Chapter XX: Electrical Treatment in Cases of Lead Poisoning

The treatment of lead poisoning by electricity is based upon two distinct ideas. First, the use of the electrolytic effects of a current to eliminate the metal from the system; and secondly, the treatment of its symptoms, especially its nervous symptoms, by electricity, in virtue of its usefulness as a remedy for paralytic disorders. In any treatment of lead poisoning these two considerations are of importance:--

1. _The Elimination of the Metal._--There is no doubt that the elimination of the metal is necessary for the recovery of a patient from the effects of the poison. In the ordinary course of events elimination probably takes place by the sweat glands of the skin, by the kidneys, and by the mucous membrane and glands of the bowel; whereas the direct effect of an electrolytic elimination would be to cause the lead to pass by a process akin to osmosis in some soluble form, most probably as a chloride of lead, from the tissues of the body to the electrolyte surrounding the body, and so to the plates or poles of the electrolytic cell or bath in which the patient is placed. Unfortunately, the experimental evidence that lead can be extracted from the tissues of the body in this way is not free from possible sources of error. The amount of lead existing in the tissues of a patient suffering from lead poisoning may not be more than a few grains in weight, and the quantity which could be deposited by electrolysis in an electric bath of the ordinary strength and duration could not amount to more than a few milligrammes. In solutions such as the juices of the body, containing but little lead, the lead ions could play but an insignificant part in the transport of the current, and therefore there are considerable difficulties in depositing at the poles of the bath a quantity of lead which could only be a small fraction of the total amount contained in the body. Lead compounds also have a somewhat special behaviour when submitted to electrolytic treatment, for whereas most metals are deposited from their solutions at the negative pole, lead compounds when submitted to electrolysis have a tendency to be deposited in part upon the positive pole, as lead peroxide, and in part upon the negative pole, in a spongy metallic form. In the presence of chlorides the lead peroxide does not adhere to the positive pole, but tends to undergo changes and decomposition. Statements have frequently been made that after the treatment of a patient by electrolysis in a bath of water, traces of lead may be found upon the poles of the bath. I have been able to detect lead on the plates in one case of my own in which the experiment was tried. But there is always some uncertainty as to the source of this lead, for in cases of workmen it may very well have come from dust and dirt containing lead which has been mechanically deposited upon the surface of their skin; or again, it may be lead which has actually come from the tissues, but has already been eliminated by the sweat glands, and is lying on the surface of the skin, so that it could be washed away by ordinary washing with soap and water. But at the same time we must not forget that even if the direct electrolytic elimination of lead is a thing which can be brought about by electricity, it is not the only way in which electrical applications may act favourably in removing lead from the system, for by their means we can also influence what may be called the natural processes of elimination, so that after electrical treatment one might expect to find traces of lead in the urine, in addition to that which might be found by a careful examination of the poles of the bath. And so far as mere opinions go, I certainly take the view that electrical treatment favours such an indirect elimination of the poison, and to that extent is of service in the treatment of cases.

2. _The Electrical Treatment of the Paralysis caused by the Lead._--This is probably as important, or more important, than the question of the extraction and elimination of the metal. In practical treatment we may say that it is the paralytic symptoms which are most readily dealt with by electrical methods. All forms of electrical application have been recommended for paralysis due to lead, _e.g._, the constant current, the interrupted current of the coil, and, more recently, the sinusoidal current of an alternating dynamo. These can all be used, and apparently with advantage. As I have frequently maintained in other places, the state of contractility in a paralysed muscle need not necessarily dictate to us the form that the electrical applications are to take. I mean that when a muscle paralysed from lead ceases to react to induction coil currents, it does not at all follow that induction coil currents are useless in its treatment; and, therefore, I consider that the widely held view that a coil should be used only for those muscles capable of responding to it is not correct. Muscles which show the reaction of degeneration, and contract only to direct applications of the constant current, will almost certainly derive benefit from a course of induction coil currents, and these should in every case be given to them, not to the exclusion of constant currents, but in addition thereto. Many of the rules laid down for the treatment of paralysis by electricity are based upon the view that the therapeutic effect of electricity upon a muscle can be measured by the amount of contraction which the electrical application can produce in it; but this is quite wrong. Even in the absence of all visible contractions in a muscle under treatment, electrical applications produce effects--vasomotor, trophic, and other--which are of service. Indeed, we may go further, and say that treatment by currents purposely made strong, in order to set up contractions in paralysed muscles with very feeble contractility, may easily be overdone, and that fatigue and injury may be caused to muscles through too severe stimulation when strong currents are demanded, in order to make them contract visibly.

In the practical treatment of paralysis due to lead, the choice of an electrical method will turn upon the supposed relative advantages of electrolytic extraction of the metal on the one hand, and of electrical stimulation of the paralysed parts on the other. For the former the electric bath with constant current is to be used, and for the latter induction coil currents or sinusoidal currents, with or without a water bath. The advantages of the sinusoidal current over that of the induction coil consist mainly in the greater smoothness with which the current varies in the former case, and in the greater magnitude of the currents which can be borne. The two methods differ from each other rather in degree than in essence. When, as is usual, the case is one of paralysis of the extensor muscles of the forearm, the use of an arm-bath as the medium for applying the electricity has very decided advantages, so that I am accustomed to treat most of my cases by the arm-bath and sinusoidal current. In cases of severe or extensive lead poisoning, or in cases where the muscles of the lower limbs are affected, I make use of the full-length bath, and at the commencement of the case would advise the use of direct and sinusoidal currents on alternate days, in order to secure electrolytic effects as well as those of simple stimulation. It is probable that hot baths, without electricity, are of very decided service in treating symptoms due to lead. In former days the thermal waters of Bath enjoyed a very considerable reputation in this disease. Thus, by combining a full-length bath with electricity, one is able to make use of the increased elimination set up by hot bathing, as well as of the increased elimination set up by general electrical stimulation. The electrolytic effect also comes in if the current used is a continuous one, but not so if it is alternating. In practical treatment, the cases of lead poisoning most commonly met with, are cases of operatives who handle lead, or some preparation of lead, in the course of earning their living. The symptoms of which they commonly complain in London, at least, are wrist drop and paralysis of the extensors of the wrist and fingers. This is the class of case which I have had under treatment during the last ten years; and the opinion which I have formed of electrical treatment is decidedly favourable. Although in a number of cases the lead has had many years in which to poison the patient, yet it is the rule that within a few weeks from the commencement of electrical applications the paralytic symptoms become very considerably decreased. Unfortunately, recovery is usually followed by a return to the old occupation; fresh infection follows, and paralytic symptoms sooner or later reappear. The patient returns for further treatment under conditions less favourable than before. He is older, the system is more seriously damaged, and his recovery is apt to be less perfect than on the previous occasion. It is this state of things which is chiefly responsible for the fact that brilliant results are not often met with in the treatment of lead poisoning due to occupation. In districts where lead poisoning is common, I would recommend an installation for electrical treatment on the following lines: (1) one or more arm-baths; (2) one or more full-length baths for the whole body. Both of these sets of baths should be supplied with sinusoidal current, generated by a dynamo on the premises, or drawn from the mains of an electric light station, if the current supplied in the neighbourhood should happen to be alternating. In each case some clockwork or other mechanical contrivance for slowly varying the current from zero to the maximum might with advantage be installed, although good results may be obtained without this. In addition, for direct treatment by constant current in special cases, it would be necessary to have a battery or other source of constant current, either for use with the bath or for local applications by means of pads and conductors of the usual class. The induction coil may be used where the sinusoidal current cannot be obtained, but wherever possible, the latter should be used in preference. A pressure of ten or twelve volts is about a suitable one for an arm-bath, and if an average of twelve and a half volts per arm-bath is taken, it is sometimes convenient to arrange the arm-baths in series, as is done, for example, at St Bartholomew’s Hospital, where four arm-baths in a series are fed from one source at fifty volts. This, it will be seen, gives twelve and a half volts per bath, minus a small loss of one volt or so over the whole circuit for the conductors. So if eight or ten baths could be employed with advantage, they might be arranged in a single series upon mains of a hundred volts pressure. In the fitting up of a new establishment, it would be convenient to provide waste pipes and water taps fixed over them, to obviate the inconvenience of filling and emptying by hand. A very convenient vessel for arm-bath treatment is an oblong stoneware picklepan, which can usually be obtained in towns; or wooden vessels of the same shape may be made almost anywhere. It is advantageous to use narrow oblong vessels of a suitable length and width to take the arms and hands, because with round tubs there is considerable loss of current, carried by the water without entering into the patient. There is also a certain waste of hot water by reason of the greater capacity of round tubs. The electrodes for arm-baths may conveniently be made of one piece of sheet copper or sheet zinc, shaped like a tennis racket, with the handle bent over in a hook, by which to suspend it to the end of the tub.

The progress of treatment is slow, and without incident. There is a gradual return of power and a gain in thickness of the wasted muscles. The duration of the case varies much with the severity of the poisoning, and the state of health of the patient. The final results are good.

H. LEWIS JONES.