The neuropathic family is thought to contain, in fact, a much larger number of members than this,5 but there is danger of exaggerating the importance of an influence of which we know as yet so little.
5 Féré, Arch. de Névrologie, 1884, Nos. 19 and 20, “La famille névropathique.”
It should be remembered, moreover, that even where an inherited taint is present its influence may be but slight as compared with that of some special exciting cause.
Some neuralgias are more closely associated with the inherited neuropathic diathesis than others. The connection is especially close in the case of migraine;6 then follow other forms of periodical headache and the visceral neuralgias. Even the superficial neuralgias7 are more or less subject to this influence. This is thought to be especially true of the facial neuralgias.
6 There is a witty French saying (quoted by Liveing), “La migraine est le mal des beaux esprits;” which might be rendered, “The disease of nervous temperaments.”
7 For tables of illustrative cases see Anstie, Neuralgia and its Counterfeits, and J. G. Kerr, Pacific Med. and Surg. Journ., May, 1885.
Reasons will be offered later for suspecting that many cases usually classed as neuralgia, and characterized by gradual onset and protracted course, are essentially cases of neuritis; and there is need of further inquiry as to how far hereditary influences are concerned in producing them, and whether such influences act by increasing the liability of the peripheral nerves to become inflamed, or only by increasing the excitability of the sensory nervous centres.
2. Age.—Neuralgia is oftenest seen in middle life and at the epochs marked by the development and the decline of the sexual functions. The affection, when once established, may run over into advanced age, but cases beginning at this period are relatively rare and very intractable (Anstie).
Childhood is commonly said to be almost exempt from neuralgia, but, in fact, there seems no sufficient reason for withholding this term from the so-called growing pains of young children8 so long as it is accorded to the almost equally irregular neuralgias of anæmia in the adult. The same remark applies to the attacks of abdominal pain in children, which often seem to be entirely disconnected from digestive disorders.