Chapter 10

That the morbid action producing the effusion is only a modification of inflammation, our author thinks may be further shown by the fact that it obeys the same laws--being translated occasionally, like it, from one part of the body to another. On this subject, Dr. AYRE makes the very pertinent remark, that in these cases, the fluid alone has been thought to be translated; but that the metastasis, is without doubt, exclusively of the action which produces the serous discharge. Analogous also to what occurs in inflammation, especially of the erysipelatous kind, the action occasioning the effusion, as seen in anasarca, commences at a given point, and gradually extends from thence in a continuous course. It ought also to be noticed, that the results of common inflammation vary according to the intensity of the cause; the lowest degree of it, occasioning an increase in the quantity of the proper fluids of the part,--a higher degree, yielding for its product coagulable lymph, and a still higher one producing pus. All these several products of common inflammation, are more or less remedial of their cause; or in other words, are the immediate means of the cessation or abatement of the inflammation which produces them. This same power is likewise a property, though in a much less degree, of the hydropic effusion, when the inflammation which produces it, is idiopathic; or in other words, not created by a visceral or other disease, or some particular excitement of the general system, as is seen in cases of anasarca.

"And here," continues our author, "it may be proper to remark upon a common error, committed by those, who, mistaking the nature of the action which produces the serous effusion, look in the _post mortem_ examination, for some of the common signs of an inflammation having existed; and who conclude, upon not finding such, that the water was derived from some mechanical or other cause foreign to the true one. But in the higher forms of abdominal inflammation, the products are pus or lymph, and these are found upon the surface of the peritoneum, with sometimes a thickening and discoloration or ulceration of its substance; whilst in the lowest form of that increased action to which the serous membranes are subject, the only product is the serous fluid, and there can be, therefore, no visible alteration produced by it in the structure of the serous tissue."

"By the hydropic or serous inflammation, obeying the same laws which govern the other degrees of common inflammation, it follows, that upon a higher excitement being superinduced upon it, the serous effusion should cease. This, therefore, is found to happen in every case, where such higher excitement is brought on. This increased inflammation is sometimes occasioned by design or accident, and at other times, it occurs in the natural and progressive course of some disease, formed within the cavity, which is the seat of the dropsical effusion."

This is exemplified in the effects of the operation for the radical cure of hydrocele; or in the operation of tapping in some cases of ovarian dropsy; or even in some instances, of ascites from chronic inflammation of the liver, spleen, mesentery, &c. In all these cases, the serous membrane, which directly or indirectly was affected to a sufficient degree to occasion a serous effusion, takes on, from the extension of a visceral disease, or from some other cause, a higher degree of inflammation--lymph is thrown out, and the cavity becomes obliterated.

"Now from these, and similar examples, which have fallen under my observations, I think it may be assumed, that ascites, when proceeding from some visceral disease, (and the principle applies to hydropic effusions from the pressure of disease in other cavities,) does so by the gradual extension of the chronic inflammation of the internal cellular or serous tissues of the diseased organ, to its outer external coverings; and that, commencing here as from a point, the serous or hydropic inflammation is progressively propagated through the whole of the serous membrane of the cavity. By the disease within the cellular tissue of the diseased viscous increasing, a corresponding increase, in these cases, will ensue of the disease on the surface of the membrane investing it; until at length a susceptibility to take on a higher action is induced, which only requires any slight occasional cause to establish. Under this condition of an increased excitement in the peritoneal or other serous membrane, coagulable lymph is discharged into its cellular tissue, and a thickening of it takes place; until at length the operation of paracentesis, which in the early stage of the disease was attended with only inconsiderable inconvenience, becomes an adequate cause of a still higher inflammation, which terminates perhaps in suppuration; and, in the _post mortem_ examination the serous fluid is found so mixed with coagulable lymph, and purulent matter, as to give a whey or milk-like appearance to the mass. The quantity of serous fluid, in these cases, is generally small, when compared with what was accumulated in the intervals of former tappings; for the vascular excitement which occasions the discharge of coagulable lymph, is destructive of that which pours out the serous fluid."

Dr. A. remarks, that, besides the particular facts deduced from observations on dropsy as a local disease, and which prove its relation to diseases of local excitement, there is a further support to be given to these views by various proofs that are afforded from observations upon the urine, of serous inflammation producing local dropsy, being frequently connected with one of a general kind. "So that the inflammatory state of the system becomes sometimes a cause of the effusion into a cavity, and at other times an effect of this state." After giving full credit to Drs. WELLS and BLACKALL for their researches into the state of the urine in dropsy, our author remarks, that there are certain conclusions deducible, which appear not to have been contemplated by those gentlemen, but which are strictly accordant with the pathological views he has endeavoured to establish in the present work.

"According to these facts, it appears, that when the disease of dropsy is under a sub-acute form, and of the anasarcous kind, it is usually idiopathic, and, often originating from cold; and in this state, as well as in the symptomatic form, though in a less degree, the urine is found to contain a portion of serum. It is nearly peculiar to this disease, and denotes, according to the quantity of it contained in the urine, the amount of that excitement in the cellular tissue, and of the general vascular system, which may be termed serous inflammation: for it is met with most considerably in those forms of the disease, in which these particular states of the body are most apparent."

Serum is therefore found in greater abundance, when anasarca precedes the local dropsy, which, in Dr. A.'s opinion, denotes the operation of a general cause. This is found to be the case especially in anasarca after scarlet fever. In cases of anasarca, the skin, kidneys, and bowels are very defective in their operation. Serum is also found, though in a smaller quantity, in those cases in which the anasarca has followed the local dropsy; for the disease of the viscus, which is the cause of the inflammation in the serous membrane of the cavity, may produce an adequate degree of the vascular excitement which gives rise to a discharge in the cellular tissue. Our author sums up his observations on this subject, by remarking, that there appear to be four distinct conditions of the system by which the occurrence of serum in the urine is regulated.

"1. It is in the greatest quantity, where along with a copious and continued effusion, there is a nearly corresponding quickness in the absorption of the serous fluid, and which will occur most commonly when the general excitement precedes, and is cause of the local one.

"2. It is consequently, _cæteris paribus_, in a less quantity where the general hydropic excitement of the system succeeds, and is dependent on the local one.

"3. It is absent, or found only in a minute proportion, in all those cases where the local increased excitement in the serous membrane is only partially extended to the rest of the system, and where the absorption from the part is inconsiderable; as particularly happens in the encysted kinds, or,

"4. Where the effusion of the serous fluid has proved remedial of the inflammation producing it; in which case the disease, as it respects the presence of water in a part, may visibly resemble another example, and yet be essentially different from it, by the serous inflammation, which produced it in both, having ceased, on its occurrence, in one of them."

Dr. A. discovers a further evidence of the relation which dropsy bears to diseases of local excitement, in the effects it produces on the general system. Thus, during the continued effusion of serum in anasarca, there is sometimes a large quantity absorbed and carried out of the body; by which a regular draught is made upon the nutrient principles of the blood, which must naturally create effects like those arising from the continued discharge of pus from a suppurating surface. In both cases the local disease, when extensive and of long duration, will necessarily occasion an exhaustion of the vital powers, by which that condition of the system termed cachexy will be induced.

"The exhausted or cachectical state, therefore, of the system, which has been so variously accounted for, and so frequently assigned as a principal cause of both local and general dropsy, is a direct consequence of the agency of some power diminishing the vital strength at its source; and in the case of a chronic and long continued serous inflammation, it will proceed from the daily abduction from the circulation of a portion of its vital fluid: and whether it be pus or serum that is drawn from the body; or whether it be from any permanent failure in the supplies of nutriment to it, the effect will be the same, as if a certain quantity of blood was daily abstracted from the system."

Dr. A. continues to remark that, under these circumstances, a suppurating surface will readily become gangrenous, from any cause temporarily exciting it, and that, in like manner, a higher inflammation may sometimes supervene upon an oedematous limb, as in the former case, and terminate in gangrene.

"Hence, therefore, the tendency of dropsical parts to fall into gangrene, and which has been urged, as an argument, in proof of debility being the cause of the serous effusion, is only what is common to other forms of local inflammation, under a similar condition of the body."

From the view he has adopted of the nature of dropsy, Dr. AYRE thinks that the excitement of the parts, giving rise to the effusion, may be either 1st. Sub-acute or chronic. 2nd. Symptomatic or idiopathic. In other words, that it may arise from a local disease, or from the common causes of inflammation; and that these causes may be either general or particular. 3d. That the serous inflammation may be either local or general, giving rise to a general or local effusion.

After offering so copious an analysis of Dr. AYRE'S sentiments respecting the pathology of dropsy, it is unnecessary to enlarge very fully on the application of his theory to the particular forms of that disease. We shall, however, offer a rapid review, of some of his opinions, and next detail the method of treatment he proposes for the cure of these dangerous maladies. We commence with hydrocephalus, which he remarks has been divided into an acute and chronic form. This division, our author thinks, is correct in a certain sense; for the disease varies much in duration,--running its course, sometimes in a few days; and at other times continuing several weeks. Yet, he continues, the terms acute and chronic must be understood as restricted to that particular form of inflammation producing a serous effusion, and not as denoting the highest and lowest degrees of common inflammation. It is from the want of this distinction that much confusion has arisen in our speculations relative to the pathology of hydrocephalus.

Dr. AYRE calls our attention to the fact, that the forms of hydrocephalus denominated by Dr. GOLIS hyperacute and acute, do not differ from the sub-acute phrenitis of nosologists, in which pus and coagulable lymph are the proper products, with sometimes a serous effusion into the ventricles as an accidental effect; all of which forms of inflammation, the serous membranes of the brain, and of other cavities are liable to take on; and adds:

"Now, the true hydrocephalus internus stands distinguished from these, in the nature of the inflammation of which it consists, in the same way, precisely, that the serous inflammation of the pleura, producing simple hydrothorax, is distinct from that higher degree of vascular excitement, which occasions an effusion of pus or lymph. Relatively to these, therefore, the disease is in a chronic form; and consists, we may repeat, of that lowest degree of inflammation to which serous membranes are subject, and the effect of which is to increase the natural secretion of the part, so as to cause, in regard to the brain, an accumulation of that fluid in its cavities."

Dropsy of the brain is usually divided into three stages. In the first, continues our author, vascular excitement exists, as denoted by pain in the head increasing in acuteness with the increase of the disease; and in infants by a restless movement of the head upon the pillow, moaning, occasional screamings, sickness, retching, impatience of light and noise, contractions of the pupils, delirious terrors, &c. The second stage is indicated by signs of pressure on the brain by effused fluid, and by an absence of pain, excepting upon raising or moving the head, convulsions, permanent dilatation of the pupils, squinting, blindness, slow intermitting pulse, hemiplegia, and a peculiar placid expression of the countenance, &c. The third stage is made up of some of these symptoms, together with other ulterior ones which follow the vascular reaction. On this subject, Dr. A. offers the following remarks:

"With respect, however, to the division thus formed of this disease, it is, I think, somewhat questionable, whether it be pathologically correct; for strictly speaking, the true disease is comprised between the incipient beginnings of the inflammation, and its termination by the effusion; since the symptoms which follow, and compose what are called the second and third stages, are little more than the consequences of the disease, and arise from the mechanical pressure of the water upon the brain. The progress, therefore, of what may be strictly considered the disease, should perhaps be considered as terminating with the occurrence of the effusion, which is often remedial of the excitement causing it; and the whole disorder, to be thus made up of two distinct states, the first consisting of symptoms, which commencing with the excitement, terminate with the serous discharge; whilst the second is composed of those of a secondary kind, and which are wholly dependent for their origin and continuance, on a mechanical pressure from the effused fluid."

Hydrocephalus may occur, either as an idiopathic or symptomatic affection. As the first, it may arise, where there exists a predisposition in the brain, from various injuries inflicted on the head by slight blows;--from all the general causes of inflammation--from the sudden drying up of long established discharges--the sudden repulsion of cutaneous eruptions, or the imperfect evolution of that or other sanative actions of the system, at the close of some febrile diseases, usually denominated defect of crisis. When, on the other hand, the disease is symptomatic, it may arise from a particular cause seated within the head, or in some distant part of the body. The former variety is not common among children, and when it does occur, it is the result of some chronic disease, as a tumour or a thickened state of the arachnoid or other membranes of the brain, resulting from a former inflammation. "Sometimes, adult patients wholly recover from chronic or sub-acute inflammation, which induced the structural disease, and this last becomes, at some future period, the occasional cause of the hydropic one." At other times, the chronic inflammation continues, and finally extends to the serous membrane, giving rise to the effusion.

"The most usual cause of the disease, however, particularly in children, is an irritation which is sympathetically communicated to the brain, from a disturbance in the chylopoietic organs; and particularly from a functional disorder of the liver. The cerebral disorder, to which a derangement in the digestive functions thus gives rise, is only one of those numerous effects which arise out of sympathies, subsisting between these organs and different parts of the system. In many cases, the same sympathetic irritation is successively and variously directed to different parts of the system. It will thus leave one organ or part, and suddenly move to another; and through the operation of causes, which are not always obvious, but which have a relation to some particular predisposition, inherent or acquired. In this way, an irritation may occasion an eruption upon the skin, and thence be translated to the bronchial lining, producing a cough; and next perhaps, to the serous tissue of the brain, exciting there a turgescent or congestive state of the cerebral vessels, by which symptoms are produced, through the pressure of the congestive vessels, that simulate those of hydrocephalus; or the true disease is brought on by an arterial re-action, ensuing upon the congestion, which is resolved by a serous effusion."

Dr. GOLIS, from observing the marked connexion "between the turgescent state of the brain from chylopoietic disturbance, and its serous inflammation, has concluded, that it essentially pertains to it;" consequently, that "whenever it occurs, it is a part of it;" that it should be considered as forming the first stage of the disease, and that in all instances, it precedes the excitement. He has, for the same reason, constituted all the symptoms of the chylopoietic disease into the first stage of hydrocephalus. Dr. AYRE shows, however, that this state of turgescence, is not essential to the disease, and is only a sympathetic effect, which in the majority of instances, requires no treatment, (at least a very subordinate one,) other than that of the primary affection. He concludes his remarks on hydrocephalus, with the following words.

"The cerebral turgescence and disturbance, therefore, in whatever degree they may exist, are only, when sympathetically produced, to be considered as morbid causes, whose presence, where the predisposition prevails, may lead to a serous inflammation of the tissues of the brain, but which do not form, in any sense, parts of the disease itself; since, under every degree of them, they are so frequently remediable, by means which are alone available, for the removal of their distant and sympathetic cause."

Of _Hydrothorax_, Dr. AYRE very justly remarks, that, as its name imports and as defined by Nosologists, it consists of symptoms, which strictly speaking, pertain only remotely to the true disease--arising, as they do, from a certain disturbance given to the lungs, by the pressure of water upon them. They are only the symptoms, therefore, of the effusion, and as the excitement sometimes terminates with the occurrence of the serous discharge, its existence, in many cases, is discoverable only by its effects--there existing no signs, which clearly point out the presence of that state, previous to the appearance of the effusion; and what are usually called, by writers on the subject, premonitory symptoms, being only those of an inferior degree of the effusion which has already commenced.

Like hydrocephalus, hydrothorax may be idiopathic or symptomatic; and proceed from a local or general cause--the nature of the inflammation being the same in both cases. It may likewise be divided into an acute and chronic form. When the disease is symptomatic, and arises from a local cause, it is generally chronic. When it arises secondarily from a disease of the lungs, our author thinks, that

"The mode by which this state is induced in the serous membranes, is by the chronic inflammation that exists in the diseased organ extending to them; and not by the same form of inflammation being set up in them, by a certain sympathy or consent of parts, which, from a loose analogy, has been thought to subsist between similar structures."

All diseases of the thoracic organs, are not equally prone to occasion effusion; some of these also, are only dangerous to life, in proportion to their disposition in occasioning such an effusion; whilst in other cases, if it occurs at all, the effusion is only the sequel of a disease essentially fatal.

"To distinguish between these two conditions, is a desideratum pathology. Modern writers on pathological anatomy have prosecuted with considerable zeal and ability, their researches into the nature of the diseases of the organs within the chest, but they have done but little towards elucidating the true relation, which subsists between the diseases of the several viscera, and the serous effusions which take place into their cavities; for, by limiting their views to the disease which the _post mortem_ examination exhibited, they have overlooked those intermediate actions or states of excitement which connect the organic disease with such effusions."

Whenever the excitement, producing hydrothorax, is idiopathic and independent of an organic disease of the lungs, heart, &c. its remote causes may be either of a general or local kind; and are the same which produce, when applied in a higher degree, or under different states of the system, the other forms of inflammation. The effusion may take place in those cases in which, the individual being predisposed, the inflammation, owing to some peculiarity in the cause, does not reach beyond its lowest grade; or in those in which the inflammation being high, and treated too late, or by insufficient means, a chronic form succeeds to the acute one, which may produce a watery effusion; or some structural disease remains and eventually becomes a cause of the effusion. The occurrence of this effect, in those latter cases, is sometimes attributed to a debility, resulting from the large depletion required in consequence of the severity of the previous inflammation.