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Urolithiasis and Renal Colic

Diagnosis/Definition

• Urolithiasis, nephrolithiasis, and ureterolithiasis refer to the presence of mineralized stones, or calculi, in the bladder, kidney, or ureter, respectively.
• Patients may present with classic symptoms of renal colic and hematuria.
• Renal colic is paroxysmal pain that ranges from mild to severe and is related to the movement of the stone through the ureter and associated ureteral spasm.
• Gross or microscopic hematuria occurs in the majority of patients with renal colic, but the absence of hematuria in symptomatic patients does not exclude nephrolithiasis.

Initial Diagnosis and Management

History: Assess for symptoms of renal colic:

• Acute onset of severe, unilateral flank or lower quadrant abdominal pain with radiation to the groin or genitalia is typical. The patient is often unable to find a position of comfort when the pain is at its peak.
• Nausea, vomiting, and diarrhea are common.
• Urinary frequency and urgency may occur when stones are near the ureterovesicular junction.
• May present as acute pyelonephritis if fever is present.
• Assess for risks of renal calculi including previous renal stones, family history, prolonged immobilization, osteolytic cancer, hyperthyroidism, gout or hyperuricemia, hypercalcemia.

Physical exam findings:

• Costovertebral angle tenderness is usually present.

Lab Tests:

• Urinalysis and urine culture. Gross hematuria may be present, although microscopic hematuria is more likely. Up to 15% of patients with stones may have no gross hematuria and a normal urinalysis.
• Serum electrolytes: BUN and creatinine, calcium, uric acid, and magnesium.
• Pregnancy test for all women of child-bearing age.
• Analysis of the stone: If stone has passed, please send the stone to the laboratory for stone analysis.
• Imaging
• Prior to specialty urology referral, all patients with suspicion of urolithiasis must have a definitive, radiological diagnosis.
• The “CT KUB” or Non-contrast spiral CT scan is the preferred study at MAMC although intravenous pyelogram (IVP) may also be obtained.
• If CT scan is obtained, please order a plain film KUB in addition to evaluate for visibility of the stone.
  NOTE: If the patient has microhematuria or gross hematuria and the imaging studies are negative for stone, please refer to the MAMC hematuria guidelines.

Differential Diagnosis:

The primary clinician should assess for, and rule out etiology of pain that may mimic renal colic. These include:

• Acute gastroenteritis
• Acute pyelonephritis
• Appendicitis
• Colitis
• Dissecting or ruptured aortic aneurysm
• Diverticulitis
• Ectopic pregnancy
• Pelvic inflammatory disease (PID)
• Renal infarction
• Urinary tract infection

Ongoing Management and Objectives

• The vast majority of kidney stones do not require surgery. If the stone is <6 mm in size, it will likely pass spontaneously.
• All patients with active urolithiasis as defined and diagnosed above should be initially managed with increased oral fluid hydration (greater than 2 liters a day), oral narcotic pain management and NSAIDs. They should also be given a urinary strainer to catch the stone if passed.

Indications for Specialty Care Referral

Routine referral: All patients with active urolithiasis as defined and diagnosed above should be given a routine consult to Urology.

Emergent referral: Refer to Urology emergently for ANY ONE of the following:

Fever

Intractable pain unrelieved by narcotic medication

Intractable nausea and vomiting that precludes oral hydration despite outpatient antiemetic treatment.

Presence or evidence of obstruction (fever, elevated creatinine, fluid around kidney on CT scan)

Patients with solitary kidney

Stone that does not pass within 2 to 3 weeks despite optimal medical management.

Criteria for Return to Primary Care

Patients will be returned to primary care after resolution of acute stone episode.

Urology will continue to coordinate follow up in patients with residual stones and those at high risk for recurrence.