What are the appropriate treatment and investigations for a patient with a recent urinary tract infection (UTI) now presenting with right flank pain and hematuria, with urinalysis showing blood in the urine but no evidence of ongoing infection?

From the Guidelines

For right flank pain and blood in urine following a recent UTI, you should seek medical evaluation promptly as this may indicate kidney stones (urolithiasis), which can develop after UTIs due to mineral crystallization, or damage to the urinary tract from the previous infection that is still healing. Given the recent UTI and current symptoms, it is essential to rule out any potential complications, such as ureteral obstruction with resultant hydronephrosis, which can be a serious consequence of stones 1. The presence of blood in the urine without current infection markers, as shown in the urinalysis, suggests that the infection may have resolved, but the underlying cause of the hematuria needs to be investigated further.

The patient's symptoms, including right flank pain and hematuria, are consistent with urolithiasis, as stones can cause irritation and trauma to the ureter, leading to blood in the urine 1. Imaging studies, such as a CT scan or ultrasound of the kidneys, are necessary to diagnose stones and assess for any potential complications or alternative diagnoses 1. The American College of Radiology recommends imaging for patients with acute onset flank pain and suspicion of stone disease, as it plays a crucial role in diagnosis, assessment of complications, and determination of appropriate therapies 1.

While waiting for a medical evaluation, it is recommended to drink plenty of water (2-3 liters daily) to help flush out any potential stones and reduce the risk of further complications. Acetaminophen (Tylenol) 500-1000mg every 6 hours can be taken as needed for pain management, but NSAIDs like ibuprofen should be avoided due to potential kidney damage. Monitoring temperature and seeking immediate medical attention if fever over 101°F, severe pain, vomiting, or inability to keep fluids down occurs is also crucial.

The treatment of urolithiasis may be conservative with supportive and medical therapy, although invasive therapies, such as percutaneous nephrolithotomy, rigid and flexible ureteroscopy, or shock wave lithotripsy, may be required in some instances, depending on the size and location of the stones 1. A thorough medical evaluation will help determine the best course of treatment and ensure prompt management of any potential complications.

From the Research

Possible Causes of Right Flank Pain and Hematuria

• Right flank pain and hematuria can be caused by various conditions, including obstructing ureteral stones, hemorrhagic cystitis, and Page kidney 2, 3
• Hematuria can also be a sign of kidney stone disease, which can be evaluated using computed tomography (CT) scans 4

Diagnostic Tests for Hematuria

• CT urography is a recommended initial imaging test for hematuria in patients at high-risk for upper urinary tract urothelial cell carcinoma (UUT-UCC) 5
• Unenhanced helical computed tomography (CT) is the most effective imaging technique for evaluating kidney stones and hematuria 4, 6
• Urinalysis may not be sufficient to diagnose ureterolithiasis, as some patients with ureterolithiasis may have minimal or no hematuria, and some patients without ureterolithiasis may have hematuria 6

Considerations for Diagnostic Testing

• The absence of hematuria in the setting of acute flank pain cannot exclude a diagnosis of ureterolithiasis, and other diagnostic testing should not be obviated 6
• Even when strongly positive on microscopy, hematuria has insufficient positive predictive value for diagnosing ureterolithiasis and may be misleading as other serious conditions resulting in acute flank pain may yield a positive test 6
• A non-contrast CT or ultrasound study should be performed in patients over 40 with microscopic hematuria, and cystoscopy should be added if gross hematuria is observed 4