It is a more extreme reduction than oliguria (hypouresis), with 100 mL/day being the conventional (albeit slightly arbitrary) cutoff point between the two.
It is often associated with other symptoms of kidney failure, such as lack of appetite, weakness, nausea and vomiting.
Failure of kidney function, which can have multiple causes including medications or toxins (e.g., antifreeze, cephalosporins, ACEIs); diabetes; high blood pressure.
High blood calcium, oxalate, or uric acid, can contribute to the risk of stone formation.
In males, an enlarged prostate gland is a common cause of obstructive anuria.