Chapter VI.DIAGNOSIS AND PROGNOSIS.
DIAGNOSIS.—In view of the description which we have given of the two forms of the disease, the diagnosis is usually accompanied by little difficulty. We have, however, noted above how a case of tubercular Leprosy, with subcutaneous nodules only, was overlooked by a doctor well acquainted with the disease; and we have occasionally seen, in the country, people described by the doctors as leprous who were not so. And, on the other hand, we ourselves were once in doubt as to the diagnosis in a tuberous case, since all the nodules were exceptionally small, and presented no characteristic appearance. But the doubt was readily dispelled by the excision of a nodule and the recognition of the bacillus. In the diagnosis of the maculo-anæsthetic cases, one is more frequently in doubt, since the maculæ have not always a characteristic appearance; sometimes they closely resemble psoriasis, and in such cases the excision and microscopical examination of a portion might clear away doubt. This we have never needed to do, since the swelling of thelymphatic glands, or a thorough investigation of the sense of touch, have always been sufficient to establish a diagnosis. Even in comparatively, recent cases there may almost always be detected some loss of sensation in the fingers and toes; sometimes it is first evident on the wrists or back of the feet. For this investigation one must either use callipers, or very slight stroking, since deeperpressurecan be at once perceived. As a rule, the maculæ themselves are somewhat anæsthetic. We recollect once seeing a syphilitic eruption exactly resembling the leprous maculæ, but here the history cleared up the diagnosis.
Maculo-anæsthetic Leprosy may in its later stages be confounded with syringo-myelia, as Charcot has already noted in giving the points of distinction between the two conditions. If the maculæ are no longer present, careful investigation will often enable one to recognise their previous presence by finding areas of skin, especially on the upper arms, the back, the thighs and calves, which are somewhat paler than the surrounding skin, and in which sensation is somewhat blunted. We have thus frequently recognised the previous presence of maculæ in patients who themselves knew nothing of them. Zambaco Pasha has stated that certainly many of the cases described in France as syringo-myelia and Morvan’s disease are cases of Leprosy; thatLeprosy in this form still exists in Brittany; and further, that he has there found some cases of nodular Leprosy. It is remarkable that in these last cases, where the proof would have been so easy, he has not demonstrated the Lepra bacillus. From the drawings which he gives in theAnnales de Dermatol. et de Syphil.(T. III., Nr. 12), some of the cases can scarcely be regarded as Leprosy, since on the hands with mutilated fingers, no muscular atrophy can be noted; but in others there is distinct atrophy, and these may very well be leprous, the more as Pitres has published in theGaz. des hôp.1892, a case diagnosed as syringo-myelia in which Lepra bacilli were demonstrated in an excised portion of the ulnar nerve. It is unfortunate that Zambaco Pasha did not demonstrate the remains of previous maculæ, which would probably have been possible in some cases, were they really cases of Leprosy. According to the rich experience of Dr. Danielssen and our own, it must be admitted that a skin eruption is never absent in true cases of Leprosy. With multiple neuritis from some other cause, it is, with a good history and careful examination, not possible to confuse Leprosy; and the same is true of progressive spinal muscular atrophy, where there is no disturbance of sensation.
PROGNOSIS.—The prognosis is very different in the two forms. As we have alreadystated, both forms may recover, since all leprous products may disappear without any fresh ones appearing.In nodular cases this is a very rare exception, while it is the rule in the maculo-anæsthetic.Recurrent outbreaks are almost invariable in nodular cases, and in them, too, nephritis is an almost constant occurrence. Patients rarely live more than eight or nine years after the definite outbreak of the disease. As already remarked, we cannot state that Leprosy of itself is responsible for the end; we are rather inclined to regard the nephritis and other complications as the direct cause of death. The patients usually die long before the disease has run its course. But in the maculo-anæsthetic form the cure of the Leprosy is almost invariably the result. What remains, however, after the cure of the leprosy, is very different. We have occasionally a complete subject with vigour and good health, but usually only a miserable rudiment of a human being, with more or less paralysed and deformed hands and feet, with unclosable eyes, of which the lower part of the cornea is opaque, and from which the tears run down over the cheeks, and with paralysed facial muscles unable to close the mouth, so that the saliva constantly dribbles from it. Such cases may, however, live long and reach great ages, if under such circumstances this can be looked upon as any advantage. They die usually from some intercurrent disease.