—As has been pointed out in Chapter VIII ([p. 135]), the anæmia of lead poisoning is one due to the destruction of the red blood-cells. This is evidenced not only by the curious sallow complexion, by the occasional presence of hæmatoporphyrin in the fæces and urine, and often by the curious yellow of the sclerotics, but also by an increase in the viscosity of the blood itself. Moreover, the urine of persons suffering from lead poisoning is invariably highly coloured, and may even show the presence of methæmoglobin. As the anæmia is generally a symptom of continued lead absorption for a long period, and does not necessarily occur with every case of colic—in fact, acute colic may often supervene without any symptoms of continued anæmia—the persons suffering from lead anæmia should be removed from their direct contact with the dangerous processes, and should be given, if possible, work in the open air. Iron and arsenic may be used, preferably in combination, whilst the iodide of iron often gives good results. Whatever preparation of iron is given, care should always be exercised in avoiding any constipating effect, and the free action of the bowel should be maintained, together with a liberal supply of milk. Potassium iodide may be also given.
With regard to the action of potassium iodide, there is division of opinion amongst various physicians as to the efficacy of the drug in the elimination of lead from the body. At the same time a very large number of persons hold that the administration of fairly large doses of potassium iodide in the case of a person suffering from chronic lead absorption may at times be associated with sudden exacerbation of the disease, and that the drug apparently may determine the production of acute symptoms, such as encephalopathy or paralysis, when these have not been previous features of the case. Our experience supports this statement, and on more than one occasion one of us (K. W. G.) has seen a distinct increase of symptoms follow the administration of large doses of potassium iodide. From a comparison with other cases it seems that these symptoms would have been unlikely to make their appearance without some secondary cause. Against this point of view must be quoted further experiments already referred to by Zinn[9], who found that when lead iodide was administered to experimental animals iodine alone was found in the urine; but it must be pointed out that no estimations were made of the fæces, and it is possible that a certain amount of lead was eliminated in this way. What exactly is the action of iodide on the solubility of lead in the body it is difficult to say; yet the use of iodine compounds has been followed with considerable success in a number of chronic inflammatory diseases, and it is possible that it may have the action of splitting off the particular lead compound from its organic association with the tissues, especially as it is well known that iodine plays a very important rôle in the process of cell metabolism. Another point which tends to support the use of iodine is the fact that the other two halogens, bromide and chloride, both of which enter largely into cell metabolism, also have a slightly beneficial effect on the excretion of lead. The dose of the iodine given should not be large to commence with, 3 grains three times a day is sufficient, the dose being run up to some 30 or 40 grains per diem, the symptoms meanwhile being carefully watched.
Other symptoms often associated with the anæmia of lead poisoning are—
Rheumatic Pains.
—These pains are suggestive of muscular affection, and are possibly due to minute hæmorrhages occurring in the muscle tissue, which have been discovered in the muscles of experimentally poisoned animals. For the rheumatic pains diaphoretics and citrates of soda and potassium may be given.
Lumbago.
—The lumbago constantly complained of in chronic lead poisoning and even in the early stage of lead absorption, is very generally related to chronic constipation rather than to a definite affection of the lumbo-sacral joints.
Nephritis.
—Affections of the kidney associated with lead poisoning are almost entirely confined to sclerosis. The presence of albumin in the urine is not a very common symptom. As has been pointed out already, the presence of lead in the urine is by no means a regular feature of lead poisoning, though it may at times be present, and the urine should always be examined for changes in the kidneys; but as a number of cases of chronic lead poisoning are associated with alcohol poisoning, the changes in the kidney cell are almost certain to be present. On [p. 95] the illustration showing the disease in the kidney produced by experimental dosage with lead, and the kidney of a fatal case of lead poisoning in a man who at the same time had a strong alcoholic history, shows fairly definitely the difference between these two points.
Acute nephritis occurs so rarely in the course of industrial lead poisoning that it cannot be considered to be a disease due to lead.