Foam in urine - Causes and Symptoms

Definition

The presence of foam in the urine may indicate the presence of various pathologies, especially of the kidney and biliary tract.

The formation of the foam is due to the entrapment of air in the urine after the emission of the same; bubble persistence is influenced by the presence of surface-active substances (such as proteins and bile salts) within them.

Foam in the urine is a symptom often associated with proteinuria, ie the abundant presence of protein in the urine (note: under normal conditions, the urine contains proteins in small quantities). This phenomenon is an expression of damage to the kidneys: instead of being retained by the renal glomerulus, the proteins are not filtered, so they are poured into the urine.

The pathologies that most frequently accompany proteinuria are primitive or secondary glomerulonephritis (caused by various conditions: from kidney or urinary tract infections to nephrotic syndrome) and metabolic dysfunctions with negative impact on the kidney (such as diabetic nephropathy).

Also the accumulation of bile salts ( colaluria ) is typically associated with dark-colored urine, with yellowish foam; this symptom can be found, in particular, in the pathological conditions that cause obstruction of the biliary tract (eg calculosis of the gallbladder).

Foamy urine can also occur in case of chronic liver diseases, infectious diseases, vesico-colic fistula, physical trauma, severe hypertension and taking certain drugs. Other pathologies causing foam in the urine are multiple myeloma, amyloidosis and congestive heart failure.

Within certain limits, the occasional presence of foam in the urine can be attributed to a very rapid emission of the urine or to a slight dehydration which increases its concentration. In men, it may be the result of small amounts of sperm left in the urethra after sexual intercourse. It should also be noted that the formation of foam can be emphasized by the residues of a detergent on the toilet surfaces.

Finally, the loss of small amounts of protein in the urine is common when following a high-protein diet, during pregnancy and when exercising a particularly heavy and continuous physical activity. In these cases, foam in the urine is a transient manifestation and disappears when the triggering event ceases.