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Emergency And Acute Medicine – Hematuria/Proteinuria
Basics And Description
Microscopic hematuria is defined as the presence of three or more red blood cells per high-power field in at least two of three properly collected urine specimens. Gross hematuria refers to visible blood in a properly collected urine sample. Proteinuria is defined as urinary protein excretion greater than 150 mg per day.
Risk factors for significant disease in asymptomatic proteinuria include diabetes mellitus, hypertension, NSAID abuse, and heroin use. Risk factors for significant disease in asymptomatic hematuria include tobacco use, occupational exposure to benzenes or aromatic amines, prior gross hematuria, age over 40 years, history of urologic disease, painful voiding, recurrent UTIs, analgesic abuse, and prior pelvic irradiation.
Etiology
Proteinuria may be glomerular, tubular, or overflow in origin. Glomerular causes include nephritic processes such as postinfectious glomerulonephritis, IgA nephropathy, lupus nephritis, and vasculitis, as well as nephrotic conditions such as minimal change disease, diabetes, and preeclampsia. Tubular proteinuria results from impaired reabsorption, while overflow proteinuria occurs with excess filtered proteins as seen in hemolysis, rhabdomyolysis, or multiple myeloma.
Hematuria may arise from urinary tract infection, nephrolithiasis, benign prostatic hypertrophy, malignancy of the bladder, kidney, or prostate, transient idiopathic causes, or acute glomerulonephritis.
Clinical Presentation And Symptoms
Patients may report dysuria, visible blood in urine, fever, flank pain, or flank ecchymosis. Initial hematuria suggests an anterior urethral source, terminal hematuria suggests pathology of the posterior urethra or bladder neck, and cyclic hematuria may indicate endometriosis. A history of recent upper respiratory or skin infection raises concern for postinfectious glomerulonephritis. Associated findings may include peripheral edema, congestive heart failure, hemoptysis as seen in Goodpasture disease, hypertension, headache, right upper quadrant pain, or signs of pregnancy-related disease.
History should focus on onset, duration, associated symptoms, prior renal or urologic disease, medication use including nephrotoxic agents or anticoagulants, and systemic illnesses.
Physical examination should be comprehensive with special attention to periorbital or peripheral edema, rashes, flank tenderness or ecchymosis, and a detailed genitourinary examination including prostate assessment.
Essential Workup
Initial evaluation includes urine dipstick testing followed by urinalysis with microscopic examination. Urine culture should be considered. Blood urea nitrogen, serum creatinine, complete blood count, platelet count, and pregnancy testing when appropriate are essential. Liver function tests and coagulation studies may be indicated based on clinical context.
Diagnostic Tests And Interpretation
Urine studies may include culture, cytology, 24-hour urine protein and creatinine measurement, spot urine protein-to-creatinine ratio, spot protein-to-osmolality ratio, and urine protein electrophoresis. Serum testing may include coagulation studies and serum protein electrophoresis.
Imaging options include renal ultrasound and noncontrast helical CT scan. Diagnostic procedures may involve cystourethroscopy, urethrogram, cystogram, retrograde pyelogram, or intravenous pyelogram when indicated.
Differential Diagnosis
Glomerular causes include IgA nephropathy, postinfectious glomerulonephritis, membranoproliferative glomerulonephritis, focal segmental glomerulosclerosis, lupus nephritis, vasculitis, Henoch–Schönlein purpura, thrombotic thrombocytopenic purpura, hemolytic uremic syndrome, Alport syndrome, and Goodpasture disease.
Nonglomerular causes include infections, inflammatory conditions, urothelial malignancy, renal and extrarenal tumors, interstitial nephritis, papillary necrosis, polycystic kidney disease, renal vascular thrombosis or embolism, sickle cell disease, malignant hypertension, metabolic disorders, urolithiasis, strictures, endometriosis, foreign bodies, benign prostatic hypertrophy, coagulopathies, trauma, recent instrumentation, and factitious causes.
Proteinuria differentials include glomerular diseases, tubular disorders, overflow states such as monoclonal gammopathies or leukemia, and transient causes such as dehydration, fever, stress, heat injury, or orthostatic proteinuria.
Prehospital And Initial Stabilization
Management begins with airway, breathing, and circulation assessment and stabilization. Life-threatening traumatic injuries are treated first. Initial laboratory evaluation should be obtained promptly.
In pregnancy, suspected preeclampsia requires aggressive blood pressure control, magnesium therapy when indicated, and immediate obstetric consultation.
Emergency Department Management
Uncomplicated urinary tract infections and pyelonephritis are treated with appropriate antibiotics. Analgesics and antipyretics are provided as needed. Rapidly progressive glomerulonephritis warrants steroid therapy and nephrology consultation. Acute renal failure may require renal ultrasound, urine electrolyte analysis, nephrology consultation, and initiation of hemodialysis.
Renal colic is managed with IV fluids, analgesia, and noncontrast CT imaging if this is the initial presentation. Gross hematuria with clot retention requires placement of a three-way Foley catheter and continuous bladder irrigation.
Disposition And Follow-Up
Admission is indicated for acute renal failure, hemodynamic instability, traumatic hematuria, obstructing ureteral stones with infection or renal failure, hypertensive emergencies, oliguria or anuria, pregnancy with preeclampsia or complicated infection, intractable pain, or inability to tolerate oral intake.
Patients may be discharged if hemodynamically stable without life-threatening pathology. Gross hematuria generally requires urology follow-up, except in young women with confirmed uncomplicated UTIs. Microscopic hematuria requires repeat urinalysis and primary care follow-up, with urology or nephrology referral as needed. Mild proteinuria may be evaluated outpatient, while nephrotic-range proteinuria or proteinuria with renal failure warrants urgent nephrology referral.
Clinical Pearls And Common Errors
Failure to recognize acute glomerulonephritis in children is a common pitfall. Spot urine protein-to-creatinine ratio correlates well with 24-hour urine protein excretion. Periorbital edema may indicate nephritic syndrome rather than allergy. Inadequate follow-up for asymptomatic hematuria, particularly in patients older than 40 years, is a frequent and significant error.
Basics And Description
Microscopic hematuria is defined as the presence of three or more red blood cells per high-power field in at least two of three properly collected urine specimens. Gross hematuria refers to visible blood in a properly collected urine sample. Proteinuria is defined as urinary protein excretion greater than 150 mg per day.
Risk factors for significant disease in asymptomatic proteinuria include diabetes mellitus, hypertension, NSAID abuse, and heroin use. Risk factors for significant disease in asymptomatic hematuria include tobacco use, occupational exposure to benzenes or aromatic amines, prior gross hematuria, age over 40 years, history of urologic disease, painful voiding, recurrent UTIs, analgesic abuse, and prior pelvic irradiation.
Etiology
Proteinuria may be glomerular, tubular, or overflow in origin. Glomerular causes include nephritic processes such as postinfectious glomerulonephritis, IgA nephropathy, lupus nephritis, and vasculitis, as well as nephrotic conditions such as minimal change disease, diabetes, and preeclampsia. Tubular proteinuria results from impaired reabsorption, while overflow proteinuria occurs with excess filtered proteins as seen in hemolysis, rhabdomyolysis, or multiple myeloma.
Hematuria may arise from urinary tract infection, nephrolithiasis, benign prostatic hypertrophy, malignancy of the bladder, kidney, or prostate, transient idiopathic causes, or acute glomerulonephritis.
Clinical Presentation And Symptoms
Patients may report dysuria, visible blood in urine, fever, flank pain, or flank ecchymosis. Initial hematuria suggests an anterior urethral source, terminal hematuria suggests pathology of the posterior urethra or bladder neck, and cyclic hematuria may indicate endometriosis. A history of recent upper respiratory or skin infection raises concern for postinfectious glomerulonephritis. Associated findings may include peripheral edema, congestive heart failure, hemoptysis as seen in Goodpasture disease, hypertension, headache, right upper quadrant pain, or signs of pregnancy-related disease.
History should focus on onset, duration, associated symptoms, prior renal or urologic disease, medication use including nephrotoxic agents or anticoagulants, and systemic illnesses.
Physical examination should be comprehensive with special attention to periorbital or peripheral edema, rashes, flank tenderness or ecchymosis, and a detailed genitourinary examination including prostate assessment.
Essential Workup
Initial evaluation includes urine dipstick testing followed by urinalysis with microscopic examination. Urine culture should be considered. Blood urea nitrogen, serum creatinine, complete blood count, platelet count, and pregnancy testing when appropriate are essential. Liver function tests and coagulation studies may be indicated based on clinical context.
Diagnostic Tests And Interpretation
Urine studies may include culture, cytology, 24-hour urine protein and creatinine measurement, spot urine protein-to-creatinine ratio, spot protein-to-osmolality ratio, and urine protein electrophoresis. Serum testing may include coagulation studies and serum protein electrophoresis.
Imaging options include renal ultrasound and noncontrast helical CT scan. Diagnostic procedures may involve cystourethroscopy, urethrogram, cystogram, retrograde pyelogram, or intravenous pyelogram when indicated.
Differential Diagnosis
Glomerular causes include IgA nephropathy, postinfectious glomerulonephritis, membranoproliferative glomerulonephritis, focal segmental glomerulosclerosis, lupus nephritis, vasculitis, Henoch–Schönlein purpura, thrombotic thrombocytopenic purpura, hemolytic uremic syndrome, Alport syndrome, and Goodpasture disease.
Nonglomerular causes include infections, inflammatory conditions, urothelial malignancy, renal and extrarenal tumors, interstitial nephritis, papillary necrosis, polycystic kidney disease, renal vascular thrombosis or embolism, sickle cell disease, malignant hypertension, metabolic disorders, urolithiasis, strictures, endometriosis, foreign bodies, benign prostatic hypertrophy, coagulopathies, trauma, recent instrumentation, and factitious causes.
Proteinuria differentials include glomerular diseases, tubular disorders, overflow states such as monoclonal gammopathies or leukemia, and transient causes such as dehydration, fever, stress, heat injury, or orthostatic proteinuria.
Prehospital And Initial Stabilization
Management begins with airway, breathing, and circulation assessment and stabilization. Life-threatening traumatic injuries are treated first. Initial laboratory evaluation should be obtained promptly.
In pregnancy, suspected preeclampsia requires aggressive blood pressure control, magnesium therapy when indicated, and immediate obstetric consultation.
Emergency Department Management
Uncomplicated urinary tract infections and pyelonephritis are treated with appropriate antibiotics. Analgesics and antipyretics are provided as needed. Rapidly progressive glomerulonephritis warrants steroid therapy and nephrology consultation. Acute renal failure may require renal ultrasound, urine electrolyte analysis, nephrology consultation, and initiation of hemodialysis.
Renal colic is managed with IV fluids, analgesia, and noncontrast CT imaging if this is the initial presentation. Gross hematuria with clot retention requires placement of a three-way Foley catheter and continuous bladder irrigation.
Disposition And Follow-Up
Admission is indicated for acute renal failure, hemodynamic instability, traumatic hematuria, obstructing ureteral stones with infection or renal failure, hypertensive emergencies, oliguria or anuria, pregnancy with preeclampsia or complicated infection, intractable pain, or inability to tolerate oral intake.
Patients may be discharged if hemodynamically stable without life-threatening pathology. Gross hematuria generally requires urology follow-up, except in young women with confirmed uncomplicated UTIs. Microscopic hematuria requires repeat urinalysis and primary care follow-up, with urology or nephrology referral as needed. Mild proteinuria may be evaluated outpatient, while nephrotic-range proteinuria or proteinuria with renal failure warrants urgent nephrology referral.
Clinical Pearls And Common Errors
Failure to recognize acute glomerulonephritis in children is a common pitfall. Spot urine protein-to-creatinine ratio correlates well with 24-hour urine protein excretion. Periorbital edema may indicate nephritic syndrome rather than allergy. Inadequate follow-up for asymptomatic hematuria, particularly in patients older than 40 years, is a frequent and significant error.
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