Last reviewed by Dr. Leena Joshi, MD, July 2026
Proteinuria is the presence of excess protein in the urine, often signaling kidney damage or disease. When combined with high blood pressure, proteinuria may indicate serious kidney problems requiring specialist care. Dr. Leena Joshi, a board-certified nephrologist serving San Mateo County, evaluates patients with proteinuria through comprehensive testing and develops individualized treatment plans to protect kidney function and address underlying causes.
What is proteinuria?
Proteinuria occurs when the kidneys allow too much protein to pass into the urine. Healthy kidneys filter waste from the blood while keeping important substances like protein in the bloodstream. When the kidney filters become damaged, protein can leak through. The most common protein found in urine is albumin. Small amounts of protein in urine may be temporary and harmless, caused by fever, exercise, or stress. However, persistent proteinuria often indicates kidney disease, diabetes complications, or high blood pressure damage. Dr. Joshi explains that proteinuria itself usually causes no symptoms in early stages, which is why routine urine testing is important. When proteinuria becomes severe, patients may notice foamy urine. Left untreated, the underlying kidney damage can progress to chronic kidney disease or kidney failure.
Signs and symptoms
- Foamy or bubbly urine that does not go away
- Swelling in the hands, feet, face, or abdomen
- Unexplained weight gain from fluid retention
- Fatigue and decreased energy levels
- Loss of appetite or nausea
- Shortness of breath from fluid buildup
- High blood pressure readings
How Dr. Joshi manages proteinuria
Dr. Joshi begins with a thorough evaluation to determine the cause and severity of proteinuria. Initial testing may include a urine dipstick test, 24-hour urine collection, and blood work to assess kidney function. Dr. Joshi also reviews medical history, current medications, and blood pressure patterns. For patients in San Mateo County with both high blood pressure and protein in urine, Dr. Joshi often recommends medications that protect the kidneys while controlling blood pressure, such as ACE inhibitors or ARBs. Treatment plans may include dietary modifications to reduce sodium and protein intake, blood sugar management for diabetic patients, and cholesterol control. Dr. Joshi monitors proteinuria levels over time to assess treatment effectiveness and adjust the care plan as needed. Regular follow-up appointments allow Dr. Joshi to track kidney function and intervene early if proteinuria worsens. The goal is to slow or stop kidney damage progression while managing underlying conditions contributing to proteinuria.
When to see a nephrologist for proteinuria
- Protein detected on multiple urine tests
- Proteinuria combined with high blood pressure or diabetes
- Declining kidney function on blood tests
- Persistent swelling or foamy urine
- Family history of kidney disease
- Proteinuria that does not improve with primary care treatment
Frequently asked questions
What causes protein in urine with high blood pressure?
High blood pressure can damage the small blood vessels in the kidneys, making the filters leaky. This allows protein to escape into the urine. Diabetes, autoimmune diseases, and certain infections can also cause proteinuria. Dr. Joshi determines the specific cause through testing.
Is proteinuria always serious?
Not always. Temporary proteinuria can occur after intense exercise, fever, or dehydration. However, persistent proteinuria detected on multiple tests may indicate kidney disease and requires evaluation by a nephrologist like Dr. Joshi in San Mateo County.
How is proteinuria diagnosed?
Dr. Joshi diagnoses proteinuria through urine testing. A simple dipstick test can detect protein, while a 24-hour urine collection measures the exact amount. Blood tests assess kidney function. Dr. Joshi may recommend additional testing to identify the underlying cause.
Can proteinuria be reversed?
In some cases, yes. When caught early and the underlying cause is treated, proteinuria may decrease or resolve. Dr. Joshi works with patients to control blood pressure, manage diabetes, and use kidney-protective medications that can reduce protein leakage.
What happens if proteinuria is left untreated?
Untreated proteinuria can lead to progressive kidney damage. Over time, kidney function may decline, potentially leading to chronic kidney disease or kidney failure requiring dialysis. Early intervention by a protein in urine nephrologist in San Mateo can help prevent these outcomes.
How often should proteinuria be monitored?
Monitoring frequency depends on severity and underlying conditions. Dr. Joshi may recommend urine and blood tests every few months for patients with persistent proteinuria. Regular monitoring helps track treatment effectiveness and detect any worsening of kidney function.
Dr. Leena Joshi sees patients at two convenient San Mateo County locations: 1750 El Camino Real, Suite 301, Burlingame, and 1800 Sullivan Avenue, Suite 507, Daly City. To schedule a consultation for proteinuria evaluation and treatment, call (650) 355-5551.
This page is for general education and is not a substitute for medical advice. Always consult your physician about your specific situation.
Medically reviewed by Leena Joshi, MD.