Key Clinical Updates in Hematuria
Evaluation of the microscopic hematuria is guided by the risk stratification for a urothelial malignancy.
The American Urological Association released guidelines for microscopic hematuria workup; patients are categorized as low-, intermediate-, or high-risk for a urothelial malignancy.
ESSENTIALS OF DIAGNOSIS
Gross hematuria requires evaluation: the upper urinary tract should be imaged, and the lower tract evaluated by cystoscopy.
In microscopic hematuria, the workup should be risk stratified.
An upper tract source (kidneys and ureters) can be identified in 10% of patients with gross or microscopic hematuria. For upper tract sources, stone disease accounts for 40%, medical kidney disease (medullary sponge kidney, glomerulonephritis, papillary necrosis) for 20%, renal cell carcinoma for 10%, and urothelial cell carcinoma of the ureter or renal pelvis for 5%. Medication ingestion and associated medical problems may provide diagnostic clues. Analgesic use (papillary necrosis), cyclophosphamide (chemical cystitis), antibiotics (interstitial nephritis), diabetes mellitus, sickle cell trait or disease (papillary necrosis), a history of stone disease, or malignancy should all be investigated. The lower tract source of gross hematuria (in the absence of infection) is most commonly from bleeding prostatic varices or urothelial carcinoma of the bladder. Microscopic hematuria in the male is most commonly from benign prostatic hyperplasia (13%), kidney stones (6%), or urethral stricture (1.4%). The presence of hematuria in patients receiving antiplatelet or anticoagulation therapy cannot be presumed to be due to the medication; a complete evaluation is warranted consisting of upper tract imaging, cystoscopy, and urine cytology (see Chapter 39 for Bladder Cancer, Cancers of the Ureter & Renal Pelvis, Renal Cell Carcinoma, and Other Primary Tumors of the Kidney).
If gross hematuria occurs, a description of the timing (initial, terminal, total) may provide a clue to the localization of disease. Associated symptoms (ie, renal colic, irritative voiding symptoms, or constitutional symptoms) should be investigated. The history should be focused on risk factors for urothelial cancer (age, male sex, smoking history, history of gross hematuria, irritative lower urinary tract voiding symptoms, history of cyclophosphamide or ifosfamide chemotherapy, family history of urothelial carcinoma or Lynch syndrome, occupational exposure to benzene chemicals or aromatic amines, history of chronic indwelling foreign body in the urinary tract) and on nonmalignant causes. The physical examination should look for signs of systemic disease (fever, rash, lymphadenopathy, abdominal or pelvic masses) as well as signs of medical kidney disease (hypertension, volume overload). The urologic evaluation may demonstrate an enlarged prostate, flank mass, or urethral disease. The evaluation of patients with hematuria and their risk stratification should not be influenced by whether they are taking any antiplatelet or anticoagulant agents.
Initial laboratory investigations include a urinalysis and urine culture. Microhematuria is defined as three or more red blood cells per high-power field ...