Among the neuralgias, headache is the most frequent attendant of influenza. It has its seat especially in the frontal and supra orbital regions, at the back of the orbit; frequently also it affects the temporal and occipital regions, or again may be evenly distributed over the entire head. The pains ("douleur de tete cruelle," Saillant) are often very intense, so that the patients moan or rave (cephalsea agitata) or sit silently with their head tightly clasped with both hands (cephalsea attonita).
Occasionally a distinct obtusion of the senses occurs,-a sort of pain stupor,-or the picture of the disease may remind one of meningitis. Besides the cephalalgia, there are frequently pains in the back and lumbar region, intercostal neuralgia, pains in the lower extremities, especially in the knees and calves; furthermore, sciatica and diverse arthralgias. These neuralgias often persist into convalescence and even become chronic. This is especially true of trigeminal neuralgia and of the sciatic, intercostal, and dorsal nerves.
Certain chronic, sharply defined, post influenzal neuralgias are designated as mastodynia, sternodynia, xiphodynia, chonclrodynia, costodynia, sacrodynia, cystodynia, coccygodynia, achillodynia. Obstinate odontalgia and otalgia of purely nervous origin were observed already in the older epidemics. There is scarcely a sensory nerve that is not occasionally, at the height or in the course of influenza, the origin of severe neuralgia.
Some authors-e. g., Stintzing, Bristowe, Preston-have statistically arranged the seat of the various neuralgias. In all these statistics cephalalgia naturally prevails with nearly 100 per cent.
Intercostal neuralgias with herpes zoster have been described by Kinnicutt, Edgren, Brakenridge, and by us. Joffroy reports six cases of severe neuralgia, picking out the nerves to. the upper arm and shoulder, followed by atrophy of the deltoid, supraspinatus, and infraspinatus, pectoralis, and biceps. These were evidently cases of neuralgia due to neuritis (see below).
We must omit the muscular neuralgias (myalgias). They occur in various groups of muscles, frequently in several together, especially in the back, thigh, and calf, which are then often very painful on pressure." Patients frequently describe these pains as especially agonizing, and use comparisons, such as that " the muscles appear to be cut through by knives," or that they seem to be "drawn out of the body with burning hooks."
The influenza neuralgias and myalgias are characterized by periodic exacerbations, especially at night.
Finally we must call attention to the general hyperesthesia of the organs of sense, and especially of the skin. The latter is often painful to pressure, or even to touch, very much as in meningitis. In close relation to neuralgia and hyperesthesia are the peculiarly localized anesthesia and paresthesia of the cutaneous nerves.
We would especially mention a case described by us of total anesthesia of the second division of the fifth nerve. Here also belong anesthesia and paresthesia occurring in the course of the nerves of smell and taste. Cases of complete loss of the sense of taste are mentioned by Ash (1836), Senator, Leichtenstern, Fry; on one side only by S. Laache; loss of the sense of smell by Leichtenstern, Zwaardemaker; finally, peculiar parosmia by Barth and Dippe. Some of these phenomena were found in the epidemic of 1410 (Pasquier). Complete loss of the sense of smell and taste is noted bv English authors in the epidemic of 1800.