Hematuria and Renal Lesions

Educational Objectives

The goal of this program is to improve prevention and treatment of respiratory infections and diagnosis and treatment of hematuria and renal lesions. After hearing and assimilating this program, the clinician will be better able to:

1. List factors in patients with hematuria that stratify them as low risk.
2. Use Bosniak classification grades to assess risk for malignancy in renal cysts.

Summary

Microscopic hematuria: a dipstick test showing a trace of blood is not diagnostic of microscopic hematuria; microscopic hematuria is ≥3 red blood cells (RBCs) per high power field of the microscope; dipsticks have high false positive rates, so should be followed by microscopic examination

Hematuria guideline recommendations: clinicians should refer all patients with gross hematuria for urologic evaluation, even if hematuria resolves; in a patient who has microscopic hematuria, consider cystoscopy and imaging; patients on antiplatelet or anticoagulation therapy need the same evaluation; in patients with urinary tract infection (UTI) and microscopic hematuria, urinalysis (UA) should be repeated after the UTI is treated to ensure hematuria has resolved

Referral to urology: not all patients with microscopic hematuria need a referral; American Urological Association guidelines risk stratify patients with hematuria; the low-risk group includes women <50 yr of age or men <40 yr of age; they are never smokers or have a limited smoking history (<10 pack-yr); <10 RBCs/HPF should not have any additional risk factors for urothelial carcinoma and it should be their first episode of microhematuria; a patient with all the above factors can be advised to repeat the UA is ≤6 mo and ≤12 mo and avoid a urologic referral; if the patient or doctor is nervous, refer to urology for cystoscopy; computed tomography (CT) would be avoided in these patients; renal ultrasonography would be performed; if the workup is negative, the recommendation is to repeat a UA in ≤12 mo

Renal cysts: often an incidental finding; one-third of people >60 yr of age have renal cysts; the Bosniak classification grades cysts from I (simple cyst) to IV (complex cyst); Bosniak I and II have essentially no risk of malignancy; a radiologist report with Bosniak classification helps in decision-making, but this is often not available; a thin septation, fine calcification, and lack of contrast enhancement are consistent with low-risk cysts; if there is any concern about enhancement, obtain CT with and without contrast, as ultrasonography does not show enhancement; ultrasonography that meets all other criteria for a Bosniak II cyst does not need to be followed by CT, and the workup can otherwise be stopped

Hyperdense cyst: benign; on contrast-enhanced study, it is white and appears as enhancing; an enhancing solid tumor, until proven otherwise, is kidney cancer; obtain nonenhanced CT to differentiate; on CT, a hyperdense cyst enhances even when there is no contrast, because it bled earlier and the proteins in the blood give an enhanced appearance; to define a hyperdense cyst, CT with and without contrast is required; if the cyst is <3 cm and there is no change in Hounsfield units on CT with and without contrast, it confirms a hyperdense cyst; it does not require any additional workup or referral to urology

Assessment algorithm: if renal ultrasonography shows a simple cyst, no further workup; a cyst with 1 or 2 fine septations and <3 cm is Bosniak II and requires no further workup; if the cyst is higher than Bosniak II, refer to urology or obtain multiphase CT; if CT shows Bosniak ≥IIF (F for follow), refer to a urologist

Exceptional cases for imaging: if the patient has a contrast allergy, premedicate; speaker’s clinic uses a combination of prednisone and diphenhydramine (Benadryl); if a patient has anaphylaxis because of a contrast allergy, they should not receive contrast, even with premedication; if someone has elevated creatinine, the CT contrast can cause renal failure; at speaker’s institution CT is avoided if creatinine is >1.5 mg/dL and magnetic resonance imaging (MRI) is advised; gadolinium-based contrast agents (GBCAs) are used in MRI and those currently used do not cause systemic nephrogenic fibrosis; unless someone is on dialysis, an MRI with contrast can be advised; GBCAs should not be used in pregnant patients as it has not been studied in pregnancy; instead feraheme can be used; ensure patient does not have very high serum iron levels before ordering MRI; modern-day pacemakers are all MRI safe; for patients with claustrophobia, give a dose of benzodiazepine 15 min before MRI; there are patients that require general anesthesia for MRI

Renal cancer: in many renal cancer cases, the speaker prefers partial nephrectomies; in the past, interferon and interleukin-2 were the only treatments for metastatic renal cell carcinoma (mRCC); currently, many targeted therapies are available, some of which are immunotherapies; single or double therapy showed good results; Thouvenin et al (2023) showed treating mRCC with 2 agents resulted in tumor shrinkage in all patients; some of the best agents eliminated metastatic cancer in >10% of patients

Readings

Arnold MJ. Microscopic hematuria in adults: Updated recommendations from the American Urological Association. Am Fam Physician. 2021;104(6):655-657; Cha D, Kim CK, Park JJ, et al. Evaluation of hyperdense renal lesions incidentally detected on single-phase post-contrast CT using dual-energy CT. Br J Radiol. 2016;89(1062):20150860. doi:10.1259/bjr.20150860; Muglia VF, Westphalen AC. Bosniak classification for complex renal cysts: history and critical analysis. Radiol Bras. 2014;47(6):368-373. doi:10.1590/0100-3984.2013.1797; Nguyen SM, Wiepz GJ, Schotzko M, et al. Impact of ferumoxytol magnetic resonance imaging on the rhesus macaque maternal-fetal interface†. Biol Reprod. 2020;102(2):434-444. doi:10.1093/biolre/ioz181; Saleem MO, Hamawy K. Hematuria. StatPearls Publishing. 2022 Aug 8. Available from: https://www.ncbi.nlm.nih.gov/books/NBK534213/; Sozio SJ, Bian Y, Marshall SJ, et al. Determining the efficacy of low-dose oral benzodiazepine administration and use of wide-bore magnet in assisting claustrophobic patients to undergo MRI brain examination. Clin Imaging. 2021;79:289-295. doi:10.1016/j.clinimag.2021.06.013; Thouvenin J, Masson C, Boudier P, et al. Complete response in metastatic clear cell renal cell carcinoma patients treated with immune-checkpoint inhibitors: Remission or healing? How to improve patients' outcomes?. Cancers (Basel). 2023;15(3):793. Published 2023 Jan 27. doi:10.3390/cancers15030793.

Disclosures

For this program, members of the faculty and planning committee reported nothing relevant to disclose.

Acknowledgements

Dr. Kim was recorded at What's New in Urology: A Primer for the Primary Care Provider, held on April 22, 2023, in Los Angeles, CA, and presented by the Cedars-Sinai Medical Center. For information about upcoming CME activities from this presenter, please visit https://cedars.cloud-cme.com. Audio Digest thanks the speakers and presenters for their cooperation in the production of this program.

CME/CE INFO

Accreditation:

The Audio- Digest Foundation is accredited by the Accreditation Council for Continuing Medical Education to provide continuing medical education for physicians.

The Audio- Digest Foundation designates this enduring material for a maximum of 0.00 AMA PRA Category 1 Credits™. Physicians should claim only the credit commensurate with the extent of their participation in the activity.

Audio Digest Foundation is accredited as a provider of continuing nursing education by the American Nurses Credentialing Center's (ANCC's) Commission on Accreditation. Audio Digest Foundation designates this activity for 0.00 CE contact hours.

Lecture ID:

NP240904

Expiration:

This CME course qualifies for AMA PRA Category 1 Credits™ for 3 years from the date of publication.

Instructions:

To earn CME/CE credit for this course, you must complete all the following components in the order recommended: (1) Review introductory course content, including Educational Objectives and Faculty/Planner Disclosures; (2) Listen to the audio program and review accompanying learning materials; (3) Complete posttest (only after completing Step 2) and earn a passing score of at least 80%. Taking the course Pretest and completing the Evaluation Survey are strongly recommended (but not mandatory) components of completing this CME/CE course.

Estimated time to complete this CME/CE course:

Approximately 2x the length of the recorded lecture to account for time spent studying accompanying learning materials and completing tests.