UOTW #99

A 35 yo male presents with sudden onset of left flank pain that was first noted sometime after waking up in the morning.  Pt reports the pain radiates to his left groin and he has associated nausea and vomiting. Review of symptoms is otherwise unremarkable.

On exam, his vital signs are as follows: HR 121, RR 28, T 36.7ºC, BP 142/94, SpO2 99% R/A. On physical exam, you note costovertebral angle tenderness.  The remainder of the physical exam is unremarkable

An ultra-portable ultrasound transducer is utilized to obtain the following image of the patients left kidney:

What do the clips show? What is the diagnosis? (Click the button for the answer!)


Hydronephrosis with large calculus seen in the UPJ



Labs resulted and the patient had a mildly elevated white blood cell count and a normal serum creatinine. Urology was consulted and they admitted the patient for intervention.

  • The incidence of ureterolithiasis peaks between 20-50 years old and is less common as a new diagnosis passed the age of 501.
  • Intraureteral stones themselves are very difficult to directly visualize, and instead an indirect sign of obstruction can be identified in the form of hydronephrosis2. However, occasionally the obstructing stone can be seen at the UPJ, such as what was seen in this patient.
  • Hydronephrosis is diagnosed when hypoechoic (black) fluid is seen starting at the renal pelvis, and extending out into the medulla.
  • The sensitivity and specificity of US for hydronephrosis when compared to CT scan has been reported in a systematic review to be 72-97% and 73-83%, respectively 2.
  • Giving a 500 mL bolus of crystalloid prior to the scan may increase sensitivity for hydronephrosis3.
  • While the ACR appropriateness criteria state that a CT scan in a patient with suspected first time ureterolithiasis is appropriate4, if a patient with a known history of ureterolithiasis presents with suspected renal colic, an US can be used to appropriately discharge the patient without the ionizing radiation of a CT scan5-6.

Different grades of hydronephrosis

Authors: Jacob Avila, MD
Peer Reviewer: Ben Smith, MD, FACEP


  1. Dalziel PJ, Noble VE. Bedside ultrasound and the assessment of renal colic: a review. Emerg Med J. 2013;30:3-8
  2. Noble VE, Brown DF. Renal Ultrasound. Emerg Med Clin N Am 2004;22:641-659
  3. Henderson S, Hoffner R, Aragona J, Groth D, Esekogwu V, Chan D. Bedside emergency department ultrasonography plus radiography of the kidneys, ureters and bladder vs intravenous pyelography in the evaluation of suspected ureteral colic. Acad Emerg Med 1998;5:666-71
  4. ACR appropriateness Criteria for acute onset flank pain. https://acsearch.acr.org/docs/69362/Narrative/ Accessed July 21,2014.
  5. Edmonds ML, Yan JW, Sedran RJ, McLeod SL, Theakston KD. The utility of renal ultrasonography in the diagnosis of renal colic in emergency department patients. CJEM. 2010;12:201-6
  6. Yan JW, McLeod SL, Edmonds ML, Sedran RJ, Theakston KD. Normal renal sonogram identifies renal colic patients at low risk for urologic intervention: a prospective cohort study. CJEM 2014;16:1-8

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