The termination of an acute neuralgic attack is usually gradual, like its onset, although in some cases of headache, and in other neuralgias to a less degree, there comes a moment when the patient suddenly declares that he is free from pain.
Neuralgic attacks are usually characterized, besides the pain, by a highly-interesting series of symptoms, which are in part transitory and functional, and in part due to structural changes in the tissues.4
4 See Notta, Arch. gén. de Méd., 1854; Anstie, Neuralgia and its Counterfeits.
The spasm and subsequent dilatation of blood-vessels in the affected area have already been alluded to. A disturbance of secreting organs in the neighborhood of the painful region, the lachrymal gland, the skin, the mucous membranes, the salivary glands, is of equally common occurrence, and is probably in great measure due to direct irritation of the glandular nerves, since the increased secretion is said to occur sometimes unattended by congestion.
The hair may become dry and brittle and inclined to fall out, or may lose its color rapidly, regaining it after the attack has passed.
The increased secretion of urine already alluded to attends not only renal neuralgias, but those of the fifth pair, intercostal, and other nerves. There may be unilateral furring of the tongue (Anstie).
The muscles supplied by the branches of the affected nerve or of related nerves may be the seat of spasm, or, on the other hand, may become paretic; and this is true even of the large muscles of the extremities.
Vision may be temporarily obscured or lost in the eye of the affected side in neuralgia of the fifth pair, and hearing, taste, and smell are likewise deranged, though more rarely. I am not aware that distinct hemianopsia is observed except in cases of true migraine, where it forms an important prodromal symptom.
In connection with these disorders of the special senses the occasional occurrence of typical anæsthesia of the skin of one-half of the body should be noted, which several observers have found in connection with sciatica. The writer has seen a cutaneous hyperæsthesia of one entire half of the body in a case of cervico-occipital neuralgia of long standing. These symptoms are probably analogous to the hemianæsthesia which comes on after epileptic or other acute nervous seizures, or after concussion accidents, as has lately been observed both in this country and in Europe, and it is perhaps distantly related to the hemianæsthesia of hysteria. Local disorders of the sensibility in the neuralgic area are far more common than this, and, in fact, are usually present in some degree. The skin is at first hyperæsthetic, but becomes after a time anæsthetic; and this anæsthesia offers several interesting peculiarities. When this loss of sensibility is well marked, areas within which the anæsthesia is found are apt to be sharply defined, but they may be either of large size or so small as only to be discovered by careful searching (Hubert-Valleroux). The sensibility within these areas may be almost wanting, but in spite of this fact it can often be restored by cutaneous faradization around their margins, and the functional or neurosal origin of the anæsthesia is thus made apparent. Where the anæsthesia is due, as sometimes happens, to the neuritis with which the neuralgia is so often complicated, it is more lasting, but usually less profound and less sharply defined.
These changes may be transient, or, if a neuralgia is long continued and severe, they may pass into a series of more lasting and deeper affections of the nutrition.