While a rupture of the blood-vessels of the kidney may be supposed to be at the bottom of a certain proportion of cases of hæmaturia, it is by no means a necessary condition of their occurrence, as it is well known that in inflammations there may be extravasations of blood without rupture of the blood-vessels. There is implied, however, in all these conditions an alteration of the vessel-walls which permits such transudation. Indeed, Ponfick1 goes so far as to say that even transudations of hæmoglobin through the blood-vessels of the kidney are impossible without the presence of serious diffuse nephritis. There is every reason to believe, however, that simple alterations of the blood are of themselves sufficient to cause such transudations. Take, for instance, the extravasations in purpura, which are not confined to the vessels of the kidney. It is impossible to conceive inflammatory conditions so general as would have to be presupposed in this disease.
1 "Ueber die Gemeingefährlichkeit der essbaren Morchel," Virchow's Archiv, Bd. lxxxviii. S. 47.
Hæmaturia from Local Causes.
It is unnecessary to consider in detail the local causes of hæmaturia. It is evident how injuries and blows upon the kidney, and impacted calculus may produce hemorrhage. The history of nephritic colic or of gravel in urine, along with blood, would suggest the latter cause. Nor is it necessary to detail the phenomena of hemorrhagic infarction which succeeds embolism and is the direct cause of hemorrhage into the tubules of the kidney. Hæmaturia is by no means a constant symptom in sarcoma and cancer of the kidney. A small amount of blood in the urine is a constant symptom in acute nephritis, where it is due to a rupture of the blood-vessels of the Malpighian tuft. It is accompanied by blood-casts and other symptoms of acute Bright's disease. Carbolic acid, cantharides, oil of mustard, and similar substances produce hæmaturia by causing congestion and inflammation of the kidney.
The parasites which may cause hemorrhage in the substance of the kidney are the Bilharzia hæmatobia, the Filaria sanguinis hominis, the Strongylus gigas, and possibly common intestinal worms which may reach the kidney through fistulous openings. The first is a thread-like worm three or four lines in length, which was discovered by Bilharz, and infests the small vessels of the mucous and submucous tissue of the veins of the intestinal tract, the pelvis of the kidney, ureter, bladder, and more rarely of the kidney itself. It is very frequent in Egypt, where Griesinger found it 117 times in 363 autopsies; also in South Africa (Cape of Good Hope), where it gives rise to an endemic hæmaturia. It has been studied by Bilharz, John Harley, and William Roberts.
The Filaria sanguinis hominis is a long, narrow microscopic worm, not wider than a red blood-disc, and one seventy-fifth of an inch long, which infests the blood. Hemorrhages result from its accumulation in the vessels, causing rupture. The cases which have been studied occurred mostly in India, China, and Australia.
The Strongylus gigas is a large worm, resembling the ordinary lumbricoid, but larger, the male being from ten to twelve inches long and one-fourth of an inch wide, while the female is sometimes more than a yard in length. It infests the kidneys and urinary passages of certain lower animals (the dog, wolf, horse, ox, etc.), but rarely those of man.
Malarial Hæmaturia and Hæmoglobinuria.
SYNONYMS.—Intermittent hæmaturia; Paroxysmal hæmaturia; Malarial yellow fever; Swamp yellow fever; Paroxysmal congestive hepatic hæmaturia (Harley).