The urine passed is turbid, particularly towards the end of the act of urination; then it is of a pink or red colour, and all intermediate shades between a pale pink and a bright arterial red colour may be observed.
The patients sometimes seem to pass unaltered blood in the urine, but on microscopic examination this blood is found to be extremely diluted. Provided the bladder is not gravely infected by the (secondary) penetration of germs into its cavity the blood corpuscles remain normal, or are scarcely changed. As soon as the bladder, however, becomes secondarily infected an almost immediate change takes place; the red blood corpuscles become crenated, broken up and dissociated; the hæmoglobin is also partly dissolved and modified, and at this stage the urine is red-brown or coffee-coloured, according to the length of time it has been retained in the bladder.
In other cases, chiefly when hæmaturia has existed for some time, the extravasated blood coagulates in the bladder, and the urine passed contains filamentous clots the size of a man’s thumb, a pigeon’s egg, or more. If the clots formed are too large to be passed, which is often the case in the ox, they may obstruct the urethra, causing retention of urine and all the accidents which accompany this condition, even including rupture of the bladder. This, in the ox, is a frequent termination. In the cow the dilatability and shortness of the urethra render retention of urine much rarer. It is certainly possible, however, and it is not exceptional, to find from 4 to 6 lbs. of clotted matter in the distended bladder. All these conditions can be detected by rectal exploration, and by attention to the symptoms of obstruction of the urethra.
Whenever there is retention of clots dysuria is extremely marked and, so to speak, permanent, the animals having continual tenesmus.
Hæmaturia observes a slow, progressive course, which, in time, ends in death by exhaustion, though this is not invariably the case. Hæmaturia is frequently intermittent, and, after having been very marked for weeks or months, may suddenly or gradually cease, and only reappear a long time afterwards. This fact is explained by a study of the development of the lesions. When ulceration occurs the sub-epithelial vessels of the mucous membrane, which have contributed to the formation of the hæmorrhagic spot, are widely open, and a capillary hæmorrhage results; but as soon as a small clot forms in this position, or local capillary thrombosis occurs, the hæmorrhage ceases, with the result that the hæmaturia disappears. Unfortunately, however, the obliterating clots are not permanent, any more than the local thrombosis—or, in the event of their proving permanent, another small lesion develops at a different point, and this lesion may at any time cause the reappearance of the hæmaturia; the process goes on until the animal succumbs. Should the lesions heal successively, spontaneous recovery may take place, but such recovery is exceptional.
The animals may not appear to suffer from the passage of blood for weeks or even months, but after a time they become less capable of replacing the loss. They become anæmic, the number of corpuscles falls from the normal figure of from six to seven millions of red corpuscles per cubic millimètre to three millions, two millions, one million, and even to five hundred or eight hundred thousand.
The richness in hæmoglobin simultaneously diminishes; wasting progresses to the point of cachexia, and the appetite diminishes while diarrhœa appears; swellings are noticeable about certain parts of the body; and the animals, continuing to pass blood, die in a state of absolute exhaustion, without apparent suffering.
This termination is the most common, unless slaughter is determined on, and is very different from the premature end which follows the formation of clots and obstruction of the urethra.
Externally the patients only show feebleness, pallor of the visible mucous membranes, and difficulty in urination. The bunch of hair at the lower commissure of the vulva is always soiled with blood-stained urine or little clots.
Hæmaturia may cause death by exhaustion in from six weeks to two months, but not infrequently it lasts for months or even years.