Can a Urinary Tract Infection (UTI) cause proteinuria?

From the Guidelines

Yes, urinary tract infections (UTIs) can cause proteinuria, which is the presence of excess protein in the urine, as supported by the 2014 study 1 that lists symptomatic UTI as a factor affecting urinary albumin-to-creatinine ratio. During a UTI, bacteria in the urinary tract trigger inflammation that can damage the filtering mechanisms in the kidneys, allowing proteins that would normally remain in the bloodstream to leak into the urine. This proteinuria is typically mild to moderate and resolves once the infection is treated effectively with antibiotics. Some key points to consider include:

• Common antibiotic treatments for UTIs include nitrofurantoin, trimethoprim-sulfamethoxazole, or ciprofloxacin, depending on bacterial sensitivity patterns and patient factors, as noted in general clinical practice.
• If you have proteinuria with symptoms like burning during urination, frequent urination, cloudy urine, or lower abdominal pain, you should seek medical evaluation.
• It's essential to complete the full course of antibiotics prescribed for a UTI, even if symptoms improve, to ensure complete eradication of the infection and resolution of proteinuria, as emphasized by the importance of proper treatment in preventing complications.
• Persistent proteinuria after successful UTI treatment may indicate kidney damage or another underlying condition requiring further investigation, highlighting the need for follow-up care. The most recent guideline 1 from 2024 focuses on the prevention, diagnosis, and management of urinary tract infections but does not directly address proteinuria caused by UTIs, making the 2014 study 1 the most relevant for this specific question.

From the Research

UTI and Proteinuria

• UTI (Urinary Tract Infection) can cause proteinuria, which is the presence of excess proteins in the urine [(2,3)].
• Proteinuria is a common indicator of kidney damage or disease, and UTI can be a contributing factor to this condition.
• Studies have shown that measuring the protein-creatinine ratio in spot morning urine can be a reliable alternative to 24-hour urinary total protein estimation 2.
• The urine protein-creatinine ratio (UPCR) in a spot first-morning urine sample is used to estimate 24-h urine proteinuria (24hUP) in patients who underwent urine protein testing 3.

Mechanism of Proteinuria in UTI

• UTI can cause inflammation and damage to the kidneys, leading to proteinuria [(2,3)].
• The inflammation and damage can disrupt the normal functioning of the kidneys, allowing proteins to leak into the urine.
• The protein-creatinine ratio in spot morning urine can be used to estimate the severity of proteinuria and monitor the progression of kidney disease 2.

Diagnosis and Monitoring

• Measuring the protein-creatinine ratio in spot morning urine is a simple and inexpensive procedure that can be used to diagnose and monitor proteinuria 2.
• The NJ equation, which uses age, gender, and UPCR, can be used to estimate 24-h total protein excretion rate and improve the accuracy of proteinuria diagnosis 3.
• Regular monitoring of proteinuria can help to detect kidney damage or disease early, allowing for prompt treatment and prevention of further damage [(2,3)].