Certain persons have isohaemolysins in their blood which dissolve the red cells of other persons and in paroxysmal haemoglobinuria autohaemolysins may be present which can destroy the patient’s own red cells. This auto-haemolysis seems operative only when a low temperature is followed by a high one. When haemoglobinaemia exists the liver converts it into bile pigment causing bilious stools and jaundice. If one-sixth of the red cells are destroyed haemoglobinuria results.
The dark, porter-colored urine of blackwater is diagnostic even to the patient. The urinary sediment consists of granular débris with occasional haematoidin crystals. Albuminuria runs parallel with the haemoglobinuria. Pain in the loins, probably, from the plugging of the renal tubules by the detritus of red cell destruction, is a feature of blackwater fever. In blackwater fever we have the early appearance, even in a few hours, in a patient who is markedly asthenic and miserable, of jaundice, porter-colored urine and albuminuria.
Haematuria
Among tropical diseases that which immediately suggests haematuria is vesical bilharziasis. The blood in the urine is in the form of red cells; it is a haematuria and not a haemoglobinuria. The passage of blood usually occurs at the end of micturition and it is either in the last few drops of urine or in the sediment obtained after centrifuging that we note the terminal spined eggs of S. haematobium which prove the diagnosis.
Red blood cells in the urine may also be noted in the haematochyluria of filarial disease.
When we have blood in the urine in yellow fever it is a haematuria and comes on about the same time as the black vomit and other haemorrhages resulting from degeneration of the endothelial linings of the blood capillaries, which only takes place about the third or fourth day of the disease.
Haematuria may also be noted in plague at the time when the haemorrhages into the skin occur.
Chyluria
Vesical varices from lymphatic obstruction, due to filarial disease, are the most frequent cause of the milky urine of chyluria. The urine usually has a pinkish tinge from blood admixture so that the condition is really a haematochyluria. The thoracic duct may not be the seat of obstruction which has taken place elsewhere when the condition is lymphuria instead of chyluria. Lymph and chyle differ in fat content, the former having from very little to about 3% while the latter has 5% or more of emulsified fat. Chyle has also more than twice as much proteid as does lymph.