A Treatise on Fever

by Southwood Smith

I. Pathology of the Solids in Fever.

1. External Appearances of the Body after Death.

The skin is always of a more dusky colour than natural; it is sometimes studded with petechiæ, which in bad cases are large and of a deep purple tint, giving to the body a spotted or speckled appearance.

Externally the body always appears emaciated, and on removing the skin, the greater portion of the adipose substance is found to be absorbed; what remains of it is of an unhealthy yellow colour. The muscular fibre is remarkably dark, and this dark colour extends, as we shall see immediately, to the internal viscera.

2. Morbid Appearances in the Head.

Of the membranes of the brain, the arachnoid is the most constantly diseased. It is seldom or never in a healthy condition. It is always either more vascular than natural, or when in this respect unchanged, it is altered in structure, being thickened, opake and milky: when in this latter state, a gelatinous fluid is usually effused beneath it. Not uncommonly, it is united at several points to the membranes above and below it. To the dura mater it very often adheres, particularly at the angles of the hemispheres, or along the course of the longitudinal sinus; and, in these cases, the adhesion is always peculiarly firm at the vertex. The dura mater itself is less constantly changed in appearance, although this membrane also is sometimes more vascular than natural, and frequently it either adheres with preternatural firmness to the skull-cap, or, on the contrary, it is quite detached from it, in consequence of effusion between it and the bones of the cranium. To the pia mater, the arachnoid is also very often adherent at several points: it is seldom that the pia mater is changed in structure, but it is generally preternaturally vascular. In like manner, the theca which encloses the spinal cord is frequently highly vascular, and contains a larger quantity of fluid than natural.

The brain itself is seldom or never in a healthy condition; the morbid changes to be distinguished in it differ greatly in degree in different cases, but still, in almost every case, some morbid change is to be discerned. These changes consist of an altered state of its substance, or of its cavities, or of both. The most usual change apparent in its substance is a higher degree of vascularity than natural. This increased vascularity is sometimes confined to the surface; sometimes it is more manifest deep in its substance; and, while common to both, it may exhibit different degrees of intensity in either. When on the surface, this preternatural vascularity is denoted by a greater fullness of the vessels, and, apparently by an increase in their number; when within the substance, by a greater number of bloody points, which are rendered visible by an incision with the scalpel. And in both situations it may exist in all degrees, from a faint blush to a deep and vivid redness. The substance itself is sometimes softer, sometimes firmer than natural. The softening differs in degree and in extent. Sometimes the entire cerebrum is manifestly and considerably softer than natural; at other times, only particular portions of it are found in this softened state. Now and then, but very rarely, abscess is discovered within its substance. It is remarkable that the cerebellum is always considerably softer than the cerebrum: whence these two portions of the organ are often observed to be in opposite states, the cerebrum being frequently preternaturally firm, and the cerebellum being almost always softer than natural. The pituitary gland also is very constantly softened, and often in a state of suppuration. When the cerebrum is preternaturally firm, the firmness is usually general.

The morbid change observable in the cavities of the brain consists in their containing an excess of secretion. This increase of secreted fluid is usually accumulated in the lateral ventricles: the quantity varies from a drachm to several ounces; when thus great, the lateral ventricles themselves are enlarged, the third and fourth ventricles are likewise distended with fluid, and the passages connecting them are proportionally full.

Common as it is to find a preternatural quantity of fluid in the ventricles, it is still more common to find it in excess between the membranes; often between the dura mater and the arachnoid, almost always between the arachnoid and the pia mater. It has been already stated, that the fluid effused between the arachnoid is of a gelatinous appearance and aspect; every where else it possesses the physical properties of serum, being thin, transparent, and of a straw colour: now and then it is thicker in consistence, opake, and even bloody, and sometimes that beneath the membranes contains flakes of lymph, or is mixed with pus.

It is observable that the two morbid conditions now described, that of excessive vascularity and that of increased secretion, are never co-existent. If the vessels of the brain and its membranes are loaded with blood, there is little or no fluid within the former or between the latter: if, on the contrary, the effusion be great, there is little or no appearance of vascularity. Effusion is the effect and the termination of vascularity; it is the ultimate result of vascular action, and the effect having ensued, the cause ceases to be apparent.

The substance of the spinal cord is seldom changed, either in vascularity or in consistence: the morbid changes which this organ undergoes have hitherto been observed only in the membrane that invests it, which, as has been just stated, is not only highly vascular, but likewise contains a much larger quantity of fluid than natural.

3. Morbid Appearances in the Thorax.

Of all the thoracic viscera, that which is most frequently diseased is the mucous membrane of the bronchi. The disease which takes place in this organ is not only the most constant, whatever be the type or the degree of fever, but it is also the most characteristic of the febrile state. Its disease is specific and uniform. It consists of preternatural redness. The character of this redness distinguishes it from that which is observed in ordinary inflammation. It is uniformly and strikingly darker, the difference in colour being precisely that which subsists between venous and arterial blood. This darkness of colour apparent in the bronchial lining, increases in degree as the tubes of the bronchi diminish in size: while it may be only just discernible in the large trunks, the colour may be nearly black in the minute branches. This change in the natural colour of the membrane is indicative, not only of an increase in its vascularity, but of alteration in its structure. It is almost always attended with a preternatural thickening of its substance, as is demonstrated by cutting through the tube and reflecting the membrane. The tubes themselves contain more or less fluid, which consists of mucus, mixed with pus. Analogous to what has been stated with regard to the vascularity of the brain and to its secretions, when the quantity of secretion contained in the bronchial tubes is great, the degree of vascularity apparent in the membrane is lessened.

In scarlet fever, the morbid changes are somewhat different. The mucous membrane covering the trachea, the larynx with its cartilages, the amygdalæ and the soft palate is inflamed; the redness is of a brighter and more vivid colour than that which has been stated to be characteristic of continued fever without an eruption: it is similar to the characteristic colour of the scarlatina tongue. But what is very remarkable, and what appears to justify the view we have taken of scarlatina and the division we have suggested of its types, when the cases are severe, the colour of the mucous membrane becomes much darker, the deepness of the tinge increasing with the severity of the affection, until, at length, the colour closely resembles that which is peculiar to ordinary fever.

As in continued fever without an eruption, so in scarlatina, the increased vascularity of the mucous membrane is accompanied with a preternatural thickening of its substance. In scarlet fever, that portion of it which covers the epiglottis, the rima glottidis, and the arytænoid cartilages, is especially found in this diseased condition. When this inflammation and thickening passes into the state of ulceration, which it often does, the arytænoid cartilages are the special seat of this process, although the ulceration often extends to the amygdalæ, and sometimes to the root of the tongue.

When in every other respect healthy, the substance of the lungs in fever is so constantly found either engorged with blood or infiltrated with serum, that these changes would seem to form essential parts of the morbid phenomena.

In examining those who die of fever, a great variety and complication of thoracic diseases, in addition to the morbid changes just described, are found. The pleuræ exhibit every degree of vascularity, from the faintest blush of redness to that which is characteristic of the most intense inflammation, and every extent of adhesion, from that of the smallest point to the complete obliteration of the cavity. The usual products of inflammation, namely, the effusion of serum and lymph, and the formation of pus and of adventitious membrane are likewise found equally varying in degree. The parenchyma of the lungs, besides the engorgement and infiltration just adverted to, presents hepatization and tubercular disease in every variety and degree; ulceration and abscess in every extent, and hæmorrhagic and calcareous depositions, together with enlargement and melanosis of the bronchial glands. But, since none of these diseases form any part of the changes of structure which are peculiar to the febrile state, it is sufficient in this place merely to advert to them.

4. Morbid Appearances in the Abdomen.

On opening the cavity of the abdomen all the viscera contained in it appear, in general, more vascular than natural, and invariably of a darker colour than in the state of health. Several of the organs are affected in a uniform and peculiar manner, but that which is by far the most constantly diseased is the mucous membrane of the small intestines; and especially that portion of it which lines the ileum and the cæcum.

The varieties of disease exhibited by this membrane may be comprehended under three, namely, vascularity, thickening and ulceration.

In all cases increased vascularity is the first stage of disease: in a great proportion of cases this increased vascularity is confined to the inferior extremity of the small intestines, which is often distinctly inflamed when not the slightest deviation from healthy structure is traceable in any other part of the canal.

The second stage of disease consists in thickening of the membrane, or in deposition of matter beneath it, or in both. Preternatural thickening of the membrane is often of very considerable extent: deposition of matter beneath it appears to be confined to the situations of the mucous glands. These glands are found in all states and stages of disease from the least to the greatest enlargement, and from the mere abrasion of their surface to the entire ulceration of their substance. Perhaps one of the glandulæ solitariæ enlarged and covered with inflamed mucous membrane may constitute the only morbid appearance discernible in the intestine; or this deposition may take place in so many of these glands as to present a most extensive surface of disease.

The third stage is that of ulceration, which may supervene when the membrane is affected in either of the modes just described; but the ulcer will not be the same in both cases: in each it will have a different and a distinctive character. If ulceration take place while the mucous coat is in a state of simple vascularity, the ulcer will in general be extensive but superficial; its surface will present a smooth appearance, and its margin will be regular and defined: if, on the contrary, it occur after thickening of the membrane or enlargement of its glands, its characters will be just the reverse: it will be less extensive, but more deep, because it must penetrate a mass of adventitious matter before it can reach the other coats; and, for the same reason, its margin will be more elevated and its surface more ragged. It is in this form of ulcer that perforation of the intestine generally occurs; in which case the mucous and muscular coats alone are ulcerated: the peritoneal gives way from gangrene.

Whenever the mucous membrane is ulcerated, whatever be the form of the ulcer, the corresponding portion of the peritoneal coat is more vascular than natural; and perforation must be attended with inevitable death, on account of the extensive and intense peritonitis excited by the escape of fæces into the peritoneal cavity.

Frequent as ulceration of the mucous membrane is in fever, and characteristic as this lesion is of the febrile state, yet it sometimes appears to be present when it does not really exist. From the quantity of adventitious matter deposited beneath the mucous coat, its surface sometimes becomes irregularly elevated, its valvulæ conniventes obliterated and its aspect smooth and glistening: in this state it may be easily mistaken, on a superficial examination, for ulceration, while more careful observation will shew that the membrane itself remains entire.

Proportioned to the extent and degree of these changes in the intestine are, inflammation, enlargement, induration and suppuration of the mesenteric glands; and invariably those glands which are embedded in that portion of the mesentery attached to the affected intestine, are the most diseased.

It is quite remarkable with what uniformity the spleen is diseased in fever. In almost every case of genuine fever hitherto examined, it has been found altered in appearance and deranged in structure. Its natural purple colour is changed to a deeper and darker tint, and, on the removal of the peritoneum that invests it, its substance, on being slightly touched with the finger, breaks down into an almost fluid mass.

The pancreas, the structure of which is so seldom changed in any other disease, is very constantly deranged in fever. Its morbid condition is invariably the same, and, what is singular, it is exactly the reverse of that produced in the spleen. It is always more firm than natural; often it is exceedingly indurated, and that portion of it which is attached to the duodenum is sometimes nearly cartilaginous.

Each organ having been described in the order of the frequency and extent of the disease it exhibits, we have hitherto said nothing of the mucous membrane of the stomach. This viscus having been regarded in France as the great source and seat of fever, particular attention has been paid to the appearances it exhibits after death. The uniform result of the most careful examination of fatal cases in London is, that the mucous membrane of this organ is less frequently, less severely, and less extensively diseased than any other portion of the same membrane. Occasionally it is more vascular than natural; this vascularity is seldom general; it is almost always confined to its pyloric half; in the few cases in which it has been very great, the membrane has been observed to be thickened and sometimes softened: but no instance has occurred in which it has been the seat of a single ulcer.

Of all the abdominal viscera, the liver is the least frequently deranged in structure, and when it exhibits any morbid change it is both less extensive and less characteristic. The blood contained in it is peculiarly dark and always fluid; its parenchyma is sometimes softer than natural; the gall-bladder contains a large quantity of bile, which is seldom healthy, being almost always in one of two states of disease, either paler and more fluid than natural, or extremely dark and very much inspissated.

The preceding comprehend all the morbid conditions of the abdominal viscera which are peculiar to fever: but the organs of this cavity exhibit other and great varieties of disease, to which, since they form no part of the febrile changes, it is sufficient merely to advert. Such are inflammation of the peritoneum; effusion of lymph upon its surface or of serum into its cavity; agglutination of the intestines; inflammation of the mesentery; false adhesions between the liver, spleen, and mesentery; tubercles in the liver; induration of its substance; tubercles and abscess of the spleen; thickening of the coats of the bladder and inflammation of its mucous membrane: in the female, vascularity and enlargement of the ovaria, to which hydatids are sometimes attached; vascularity of the external surface of the uterus, and inflammation of the os tincæ and of its internal membrane: it is rare to find any appearance of disease in the kidney in either sex.

Such is the circle of organs which are observed to be specifically diseased in fever, and with the most remarkable constancy. We go on to give individual cases in illustration of these morbid changes and of the symptoms with which they are accompanied.