DISEASES OF THE KIDNEYS, INCLUDING THE PELVIS OF THE KIDNEYS.

BY ROBERT T. EDES, M. D.

Anomalies of Shape, Size, Number, and Position. THE kidneys are two glandular organs, of a concavo-convex shape so characteristic as to be frequently used as a term of comparison, situated on each side of the vertebral column, with the longer diameters nearly parallel thereto, but slightly convergent toward the upper extremity, and extending from about the upper border of the eleventh rib on the left side and the middle of the corresponding rib on the right to the second or third lumbar vertebra. Hence they are somewhat less than half covered by the last two ribs.

The upper extremity is a little the wider and the thinner, and by this peculiarity and a recollection of the position of the vessels (from the front, vein, artery, ureter) the two kidneys may be assigned to their proper sides after removal from the body.

They are behind, and at their upper extremities nearly in contact with, the peritoneum, resting, with their more or less voluminous envelope of adipose tissue, upon the great muscles of the loins. The fat which in the normal condition surrounds the kidneys varies, as might be supposed, within wide limits, and is by no means devoid of importance, since its deficiency is undoubtedly a predisposing cause for some of the displacements hereafter to be described. In this fatty mass may also be situated perinephritic abscesses, and into it spread with considerable facility morbid growths originating in the kidney itself.

At the middle of the inner borders of the kidneys are situated the hiluses into which enter veins, arteries, ureters, nerves, and lymphatics, united by connective tissue and forming a sort of pedicle.

The normal weight of each kidney is to be expressed by a rough average as from four and a quarter avoirdupois ounces, or one hundred and twenty grammes, on the one hand, to seven ounces, or two hundred grammes, on the other; but since a deficiency in the size of one is not unfrequently compensated by an increase in the other, it would be safer to give the weight of the pair as from two hundred and forty to four hundred grammes, the lesser number representing those organs which are not only small but anæmic, and the larger those which are either distinctly hypertrophied or much congested: many diseased kidneys will also be found within these limits.

The size of the kidney is in a general way proportioned to the size of

the body the proportion is stated as 1 to about 240. A disproportionate change in the size of both kidneys without any change in structure is a true hypertrophy, and may be met with in persons whose habits as regards the ingestion of fluids (especially such as are freely secreted by the kidneys-for instance, beer or other forms of dilute alcohol) tend toward excess, or where a disease like diabetes throws a large amount of diuretic material into the circulation.

The deep position of the kidneys makes them usually inaccessible to physical exploration to any practical extent. In stout persons they are so entirely covered by their own immediate envelope of fat, by the adipose tissue of the mesentery, and by the thick abdominal walls as to be completely indistinguishable. In thinner persons deep palpation with both hands may enable us to say that there is a diminished resistance to pressure, as in the case of movable kidney, or that there is or is not any decided enlargement. Slighter changes in size cannot be accurately determined, although Bartels' states that he was once enabled to detect a considerable enlargement in a case of parenchymatous nephritis by double palpation. In moderately thin persons the lower end of the kidney can be more or less distinctly felt.

A position upon the hands and knees (not the gynecological semi-prone position), allowing the whole abdomen to gravitate directly away from the backbone, is said to afford, by the varying concavity of the lumbar region on the two sides, information as to the absence of either kidney from its usual place. When the kidney, however, is displaced, and when it comes decidedly forward from increase in its own size or from the pressure of a tumor behind it, it may very often become extremely accessible.

Percussion gives even less information than palpation, since the dulness of the lumbar muscles extends laterally beyond that of the kidneys, and is of itself so complete as to offer no change from the addition or subtraction of the resistance of the underlying organ.2

The most marked anomaly in the shape of the kidneys when both are present, and the only one which possesses a clinical interest, is that known as the horseshoe kidney, being a more or less complete fusion of the organs of each side in front of the vertebral column and the great vessels. This fusion is usually at the lower end, but may be in the middle or at the upper end. Sometimes there is a portion lying directly in front of the vertebral column so large and thick as to appear almost like a middle lobe or a third kidney. In a few rare instances this portion has formed a pulsating enlargement mistaken for an aortic aneurism or other abdominal tumor. In others compression of the great vessels has given rise to phlebitis, or the abnormal position of the ureters has obstructed the passage of the urine, with the results, as regards the secondary affection of the kidneys, to be described below. 1 Ziemssen, vol. xv.

2 It is probable that Simon's method of thrusting the hand into the rectum and large intestine might be made available by a person with a small hand and arm for diagnosis in doubtful cases where the value of the information to be obtained would be sufficient to compensate for the risk of serious injury.

The removal of the kidneys may be accomplished through the rectum-and has been effected many times by myself and assistants--in cases where a complete autopsy is refused. The manoeuvre is not very difficult through a large and especially a female pelvis, but under other circumstances may be somewhat fatiguing. Considerable postmortem information in regard to other organs may be obtained in the same way,

These instances are, however, among the curiosities of medicine, and no rule for their diagnosis can be laid down. A horseshoe kidney is usually discovered only after death, and with no special frequency in cases of renal disease.

Variations in the number of the kidneys possess this point of practical interest, that diseases affecting a single organ are more dangerous than if another exists which can take upon itself extra duty. Apparent absence of one kidney may be due to atrophy, attended with very small size of the renal vessels; in which case a small mass of connective tissue is found at the upper end of the ureter, which is usually illy developed. The other kidney is usually hypertrophied.

The kidney may fail to be developed. In this case there are no vessels corresponding to the renal artery and vein, and the ureter is stated to be invariably absent, but the writer has seen a specimen where the left ureter terminated superiorly in a rounded cul-de-sac, no kidney or suprarenal capsule being present. The other kidney was of rather large size in proportion to the size of the patient, but of the usual form. This defect is apt to be associated with some anomaly of the genital organs.

Another condition, apparently similar, but really due to a fusion of the two embryonic kidneys, is sometimes found. In this the single organ, situated upon one side, is irregular in form and in the number and origin of its vessels. There are usually two ureters, arising one above or beside the other, and directed to their proper positions in the floor of the bladder. A single ureter arising from a single kidney has been seen to empty upon the opposite side of the bladder.

Supernumerary kidneys have been noted. In one case an extra pair, situated below the others, were intensely inflamed, while the normal organs were not so.

A position of one kidney has been noticed considerably higher than normal, so as to push the spleen from its place. A more common anomaly, however, is the situation of one kidney at a point much below the usual, most commonly at the brim of the pelvis. When this happens the kidney itself is usually more or less distorted in form, and receives its blood-supply from several small arteries which enter it at irregular points, forming as it were several small hiluses. They may originate from the aorta or from one or both iliacs. The ureter is correspondingly short. This position is of some importance, since a pelvic tumor is formed which has in one instance proved an obstacle in childbirth, while in another the misplaced kidney itself underwent an acute nephritis from the pressure of the fetal head. The kidney tumor has in a few instances been felt in this position during life, but its nature has not been diagnosticated.

Floating Kidney.

The most clinically important change in the position of the kidney is not a permanent one, but varies from time to time with the posture of the patient and the altered conditions of pressure-externally by dress or apparatus, or internally by the other abdominal organs. It is known as floating or wandering kidney. In this affection the kidney ceases to

be firmly imbedded in the fat usually found in the lumbar region, constituting a support and packing for these organs as well as for the suprarenal capsules, and is allowed more or less liberty of movement, which is restrained by a pedicle consisting of the ureter, vessels, and nerves, with more or less connective tissue. As it passes downward and forward it comes into more intimate relations with the peritoneum, which usually covers only the anterior surface, often with an intervening layer of fat, so that it may even gain a sort of special investment or meso-nephron. The extent of the excursions of which the tumor thus formed is capable must naturally vary considerably. Sometimes the organ can be pushed or make its own way forward so as to come into contact with the anterior abdominal wall on the same side, and not much lower than the normal position, or it may pass considerably downward, and thus be confounded with tumors arising from the pelvis.

This affection is much more frequent among women than in men, and the right kidney is more frequently movable than the left: both, however, are sometimes dislocated. It is observed in a much larger proportion of cases in the laboring classes than in those whose work is less severe and carried on in less constrained attitudes. Judging from the relative amount of the literature of the subject, it would appear to be much less frequently observed in this country than among the lower classes of Germany, where so large a proportion of the severest outdoor labor is carried on by women.

Various causes are assigned for this displacement. It is stated to be usually congenital, but is not described as found post-mortem in children with at all the frequency that it occurs in adults; and it is certainly possible in adults to fix in many cases the beginning of the disease with a reasonable degree of certainty. That a certain amount of predisposition, or peculiarly favorable position of the kidney, or an unusual laxity of connective tissue, exists in a certain number of cases is undoubtedly

true.

The next most important factor is undoubtedly a laxity of the abdominal walls, affording a less firm and unyielding support to the contained viscera, and a deficiency, usually an acquired one, of the fat surrounding the kidney, which enables it in the normal condition to be supported by the layer of peritoneum passing across its front from the spinal column to the flank. This is seen in a certain set of cases where the trouble dates from an acute disease or a rapid emaciation. The wellknown influence of repeated pregnancies is undoubtedly exerted in this way.

Another set, especially those exceptional cases which occur in stronglybuilt and not thin persons, are referable to severe shocks received in gymnastic exercises, hard riding, or falls from a horse.

One of the most frequent causes, and one which accounts for the fact of the affection being most prevalent among the working classes, is the use of a tight strap or cord to support the garments. Corsets, which exercise a more even pressure over a larger surface, do not have this effect. The right kidney, from the position of its superior extremity in front of the liver and its slightly higher place in the abdomen, appears to be more influenced by this pressure than the left. The movements of respiration, especially when reinforced by the forced inspiration and com