Urine output may vary in quantity, appearance, or composition from the norm.
Specific conditions can lead to unusually high urine output in adults, exceeding approximately 3 liters per day. On the other hand, extremely low urine production, less than about 0.4 liters per day, could be a sign of severe dehydration or acute kidney failure. In extreme cases where the kidneys are severely damaged, they may cease urine production altogether. Blockages in the urinary tract, such as a stone, can also halt the flow of urine.
Urine that appears cloudy could be a result of a urinary tract infection, a stone, or the presence of salts. The occurrence of blood in the urine, known as hematuria, might be caused by bleeding within the urinary tract. The color of urine can also change due to consumption of particular foods or medications. Excessive protein in the urine can make it look frothy.
Certain medical conditions lead to the excretion of unusual substances through urine. For instance, in diabetes mellitus, urine contains glucose. In conditions like glomerulonephritis (inflammation of the kidney’s filtering units) or nephrotic syndrome, protein leaks into the urine. There are also disorders that result in abnormal levels of typical waste products or chemical imbalances. Kidney failure decreases the overall excretion of waste products like urea. In addition, various kidney disorders like Fanconi’s syndrome and renal tubular acidosis might cause urine to become excessively acidic or alkaline, or lead to the presence of excess amino acids, phosphates, salts, or water.