1911 Encyclopædia Britannica/Dropsy

DROPSY (contracted from the old word hydropisy, derived from the Gr. ὕδρωψ; ὕδωρ, water, and ὤψ, appearance), the name given to a collection of simple serous fluid in all or any of the cavities of the body, or in the meshes of its tissues. Dropsy of the subcutaneous connective tissue is termed oedema when it is localized and limited in extent; when more diffuse it is termed anasarca; the term oedema is also applied to dropsies of some of the internal organs, notably to that of the lungs. Hydrocephalus signifies an accumulation of fluid within the ventricles of the brain or in the arachnoid cavity; hydrothorax, a collection of fluid in one or both pleural cavities; hydropericardium, in the pericardium; ascites, in the peritoneum; and, when anasarca is conjoined with the accumulation of fluid in one or more of the serous cavities, the dropsy is said to be general (see also Pathology).

Dropsy (excluding “epidemic dropsy,” for which see below) is essentially a symptom and not a specific disease, and is merely an exaggeration of a certain state of health. Fluid, known as lymph, is continually passing through the capillary walls into the tissues, and in health this is removed as fast as it is exuded, in one or more of three ways: part of it is used in the nutrition of the tissues, part is returned to the general circulation by the veins, and part by the lymphatics. Any accumulation constitutes dropsy and is a sign of disease, though not a disease in itself. The serous effusions due to inflammation are not included under the term dropsy. A dropsical fluid varies considerably in composition according to its position in the body, but varies only slightly according to the disease which has given rise to it. Its specific gravity ranges between 1008 and 1018; the mineral salts present are the same and in about the same proportion as those of blood, nor do they vary with the position of the exudation. The quantity of albumin, however, depends much on the position of the fluid, and slightly on the underlying disease. In oedema the fluid contains only traces, whereas a pleural or peritoneal effusion is always highly albuminous. Also an effusion due to heart disease contains more albumin than one due to kidney disease. In appearance it may be colourless, greenish or reddish from the presence of blood pigment, or yellowish from the presence of bile pigment; transparent or opalescent or milky from the presence of fatty matter derived from the chyle. The membrane from which the dropsical fluid escapes is healthy, or at least not inflamed, and only somewhat sodden by long contact with the fluid—the morbid condition on which the transudation depends lying elsewhere.

The simplest cause of dropsy is purely mechanical, blood pressure being raised beyond a certain point owing to venous obstruction. This may be due to thrombosis of a vein as in phlegmasia dolens (white leg), retardation of venous circulation as in varicose veins, or obstruction of a vein due to the pressure of an aneurism or tumour. Cardiac and renal dropsy are more complicated in origin, but cardiac dropsy is probably due to diminished absorption, and renal dropsy, when unassociated with heart failure, to increased exudation. But the starting point of acute renal dropsy, of the dropsy sometimes occurring in diabetes, and that of chlorosis is the toxic condition of the blood. For accounts of the various local dropsies see Hydrocephalus; Ascites; Liver, &c.; general dropsy, or dropsy which depends on causes acting on the system at large, is due chiefly to diseases of the heart, kidneys or lungs, occasionally on lardaceous disease, more rarely still on diabetes or one of the anaemias.

Broadly speaking, 50% of cases of general dropsy are due to disease of the heart or aorta, and 25% to renal troubles. The natural tendency of all diseases of the heart is to transfer the blood pressure from the arteries to the veins, and, so soon as this has reached a sufficient degree, dropsy in the form of local oedema commences to appear at whatever may be the most depending part of the body—the instep and ankle in the upright position, the lower part of the back or the lungs if the patient be in bed—and this tends gradually to increase till all the cavities of the body are invaded by the serous accumulation. The diseases of the lungs which produce dropsy are those which obstruct the passage of the blood through them, such as emphysema and fibrosis, and thus act precisely like disease of the heart in transferring the blood pressure from the arteries to the veins, inducing dropsy in exactly a similar manner. The dropsy of renal disease is dependent for the most part on an excess of exudation, due largely to an increase of arterial and cardiac tension. This in its turn produces arterial thickening and cardiac hypertrophy, which, if the case be sufficiently prolonged, brings about a natural removal of the fluid. In kidney cases, in the absence of cardiac disease, the dropsy will be found to appear first about the loose cellular tissue surrounding the eyes, where the vessels, turgid with watery blood, have less efficient support. The dropsy of chlorosis is very similar to renal dropsy, a toxic condition of blood being present in both; also other forms of anaemia, as also hydraemia, tend to produce or assist in the production of dropsical effusions.

For the treatment of dropsy the reader is referred to the articles on the several diseases of which it is a symptom. Briefly, however, tapping of the abdomen or puncture of the legs are constantly resorted to in severe cases. Dehydration by diet is very valuable under certain circumstances when the dropsy is other than renal. And there is the routine treatment by drugs, purgative, diaphoretic and diuretic as the symptoms of the case may demand.

It may be well to mention that there are certain affections which may be termed spurious dropsies, such as ovarian dropsy, which is only a cystic disease of the ovary; hydrometria, dropsy of the uterus, due to inflammatory occlusion of the os uteri; hydronephrosis, dropsy of the kidney, due to obstruction of the ureter, and subsequent distension of these organs by serous accumulations; other hollow organs may also be similarly affected.

Having no known relation to the preceding is epidemic dropsy, the first recorded outbreak of which occurred in Calcutta in the year 1877. It disappeared during the hot weather of the following year, only to recur over a wider area in the cold months of 1878 to 1879, and once again in the cold of 1879 to 1880. Since then only isolated cases have been recorded in the immediate neighbourhood of Calcutta, though epidemics have broken out in other places both by land and sea. At the end of 1902 an outbreak occurred in the Barisal gaol, Bengal, in which nearly one-third of the cases ended fatally. Dropsy was an invariable feature of the disease, and was either the first symptom or occurred early. The lower limbs were first affected, trunk and upper limbs later in severe cases, the face very rarely. It was accompanied by pyrexia, gastro-enteritis, deep-seated pains in limbs and body, and burning and pricking of the skin. Various rashes appeared early in the attack, while eczema, desquamation and even ulceration supervened later. Anaemia was very marked, giving rise in Mauritius to the name of acute anaemic dropsy. The duration of the disease was very variable, the limits being three weeks and three months. Death was often sudden, resulting chiefly from cardiac and respiratory complications. The cause of the disease has remained obscure, but there is reason to suppose that it was originally imported from the Madras famine tracts.