Tag Archives: Nephrolithiasis

Is the KUB dead?

May 1, 2014


Before CT abdomen became commonplace in the ED, a plain radiograph of the abdomen (KUB for Kidneys, Ureters, and Bladder) was often a screening for kidney stone.  Currently, ultrasound and CT abdomen are used quite often to diagnose ureterolithiasis as they offer much more information.  Is the KUB dead?

The answer is no.  KUB still has a place particularly in monitoring the progress of known kidney stones.  I personally use them for repeat customers to assess progress (or more often prove to urology that they have not progressed).  Helpful hint:  if a patient is presenting for a second ED visit for kidney stone pain, check their scout film if they had a prior CT.  If you can see the stone on scout film, you can definitely re-image the patient with a KUB to reevaluate the location of the stone.  Here is an image of an 8mm stone in the upper right ureter (lateral to L3)  as seen on KUB:

KUB stone

This patient has an 8mm stone and presented to the ED with failed outpatient management.  The stone hadn’t moved from a prior CT scan after 1 week of symptoms.  Urology elected to take the patient to the OR for operative management. 

Please comment if you have another good use of the KUB in the ED. 

Author:  Russell Jones, MD


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Big stone…

September 14, 2013


Middle-aged male came in with left flank pain…

Staghorn Calculi 1 Staghorn Calculi 2

This patient has a large staghorn calculi with stranding around the area of the expected renal calyx.  This is highly suspect for a calyceal rupture.

This is an excerpt taken from the American Urological Association’s 2005 guidelines on the management of staghorn calculi:

Staghorn calculi are branched stones that occupy a large portion of the collecting system. Typically, they fill the renal pelvis and branch into several or all of the calices. The term “partial staghorn” calculus designates a branched stone that occupies part but not all of the collecting system while “complete staghorn” calculus refers to a stone that occupies virtually the entire collecting system. Unfortunately, there is no consensus regarding the precise definition of staghorn calculus, such as the number of involved calices required to qualify for a staghorn designation; consequently, the term “staghorn” often is used to refer to any branched stone occupying more than one portion of the collecting system, ie, renal pelvis with one or more caliceal extensions. Furthermore, the designation of “partial” or “complete” staghorn calculus does not imply any specific volume criteria.

The guidelines can be found here:


Although all types of stones can grow to staghorn calculi, most are composed of struvite and/or calcium carbonate apatite.  These stones have a strong association with urinary tract infection from organisms that produce urease.  These stones are often causative agents in calyceal rupture, as in the patient above.  Management is dependent on the patient’s symptoms, signs of urosepsis, and multiple other cofactors.  Per the report above, percutaneous nephrolithotomy is the first-line procedure of choice for most patients.  Sometimes shock-wave lithotripsy is required as well as percutaneous nephroscopy.  Please refer to the above guidelines for more information if desired.

Author:  Russell Jones, MD


1.  Preminger GM, et al.  AUA Report on the management of staghorn calculi.  2005.  http://www.auanet.org/education/guidelines/staghorn-calculi.cfm.  Accessed 9/2013.

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48-year-old male with R flank pain

October 1, 2012


Chief Complaint:  “My right side hurts”

On a busy night in the ED you encounter a 48-year-old male with right flank pain.  Onset was sudden, severe, 10/10, waxing and waning pain.  You obtain a urine dip which shows 3+ blood.

Here is his non-contrast CT abdomen/pelvis:

What is the diagnosis?

Answer:  Ureterolithiasis

This man has a 0.6cm stone in his ureter.  The CT scan shows two slices, one visualizing a hyper dense spherical structure in the ureter and the other demonstrating hydronephrosis with perinephric stranding.  This is considered an obstructing stone.

Kidney stone causing acute pain is one of the most common, most satisfying ED diagnoses.  These patients usually are in significant pain, sometimes sweating bullets from their pain!  And we can and usually make them better.  In fact, IV ketorolac is one of the most efficacious medicines available for stones.  I personally love the kidney stone…I feel like I can make a difference with this diagnosis.

Emergency Medicine Practice (one of my favorite CME publications) in July 2011 provided a great review of renal calculi. In particular it quoted an an article which found a 98.3% sensitivity and a 100% specificity of ultrasound in patients suspected of  having renal colic.  CT had a sensitivity and specificity approaching 100%.  The article also discusses admission criteria, special cases such as pregnancy and pediatrics, as well as recommendations for those patients sent home from the ED.  I will refer you to the article for details.


1.  Carter MR, Green BR.  Renal Calculi:  Emergency Department Diagnosis and Treatment.  Emergency Medicine Practice; 13 (7), 2011.

Author:  Russell Jones, M.D.

Imaging Study:  CT abdomen/pelvis without contrast

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