An 18-year-old man comes to the office because a college physical urinalysis indicated that he had proteinuria. The patient does not recall having a previous urinalysis. He denies flank pain, hematuria, dysuria, nocturia, edema, urinary frequency, hypertension, or family history of kidney disease. His review of systems provides no significant information. He is in excellent health, with the exception of one or two upper respiratory infections per year. He takes no medications. He has no known drug allergies. He does not use tobacco or illicit drugs and rarely drinks alcohol. He has no history of a sexually transmitted disease and he is not sexually active.
His blood pressure is 120/76 mm Hg, pulse is 64/min, and respirations are 12/min. On examination, he appears healthy. Cardiovascular, pulmonary, and abdominal examinations show no abnormalities. He has no edema.
The patient's laboratory studies reveal:

Which of the following is the most appropriate course of action?

Question

An 18-year-old man comes to the office because a college physical urinalysis indicated that he had proteinuria.  The patient does not recall having a previous urinalysis.  He denies flank pain, hematuria, dysuria, nocturia, edema, urinary frequency, hypertension, or family history of kidney disease.  His review of systems provides no significant information.  He is in excellent health, with the exception of one or two upper respiratory infections per year.  He takes no medications.  He has no known drug allergies.  He does not use tobacco or illicit drugs and rarely drinks alcohol.  He has no history of a sexually transmitted disease and he is not sexually active.
His blood pressure is 120/76 mm Hg, pulse is 64/min, and respirations are 12/min.  On examination, he appears healthy.  Cardiovascular, pulmonary, and abdominal examinations show no abnormalities.  He has no edema.
The patient's laboratory studies reveal:

Which of the following is the most appropriate course of action?

Quizplus · Accepted Answer

This patient presents with isolated proteinuria, defined as proteinuria without hematuria or elevated serum creatinine. His unremarkable history, normal estimated glomerular filtration rate, normal blood pressure, and normal urinalysis collectively suggest the absence of significant kidney disease. Orthostatic proteinuria is a condition seen in children, adolescents, and young adults under the age of 30. It is characterized by significant proteinuria in the upright position, but minimal to no proteinuria in the supine position. Long-term follow-up of individuals with this condition has shown resolution of the proteinuria with advancing age in most patients, without development of renal failure. A spot urine sample for protein and creatinine provides a reasonable assessment of quantitative proteinuria, and should be collected during the first morning void and then later in the day in the upright position. Demonstration of little to no proteinuria in the supine position compared to significant proteinuria in the upright position supports the diagnosis. (Choice A) While HIV nephropathy can present as proteinuria, this patient appears to be at low risk for HIV and does not have evidence of kidney disease. (Choice B) In the absence of evidence of active renal disease, a renal biopsy is not indicated. (Choice C) Because this patient has normal renal function and no genitourinary tract symptoms, there is no clear indication for kidney imaging. (Choice E) Electrophoresis of urinary proteins can provide information on the molecular size of proteins in the urine. However, this is not indicated in this patient without evidence of active kidney disease or a systemic disorder. Educational objective: Orthostatic proteinuria is a benign condition commonly seen in children and young adults (2-5%). It is generally less than 1 g/day, but may surpass 3 g/day in select patients. The diagnosis can be established by finding a difference in quantitative proteinuria estimated by spot urine protein-to-creatinine ratio obtained upon arising (little, if any, proteinuria) and at the end of the day before recumbency (significant proteinuria). __________ References: Proteinuria in adults: a diagnostic approach (http://www.ncbi.nlm.nih.gov/pubmed/11011862)

An 18-Year-Old Man Comes to the Office Because a College