2013MINI-LECTURE

Renal Stone Disease

Objectives

Identify common risk factors for renal stone disease

Identify common signs and symptoms for renal stone disease

Know the common types of renal stonesFamiliarize with basics of renal stone

management, including knowing when to consult urology

Case

49 year old woman with history of hypertension, diabetes presents with four day history of right sided flank pain and “pink urine.” What is the most appropriate imaging to diagnose this patient with renal stone disease?

A: KUBB: UltrasoundC: Contrast-enhanced CTD: Non-Contrast CT

Etiology

Supersaturation of urine with solutesSolubility is affected by urine pH, volume and

total excretionThose factors can often be modified with

medications and diet

Risk Factors

Male sexObesityFamily HistoryH/o stone disease (1/2 will have recurrence)Dietary factors

Lower fluid intake, higher animal protein, higher Vitamin C

Medical factors

Signs/Symptoms

Typical symptoms Sudden onset Unilateral colicky flank pain radiating to groin

(localization of pain evolves as stone migrates) Often with nausea/vomiting Hematuria (microscopic or gross)

Differential

Differential for flank pain with hematuria UTI Renal Cell Carcinoma Ectopic pregnancy Dissecting AAA with renal artery involvement

Types of Stones

In order of prevalence Calcium Oxalate Calcium Phosphate Struvite Urice Acid Cystine

Workup

Urinalysis: may show Hematuria (90% sensitive) Signs of infection Crystals Elevated pH (urea-splitting bugs?) or low pH (RTA?)

Metabolic workup: Consider only if recurrent

Workup

Imaging Non-Contrast helical CT with Stone protocol is the

gold std (can detect stones not visible by KUB/IVP and has significantly better sensitivity/specificity)

Ultrasound: For patients needing avoidance of radiation (pregnant, childbearing age)

IVP: No longer favored due to lower sensitivity, HIGHER radiation exposure

KUB: Will miss radiolucent uric acid stones, small stones, stones with overlying bony structures.

Treatment

Urologic Intervention? X<5mm : most pass spontaneously. Possible

observation and pain control X>5mm : less than 20% chance of passage and may

need urologic interventionSo when to consult urology?

If > 5mm For ANY size with ….

Urosepsis, AKI, anuria, unyielding N/V/Pain -> Inpatient consult

Failed conservative management and stone did not pass spontaneously -> Inpatient or Outpatient consult depending on severity

Summary

Identified common risk factors for renal stone disease

Identified common signs and symptoms for renal stone disease

Know the common types of renal stonesFamiliarized with basics of renal stone

management, including knowing when to consult urology