From the Guidelines
Protein in urine, known as proteinuria, is most commonly caused by diabetes and high blood pressure, which gradually damage kidney filters over time, as well as other conditions such as urinary tract infections, glomerulonephritis, and certain medications 1. The causes of proteinuria can be categorized into several groups, including:
- Diabetes and high blood pressure, which are the most common causes of proteinuria, as they can damage the kidney's filtering system over time 1
- Urinary tract infections, which can cause temporary proteinuria due to inflammation 1
- Glomerulonephritis, an inflammation of the kidney's filtering units, which can result in protein leakage 1
- Certain medications, such as NSAIDs, antibiotics, and chemotherapy drugs, which can cause kidney damage leading to proteinuria 1
- Preeclampsia in pregnant women, characterized by high blood pressure and significant protein in urine 1
- Other causes, including heart failure, autoimmune diseases like lupus, multiple myeloma, and genetic kidney disorders such as Alport syndrome 1 It is essential to note that dehydration, extreme exercise, stress, and fever can cause transient proteinuria that resolves once the underlying condition improves 1. If protein is detected in the urine, follow-up testing is crucial to determine the cause and appropriate treatment, as persistent proteinuria may indicate serious kidney disease requiring medical intervention 1.
From the Research
Causes of Protein in Urine
- Diabetic renal disease is a common cause of proteinuria, which can lead to renal failure and is often associated with hypertension 2
- Nephrotic syndrome (NS) is another cause of proteinuria, characterized by peripheral edema, heavy proteinuria, and hypoalbuminemia, often with hyperlipidemia 3
- Secondary causes of NS include diabetes mellitus, systemic lupus erythematosus, and medication adverse effects 3
- Idiopathic or primary NS is the most common type, with membranous nephropathy and focal segmental glomerulosclerosis being the most common histologic subtypes in adults 3
Associated Conditions
- Hypertension is often associated with diabetic renal disease and can precede the diagnosis of diabetes in non-insulin-dependent diabetic (NIDDM) patients 2
- Hyperlipidemia is a common complication of NS 3
- Venous thrombosis and infection are potential complications of NS 3
- Acute kidney injury can occur as a result of the underlying medical problem in NS 3
Diagnostic Considerations
- The diagnosis of NS is based on typical clinical features with confirmation of heavy proteinuria and hypoalbuminemia 3
- Patient history and selected diagnostic studies can rule out important secondary causes of NS 3
- Renal biopsy is often recommended to guide management and prognosis, especially in patients with suspected underlying systemic lupus erythematosus or other renal disorders 3