40 Straus, Arch. de Neurologie, tome i. p. 536.
In addition to these forms of vaso-motor affections there is a condition of instability of vascular tone which manifests itself by sudden transient changes in the circulation of various organs. This is a functional affection, usually due to malnutrition. It is seen in many cases of neurasthenia and hysteria, and manifests itself by sudden flushes or pallor, alternations of heat and cold, local sweating, attacks of mental confusion, and inability to use any organ continuously from disturbance of the power of the vaso-dilators to maintain a condition of functional hyperæmia.41 Little is actually known about the causes of this state of the vascular system, although much has been written about it. (For a fuller description the article on Neurasthenia may be consulted.)
41 Anjel, Arch. für Psychiatrie, xv. 618.
Many functional derangements of the internal viscera have been ascribed to such vaso-motor instability with more or less probability,42 but hypothesis of this kind, however plausible, is evidently beyond confirmation. It is especially in affections of this kind that causes of reflex irritation are to be carefully sought. Cutaneous angio-neuroses, such as have just been described, may affect any part of the body. They usually appear suddenly, producing much discomfort and an impairment of function in the part if it is an extremity. They disappear as rapidly as they come. The duration of such attacks varies from a few minutes to several days. They are very liable to recur. If it is the vessels under the control of the cervical sympathetic which are affected, the symptoms will be those of migraine or of lesion of the ganglia.43 If it is the vessels in the extremities which are involved, the condition of digiti mortui or erythromelalgia or symmetrical gangrene44 may be produced.
42 Fox, The Influence of the Sympathetic System in Disease, London, 1885.
43 See p. 1263.
44 See p. 1257.
A singular epidemic occurred in France in 1828 and 1830 which was termed acrodynia. Many persons were suddenly seized with vomiting and purging, and soon after the onset the extremities became red or mottled in blotches, swollen and œdematous, and hot, painful, and tender. The attacks lasted from a few days to two months, and during this time the skin became thick and hard, the muscles weak and subject to spasms, and the general health was impaired. Relapses occurred in many cases, but all finally recovered, and hence the exact nature of the disease was not ascertained.
COURSE.—In any case of vaso-motor neurosis the course of the disease and its termination will depend chiefly upon its cause. If the cause is some permanent lesion of the nervous system, the condition will remain, and in this case the termination will depend upon the severity of the symptoms. Angiospasm may be so severe as to lead to gangrene ana the separation of the part affected, or may be so slight as to cause only subjective discomfort and a little pallor. Angio-paralysis may lead to an extreme degree of congestion, which is attended by heat and pain at first, later by paræsthesia and coolness, with increased liability of the part to be affected by changes in the surrounding air. This stage is succeeded by one of less marked dilatation of the vessels and a spontaneous partial recovery, although the more moderate symptoms may continue indefinitely and seriously impair the function of the part. If the cause is a temporary derangement of function in the vascular mechanism, is reflex irritation which can be removed, or is a curable organic disease, the symptoms will subside rapidly or gradually and perfect recovery may follow. If the condition is one of irritability in the vaso-motor centres, producing alternations of flashing or pallor, such as is observed in nervous exhaustion, it may recur irregularly for a considerable length of time until the causative condition can be removed.
PROGNOSIS.—The prognosis must be determined in each case by a consideration of the cause of the affection, of the nature of the symptoms, of the severity of the disease, and of the possibility of success in both symptomatic and causative treatment. In the angio-paralytic cases an eventual spontaneous relief from much of the discomfort may be promised, although the duration of the symptoms cannot be predicted.