A discussion on ankylostomiasis / G.M. Giles [and others].

Date:
1900
Catalogue details

Licence: Public Domain Mark

Credit: A discussion on ankylostomiasis / G.M. Giles [and others]. Source: Wellcome Collection.

    11/16 (page 545)
    Ahe white corpuscles are reduced much more than the red, so ^at there the proportion is 1 to 1,170. The specific gravity Sb but slightly reduced in proportion to the anaemia. The figures given by Cabot and by Waddell15 in India in cases of fphmnic malarial anaemia agree very closely with those re¬ corded above, so that it is evident that the anaemia of the epidemic is identical with that of malaria in other places. S-We may now turn to the conditions met with in ankylo¬ stomiasis, with regard to which there is so much difference of 'Opinion and positive error in even the most recent works on tropical diseases. A glance at the fourth line of the table ‘shows at once the contrast between the type of the anaemia in the worm disease and that of malarial cachexia.) The most important distinction is that in ankylostomiasis the haemo¬ globin is reduced twice as much as the number of the red corpuscles, so that the colour index sinks to 0.31, or about one- half of the normal in healthy people of Assam. Again, the white corpuscles, although absolutely reduced in numbers, ere relatively less reduced than are the red, so that the pro¬ portion rises to 1 to 524 against 1 to 6S4 in the healthy con¬ trols ; a change which I subsequently found had also been noted by Lutz. Once more the specific gravity of the blood is greatly reduced having averaged only 1034. the reduction being greater in proportion to the degree of the anaemia, as estimated by the percentage of haemoglobin, than it was in malarial cases of an equal degree. Thus in every point the <ype of the anaemia of the two diseases is radically different. But this is not all, for it is not sufficient from the diagnostic point of view to show that the average changes differ unless it can also be proved that the extremes met with in either con¬ dition do not overlap to any extent those met with in the other. As a matter of fact I have found that they do not over¬ lap at all in the case of the essential point, namely, the colour index, for the lowest point met with in uncomplicated cases of malarial anaemia was always over 0.5, while the highest en¬ countered in ankylostomiasis was always under 0.4 in Assam, so that this point serves as a certain means of differential diagnosis between the two forms of anaemia. In view of the statement in recent textbooks on tropical diseases that the haemoglobin value of the corpuscles is not depressed corre- «pondingly to the fall in numbers—a statement which appears 4o have been copied from one book to another—I may be asked if there is any confirmation to form the results recorded •above. There is, for Dr. Sandwith of Cairo, iti a valuable paper on ankylostomiasis in Egypt, gives estimations of the haemoglobin and the number of the red corpuscles in 173 cases -of the disease, which show the percentage of haemoglobin to be reduced nearly twice as much as that of the red corpuscles, -eo-that the colour index was reduced to about one-half, just as it was in my own cases, allowing for the abnormally low haemoglobin value of healthy Assamese. Further, I have re¬ ceived communications from several workers in India to the effect that they had been able to confirm my observations on these points. Lastly, in a few instances of malarial cachexia (under 7 per cent, of kala-azar cases) there were sufficient of the worms •present to constitute a definite factor in the production of the anaemia, and in all of them the blood changes were found to be intermediate between those of the two primary conditions, as is shown in the fifth line of the table. One of these cases is of particular interest. It was an early case of the epidemie malarial fever in which no clinically evident aDccmia had yet appeared, but in which the spleen and liver were enlarged. On examining the blood the haemoglobin value or colour index was lower than usual in pure malarial ansemia, so that I at once told the medical man in charge of the case that I suspected the patient to harbour an active number of ankylostomata, and proposed to give him thymol. This was done and 159 of the worms were passed. In this case, then, the blood test was found to be delicate enough to detect the presence of a not very large number of the parasites before even clinically evident anaemia was present. Further, I have found the characteristic alterations to persist for many months after the removal of the worms, especially in the absence of proper treatment by complete rest and iron, and in one case in which a patient had been successfully treated for ankvlo- stomiasia, but was subsequently attacked by kala-azar, a colour index intermediate between those typical of either disease was found although no worms were present, showing that the effect of the previous attack of ankylostomiasis on the blood had not completely passed away. Now the duration average of kala-azar cases is but seven months (against several years in ankylostomiasis as a rule), so that it is evident that in any case of the epidemic fever in which ankylostomata have played a definite part in the production of the ansemia, their action will be at once revealed by the approximation of the type of the ansemia to that of ankylostomiasis, as evidenced by a low colour index, even if all the worms have already dropped off. Yet in less than 7 per cent, of the cases was this found to be the case, which alone is complete proof that ankylostomiasis is not an essential or even a common factor in the production of the ansemia, which is found by all observers to be a constant feature of kala-azar, and hence the worms cannot be a primary cause of the disease itself. Other examples of the value of the blood examination in differen¬ tiating forms of ansemia are given in my report.3 One was a man who had a large liver and spleen, but who said he had not suffered from fever recently, while in some respects he resembled a case of ankylostomiasis, so that it was impossible by: clinical means to decide by which disease his ansemia had been caused, the blood estimations showed the ankylo¬ stomiasis type, which was therefore diagnosed and subse¬ quently was found to be correct and successfully treated. It only remains to briefly explain the differences of type in the ansemia of the two diseases, and to point out the thera¬ peutical indications to be derived from them. First, with regard to the colour index, it will be at once evident that the differences noted arejust such a3might be expected, for in the case of ankylostomiasis the haemoglobin is being continually slowly drained out of the system, and while it can only be replaced with great difficulty, especially in the case of people who are living on purely vegetable diet, on the other hand the red corpuscles are being rapidly formed in the bone marrow, for I have found the yellow marrow of the shafts of the long bones to be converted into red marrow both in anky¬ lostomiasis and in malarial anaemia, just as it is in pernicious anaemia. The red corpuscles being more easily and rapidly replaced than the haemoglobin, the colour index or amount of this substance in each corpuscle must necessarily fall, just as it does in all forms of slow haemorrhage. In malaria, on the other hand, the haemoglobin is not lost to the system, but is stored up in an organic combination in the liver and spleen, etc., from whence it can be absorbed to restock the red cor¬ puscles as they are turned out. This process probably accounts for the occasional disappearance of the black pigment from these organs in the later stages of the more chronic cases of kala-azar, which has been pointed out by Ross,4 especially tho’e who are tending toward recovery. The decrease of the white corpuscles in the malarial ansemia is doubtless due to to the constant fight that they are carrying on with the para¬ sites in the blood, as indicated by the slight leucocytosis which may occur, while in ankylostomiasis, on the other hand, they are not especially destroyed, while they are more easily replaced than are the red corpuscles, and hence a relative in¬ crease of the white cells occurs. It should be mentioned that in malaria the white corpuscles should be counted during the absence of fever, or else they may appear to be normal when greatly deficient, owing to the occurrence of a relative tem¬ porary leucocytosis during fever. The lower specific gravity of the blood, relatively to the degree of ansemia in anky¬ lostomiasis, than in malarial ansemia is explicable on the ground that in the former disease there is a steady loss of albuminous constituents of the blood, so that the blood becomes more watery. In this connection it is worthy of notice that I found bsemic murmurs to be much more common in the anaimia of ankylostomiasis than in that due to malaria of similar degrees—a fact which supports the theory which attributes these murmurs to alterations in the specific gravity of the blood. All the changes met with, then, are just those which might have been expected to result in either case. Finally the correct treatment of these two diametrically opposite forms of anaemia should obviously be different, for in that due to ankylostomiasis iron is urgently indicated in order to assist in the production of haemoglobin, while arsenic will be of less importance, as it is not much use stimulating the output of red corpuscles when there is no hemoglobin with which to stock them. In the anaemia of malaria pre-