See Carum.

Caros, carus, Caros 1725 or carus, synonymous with sopor, (from the head, which is chiefly affected).

It is a slight degree of apoplexy, in which some broken incoherent answers are obtained from the patient. When called, he scarcely opens his eyes; yet, if stimulated, he hath feeling enough to manifest his uneasiness. The walnut tree is named from this disease, Caryon, q. v.

The coma lethargus, coma vigil, coma somnolentum, cataphora, differ only in degree; but apoplexy is the most violent of these diseases. Galen says, that if the carusoppresses respiration, as in those who snore in their sleep, it must be considered as apoplexy. See Coma.

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Boerhaave observes, that a carus is a slight apoplexy from a hot cause, attended with a fever; and a lethargy is a slight apoplexy from a cold cause.

Hippocrates sometimes calls this disorder aphonia; Galen, in his Method. Med. lib. xiii. catoche; Coelius Aurelianus,gravatio; and Pliny, gravedo. Dr. Cullen arranges carus as synonymous with apoplexia. In a carus there are insensibility and sleepiness, with quiet respiration. It sometimes signifies a loss of sense and voluntary motion, respiration remaining uninjured.

The immediate cause of sleepy affections seems to be a defect of, or an impediment to the passage of the vital principle. The remote causes are, whatever diminishes the vis vitae, or that can obstruct its influence; as tumours pressing on the brain, a turgescency of the vessels from obstructed menses and haemorrhoids, a too free use of spirituous liquors, exposure to offensive vapours, blows on the head, etc.

Coma vigil is known by a burning and extensive pain in the head, attended with a sense of ebullition in it. There is a strong inclination to sleep, but the patient cither does not sleep, or awakes immediately with little or no relief: there is, however, no delirium. This disorder is always symptomatic, often attends acute fevers, and occasionally is the prelude of a phrensy, sometimes of an hemiplegia.

Coma somnolentum, (from somnus, sleep). In this disorder the patient is languid, and his chief complaint is a constant drowsiness. He often falls asleep at meals, in conversation, and in the midst of business; and, when awaked, he soon sleeps again. Luxurious old men are most subject to it. It is a primary disorder, and unattended with fever, but often the first symptom of apoplexy. This and the former species equally arise from over distended vessels: but, in the coma vigil, the distention is only in a degree to produce irritation; in the second it is increased so as to occasion compression.

Carus is a profound sleep, from which the patient is with great difficulty roused, though he seems sensible of pinching, or pricking him with pins, he either does not speak, or he immediately relapses into the same degree of sleep. This disorder is either idiopathic or symptomatic, and often attended with a fever. When symptomatic, it is said to be of three kinds; but is only the same disease in the different periods of that complaint, of which it is a symptom. The first happens early in acute fevers; and, if convulsions and hiccough come on, is soon fatal. The second appears after acute fevers; and, when the patient is exceedingly weak, the sleep will continue for several days: if it happens in acute fevers on critical days, with a sweat, and the countenance not changed, it is salutary. The third happens a day or two before death, when, the patient's strength being exhausted, he lies deprived of sense and motion, as it were in a profound sleep, and under it expires. In this state the countenance sinks.

Lethargus, (from Caros 1727 forge/fulness, and slothful,) also called veternus, a lethargy; is a heavy perpetual sleep, with scarcely any intervals of waking. When awakened, the patient answers; but, ignorant or forgetful of what he said, he immediately sinks into the same state of sleep: indeed it is attended with such a stupidity and forgetfulness, that whatever the patient begins to do, he forgets to proceed in it, and falls asleep. It is attended with a fever, which is chiefly discovered by the frequency of the pulse; and does not invade so suddenly as an apoplexy, nor kill so soon. By some it is considered as generally symptomatic; it is often the attendant of fevers, and usually a very dangerous symptom. In this disease there seems to be an utter loss of all the rational powers, and inaptitude to motion, whence some have named it desidia obliviosa. Dr. Cullen thinks it a symptomatic apoplexy.

Bonetus, in his Sepulchretum Anatomicum, observes, that in those who died of sleepy disorders, a copious serum was found diffused through the substance of the brain, chiefly in the cortical part: in some he found the ventricles replete with serum, and the cortical part unaffected; and these, he says, were never troubled with lethargic diseases. But he observes, that the more this watery fluid penetrated into the medullary part of the brain, the more obstinate was the sleepiness during the life of the patient. In some who died of drowsiness, he found abscesses, tumours, and scirrhosities of the brain; but these were only on its anterior and cortical region. In some he found the vessels of the pia mater very much distended with blood.

The coma vigil should be distinguished from the pervigilium; each of these disorders from one another; and all from apoplexy, hysteric fits, syncope, and hydrocephalus.

In whatever view we consider this disease, it will appear to be chiefly a less violent apoplexy, varying in its degrees rather than its nature or causes. To distinguish the different species from each other, or from apoplexy, is therefore of little practical importance; but these diseases often so nearly resemble a fit of hysteria, syncope, or the advanced state of hydrocephalus, that some little attention will be required.

The previous state of the patient will point out the hysteric paroxysm. In this last disease, however, the pulse assumes every variety both in strength and quickness; but the constitutions which each affects are very different, and the previous indisposition of the stomach, the attack commencing with flatulence, the neck swelling, the absence of either a fulness or redness in the face, which occurs when carus proceeds from over distended vessels, or a peculiar sinking in the features, when from narcotic vapours, sufficiently distinguish the complaint. In an hysteric fit the countenance is little altered.

Nearly the same symptoms distinguish carus from syncope; to which we may add, that the latter, if common, cannot easily be mistaken; if a single occurrence, the cause will point out its nature. The distinction of hydrocephalus is not so easy. In the early state of irritation the disease does not resemble carus: in its latter period, the strabismus, and the slow pulse, sufficiently point out water in the head. Yet there are cases where neither occurs, and where even the pupil dilates and contracts. The history of the complaint must then come in aid, and little difficulty will arise. If we suppose an error, no great harm can result; and, in doubtful cases, the practitioner should act as if it were carus.

A more important consideration is, whether carus be idiopathic or symptomatic. It is often a symptom only of disordered stomach; and, as we have remarked, it is a symptom of fevers. In the whole course of medical practice, we know no case of greater difficulty than the distinction of complaints affecting the head and the stomach with respect to the primary affection. After a long practice, we are often deceived; nor can any precise limits be drawn. Every case is peculiar to it-self; and the practitioner can only he assisted by an attentive examination of the origin and progress of the complaint, the effects of remedies, and the various juvantia and laedentia of the dietetic kind. Even the apparently pathognomic symptom of a noise in the ears is, in elderly persons, more frequently the effect of weakness than of over distended vessels.

When a complaint of this kind occurs in fevers, it is, as we have hinted, a dangerous symptom; and it then seldom arises from over distended vessels, but from weakness. In slow fevers, however, which approach insidiously, this symptom unexpectedly comes on; and all the evacuants, with every method of rousing the patient, are employed, till the powers of life, at once exhausted, yield. We may repeat the metaphor formerly employed, which the young eager practitioner should constantly keep in mind: a gentle gale may animate the flame which a violent wind will extinguish.

An attack of apparent carus, or even of its increased degree approaching apoplexy, often happens in young and strong persons from long exposure to the sun. In such cases we have seen leeches, blisters, and the whole train of evacuants, employed with little success. The disease is in fact a less degree of the coup de soleil; and moderately warm stimulants, with tonics, and, above all, rest, with patience, are only adequate to the relief. Its immediate cause is obscure; but, whatever it may be, we are not yet in a condition to explain it. Various preliminary facts must be previously stated.

Narcotic poisons and effluvia are more common causes of carus than of apoplexy. These also require a stimulating plan. Cold water dashed on the surface, oxygenous gas injected into the lungs, volatile spirits applied to the nose, and stimulating cataplasms to the feet, are all necessary. In other respects the treatment does not essentially differ from that of apoplexy.