From the Guidelines
Hematuria and proteinuria are significant clinical findings that require prompt evaluation and management to prevent progressive kidney damage and potential morbidity and mortality. When these symptoms are detected, a comprehensive workup should be initiated, including urinalysis with microscopic examination, urine protein quantification, and assessment of kidney function through blood tests measuring creatinine and estimated glomerular filtration rate (eGFR) 1.
Key Considerations
- Patients with significant proteinuria (>1 gram per day), persistent hematuria with dysmorphic red blood cells or red cell casts, or declining kidney function should be referred to a nephrologist for further evaluation and management.
- Blood pressure control is essential, typically using ACE inhibitors like lisinopril (starting at 10mg daily) or ARBs such as losartan (50mg daily), which help reduce proteinuria and slow kidney disease progression 1.
- Patients should temporarily discontinue medications that may cause or worsen these symptoms, including NSAIDs and certain antibiotics.
Evaluation and Management
- A thorough history, physical examination, urinalysis, and serologic testing should be performed prior to any initial imaging 1.
- Cystoscopy should be considered in addition to any imaging evaluation, especially in patients with gross hematuria or suspected urinary tract infection 1.
- The use of anticoagulant therapy does not alter the urologic evaluation of microhematuria 1.
Prognosis and Treatment
- Reduction of proteinuria to <1 g/day is associated with a more favorable prognosis, irrespective of whether the initial proteinuria was >3 g or of lesser degrees 1.
- BP is also an important risk factor, and if the proteinuria in patients is >1 g/day, a target BP <125/75 mm Hg has been recommended 1.
- The patient's proteinuria and blood pressure should be closely monitored, and adjustments to treatment should be made as needed to achieve optimal control and prevent progressive kidney damage.
From the Research
Definition and Causes
- Hematuria and proteinuria can be benign or signs of underlying pathology, and their evaluation should consider the patient's age, medical history, and other factors 2.
- Proteinuria can be glomerular or tubular in origin and may be transient, orthostatic, or persistent, while hematuria can be gross or microscopic and originate from the glomeruli or other sites of the urinary tract 3.
Diagnosis and Evaluation
- Routine screening for proteinuria is not recommended in the general population, but it is recommended for high-risk patients, such as those with diabetes and hypertension 2.
- Asymptomatic patients should not be screened for hematuria, but patients with persistent hematuria or proteinuria should be referred to a nephrology or urology subspecialist 2, 3.
- The evaluation of proteinuria and hematuria should include the calculation of glomerular filtration rate (GFR) estimates and the assessment of albuminuria or proteinuria as creatinine-normalized urinary ratios 4.
Clinical Presentation and Management
- The clinical presentation of glomerular diseases can include hematuria, nephritic syndrome, and nephrotic syndrome, and the management of these conditions depends on the underlying cause and severity of the disease 5.
- The nephrotic syndrome is defined by heavy proteinuria, hypoalbuminemia, and peripheral edema, while the nephritic syndrome is associated with hematuria, proteinuria, and abnormal kidney function 5.
- Treatment of glomerular diseases includes non-specific measures aimed at controlling hypertension, edema, and proteinuria, as well as disease-modifying immunosuppression 5.
Laboratory Tests and Interpretation
- The quantity of proteinuria increases with decreasing kidney function, and the rate of glomerular proteinuria remains nearly constant in different GFR groups, while tubular proteinuria increases with decreasing GFR 6.
- The urinary ratio of albumin or total protein to creatinine is measurable in untimed spot urine and reflects the urinary excretion rate of albumin or total protein, but can be biased by interassay creatinine differences or unusual levels of creatinine generation or renal tubular creatinine secretion 4.