The appearance of hamorrhagic nephritis (luring an epidemic of mumps, or as a sequel of this disease, is rare (Mettenheimer, IIenoch).
Nephritis with cedema has been repeatedly observed in the course of whooping-cough, and the anatomical changes have been found to consist in a degeneration of the epithelium of the urinary duct.
Typhoid in any stage may lead to nephritis, and it may be said that albuminuria is a frequent complication of the abdominal typhoid of children, appearing even on the second day of the illness.
In infancy nephritis of the luemorrhagic type has been repeatedly observed in connection with malaria, influenza, meningitis, pneumonia, glandular fever, erysipelas, erythema nodosum and general sepsis. The nephritis which follows tonsillitis is also of practical importance, because it may readily be overlooked, owing to its gradual and insiduous onset. The urine contains albumin in moderate quantities, and blood, and the children feel tired and are inclined to cedema. The lingering character of the trouble is often interrupted subsequently by acute exacerbation.
General eczema is also acknowledged to be one of the causes of nephritis of older children. Guaita believes that this is the cause of the sudden deaths which sometimes occur from eczema. As to the nephritis due to therapeutic interference—either external or internal applications of certain medicines (balsam of Peru, styrax, tar, iodine, carbolic acid)—the remarks which were made in regard to other forms of nephritis are true in regard to this form also.
As for the more recent observations upon the damaging effects of salioylate of soda upon the kidneys of adults, it appears of sufficient interest to mention that StetTen long ago pointed out the relation of albuminuria and casts to salicylic medication.
The so-called primary nephritis of unknown origin, a. class which will probably become smaller and smaller, is represented by the most varied symptoms Sometimes its character is hamiorrhagic, some times not. The treatment follows the principles already discussed in speaking of scarlatinal nephritis, just as in the other forms of nephritis which have been described in this chapter.
Wagner's dictum in 1882 is on the whole still valid to date. "Our present knowledge of the various forms of acute Bright's disease, is not sufficiently advanced to enable us to form a positive conclusion as to the exact etiology, either from the condition of the urine, or from the ultimate persistence of symptoms." 2. Chronic Nephritis The obscurity of many points in the study of chronic nephritis in adults is still more embarrassing when we attempt to examine its pathol ogy in infancy. A few positive signs are arrayed against many nega tive ones. The study of its etiology is also beset with difficulties. We are often in the dark as to the time of onset of the disease, because the symptoms develop imperceptibly, or arc, as many writers say, chronic from the beginning. Only occasionally do we obtain a char acteristic picture. In other cases they are not recognizable. At any rate we can never say that the symptoms are as definite as in the more important forms of acute Bright's disease. The pathologic anatomy, owing to the nunierous transitions, is also ill-defined. The study of the extension, and the course of the disease is attended by great difficulties, and it is almost a lucky chalice if we are able to follow the destiny of the small patient beyond the age of fourteen.
From what has gone before, it is no wonder that in the regular course, opinions as to the frequency and course differ so widely. We will only mention that for instance Baginsky emphasizes the frequency of chronic nephritis in infancy, while Biedert says that the affection is very rare. The fact, too, that the characteristic aspect of orthotic albuminuria is still historically uncertain, may contribute to the general confusion.
As a result of this condition of affairs, it will be better to base our statements upon the results of Heubncr's examinations, which extended over many years, than to rely upon a literature which is so rich in eon tradictions. We have adopted the classification of Wagner and Heubner.