Hysteria and neurasthenia not infrequently arise from influenza or are enormously exaggerated by it.
All forms of hysteria have been observed after influenza, particularly hysterical convulsions and the so called hystero epileptic attacks, occasionally associated with fits of crying (Grasset, Krannhals, German army reports), isolated clonic tonic spasms in the muscles of the arm, nodding of the head, spasm of the abdominal muscles, arc de cercle (van Deventer), hysteric tremor, aphonia, aphasia, various forms of anesthesia, paralyses, and contractures. We may omit quoting all names and content ourselves by calling attention to the fact that many of the cases quoted in literature as " myelitis," " cerebral monoplegia with anesthesia," and others were very probably of hysteric origin.
Post influenzal neurasthenia generally has the characters of the hypochondriacal variety.
Is a neuropathic predisposition the basis of hysteria and neurasthenia when following influenza? This question, which we shall consider more in detail when we discuss the post influenzal psychoses, is probably to be answered in the affirmative in most cases. On the other hand, the fact must not be overlooked that severe post influenzal hysteria has frequently been observed in vigorous males in the prime of life, as well as in children, in whom no hereditary or acquired neuropathic tendency could be found. Worms, Josserand, Huchard, and we ourselves particularly emphasized the absence of demonstrable predisposition in these cases. "La grippe peut faire naitre une hysterie, qui ne s'etait jamais manifested jusque la." We do not wish to underestimate the significance of predisposition, but only to direct attention to the fact that the occurrence of the "hysterical" symptom complex is occasionally less dependent upon individual disposition than upon the localization of the toxic disturbance of cerebral functions. On the other hand, in the seven cases of severe post influenzal hysteria which van Deventer observed in children, hereditary or acquired neuropathic tendencies could be shown in each.
The influenza psychoses would naturally follow the consideration of hysteria and neurasthenia, but we prefer to discuss them at the end of this section, and first to consider the remaining previously omitted functional neuroses, taking first the affections of the spinal cord.
Cases of astasia abasia arising chiefly on a hysteric neurasthenic basis have been reported by Heifer, Mobius, and Herzfeld. Exophthalmic goiter as a sequel of influenza has been described by Mosler, Colley, Reinhold, Sansom, Szyszllo, and Cnyrim. Bossers reports two such cases from the Amsterdam hospital.
Certain vasomotor trophic neuroses occurring during and after influenza (general and localized redness of the skin, certain exanthem atous forms, hyperidrosis universalis, symmetric asphyxia of the extremities, falling out of the hair, and premature grayness, etc.) will be considered later, when discussing the individual organs. Under the latter heading we shall also consider the importance of the influenzal and post influenzal cardiac neuroses.