When descending degeneration takes place there may be found, coinciding with increased reflex activity and contracture, increased sensitiveness to the electric currents. If the degeneration extend to the anterior columns, as happens in rare cases, the muscles waste rapidly and exhibit the reactions of anterior poliomyelitis—i.e. degenerative.
What has just been said applies to the muscles paralyzed by a central lesion. If, however, with or without a complete hemiplegia, a limited lesion, as in the pons, affects the nucleus of a nerve, the peripheral distribution of that nerve is cut off from its nutritive centre, and it undergoes the usual changes which lead to the reaction of degeneration, so that, in some unusual forms of paralysis, the two kinds of reaction, normal and degenerative, may be present in different sets of muscles.
DIAGNOSIS.—The apoplectiform attack due to hemorrhage or occlusion of the cerebral arteries is to be distinguished from narcotic poisoning, specially by opium or alcohol, or by coal gas; epilepsy with its succeeding coma; uræmia (so called) or cerebral symptoms connected with renal disease; comatose form of pernicious intermittent; diabetic coma; sunstroke; hysteria, and various other forms of intracranial disease, especially meningitis; concussion and compression of the brain, which often involve hemorrhage; the apoplectiform attacks of intracranial syphilis and of general paralysis, as well as the congestive attacks (coup de sang, rush of blood to the head).
The first of these distinctions is, in a practical point of view, among the most important and often the most difficult, so that distinguished authorities insist not only on the difficulty, but impossibility, of making a positive diagnosis in every case. The physician who is most familiar with all the different conditions which may cause coma is least likely to jump at a conclusion.
Persons are constantly being picked up in the street partially or wholly unconscious, or found alone in a room without history and away from friends. The physician must then form his opinion from the present condition, which without a history may be very obscure, though with one it might present no difficulty. An empty laudanum- or whiskey-bottle may be of assistance, the former of much, but the latter of less. The smell of the breath may give a hint, but even if the smell of alcohol be detected, considering the widespread belief in its virtues as a panacea, it may be as well the result of amateur therapeutic attempts as an indication of the cause of the attack. Neither does it follow that because a man has been or is drunk he has no organic disease in his brain. Alcohol should simply make us more careful to examine for possible injuries. In regard to both these poisons—and in fact in the diagnosis of these conditions generally—the first thing to be sought for, after assuring one's self that the patient can breathe and is likely to do so for a few minutes, is some evidence of hemiplegia. This is not so easy as it might appear at first sight, since the general muscular relaxation may be so complete as to cover up local manifestations. The face, however, may show inequality in its lines or one cheek flap more loosely than the other. The patient is not likely to undertake voluntary movements at the request of the physician, but he may make semi-voluntary ones if annoyed by the examination. The flaccidity of the arms may vary. Irregularity of the pupils is a piece of evidence to be received with some caution, as it may be habitual or the result of disease in the eye. Conjugate deviation of the eyes and head is a form of paralysis, or sometimes of unilateral spasm, which when present is of great significance. In opium-poisoning—and to a less extent in alcoholic coma—the pupils are much contracted, while they are not always so in apoplexy. Respiration is usually much more rapid in apoplexy than in opium-poisoning, and this, in the absence of distinct signs of hemiplegia, would be one of the most important means of distinction. The pulse is more nearly normal in frequency, while that of opium is either slow and hard or more often frequent and feeble.
After the time for the initial depression has passed, rapidly-rising temperature is very strong evidence in favor of apoplexy. If the patient be only partially unconscious and able to protest against being handled, to make some short answers, or even be inclined to be combative, this is not to be taken as evidence of alcohol. Hemiplegia may then be noticed. This condition of excitement may be observed in the early stage of an apoplectic attack before it deepens into coma. Unfortunately, when the lesion is situated in certain portions of the brain, as in the extremities of either the frontal or occipital lobes, there may be no paralysis, but then also there is less likelihood of the extreme symptoms we are supposing to be present. In the cerebellum, however, the symptoms may be very severe without hemiplegia, and the diagnosis correspondingly difficult. Vomiting, not caused by the presence of large quantities of food or liquor, and persisting after the stomach is once emptied, would be of some value in this case, but it would often be necessary to wait for a diagnosis. Cerebellar hemorrhage is, however, a very rare accident, and cerebellar embolism sufficiently large to cause apoplectiform symptoms still more so. A limited lesion in the pons may cause gradually-increasing stupor without distinct paralysis.
Chloroform, especially if swallowed, and chloral might possibly give rise to difficulties in the way of diagnosis, and would have to be distinguished on the same general principles as alcohol and opium.
The poisonous gases arising from burning coal, consisting chiefly of carbonic oxide and dioxide, or illuminating gas, consisting of carburetted hydrogen with a little carbonic oxide, cause unconsciousness, coma, and sometimes convulsions and vomiting. In case of a person found unconscious in bed the possibility of poisoning by one of these should not be lost sight of, nor, on the contrary, assumed to be a cause without investigation. A case has been reported where, after acute poisoning by coal gas, there occurred, presumably as the result of local anæmia, alternate paralysis, convulsions, and aphasia.47 The new water-gas process is said to furnish a product considerably richer in the poisonous carbonic oxide than that now most in use.
47 Boston Med. and Surg. Journal, Nov. 26, 1885.
The stupor succeeding an epileptic convulsion resembles apoplexy, and the fact that cerebral hemorrhage may be accompanied by some convulsions increases the possible similarity, but it requires only a short time for epilepsy to make itself manifest, either by a renewal of the convulsions or a rapid recovery without paralysis. According to Trousseau, however, many attacks of so-called congestion of the brain are really epilepsy. Puerperal eclampsia comes under the same head, but when convulsions are violent they may give rise to actual hemorrhage. Unilateral epileptiform convulsions are likely to be dependent on organic disease of the brain, usually not of the kind at present under consideration, but more frequently of a tumor.