The American Urological Association (AUA) recently published guidelines for asymptomatic microhematuria. The document includes 19 guidelines with recommendation levels ranging from A to C (high to low) and some expert opinion recommendations included. The full guidelines can be accessed at www.auanet.org/content/media/asymptomatic_microhematuria_guideline.pdf.
Q: A 45-year-old man came into my office complaining that he had seen “pink” in his urine. I dipped the urine in the office, and it was positive for blood. What should I do now? Should I send him directly to nephrology or urology? Or should I do a work-up myself? And if I do the work-up, what tests should I order?
When treating the patient with hematuria, it is important to keep in mind both the most common benign causes and the more serious causes of hematuria. The most common benign causes, according to the AUA guideline 6,1 include infection, menstruation, vigorous exercise, trauma, anticoagulant use, and a recent urologic procedure. The potentially serious causes include glomerulonephritis (which can be rapidly progressive) and malignancy.
The AUA (guidelines 1 to 4, based on expert opinion)1 recommends confirming hematuria with a microscopic exam rather than relying on a urine dipstick.
The common benign causes of hematuria can usually be identified in the course of a thorough history and physical. Because hematuria can be a harbinger of renal disease, however, serum creatinine and blood urea nitrogen (BUN) should be ordered at the initial evaluation in the primary care setting.
If a benign cause of hematuria is identified and renal function is normal, the patient should be treated by the primary care provider and re-evaluated as indicated, based on the underlying diagnosis. If there is a rise in serum creatinine or a reduction in estimated glomerular filtration rate (eGFR) in conjunction with the hematuria, the patient should be referred to nephrology for further evaluation.
If no benign cause of hematuria is identified and renal function is unaffected, the patient should be referred to urology for urologic evaluation.1
Alexis Chettiar, ACNP, East Bay Nephrology Medical Group, Oakland, CA
Q: I have a 58-year-old female patient who is taking warfarin for atrial fibrillation and is complaining about blood in her urine. She is postmenopausal, so I think it is just the warfarin. Other than checking her international normalized ratio (INR), what else should I be doing?
In addition to checking an INR, it is important to investigate benign causes for the hematuria [as listed earlier]. Asymptomatic hematuria requires obtaining a thorough history, which includes common risk factors for urinary tract malignancy, physical exam, and laboratory evaluation. Initially, a noncontaminated urinalysis with culture and sensitivity should be obtained to rule out infection.
If a benign cause cannot be found in any patient undergoing anticoagulation therapy, the AUA (guideline 6)1 recommends a urologic and nephrologic evaluation. Anticoagulation therapy would include all anticoagulant and antiplatelet agents, such as aspirin, Plavix (clopidogrel), Pletal (cilostazol), Coumadin (warfarin), heparin, or heparin derivatives, such as Lovenox (enoxaparin).
The urologic evaluation may include urology referral, cystoscopy for patients 35 or older, and multiphasic CT urography, performed with and without contrast. A nephrologic evaluation would initially include a urinalysis, calculated eGFR, creatinine, and BUN, and a nephrology referral when indicated. A thorough evaluation is indicated for all patients with hematuria who are on anticoagulant therapy to ensure that a urinary tract malignancy is not present.
AUA guidelines 10 through 131 address alternative tests for patients with kidney disease in whom contrast dye is contraindicated.
Kristy Washinger, MSN, CRNP, Nephrology Associates of Central Pennsylvania, Camp Hill, PA
Q: A 39-year-old woman came to my office for an annual physical, and there was blood in the urine when I sent her urine out for microscopy. She is having abnormal menses, so she could not be sure this was not contamination (and neither could I). I repeated the urine and it was positive for blood on micro. What do I do now? Where do I refer her?
There are numerous causes of microhematuria, and the answer can often be found by considering the possible differential diagnoses. The causes of hematuria include urinary tract infection (UTI), bladder or kidney stones, kidney disease, use of certain medications, strenuous exercise, and trauma.2 Health care professionals should follow a process to make logical assessments and decisions in the care of this 39-year-old woman with microhematuria.
What to do first? The first step is to obtain a complete history, including any associated symptoms, medication history, last menstrual period, family history, previous medical history, recent trauma, strenuous exercise, and easy bruising or bleeding. In this case, since the urinalysis was repeated and remained positive for hematuria, the next step is to consider a renal function panel and complete blood count (CBC).
A renal function panel (sodium, potassium, chloride, carbon dioxide, anion gap, glucose, urea reduction ratio, creatinine, albumin, calcium, and phosphorous) will help to rule out existing renal function dysfunction.
The CBC will help to rule out any blood loss or presence of systemic involvement. Also, look at other results noted on the urinalysis, such as protein, nitrates, and leukocytes. Looking for protein will help the clinician determine whether fever, diabetes, chronic kidney disease, or hypertension may be the cause. Nitrates will appear as a result of UTI, and leukocytes may suggest a UTI or possible contamination. Dysmorphic red blood cells (RBCs with irregular shapes) found on the microscopic exam of the urine indicate a glomerular etiology, in which case the patient should be referred to nephrology for possible renal biopsy. If the red blood cells are nonglomerular (ie, the glomerulus is not the source of the bleeding) and there is no other obvious cause, then the patient should be referred to urology.
When is it time to refer? If microhematuria is persistent, the patient will need to be referred to a urologist for further evaluation. According to AUA guidelines 7, 8, and 16 through 19,1 cystoscopy should be considered for patients 35 or older with asymptomatic hematuria. For younger patients, a cystoscopy may be considered at the discretion of the provider. Although blue light cystoscopy has FDA approval, in the opinion of the AUA, the risks of the technique outweigh its benefits. Blue light cystoscopy is reported to improve identification of bladder tumors.3
For patients with a history of persistent asymptomatic hematuria, no further urinalyses are needed after two consecutive yearly tests with negative results. Those with a negative urologic workup should have urinalyses performed annually. If a patient has persistent or recurrent asymptomatic microhematuria with an initially negative urologic workup, then patients should be considered for reevaluation by urology every 3 to 5 years.1
In conclusion, the best approach to microhematuria is to obtain a thorough history, check the necessary labs, and if microhematuria persists, make the necessary referral to the appropriate specialist, ensuring that the patient receives the best possible care.
Tia Austin Hayes, FNP-C, JMM Renal Clinic/Outpatient Dialysis, University of Mississippi Department of Nephrology; Donna Anderson, PA-C, CAQ, Nephrology Specialists of Oklahoma, Tulsa
Q: I am studying for my boards and am deep into the renal/urology section. I graduated so long ago that IVPs were the evaluation of choice. What is the “expert opinion” now on managing the patient with hematuria? Do we go straight to cystoscopy or use a different test?
First-line evaluation for asymp¬tomatic microscopic hematuria now requires CT urography instead of IV pyelography (IVP) or cystoscopy (see AUA guideline 10).1 The CT should be done with and without IV contrast and be multiphasic in nature. Specific high-resolution evaluation of the urothelium of the upper urinary tracts during the excretory phase must be included. This is the most sensitive and specific radiologic examination to adequately evaluate for a renal mass in the parenchyma as well as for abnormalities in the upper tracts simultaneously.1
Using contrast dye in a patient with decreased renal function is always problematic. Precautions to be taken include withholding ACE inhibitors and angiotensin receptor blockers before and after the procedure and hydrating the patient before, during, and after administration of contrast dye.
Sarah Sparks, NP, St. Luke’s Clinic–Nephrology, St. Luke’s Health System, Boise, ID
1. Davis R, Jones JS, Barocas DA, et al; American Urological Association. Diagnosis, Evaluation, and Follow-up of Asymptomatic Microhematuria (AMH) in Adults: AUA Guideline. Linthicum, MD: American Urological Association Education and Research, Inc; 2012. www.auanet.org/content/media/asymptomatic_microhematuria_guideline.pdf. Accessed January 24, 2013.
2. National Kidney and Urologic Diseases Information Clearinghouse. Hematuria: blood in the urine (2012). http://kidney.niddk.nih.gov/kudiseases/pubs/hematuria. Accessed January 17, 2013.
3. Geavlete B, Jecu M, Multescu R, et al. HAL blue-light cystoscopy in high-risk nonmuscle-invasive bladder cancer: re-TURBT recurrence rates in a prospective, randomized study. Urology. 2010;76(3):664-669.
Feldman AS, Hsu C-Y, Kurtz M, Cho KC. Etiology and evaluation of hematuria in adults (2012). www.uptodate.com/contents/etiology-and-evaluation-of-hematuria-in-adults. Accessed January 17, 2013.
Jayne D. Hematuria and proteinuria. In: Greenberg A, ed; National Kidney Foundation. Primer on Kidney Diseases. 5th ed. Saunders; 2009:33-42.