POLYURIA

POLYURIA

1242 any important therapeutic aid. By this time the English reading public ought to be almost as familiar as the French with the symptoms which const...

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1242 any important therapeutic aid. By this time the English reading public ought to be almost as familiar as the French with the symptoms which constitute the Mondor malady. But who deserves the credit of first describing an undoubted case in the English language-that is..

quite

another matter.

Rothlinhas shown that

F. PARKES WEBER.

London, N.W.I.

A NOVELTY IN SPURS

SiR,ŃYour review of Pulmonary Tuberculosis (May 8) expects too much of surgical methods. Even the

knight in Alice Through " long-term spurs"!!

the

Looking-Glass

did not

own

F. A. BEARN.

Buxton.

POLYURIA 15 you state that " change glomerular filtration-rate is little concerned in the regulation of urine flow in the adult " and you give no consideration to the factor of glomerular intervention in such regulation. From the evidence I intend to adduce. it is apparent that glomerular change is unmistakably reflected in the amount of the urine produced ; that it serves as an index of the renal haemodynamics ; and that it offers a guide to the understanding and treatment of certain diseases, including the toxaemias of pregnancy.

SIR,-In your leader of May

in

In

the

polyuria accompanying diabetes insipidus, you the defect of tubular function and its treatment, but you fail to mention that such polyuria can be controlled by the glomeruli. For Bykov1 has shown that the intact kidney of dogs conditioned to antidiuresis can still display such conditioning even after hypophysectomy has produced in them diabetes insipidus, thereby indicating a renal control independent of the antidiuretic hormone (A.D.H.) and the tubular regulation it imposes. Denervation of the kidney abolishes this response and therefore it is apparent the antidiuretic effect is due to the only remaining mechanism that could produce it-namely, a glomerular shut-down which reduces the glomerular filtration-rate. Glomerular shut-down can be effected by the influence of the cerebral cortex, so it may be presumed that with such stimuli constantly at work the glomerular state must considerably affect the urine flow. In this connection, Hoff2 has shown experimentally that when the cortex of the brain is stimulated electrically there follows a considerable ischaemia of the renal cortex, which, if oft repeated, can result in ’’ nephron nephrosis." Then again, the dependence of urine now on glomerular filtration-rates has been demonstrated by Lawson,3 who observed an immediate rise of water and salt excretion after the injection of Albunun in a nephrotic patient ; this was too immediate a change to be ascribed to any cause other than the raised glomerular filtration-rate that accompanied it. Urine flow depends on glomerular change even when the extracellular space is contracted, for Shannonhas shown that serious dehydration, produced by deprivation of water, caused dogs with diabetes insipidus to excrete less urinethe result of reduced glomerular filtration. In fact, on occasion hormone effects on variations of urine flow can be completely excluded as in the preliminary experiments of Harvey L. White.5 By moderate constriction of the lumen of one renal artery in dogs with an exteriorised bladder base, he demonstrated that that kidney excreted only half the water and half the salt it normally did, while the excretion of the intact kidney showed a corresponding increase. This could not be ascribed to a circulating hormone, which would have produced a similar and equal effect on each side. Confidence in biochemical determinations to interpret renal haemodynamics must be considerably shaken by the fact that they failed herein to reveal any alteration in glomerular filtration-rates or in renal plasmaYet- the occurrence of flow as underlying the changes. glomerular spasm or diversion of renal blood-flow from cortex to medulla is challenged by such determinations. emphasise

Bykov, K. M. The Cerebral Cortex and the Internal Organs. (In Russian.) 1947. 2. Hoff, E. C., Kell, J. F. jun., Hastings, N., Sholes, D. M., Gray, E. H. J. Neurophysiol. 1951, 14, 317. 3. Lawson, H. D. Transactions of the 2nd Josiah Macy Conference on Renal Function. New York, 1950 ; p. 40. 4. Shannon, J. A. Ibid, p. 35. 5. White, H. L. Ibid, p. 128. 1.

Renal ischaemia can often determine antidiuresis. Indirect evidence of its occurrence and of its responsibility for oliguria is provided by the new hypotensive drugs. And the relief of ischaemia in the presence of an expanded extracellular space can be a cause of polyuria. be

overcome

experimental renal ischaemia can by dihydroergocornine (D.g.o.180)-a drug

which produces diuresis in toxaemia or even in anuria, indicating that it has ,been effective in overcoming the underlying glomerular spasm. Whitney 7has shown that renin has an antidiuretic action in dogs, even those with diabetes insipidus. By its use in normal animals or in animals with diabetes insipidus the glomerular filtration-rate was diminished by 33-4% and the renal plasma-flow by 40-8%. The accompanying antidiuresis must have been influenced by the diminished rate of filtration. Basing his work on the original experiments of Masson,8 Gaunthas demonstrated that the relief of glomerular spasm in the presence of an expanded extracellular space can cause polyuria. He primed" unilaterally nephrectomised rats with deoxycortone acetate and a fluid intake of " nothing but normal saline for 30 days. This caused a marked increase in the daily water exchange, the fluid intake at the Blood pressure was end ranging from 105-284 ml./day. elevated mildly from an initial mean of 119 to a terminal mean of 139 mm." Subsequently a renin preparation was injected for 24-48 hours into one of a paired series. Over half these cases developed massive oedema, while oliguria and convulsions and death occurred in nearly all. It was apparent that the glomerular shut-down produced by renin aggravated the sensitivity " provoked by deoxycortone and sodium chloride. The kidneys of these animals showed " severe damage consisting of hydronephrosis, distension of the tubules with plasma, tubular necrosis, hyaline changes in some glomeruli, and diffuse nephritis in others." It was considered that ’Apresoline,’ which Schroeder 10 thought blocked the effects of angiotonin, should be studied for its effects at this stage. Consequently the second of the pair in the series had apresoline injected 24 hours after the renin. Death from renal failure no longer resulted, nor did convulsions supervene. Such treatment reduced the hypertension, and the oedema rapidly vanished and was accompanied by a phenomenal diuresis, while the kidneys showed only slight abnormalities, probably the result of the " priming " treatment alone. To quote the authors,11 "as a working hypothesis it might be suggested that renin caused a fatal renal ischaemia and the apresoline prevented this action of renin." If this assessment is acceptable, then renal ischaemia may be responsible for the oliguria/ anuria, while its abolition may lead to diuresis. "

"

Finally, Selkurt 12 has published an extensivereview of the literature on renal sodium excretion, and he has added his own results. He challenges the orthodox " the evidence preponderantly reabsorption theory : favours the view ... that excretion is a changing fraction of the amount filtered, rather than a constant fraction (proximal segment) plus a constant amount (distal segment) as postulated by Wesson, Anslow, and Smith." 13 He also criticises biochemical findings : " The possibility remains open that small alterations in glomerular filtrationrate, undetectable by present techniques, may account for changes in the urinary excretion of sodium (TJNaV) often considered significant in certain experiments of an acute nature. As a corollary it seems unwarranted to conclude that whenever an alteration in UNa V occurs in the absence of detectable changes in glomerular filtration-rate a change in endocrine regulation (pituitary, adrenal) is the necessary alternative without more intensive investigation to prove the claim." This supports my argument that far too much reliance is being placed on biochemical data. It should be realised that " a deviation of as little as 1% from 6. Rothlin, E., Cerletti, A. J. Mt Sinai Hosp. 1952, 19, 138. 7. Whitney, J., Smith, S., Marmotson, J., Guodman, H., Sellers, A.

Amer. J. Physiol. 1954, 176, 419. 8. Masson, G. M., Corcoran, A. C., Page, I. H. J. Lab. clin. Med. 1951, 38, 213. 9. Gaunt, R., Renzi, A. A. Ciba Clinical Symposium, 1954, vol. 6,

no. 1, p. 29.

10. Schroeder, H. A. Circulation, 1952, 5, 28. 11. Gaunt, R., Renzi, A. A. Amer. J. Physiol. 1953, 175, 313. 12. Selkurt, E. E. Physiol. Rev. 1954, 34, 287. 13. Wesson, L. G. J., Anslow, W. P. jun.. Smith, H. W. Bull. N.Y. Acad. Med. 1948, 24, 586.

1243 the amount of sodium normally filtered and reabsorbed would the gain or loss of 11 g. of sodium and attendant anions per day—a not insignificant amount." Selkurt concluded : " It has become obvious that sodium excretion by the mammalian kidney during varied physiological circumstances is regulated by changes in glomerular filtration-rate or by alteration in tubular absorption. Frequently it is difficult to decide which is the dominant mechanism particularly when they are simultaneously involved. Often when alterations in filtration-rate are undetectable or small, investigators are prone to conclude that tubular reactivity towards sodium has been altered." mean

The importance of glomerular spasm is gradually becoming evident. On its appreciation depends the rational treatment of pre-eclampsia, revealed in the use of drugs such as dihydroergocornine, Veratrone,’ and apresoline. An imperfect understanding of renal physiology, especially of the part played by the Trueta or Oxford mechanism, and a too ready acceptance of biochemical data are obscuring the significance of renal ischæmia in œdema, in hypertension, in albuminuria, and in convulsions—especially when these conditions are combined, as in eclampsia. JOHN SOPHIAN.

London, W.1.

BACKACHE AND THE DISC

I congratulate Mr. Rose on his paper last this much-canvassed ’matter: not only is it objective and well based, it is extremely helpful to the practising surgeon. May I also thank you for the retention of the spelling of the word " disc " ; it may be theoretically right to replace the " c with a " k " but I believe we should discard (or should I say " diskard ") the office boy’s

SiR,-May

week

on

"

mentality. London, W.I.

W. GRANT WAUGH.

THE PLIGHT OF SENIOR REGISTRARS

SiR,ŃI agree entirely with the views expressed by " A Senior Registrar’s Wife " (May 8). When my husband was demobilised we decided, after much consideration, that he should embark upon the long and arduous training required to become a con.. sultant. Every encouragement was given by the authorities. Let me make it quite clear that we did not imagine that an appointment would be easily attained ; we expected great financial hardship and gruelling work for a number of years, and this we have had in full measure. However, we did believe there would be a reasonable number of consultant vacancies at the end. But now we find these hopelessly inadequate, and no effort is being made to create more. We entered the National Health Service with a promise of a wide expansion of the consultant services, and remuneration according to the recommendations of the Spens Committee. What has happened to these promises ? Our contemporaries who entered general practice are financially secure : they have the benefit of the betterment factor " and back pay. Is this not unfair ? Let anyone who would accuse me of being mercenary attempt to sustain a decent standard of living and educate two children on a senior registrar’s salary. The newly qualified doctor sees the hazards and wisely steers clear. In a few years there will be a great shortage of hospital staff ; but where shall we be then ? A large number of senior registrars find that, through no fault of their own, they are redundant. How tragic that young men who started out with such high ideals should become disillusioned and frustrated. Our husbands have not been lazy, or they would not have stayed the course; they are not stupid, or they would never have passed the higher examinations. Who cares about their plightI Apparently nobody. "

ANOTHER REGISTRAR’S WIFE.

ARTIFICIAL RESPIRATION BY INTERMITTENT POSITIVE PRESSURE SiR,-Dr. Crampton Smith and his colleagues are to be congratulated on a valuable paper (May 8), but their remarks on neck seals in tracheotomised patients in tank respirators call for some comment. An efficient neck seal under these conditions does not involve such " great difficulty " as their remarks suggest, and such a seal has been used in the U.S.A. for a good many years. U-shaped metal " tracheotomy bars," of which there are several designs, are attached by adjustable fittings to the head of the tank or to the collar surround, and push the collar inwards in the midline of the neck, allowing the seal to be made below the tracheostomy. Collars need to be of yielding foam rubber and over-size, the type supplied with the NuffieldBoth respirator being unsuitable for this purpose; the ingenious plastic " spiral twist collarsare particularly suitable for use with tracheostomies. "

In view of the importance of planning for a possible of respiratory poliomyelitis, it should be known that tracheotomised patients with bulbar paralysis can be treated in a tank respirator. The difficult choice

large epidemic

between this older-established method and the newer one of intermittent positive endotracheal respiration depends on many factors. BRIAN McNICHOLL. MCNICHOLL. Galway, Eire. GRADUATE WIVES

SiR,-With reference to Dr. Lycett’s letter (May 29)

quite agree that part-time sessional work is most unsatisfactory both to the patients, who meet a succession of doctors who know nothing of their background, and to the doctors who see no continuity in their work. However, I see no reason why married women should not be employed full-time in the public-health service. Most authorities have a maternitv-leave scheme wherebv they can have adequate time off for each confinement ; and, if the salary is large enough, they can employ good domestic help : there is no reason why the family or the I

work should suffer. Indeed, most women with sufficient intelligence to obtain a medical degree find full-time domesticity frustrating and irritating. I can assure Dr. Lycett that in maternity and childwelfare work personal experience of raising one’s own family is of equal if not greater value than the D.P.H. or D.C.H. From the point of view of the family, publichealth work has the great advantage of regular hours. I regard a woman doctor living among and bringing up a family as the ideal health educator. HAZEL B. BAKER. Wednesbury, Staffs.

SiR,-I would like to reply to

a

few remarks

by

correspondents in your issues of May 22 and 29. I regret that Dr. Gillie and Dr. Beard should have supposed that I suggested that married women doctors should attempt to undercut the market as a method of obtaining employment : this would obviously be unethical, to say the least of it. I did

mean,

however, that it

might be possible to evolve a system in our public-health clinics whereby there were some specialised supervisory staff, who would be paid at a higher salary, and some parttime doctors (less specialised) working for a lower salary, thereby relieving the specialists of some of the donkeywork. After all, the house-surgeon is not accused of undercutting the market because he works for a lower salary than the consultant. I am glad to be assured by Dr. Gillie that the anomaly between full and part-time workers (or those working on a sessional basis) has been at any rate partly reduced, though this does not altogether seem to be the ease in the blood-transfusion service where a part-time worker 1. Made by the Iron Lung Company of America and by the J. H. Emerson Company, both of Boston, Mass._