Benign Proteinuria Flashcards
What are the normal protein excretion levels in a 24-hour urine collection?
Less than 150 mg/day.
What is the most common cause of isolated proteinuria in children and young adults?
Transient proteinuria, which is often due to fever, exercise, prolonged standing, stress, or dehydration.
What are the common causes of transient proteinuria?
Heavy exertion, stress, fever, seizures, exposure to cold temperatures.
What is orthostatic proteinuria?
Increased protein excretion in the upright position with normal excretion in the recumbent (lying down) position.
Which patient demographic most commonly experiences orthostatic proteinuria?
Orthostatic proteinuria is the most common cause of proteinuria in adolescents (60%-75% prevalence) and rarely occurs after age 30. In addition, patients tend to have a larger than average BMI.
How is orthostatic proteinuria diagnosed?
Confirmed by a split (day vs. night) 24-hour urine collection.
- Diagnosis can be confirmed by comparing the urine protein-to-creatine ratio in urine samples collected in both the supine and standing positions. Another confirmatory test is to compare protein excretion in a split 24-hour urine collection divided between the daytime (after morning void until bedtime) and nighttime periods. Orthostatic proteinuria is confirmed in patients with a significant elevation in daytime protein excretion but a normal nighttime rate. Clinical features suggesting an alternate diagnosis include history of nephrotoxic agents, acute glomerulonephritis (eg, hypertension, hematuria, acute kidney injury), or nephrotic syndrome (eg, proteinuria >3-3.5 g/24 hr, hypoalbuminemia, edema).
What is the recommended next step in evaluating adolescent proteinuria when urinalysis shows 2+ protein with no hematuria or hypertension?
Perform a split (day and night) 24-hour urine collection for protein.
What condition should be ruled out in a patient with persistent proteinuria and abnormal urine sediment?
Glomerulonephritis or nephrotic syndrome.
What is the clinical significance of orthostatic proteinuria?
Benign condition, commonly found in adolescents, with no associated kidney disease.
What is the prognosis of orthostatic proteinuria?
Resolves spontaneously without treatment; excellent prognosis. The resolution tends to occur with advancing of age.
What are the main differences between orthostatic and pathologic proteinuria?
Orthostatic proteinuria is benign and resolves with age, while pathologic proteinuria is persistent and associated with abnormal urine sediment or kidney dysfunction.
