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Evaluation and treatment of kidney stones for the primary care provider
Jason Bylund, MDUniversity of Kentucky
Division of Urology
Objectives
• Review basic principles of evaluation of the patient with suspected kidney stone event
• Describe urgent or emergent clinical scenarios associated with stones
• Discuss medical and surgical treatment options for patients with stones
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Disclosures
• None
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Background
• Urinary tract stones, urolithiasis, will affect approximately 5-10% of American adults in their lifetime1
• Renal colic accounts for over a million ER visits annually2
• Rates higher in “Stone Belt”
Presentation• Acute stone episode vs incidental
finding
• Common presenting symptoms:• Flank pain radiating to groin (renal colic)
• Nausea/vomiting
• Hematuria
• Voiding symptoms (frequency, urgency, dysuria)
• Writhing or pacing
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Obstructing ureteral stone Diagnosis• History
• History of stones, risk factors, co-morbidities, medications
• Physical exam• Abdomen, CVA (no peritoneal signs)
• GU and rectal exam to rule out other causes
• Labs• CBC, BMP, UA
Imaging
• CT (low dose) stone protocol – gold standard
• KUB – radiopacity, monitoring
• Renal U/S – select cases
• IVP – useful for functional evaluation and anatomical mapping
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Red flags• Fever
• Evidence of UTI
• Solitary kidney
• Acute kidney injury
• Uncontrolled pain, nausea, vomiting
• Perinephric stranding
• Hydronephrosis
Treatment?• Pain control
• NSAIDs, narcotics, abx
• Emergent renal drainage?• Stent vs percutaneous nephrostomy tube
• Medical expulsive therapy• Alpha-blockers, IVFs?
• Elective surgical treatment• Shockwave lithotripsy• Ureteroscopy, laser lithotripsy• Percutaneous surgery• Laparoscopic/open surgery
Percutaneous nephrostomy tube
PCNT
PCNT Cystoscopy with stent placement
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Medical expulsive therapy• If no indication for acute intervention, trial of
passage is an option
• Likelihood of passage is inversely related to stone size and proximity to kidney2
• Likelihood of stone passage by size3:
• <5mm: roughly 2/3
• 5-10mm: less than half
• Alpha-blockers efficacy recently called into question
Surgical options
• Shockwave lithotripsy
• Ureteroscopy
• Percutaneous nephrolithotomy
• Open or laparoscopic surgery
Shockwave lithotripsy
• Clearance rates 74%, 73%, 82% for distal, mid, and proximal stones overall3
• Non-invasive
• Stone fragments pass on their own (hopefully)
Ureteroscopy
• Clearance rates of 94%, 86%, and 81% for distal, mid, and proximal stones overall3
• Lasers and other lithotripters can be used with a variety of baskets and graspers to fragment and extract the stones
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PCNL
• Most invasive
• Most effective for large stone burden
• Typically requires hospital stay
• Complications include:• Bleeding
• Bowel injury
• Lung injury
PCNL
Stone analysis
• Calcium oxalate – most common
• Calcium phosphate – distal RTA
• Struvite – associated with infection
• Uric acid – associated with gout and other conditions
• Cystine – metabolic disorder
Metabolic evaluation
• Stone analysis
• Blood work• BMP, Calcium, PTH, uric acid
• 24h urine• Volume, electrolytes, stone inhibitors
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Preventive measures
• Based on the results of the metabolic evauation, a variety of possible preventive measures can be implemented
Lifestyle modifications
• Increased fluid intake (does not impact inhibitory substances)
• Decreased sodium intake
• “Normal” calcium intake
• Decreased red meat intake
Medications
• Potassium citrate• Hypocitraturia
• Alkalinization
• Chlorthalidone or hydrochlorothiazide• Hypercalciuria
Case #1
• Healthy 34 year old with no history of stones presents with flank pain, nausea, and microscopic hematuria.
• Evaluation?
• Refer?
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Case #2
• 52 year old with long history of stones presents with her typical renal colic
• Evaluation?
• Refer?
• (If fever?)
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Case #3
• 46 year old with long history of stones, no current symptoms, worried about future episodes
• Evaluation?
• Refer?
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Questions?
• UKMDs: 1 (800) 888-5533
References• 1 Kraft KH and Pattaras JG. “Medical management of Urolithiasis,”
AUA Update Series, Vol 26 #36, 2007
• 2 Pearle, MS. “Management of the Acute Stone Event”, AUA Update Series, Vol 27 #30, 2008.
• 3 Preminger, et al. “2007 Guideline for the Management of Ureteral Calculi,” EAU/AUA Nephrolithiasis Guideline Panel, 2007.
