CHAPTER IV.

MULTIPLE NEURITIS.

UNDER the terms multiple neuritis, multiple peripheral neuritis, polyneuritis, beri-beri, kakké, etc., are embraced a number of conditions which have groups of symptoms mainly referable to disturbed functions of the peripheral nerves. The old-time distinction between central and peripheral organs and the clinical features of these cases directed attention mainly to the nerve-trunks and endings. In view of our present knowledge of the neuron unit, supported by numerous observations showing spinal nuclear involvement and even cerebral cortical disturbance in multiple neuritis, the term peripheral must be dropped. By multiple neuritis or polyneuritis is here meant a malady in which the anatomical lesions open to our present means of investigation are usually more pronounced in the nerves than in the central organs, and commonly consist of degeneration of the axis-cylinder process. Cases in which no histological change is found can not always be excluded, as many of the numerous poisons giving rise to the disease may, so far as we can detect, sometimes produce dynamic modifications alone. It is also allowable to suppose that the early effects of such poisons are perturbative of nerve-cell activity, to which the degeneration in the distant axiscylinder process is secondary, and that if the poisoning be slight in degree, or the investigation be made before the secondary results are developed, no change whatever will be presented. Finer methods, however, are daily displacing post-mortem appearances which were formerly considered normal, and the dynamic cases are being steadily brought within the domain of the morphologically abnormal. It is questionable if polyneuritis were not better classed as a general disease of the nervous system. The preponderance of neuritic conditions has dictated its description in this connection.

Etiology.-Polyneuritis is the result of a systemic poisoning or of conditions which entail depraved nutrition, such as pernicious anemia, or of both. The toxic substances which are capable of producing a multiple neuritis are most commonly alcohol and lead; less frequently arsenic, mercury, silver, phosphorus, sulphid of carbon, oxid of carbon, and ergot. Certain autotoxic substances may be developed that have the same pathogenic power, as in diabetes, nephritis, and intestinal disturbance.

The infections furnish another group of causative agents. Most of the infectious fevers-typhoid, typhus, the exanthemata, erysipelas, puerperal infection, acute rheumatism, influenza, and, above all, diphtheria— are occasionally followed by a multiple neuritis, which usually appears during convalescence. In rare instances the neuritic disturbance appears early in these infectious diseases, and again rarely it may follow them after a considerable period of time, even after several months have intervened.

Syphilis and tuberculosis have both been cited as causal of polyneuritis. Undoubtedly they both predispose to it by the systemic depression they occasion, and both are capable of producing a local neuritis by their specific proliferations. The anesthetic form of leprosy is frequently marked by a polyneuritis which is actually a peripheral disease and due to the invasion of the nerve-trunks by the bacillus lepræ. Malaria can undoubtedly produce it. Eisenlohr, in Homburg, and Graeme Hammond, in Connecticut, have reported small epidemics of the disease, which also in the form of beri-beri is common in certain parts of Asia, South America, and on shipboard during long voyages.

Cachexias of all sorts, but especially those associated with the pernicious anemias and cancer, are likely to develop polyneuritis. Old age, and especially old age marked by extreme arteriosclerosis and atheroma, may be the occasion of the disease by failure of nutrition both in the trophic spinal apparatus and in the peripheral nerve-trunks. Multiple neuritis occurs infrequently before adult age. In children it is usually due to infection, especially diphtheria, measles, and influenza. Much more rarely it is caused in childhood by lead or arsenic. Arsenic has caused polyneuritis in some cases of chorea where it has been too freely used. After adult age is reached all forms are comparatively common. Alcoholic polyneuritis is most frequent between thirty and forty. The senile and atheromatous forms appear only after sixty. Women furnish the greater proportion of alcoholic cases; men, of the rheumatic and toxemic variety. Occupation plays a large part. Painters, plumbers, type-setters, rubber-workers, match-factory employees and employees in white-lead factories, and lead-miners are especially exposed. Various other pursuits requiring the use of lead, arsenic, and mercury, or the handling of spirituous liquors, the last by indulgence, furnish many cases. Very often more than one cause is operative, as when tuberculosis leads to constant alcoholic stimulation, or the onset of physical or mental depression in an alcoholic precipitates the attack of polyneuritis. Morbid Anatomy.-Lesions in the Nerves. In the very great majority of cases the condition found in the nerve-trunk is one of degeneration comparable to that caused by traumatism, with the difference that in polyneuritis the nerves show many axis-cylinders in a comparatively normal condition. Indeed, all grades of Wallerian degeneration may be encountered in a single nerve, the fibers being differently affected by the toxic agent. It is also evident that the intensity of the toxic process and the duration of the disease will produce corresponding modifications in the nutrition of the axis-cylinder. It is possible that eventually we will be able to distinguish a variation in the degeneration produced by the various provocative agents, but at present they escape detection. The degeneration following lead-poisoning is apparently identical with that caused by toxins. The intensity of the neuritis generally decreases from the periphery toward the centers. Hyperemia of the endo- and perineurium is frequently observable. In addition to the axis-cylinder changes in some cases, usually those of long standing, there is an increase in the adventitia. A considerable thickening of the nerve-trunk results. This fibrous proliferation may even be excessive

2

and at exposed points sometimes produces nodular enlargements. Syphilitic, leprous, and tubercular changes incident to these various diseases are also encountered. In the leprous form the nerve may also contain the characteristic bacilli. Ceni, Cocq, and others, by inoculation experiments in lower animals, have produced the same changes in the nerves and in the spinal cord as are found in human subjects, but not in the brain.

Lesions of the Spinal Cord.-In a considerable and constantly growing number of cases the cellular parts and even the conduction tracts of the spinal cord have shown involvement. Oertel, Dejerine, and Pernice have described lesions of the anterior horns in diphtheric neuritis. Many, among them Finlay, Achard, and Schaeffer, have noted the same thing in alcoholic neuritis. Others again, as Thiersch and Rosenbach, recognize a simple atrophy of the cornual cells in lead-palsy. The cells of Clarke's column, and the fibers of the posterior and cerebellar tracts have presented diffuse lesions of an inflammatory and degenerative nature. Henschen3 records a case of typical diphtheric polyneuritis followed by acute disseminate sclerosis. The spinal cellular changes consist either of a changed crenelated form with vacuolation, or of changes of an inflammatory character, sometimes with hemorrhages. The lesions of the spinal white matter are principally degenerative.

Lesions of the Brain.-Pernice and Scagliosi in diphtheric cases found the principal changes in the brain, cerebellum, and cord, and referred them to circulatory disturbance followed by degenerative changes and hemorrhage. The cortical cells showed atrophic degeneration, which, as in the cord, especially affected their protoplasmic prolongations. The well-known effects of alcohol and lead on the cerebrum are also found. Dehio,5 experimenting on animals with poisonous doses of alcohol, found by appropriate stains that many of the cortical cells were changed in whole or in part. The presence of psychical symptoms in many cases of polyneuritis abundantly proves that the affection is one that does not spare the highest nervous apparatus.

On the other hand, in many cases of polyneuritis no changes have been detected. Thus Hosche, in a carefully examined case of widespread diphtheric palsy, found absolutely no change, even in the muscles which had been paralyzed. He, therefore, attributes the symptoms to toxins which operated without causing anatomical changes. The optic nerve, which is, in fact, a cerebral structure, is often affected in polyneuritis. We have here to recall the whole list of toxic amblyopias. Alcohol again plays the most frequent part. The medulla and the cranial-nerve nuclei are subject to the same changes as the analogous portions of the spinal cord.

Lesions in the Muscles.-The muscles supplied by the affected nerves in polyneuritis undergo changes similar to those in simple neuritis

1 "Rif. Med.," Feb. 5, 1896.

2" Rev. Men. des Maladies de l'Enfance," Sept., 1895. 3" Fortschritte der Medicin," 1896.

4 Rif. Med.," Oct. 8, 1895.

566 Centralblatt f. Nervenk. u. Psych.," March, 1895. 646 Münch. med. Wochens.," March 12, 1895.

or in nerve-division, but usually less in degree. The escape of numerous fibrils in the nerve-trunks is probably to be correlated with the persistence of numerous apparently normal fibers in the atrophied muscles. Another and important feature, however, is added, and that is the tendency to fibrous hyperplasia in the affected muscles, constituting in wellmarked cases an interstitial myositis, which, in its turn, may act detrimentally upon the sarcode elements. This muscular fibrosis also explains in part some of the tendinous contracture deformities of late cases. The presumption is that an element of irritation is present which acts through the apparently normal nerve-fibrils, though Babinski is disposed to attribute it to the pathogenic effect of the toxic agent directly on the muscle.

Changes in the trophic and secretory functions of the nerve are, like the motor and sensory, less pronounced than in a simple neuritis, but do appear, and are marked by disappearance of the fatty panniculus, by thinned and glossy skin, vascular disturbances, mottling, edema, lack of perspiration, and by modified growth of hair, nails, and epithelium.

Symptoms. The symptoms arising from so wide-spread a disease are correspondingly varied. It is necessary to take them up systematically, but it may be said, once for all, that they are symmetrical, as a rule, affecting both sides of the body in a similar manner. This might be expected from a toxic cause of systemic distribution. It is, however, a fact that the symptoms usually commence first on one side and frequently are slightly more marked on one side than on the other throughout the disease. They may be alternately exaggerated on the two sides. Some toxic agents, as lead, affect more especially the upper extremities; others, particularly alcohol, principally involve the lower. Again, in some cases the motor symptoms predominate; in others, the

sensory.

Muscular and Motor Symptoms.-The Lower Extremities.-The motor disturbance in polyneuritis is principally one of deficit, a paresis that only in severe cases reaches complete paralysis. It is most marked at the distal extremities of the limbs, and in the great majority of cases affects first and most the extensor muscles. In the lower extremity the extensors of the toes, the peroneal muscles, and the dorsal flexors of the foot are the ones usually most implicated. In marked cases footdrop is complete. The foot falls into line with the leg and the plantar surface turns inward, passively producing an equinovarus position when the patient is recumbent, or when the foot is raised from the floor (Figs. 105 and 106). In milder cases the patient can not raise the toes from the floor while standing on the heels, or, in other words, can not dorsally flex the foot beyond a right angle. The toes remain in a flexed, bunched position, and can not be extended or separated. Efforts against resistance at once disclose the weakness of these muscles. A peculiar and characteristic gait is developed. In order to clear the ground the patient is compelled to raise the foot by flexing the thigh. The leg is then thrown forward like a flail; the toe is pendent; the outer border of the foot is depressed and brought to the ground toe first, or in a flat-footed

manner, or the outer border of the foot strikes the floor first. The other foot is then advanced in precisely the same manner. From this high knee-action Charcot denominated the gait "steppage." The dangling foot sometimes wears the boot at the toe and frequently scrapes up

the dirt of the pavement. In very rare instances a contrary position of the foot and an opposite sort of gait has been produced by loss of power in the calf-muscles, the anterior group being spared. The

patient in such cases in walking brings the heel first to the ground with the foot inverted and dorsally flexed.

When the thigh-extensors are also affected and the muscles at the root of the limb are weakened, the use of the member becomes well-nigh