96 TROPICAL MEDICINE AND HYGIENE 



associated with renal disease or uraemia ; vomiting is 

 persistent. In rare cases, although the urine clears and is 

 even abundant, the patient does not improve. In these 

 the urine is of low specific gravity, 1,001 or 1,002, and 

 with the exception of the water the kidneys are practi- 

 cally not excreting. These cases are fatal, and there will 

 be found extensive blocking of the tubules. The con- 

 dition more closely resembles that due to blockage of 

 the ureters. 



This is the commonest cause of death, and if it can 

 be avoided the mortality from blackwater fever is low. 



Diagnosis. The diagnosis is made on the character of 

 the urine. This is dark red, practically black. If diluted 

 the red colour appears and the urine is clear and trans- 

 parent. On shaking the urine the froth that forms on the 

 surface is red. If allowed to stand a thick deposit soon 

 forms, but this is not present in abundance when the 

 urine has been recently passed. The deposit in the quite 

 fresh urine is scanty. Casts are easily found, and later in 

 the course of the disease are even more abundant ; some 

 may still be found weeks after the urine is free from 

 albumin. These casts are usually granular and contain 

 bright yellow granules, not uric acid, similar to those 

 found in the organs; blood cells are rarely found; bladder 

 epithelium may be moderately abundant after the first 

 day. When the urine is kept much deposit is formed ; 

 this is composed usually of casts, coagulum and altered 

 haemoglobin. 



The urine in paroxysmal haemoglobinuria is similar, 

 and that disease would certainly be diagnosed as black- 

 water fever if a case occurred in a blackwater district. 



If methaemoglobin only be passed the difficulty in 

 diagnosis is much greater, as the brown urine is not very 

 unlike some high coloured normal urine, and may be 

 mistaken for bile-stained urine ; fortunately the cases where 

 this occurs early are mild. In all cases if the urine be 

 boiled the albumin coagulated will be a dark brown 

 colour. 



