One other form of eye change requires attention—namely, retinal changes due to circulatory disturbances. In an advanced case the whole picture is one of severe albuminuric retinitis, but in the earlier stages some engorgement of the vessels without alteration of the surrounding tissue is seen. Elschnig[21] associated this alteration in the vessels of the eye with vaso-motor changes caused by direct action of the poison, producing a vascular constriction or dilatation, and is inclined to regard the kidney disease frequently associated with this condition of the eye as something quite apart. He would regard the two affections as independent, and merely correlated through their common origin—lead intoxication. It has even been suggested by some observers that the change in the eye is secondary to cerebral œdema. Thus Mannaberg[22] regards the encephalitis of saturnine origin as associated with chronic œdema of the brain and spinal cord, which thus produces reflex irritation of the nervous system of the eye. Bikler[23] and Weber[24] consider the symptoms as circulatory. From whatever cause the disease is set up, sooner or later changes in the form of obliterative arteritis take place, with gradual but ultimately complete loss of vision.
There are said to be no characteristic eye symptoms in acute cases of lead poisoning, whereas with chronic lead poisoning in many cases there is central and peripheral affection. The affections may be further divided into subjective and objective. Many of the subjective symptoms, such as loss of sight and blindness, are associated with definite eye lesions, which may be seen with the ophthalmoscope, but other definitely objective lesions may be present without any influence on sight to commence with. Folker[25] describes five cases of lead amblyopia in lead-workers from a pottery district, in all of which there was a peculiar symptom—the gradual failing of sight associated with colour flashes. When examined, the discs were described as white, and the vessels small.
Lockhart Gibson[26], in describing the cases of eye disease amongst the children in Queensland, found one symptom apparently in all the eyes examined—namely, great swelling of the discs. This swelling of the discs might be accompanied with no loss of sight whatever, and at other times had been accompanied with defective sight for many months previously. Some of the discs were excessively swollen. There were also to be seen patches of pigment and irregular swelling of the vessels, but no definite hæmorrhages. In the more acute cases, and particularly those associated with complete paralysis of the ocular muscles, total blindness usually followed.
As a rule, when complete amaurosis occurs in lead poisoning, blindness follows through double optic neuritis or neuro-retinitis, but amblyopia may be present without fundus changes. Occasionally the loss of sight may be regarded as of central origin. The renal disease so often associated with lead poisoning may cause the retinal changes accompanying it. An albuminuric neuro-retinitis may occur without albumin in the urine. As a rule, the eye of a lead-worker reacts to light and accommodation. Ophthalmoscopic examination may show very pink discs, patches of pigment scattered about irregularly outside the discs, with occasional definite hæmorrhage. The edge of the discs may show blurring, with further sclerosis and peri-arteritis of the vessels, a white sheath around the arteries being often visible. The neuritis on one or both sides may be associated with disturbances of sight, and diffusely red and cloudy papilla, with swelling or hæmorrhages. In choroidal atrophy pigmentation may also be seen.
Muscular System.
—One further point may be referred to in relation to the muscular system—namely, the occurrence of pain of a rheumatic type. Quite a number of cases of mild degrees of lead poisoning complain of arthralgic symptoms—that is to say, “rheumatism.” Careful examination of such cases shows no evidence that the pain is a true arthralgia, neither does it seem to have a true relation to gout. The pain as a rule is referable to the muscles themselves, and in such instances digital examination of the muscle in the region of the pain generally exhibits deep-seated tenderness. There does not appear to be any special marked tenderness along the trunks of the nerves supplying the muscle, nor is there evidence of hyperæsthesia of the skin. Such hyperæsthesia does occur in lead poisoning, but is generally associated with cerebral lesions. The pain, therefore, must be regarded rather as myalgic, and intercostal distribution of the pain is not infrequent; but although the symptom is one that is often complained of, it is an exceedingly difficult one to differentiate from other myalgias as a definite symptom of lead poisoning. The chief point in favour of the inclusion of this so-called lead rheumatism as a symptom of lead poisoning is the frequency with which it is noted in the reports by certifying surgeons. While, therefore, having no evidence to regard it as necessarily a definite symptom of poisoning, it is one which has been recorded in a considerable number of cases. As has been already suggested, there is some reason to think these myalgic pains may be due to minute hæmorrhages taking place in the muscles, thereby producing localized irritation to some extent comparable with the “bends” of divers.
Post-Mortem Signs of Plumbism.
—Very real difficulty exists in determining from naked-eye appearances at a post-mortem examination whether the cause of death be due to chronic plumbism or not. The changes produced by several other forms of intoxication, notably chronic alcoholism, produce many of the same changes in the tissues as lead. Inspection of the organs in the case of plumbism can only give rise to a surmise that the cause of death is due to lead poisoning.
There are, however, certain macroscopical appearances at an autopsy in the case of saturnism which should be carefully noted, and although alone they do not constitute sufficient evidence upon which to pass a definite opinion, they are still important as diagnostic signs in the light of histological and chemical examination.
Particular note should be paid at an autopsy of a case of suspected lead poisoning to the following points: