The Diagnosis of Kidney Diseases With Special Reference to the Significance of Slight Albuminaria.
Dr. E. Bellinger believes that casts have about the same significance as the renal albumen. There are many drugs that cause their appearance, especially the hyaline variety. Severe muscular exertions and over-indulgence in certain forms of food and alcoholics also produce them where there is nephritis.
Merely their presence in a single specimen of urine which has been allowed to stand and the upper portion decanted off and the lower part carefully centrifugated, cannot be taken in itself as evidence of Bright's disease—even if a few granular casts are found. When irritated, the non-nephritic kidney seems capable of producing them in larger numbers than can the diseased kidney—especially the interstitial nephritis in patients of advanced age (Emerson).
Conclusions.—In doubtful cases no positive opinion should be expressed until many specimens of urine have been examined, for it is the persistence of renal albumen and casts that is of more serious import than is their occasional presence in considerably larger quantities.
The 24-hour specimen should be measured and a comparison made between the amount ordinarily passed and when an excess of water is being taken. The specific gravity is of much importance if the amount of fluids ingested is considered. In addition the condition of the heart, blood vessels, arterial tension, diet, intestinal canal, habits and past history should receive due attention.
Many patients with orthostatic albuminuria of renal origin will go for years without any evidence of nephritis but our prognosis must not be made from the urine alone but from the entire picture. Prudence demands that we be conservative and yet not to be too pessimistic and give patients unnecessary alarm about conditions that may not be dangerous.
Success in discriminating between the insignificant forms of albuminuria and those indicating renal disease, depends more upon eliminating nucleo-albumin and extra renal albumin and albumose than in any further refinement in our chemical examinations.
It is important that we discard dogmatic statements and preconceived ideas that albuminuria necessarily means Bright's disease and at the same time it is of as much consequence that we be not too positive in our assertions that orthostatic or the so-called physiological albuminuria is always harmless.—Med. Fortnightly.