II. A consideration of the anæmias induced by disturbance in the blood-making organs themselves presents difficulties proportionate to our ignorance of the details of hæmatogenesis. We may regard, as above stated, the spleen, the general lymphatic tissue, and the marrow as the sites of production of corpuscles which are passed into the circulation fully formed. Certain of these organs—the spleen and marrow particularly—are also concerned with blood-destruction as well as blood-elaboration; but there is evidence to show28 that they, to use an ordinary simile, consume their own smoke, using the waste products for the purpose of further manufacture. Looking now upon the hæmatogenetic tissues as a single organ scattered through the body, let us consider what general disturbances of function it may suffer comparable to those met with in other structures. We can evidently suppose the physiological activity to be diminished or increased, and we should expect to find corresponding to these changes equivalent alterations in the character of the blood. Unfortunately, our knowledge of the normal processes as they go on in these tissues is so scanty that it amounts to a discussion upon the disturbances of a function itself imperfectly understood.
28 Quincke, quoted above.
With diminished functional activity in an organ we commonly meet with reduction in volume, the one depending on the other: now, the only instance in the blood-making organs in which a decrease in size and diminished functional activity go together is in the senile atrophy in which the spleen becomes small, the marrow more fatty, and the lymph-glands sclerotic, and in consequence the blood also is reduced in amount; but this is only a part of the general failure of nutrition in old age. Pathologically, there is no such well-recognized condition of uniform atrophy of spleen, lymph-gland, and bone-marrow, with a corresponding general reduction in the elements of the blood. Certain cases of idiopathic anæmia come close to it, in which these parts are wasted, but there are other differences which make the two conditions scarcely comparable. In fact, as we shall see, diminished activity in blood-making is usually associated with an increase in what we call hæmatogenetic tissues. Of increased functional activity in these parts we know very little, apart from the changes met with in cases of traumatic anæmia, in which the hyperplasia of the spleen and bone-marrow may be regarded as intimately connected with the rapid development of red corpuscles.
One fact is evident: that a progressive increase in the cytogenic tissues, local or general, is associated with disturbance in the process of blood-formation, and sooner or later induces anæmia. Thus, progressive enlargement of the spleen or of the lymph-glands or marked hyperplasia of the marrow, either singly or combined, is invariably accompanied with alteration in the characters of the blood. Even in those rare instances in which the lymphoid elements of the tonsils and fauces or of the gastro-intestinal canal are chiefly involved the same change may take place.
The nature of the process in the organs is of a hyperplastic character. In the spleen the pulp at first increases and the Malpighian bodies enlarge, but ultimately there is such a development of the fibrous reticulum that the consistence is greatly augmented and the organ becomes indurated. Histologically, there is very little distinction to be made between forms of chronic enlargement of this organ. In the lymph-glands there is increase in the cells; the tissue becomes more succulent, and is in a state of hyperplasia which may terminate in a great development of the fibrous elements, with induration. So also with the bone-marrow: in the short and flat bones, where in the adult a reddish or slightly fatty tissue exists, the fat disappears entirely, and the long bones, normally filled with yellow marrow, become occupied with a red-gray or greenish-gray cytogenous tissue not unlike spleen-pulp, and in many instances more consistent than the red marrow of early life.
A reduction in the number of red corpuscles is the chief and most constant change in the blood; anæmia seems to be the invariable result, whether the spleen, marrow, or lymph-glands are affected singly or together, and is the central feature in the entire group of cases. This diminution in the red cells may or may not be accompanied by an increase in the white corpuscles, which in some cases may be so striking as to be regarded as the special blood-change, and is, as a rule, permanent, though it may be a variable or even a transitory state.
The general and histological differences between forms of hypertrophy of these blood-making organs are exceedingly slight, and in their clinical features they present a large number of symptoms in common; indeed, we may say that all the important symptoms are present, whether the spleen is affected alone or with the lymph-glands and bone-marrow, or whether these parts are independently involved, and whether there is simple reduction in the red or with it an increase in the white corpuscles. Such common features are—the progressive anæmia with its group of circulatory symptoms; the irregular febrile reaction, essential fever of anæmia; the absence of marked emaciation; the tendency to effusions of serum; the progressive debility; the occurrence of hemorrhages; gastric and intestinal disturbances; and resistance to treatment.
The affections characterized pathologically and clinically by so many similar features are known and recognized as distinct diseases under the names leukæmia, Hodgkin's disease or pseudo-leukæmia, splenic anæmia, and idiopathic anæmia (some cases); and we shall now consider these a little more closely.
First, of the hyperplasias of the cytogenic tissues associated with simple anæmia. The various groups, spleen, lymph-glands, and marrow, may be involved singly or together; usually one is first affected, and the others, if at all, subsequently. Progressive enlargement of the spleen induces sooner or later anæmia, the anæmia splenica of Griesinger. These cases are by no means rare: certain of them represent the final stage of a malarial intoxication, but there are others in which the enlargement seems causeless. There may also be hyperplasia of the bone-marrow, less often of the lymph-glands. The anæmia may be profound, and the clinical picture is that mentioned above. Two cases of it under my care died of hæmatemesis. The diagnosis of this affection from splenic leukæmia rests solely on the microscopical examination of the blood. It is also classed as the splenic form of Hodgkin's disease or pseudo-leukæmia.
Primary enlargement of the lymph-glands with anæmia constitutes Hodgkin's disease or pseudo-leukæmia, in which there may be general hyperplasia of the lymphatic elements throughout the body, with nodular growths of adenoid tissue in other organs. The spleen and marrow are not often affected. Here, too, the diagnosis from lymphatic leukæmia rests with the microscope.