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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?

• jasonbylund@uky.edu

• 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.