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Limited Ultrasound for Acute Renal Colic

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Limited Ultrasound for Acute Renal Colic, Nephrolithiasis Imaging with Ultrasound, Urolithiasis Imaging with Ultrasound, Ureteral Calculi Imaging with Sonography, Kidney Stone Imaging with Sonography

  • See Also
  1. Nephrolithiasis Imaging
  2. Nephrolithiasis
  • Indications
  1. Urolithiasis (considered primary evaluation in Europe)
    1. Consider in combination with Abdominal XRay
    2. Consider repeating Bedside Ultrasound after intravenous hydration
  2. Pregnant patient and Children
  3. Cholecystitis suspected
  4. Gynecologic process suspected
  • Efficacy
  1. Compares favorably to IVP and CT Abdomen
    1. Test Sensitivity: 64-93%
    2. Test Specificity: 97-100%
    3. Patlas (2001) Brit J Radiol 74:901-4 [PubMed]
    4. Sinclair (1989) Ann Emerg Med 18(5): 556-9 [PubMed]
  2. Ultrasound is a safe evaluation tool for Ureterolithiasis without significant missed serious conditions
    1. Smith-Bindman (2014) N Engl J Med 371(12):1100-10 +PMID:25229916 [PubMed]
  • Findings
  1. Hydronephrosis
  2. Renal Stones
  3. Absent unilateral ureteral jet flow into Bladder
  • Imaging
  1. Transducer
    1. Curved Linear Array Probe (2-5 MHz)
    2. Position probe in lateral Abdomen, upper quadrant on each side
  2. Precautions
    1. Left Kidney is more difficult to image due to higher lying Kidney and overlying gas in LUQ
      1. Consider positioning probe in a more lateral, mid-axillary position
      2. Have patient take a deep breath to bring Kidney down into window
    2. Dehydration decreases Test Sensitivity
      1. Hydronephrosis and ureteral jets are more difficult to detect in Dehydration
      2. Consider repeat Ultrasound after intravenous hydration
    3. Renal pyramids may appear similar to Hydronephrosis (especially in a hydrated patient)
      1. However, renal pyramids are limited to the cortex
  3. View: Each Kidney
    1. Longitudinal Plane (long axis with indicator at 12:00)
    2. Transverse Plane (short axis with indicator at 9:00)
    3. Hydronephrosis findings
      1. Calyces will be gradually more distorted as Hydronephrosis progresses from mild to severe
        1. Imagine a slowly appearing hand print.
        2. Mild Hydronephrosis
          1. Finger tips (black, anechoic calyces) are visible
        3. Moderate to severe Hydronephrosis
          1. Chubby fingers appear as well as the palm (central black, anechoic renal Pelvis)
      2. Mild Hydronephrosis
        1. Proximal ureter is dilated but renal architecture is preserved
        2. Divides the major calyces
      3. Moderate Hydronephrosis
        1. Calyces enlarge (central anechoic renal Pelvis with stubby projections towards renal cortex)
        2. Divides the minor calyces
      4. Severe Hydronephrosis
        1. Calyces enlarge and coalesce into one large anechoic region with loss of papillae
        2. Cortex is compressed
    4. Renal Calculi
      1. Stones are best identified on Ultrasound at the ureterovesical junction (UVJ)
      2. Hyperechoic stone-like lesions with posterior "clean" shadowing (similar to Gallstones)
        1. Shadow size correlates with stone size
      3. Stones will glitter from reverberation artifact when color doppler is applied
  4. View: Bladder
    1. Longitudinal Plane (long axis with indicator at 12:00)
    2. Transverse Plane (short axis with indicator at 9:00)
      1. Obtain view of trigone with doppler to demonstrate bilateral ureteral jets
      2. Presence of bilateral ureteral jets in a well hydrated patient excludes ureteral obstruction
  • References
  1. Mateer and Jorgensen (2012) Introduction and Advanced Emergency Medicine Ultrasound Conference, GulfCoast Ultrasound, St. Pete's Beach
  2. Noble (2011) Emergency and Critical CareUltrasound, Cambridge University Press, New York, p. 227-39
  3. Reardon (2011) Pocket Atlas Emergency Ultrasound, McGraw Hill, New York, p. 163-88