What is the appropriate management for a 38-year-old man with microscopic hematuria and a history of nephrolithiasis (kidney stones)?

From the Guidelines

For a 38-year-old man with microscopic hematuria and a history of nephrolithiasis, the most appropriate management should include a comprehensive evaluation to determine the cause of hematuria while considering his stone history, as recommended by the American College of Radiology Appropriateness Criteria 1. Initial management should involve a complete urinalysis with microscopy, urine culture, and measurement of urinary calcium, oxalate, citrate, and uric acid levels to identify metabolic abnormalities. Imaging studies are essential, starting with a non-contrast CT scan of the abdomen and pelvis, which is the gold standard for detecting kidney stones, as supported by the American College of Radiology Appropriateness Criteria 1. Some key points to consider in the management of this patient include:

• If stones are identified, treatment depends on their size, location, and symptoms.
• Small stones (<5mm) can often be managed conservatively with increased fluid intake (2-3 liters daily) and pain management with NSAIDs like ibuprofen 400-600mg every 6-8 hours as needed.
• For recurrent calcium oxalate stones, dietary modifications including reduced sodium intake, normal calcium consumption, and limited oxalate-rich foods are recommended, as suggested by the American College of Physicians 1.
• Thiazide diuretics such as hydrochlorothiazide 25mg daily may be prescribed to reduce urinary calcium excretion.
• For uric acid stones, alkalinization of urine with potassium citrate 10-15mEq twice daily and allopurinol 300mg daily may be beneficial.
• If microscopic hematuria persists after stone management, further urologic evaluation including cystoscopy and upper tract imaging should be considered to rule out other urological conditions like bladder cancer or upper tract urothelial carcinoma, particularly given the patient's age and risk factors, as advised by the American College of Physicians 1.

From the Research

Management of Microscopic Hematuria with a History of Nephrolithiasis

The management of a 38-year-old man with microscopic hematuria and a history of nephrolithiasis involves a thorough evaluation to determine the cause of the hematuria and to assess the risk of malignancy.

• The patient's history of nephrolithiasis is a significant factor, as kidney stones can cause microscopic hematuria 2.
• Microscopic hematuria is often discovered incidentally and has many causes, including benign processes, kidney disease, and genitourinary malignancy 3.
• The evaluation of microscopic hematuria should include laboratory tests to rule out intrinsic renal disease, imaging of the urinary tract, and referral to nephrology and urology subspecialists if no benign cause is found 2.

Imaging Studies

• Non-contrast helical computerized tomography (CT) is essential to confirm the diagnosis of nephrolithiasis and to rule out other extrarenal causes of symptoms 4.
• CT urography (CTU) with unenhanced CT may not be necessary in adults younger than 50 years with asymptomatic microscopic hematuria, as the risk of upper urinary tract malignancy is low 5.
• Unenhanced CT has a high sensitivity and specificity for detecting upper urinary tract findings, including renal calculi, and can reduce radiation and minimize contrast agent-associated risk 5.

Urinalysis

• Hematuria testing has a high sensitivity but low specificity for detecting renal colic, and the presence or absence of blood on urinalysis cannot be used to reliably determine which patients have ureteral stones 6.
• The utility of hematuria testing in patients with suspected renal colic is limited, and imaging studies such as unenhanced helical CT are more accurate for diagnosing nephrolithiasis 6.