Urgent considerations
See Differentials for more details
While proteinuria is rarely a medical emergency, the presence of certain clinical features may indicate a more serious disease process warranting immediate evaluation. New-onset proteinuria with features of systemic disease (e.g., progressive renal dysfunction, other organ system abnormalities) should be evaluated as soon as possible.
Renal vein thrombosis
Patients with nephrotic-range proteinuria and marked hypoalbuminemia (generally <2.0 g/dL) who present with acute renal failure or concern for pulmonary embolism may have renal vein thrombosis. The diagnosis is further suggested by new-onset hematuria, acute flank pain, and increasing proteinuria. Diagnosis can be confirmed by renal ultrasonography, magnetic resonance venography, and traditional venography. Anticoagulation is the mainstay of therapy, with catheter-directed thrombolysis being used in select circumstances.[44] These patients are also at risk of lower-extremity deep venous thrombosis.
Rapidly progressive glomerulonephritis
Consider rapidly progressive glomerulonephritis in patients with proteinuria, hematuria, and acute renal failure. Diagnostic efforts to evaluate for etiologies of acute renal failure (e.g., postinfectious glomerulonephritis, systemic lupus erythematosus, membranoproliferative glomerulonephritis, IgA nephropathy, thrombotic microangiopathy, antiglomerular basement membrane disease, antineutrophil cytoplasmic antibody [ANCA]-associated vasculitis) should be made immediately. This may include appropriate serologic testing and renal biopsy. Failure to diagnose a rapidly progressive glomerulonephritis may lead to irrecoverable loss of kidney function, morbidity, and even death.
Preeclampsia
New-onset proteinuria may be a sign of preeclampsia in pregnant women. Finding 1+ of protein on a urine dipstick should prompt an inquiry about symptoms of preeclampsia (visual disturbance, headache, epigastric pain, and edema), measurement of blood pressure, and quantification of proteinuria.[30] These women should be referred urgently to an obstetrician to assess fetal wellbeing and to consider urgent delivery. Untreated preeclampsia may progress to eclampsia, a life-threatening condition characterized by grand mal seizures in a woman with preeclampsia.[45]
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