From the Guidelines
Foamy urine is a symptom that can be caused by various underlying conditions, including proteinuria, which is the presence of excess protein in the urine, often associated with kidney damage or disease 1.
Causes of Foamy Urine
- Proteinuria: characterized by the presence of excess protein in the urine, often associated with kidney damage or disease 1
- Nephrotic syndrome: a condition characterized by heavy proteinuria (>3.5 g/1.73m2/24 hours), hypoalbuminemia, and edema 1
- Kidney stones: can cause foamy urine due to the presence of excess minerals in the urine
- Urinary tract infections: can cause foamy urine due to the presence of bacteria or other microorganisms in the urine
- Chronic kidney disease: can cause foamy urine due to the progressive loss of kidney function over time 1
Key Points
- The ratio of protein or albumin to creatinine in an untimed urine specimen is the preferred method for measuring proteinuria 1
- Microalbuminuria refers to albumin excretion that exceeds the normal range but is below the minimum level for detection by tests for total protein 1
- Certain medications, such as diuretics and ACE inhibitors, can also contribute to foamy urine 1
From the Research
Causes of Foamy Urine
Foamy urine, also known as proteinuria, is a condition where excess protein is present in the urine. The causes of foamy urine can be attributed to various factors, including:
- Kidney damage or disease, such as nephrotic syndrome 2
- Diabetes, which can cause damage to the kidneys and lead to proteinuria 3
- Poor renal function, characterized by high levels of creatinine, blood urea nitrogen, and low estimated glomerular filtration rates (eGFR) 3
- Increased serum phosphate and glucose levels, which can contribute to kidney damage and proteinuria 3
- Damage to the glomerular filtration barrier, which can allow proteins to pass through and enter the urine 4, 5
Risk Factors for Proteinuria
Several risk factors have been identified as contributing to the development of proteinuria, including:
- High serum creatinine levels, which can indicate poor renal function 3, 4
- Increased serum phosphate levels, which can contribute to kidney damage and proteinuria 3
- Diabetes, which can cause damage to the kidneys and lead to proteinuria 3
- High blood pressure, which can damage the kidneys and increase the risk of proteinuria 5
- Family history of kidney disease, which can increase the risk of developing proteinuria 2
Mechanisms of Proteinuria
Proteinuria can occur due to various mechanisms, including:
- Damage to the glomerular filtration barrier, which can allow proteins to pass through and enter the urine 4, 5
- Increased permeability of the glomerular filtration barrier, which can allow proteins to pass through and enter the urine 5
- Activation of tubular epithelial cells, which can produce cytokines and chemoattractant peptides that contribute to kidney damage and proteinuria 6