath; for in them the lungs are supplementing the kidneys. If, then, in any case there be sudden suppression of the excretory power of the kidneys, there may be an excess of ammonia in the breath. I have unmistakably seen examples where this excess was clearly manifested—so clearly that the exhaled vapour gave distinct fumes to the hydrochloric acid rod, and even changed the colour of reddened litmus. On the other hand, there are cases where the very cause of the development of the acute symptoms lies in the fact that the compensating eliminative function of the lungs has become suppressed : in such state there will be no ammonia found in the breath ; it would be a saving clause if the alkali were there.
I have but one word more to say respecting the absolute diagnosis. It relates to the degree of consciousness manifested by uræmic patients in the extreme state.
There are periods when the coma is so profound that nothing arouses the sufferer. There are, again, other times when he arouses of himself, or is quite capable of being aroused, and of speaking or attempting to speak, and of sitting up, and of swallowing foods or medicine, and of acting altogether with a considerable amount of intelligence.
The symptoms above described, taken in all their entirety, are sufficient to give a correct picture of uræmic disease. But it is worthy of remark that there are special symptoms in different cases which, without removing the idea of the general fact that the arrest of the function of the kidneys is the cause of the symptoms altogether, suggest forcibly either that the poison is different in certain instances, or that, being the same in all, it acts variously in different persons, by difference of dose, or by peculiarity of effect on the individual organism. Thus in one case the pupil may be dilated, in another natural in size; in one patient there shall be active convulsions, in another no convulsion whatever.; in one there shall be marked derangement of the bowels, in another no intestinal irritation shall be presented; in one there