1902 Encyclopedia > Fever


FEVER (from ferveo, to burn). This term, which may be defined as a condition of the body characterized by an increase in temperature, is used in medicine with a wide application. Fever is one of the most common accompaniments of diseases in general, and serves to make the distinction between febrile and non-febrile ailments. In many cases the fever must be regarded as only secondary to, and symptomatic of, the morbid state with which it is found associated. But there is a large class of diseases in which fever is the predominant factor, and which, although differing widely among themselves as to their characters and pathological manifestations, are believed to arise from the introduction into the system of something of the nature of a poison, upon which all the morbid phenomena depend. To such diseases the term primary or specific fevers is applied.

In considering the general subject of fever regard must be had in particular to the two main features of the febrile process, - viz, the abnormal elevation of temperature, and the changes affecting the tissues of the body in reference thereto. Indeed, the two points are inseparably associated.

The average heat of the body in health ranges between 98.4° and 99.5° F. It is liable to slight variations from such causes as the ingestion of food, the amount of exercise, and the temperature of the surrounding atmosphere. There are, moreover, certain appreciate diurnal variations, the lowest temperature being between the hours of 1.30 and 7 A.M., and the highest between 4 and 9 P.M., with trifling fluctuations during these periods.

The development and maintenance of heat within the body is generally regarded as depending on the destructive oxidation of all its tissues, consequent on the changes continually taking place in the processes of nutrition. In health this constant tissue disintegration is exactly counterbalanced by the introduction of food, while the uniform normal temperature is maintained by the due adjustment of the heat thus developed, and the processes of exhalation and cooling which take place from the emunctories of the body, particularly the lungs and skin. In the febrile state this relationship is no longer preserved, the tissue waste being greatly in excess of the food supply, while the so-called law of temperature is in abeyance. In this condition the body wastes rapidly, the loss to the system being chiefly in the form of nitrogen compounds (urea, &c.). The extent of this loss has been made the subject of research by many authorities, more particularly by Dr Senator, whose general conclusion is that in the early stage of fever a patient excretes about three times as much urea as he would do on the same diet if he were in health – the difference being that in the latter condition he discharges a quantity of nitrogen equal to that taken in the form of food, while in the former he wastes the store of nitrogen contained in the albumen of the tissues and blood corpuscles. The amount of fever is estimated by the degree of elevation of the temperature above the normal standard. When it reaches as high a point as 106° F. The term hyperpyrexia (excessive fever) is applied, and is regarded as indicating a condition of danger; while if it exceeds 107° or 108° for any length of time, death almost always results. Occasionally in certain fevers and febrile diseases the temperature may attain the elevation of 110°-112° prior to the fatal issue.

The clinical thermometer now in general use furnishes the physician with the means of estimating accurately the temperature and tracing its fluctuations, while the information it affords serves in many cases to indicate the particular form of fever, even at an early stage, as well as to prognosticate its probable result.

The leading general symptoms characteristic of the febrile state are certain phenomena connected with its onset, accession, and decline, necessarily modified in degree by the form the fever assumes, and by attendant complications. The commencement is usually marked by a rigor or shivering, which may only exist as a slight but persistent feeling of chilliness, or on the other hand, be of a violent character, and, as occasionally happens with children, find expression in the form of well-marked convulsions. Although termed the cold stage of fever, the temperature of the body in this condition is really increased. There are besides various accompanying feelings of illness, such as pain in the back, headache, sickness, thirst, and great lassitude. In all cases of febrile complaints it is of importance for the physician to note the occurrence of the first rigor, which in general fixes the beginning of the attack. This stage is soon followed by the full development of the febrile condition, the hot stage. The skin now feels hot and dry, and the temperature, always elevated above the normal standard, will often be found to exhibit diurnal variations corresponding to those observed in health, - namely, a rise towards evening, and a fall towards morning. There is in general relative increase in the rate of the pulse and the number of respiration. The tongue is dry and furred; the thirst is intense, while the appetite is gone; the urine is scanty, of high specific gravity, containing a large quantity of solid matter, particularly urea, the excretion of which is, as already stated, remarkably increased in fever; while, on the other hand, certain of the saline ingredients, such as the chlorides, are often diminished. The bowels are in general constipated, but they may be relaxed, as is often the case in typhoid fever. The nervous system participates in the general disturbance, and sleeplessness, disquietude, and delirium, more or less violent, are common accompaniments of the febrile state. The waste of the muscles and corresponding loss of strength is very marked, and continues even although considerable quantities of nutriment may be taken.

The decline of the fever takes place either by the occurrence of a crisis of sudden termination of the symptoms, often accompanied with some discharge from the body, such as profuse perspiration, copious flow of thick urine, and occasionally diarrhea, or by amore gradual subsidence of the febrile phenomena, or, as it is technically termed, a lysis. On the other hand, death may result either from hyperpyrexia or from gradual exhaustion, the patient often passing into the typhoid state (a condition of extreme prostration of the physical powers, with which are associated low delirium and coma, and which is an occasional mode of death in all acute diseases); on the fatal event may occur suddenly from syncope after slight exertion, in which case it is believed to be due to a softened state of the substance of the heart, one of the known accompaniments of fever.

Certain well-marked types of fever are recognized, these being determined by the clinical history and peculiar character and sequence of the symptoms.

The term continued fever is applied to those forms in which the febrile temperature persists for a more or less definite period, uninterrupted by any distinct intermission till the crisis is reached. To this type belong simple continued fever or febricula, typhus and typhoid fevers, and the eruptive fevers or exanthemata, - viz., small pox, measles, and scarlet fever. Relapsing fever is a form of continued fever the chief characteristic of which is the occurrence in about a week after the crisis of a distinct relapse and repetition of all the symptoms. Occasionally second and third relapses take place.

The term remittent is applied to those forms of fever the course of which is interrupted by a short usually daily diminution of the febrile phenomena, followed by a recurrence of all the symptoms. Such fevers are chiefly met with it tropical climates, but occasionally continued fevers assume this form, particularly in children. The condition known as hectic fever, which occurs in the course of wasting diseases, is markedly remittent in its course.

In intermittent fever or ague there is a distinct periodic subsidence of the symptoms, which, according to its duration, characterizes the variety as quotidian (where the paroxysm recurs in 24 hours), tertian (in 48 hours), quartan (in 72 hours). Intermittent fevers are most common in the tropics, and are believed to be due to malarial poisoning.

The term malignant is employed to describe forms of fever in which the blood appears to undergo rapid deteriorating changes, sometimes designated blood-poisoning . yellow fever may be said to belong to this category and the continued fevers, more especially typhus and the exanthemata, occasionally assume a malignant form from the beginning. The chief forms of fever will be found described in detail under separate headings.

With respect to the treatment of the febrile condition in general, it may be remarked that modern therapeutics have furnished several methods, of great importance and efficacy. It will be sufficient to refer to two of these, - namely, the external application of cold, and the administration of antipyretic remedies or febrituges. The former of these methods is accomplished by means of baths in which the fever patient is placed, the water being somewhat below the febrile temperature, and gradually cooled down by the addition of cold water till a temperature of from 60°-70° is reached. This process, when continued for only a short time and frequently repeated, has been found to yield most valuable results in many instances of high temperature, both in continued fever and in such febrile ailments as acute rheumatism. The relief to the patient is remarkable, the body rapidly parting with its heat, and the effect usually continues for hours. The explanation suggested by Professor Binz is that "in fever the vessels of the skin are generally much contracted. The cool water acts as a strong stimulant on them, and causes a somewhat stronger contraction to take place, but this is only of short duration. Relaxation for a longer time is the necessary consequence. The hitherto bloodless and try skin becomes filled and moist, and thus the irradiation of warmth goes on. The cooler the bath the longer it lasts."

Certain drugs possess the power of reducing the heat of fever, and are now largely employed for this purpose. The most important of these is quinine, which, when administered in large doses (gr. X.-xxx), has a marked effect in lowering he febrile temperature, and, if repeated, of keeping it down. It has been supposed that this effect of quinine is due to its action as an antiseptic upon the poison in the blood giving rise to the fever; but there seems a greater degree of probability in the view that it acts as an antitriptic by retarding those excessive tissue changes with which the development of heat is undoubtedly connected. This opinion is strengthened by the fact that after the administration of quinine the amount of urea discharged from the body is greatly diminished. It is said that quinine acts best at those periods of the day when the febrile temperature is inclined to undergo slight remission. Many other substances are used for their antipyretic action, among which may be mentioned digitalis, aconite, salicin, salicylic acid, &c. Alcohol is strongly recommended by some physicians for this purpose, but while its effect in large doses is no doubt to lower the temperature, its extensive employment in fever is objectionable on many important grounds. (J. O. A.)

The above article was written by J. O. Affleck, M.D., F.R.C.S; Senior Assistant Surgeon, Edinburgh Royal Infirmary; Lecturer on the Practice of Medical Surgery, Edinburgh.

About this EncyclopediaTop ContributorsAll ContributorsToday in History
Terms of UsePrivacyContact Us

© 2005-23 1902 Encyclopedia. All Rights Reserved.

This website is the free online Encyclopedia Britannica (9th Edition and 10th Edition) with added expert translations and commentaries