We have previously stated that influenza occasionally commences with peculiar cerebral manifestations: with a sudden attack of giddiness and obfuscation of the senses, or with an "apoplectic"* or epileptic seizure, followed by unconsciousness lasting several hours. A patient coming out of such an alarming initial stage not infrequently recovers from what turns out to be a mild attack of influenza within a few days. We consider these to be cases of " acute intoxication by influenza toxins."
A similar pathogenesis perhaps may explain the numerous cases described in the literature in which, sometimes at the onset or sometimes during the course of influenza, there develops a marked somnolence which may lead up to coma without any other cerebral manifestations. Virey reports such cases of somnolence lasting from twelve hours to two days; Henry (Neuenburg), cases lasting eighteen hours; Barret (Hamburg), cases lasting from ten to twelve days; and Fr. Midler (Pforzheim), cases in which the coma lasted for fourteen days.
* Compare above, p. 593; furthermore, Basqueiraz (Swiss reports, p. 153).
Cases belonging to this category have been described by Prentis, Macphail, Trastour, Ph. Wipham, Kormann, and Gibson. But even in the earliest epidemics, this comatose form of influenza caught the attention of observers.
They are mentioned by Wittich and Sennert in the epidemic of 1580 in Saxony and in Italy (Rome), by Ozanam in the year 1691, and by Beccaria (Bologna) in the year 1779. The epidemic of 1712 in Tubingen, which seems to have been distinguished by the gravest cerebral manifestations, was given the name, as reported by Camerer, of "sleeping sickness."
In respect of similar designations in the earlier influenza epidemics -here also belongs the name cephalitis epidemica (Sauvages)-we must assume that rare and consequently striking complications gave rise to the name for the disease, for no observer of our time would think of applying such names to the more recent epidemics. It is quite possible that some so called influenza epidemics of previous centuries were not influenza at all, but something entirely different, as, for instance, cerebrospinal meningitis.
The simple coma due to influenza toxin as one of the manifestations of the influenza process generally runs its course with high fever, a valuable point for differential diagnosis from other toxic forms, like uremic and diabetic coma. Coma as an accompanying manifestation of grave cerebral affections, like meningitis and influenzal encephalitis, obviously does not belong in this category.
Cataleptic conditions of shorter or longer duration occasionally accompany this toxic coma (Inglott, Pacini). Probably most of such cases belonged to the class of "hysteric somnolence" (sommeil hyste rique), or, like N. Raw's case, to the psychoses (katatonic conditions with stupor).
This will be the proper place to consider the so called "nona," concerning which more has been published in the lay than in the medical journals. It was supposed to be a form of influenza which appeared in May, 1890, in some parts of upper Italy, immediately after the pandemic. The patients, attacked by fever and delirium, succumbed in a few days in a state of deep coma, in some instances with pneumonia as a complication. The interpretation of nona as an epidemic of cerebrospinal meningitis (Tranjen) is not admissible on account of the occurrence of pneumonia, which is never seen in true epidemic meningitis. A pneumonia epidemic with an unusually frequent occurrence of pneumonic meningitis is a more feasible explanation, but it does not accord with the described course of the disease. Indefinite as are the reports concerning nona, its connection with influenza is, nevertheless, very probable. Perhaps it was an epidemic occurrence of the grave comatose form of influenza, as Longuet supposed, or of acute hemorrhagic encephalitis and influenzal meningitis, as Leichtenstern believed; other rare complications, as the literature shows, have been observed in a few scattered places with remarkable frequency, although, as a rule, extremely uncommon. Adhue sub judice lis est.
The remark of Ebstein that the lay term "nona" arose out of confusion with a medical expression, "coma," is very likely correct when we remember how the word influenza was distorted by the laity.