History:
35yo female presents to your ED with acute right flank pain. The pain is severe and intermittent, x approx 24h, associated with intermittent nausea and 2 episodes of non-bloody, non-bilious emesis. No diarrhea, constipation, anorexia. No fever. Urine reported to be dark, denies hematuria, no vaginal discharge or bleeding. LMP 1 wk ago. PMH notable for nephrolithiasis with 1 previous episode of ureteral colic that was managed conservatively 2 yrs ago.

Exam:
Afebrile, BP 160/85, HR 105, RR 22, SpO2 98% RA. Her exam reveals right mid-abdomen mild tenderness, neg Murphy’s/McBurney’s point tenderness. Mild right flank tenderness and a normal pelvic examination.

Evaluation and management:
You order 1L 0.9% saline, 4mg of morphine IV, 30mg of ketorolac IV. A CBC, BMP, UA and U preg are ordered, and because you read the attached article from NEJM in September of this year, you realize that a physician performed POC US of the kidneys is an appropriate first line imaging test in this patient with suspected ureteral colic.

Labs: 

• wbc 13.2k, hemoglobin and platelets are wnl.
• BUN 11 creatinine 0.8, normal anion gap, electrolytes and glucose are wnl
• UA: <5 wbc, >100 rbc, no ketones, LE and nitrite neg, trace bacteria

US Image Review:

• long axis of left kidney:
• 
• long axis of right kidney: (Video of week 1)
• short axis of left and right kidney images are not included but arenormal
• short and long axis images of bladder:
• 
• The video of the long axis of the right kidney reveals moderate hydronephrosis while the rest of the images demonstrate a normal left kidney and a normal appearing urinary bladder. You return to the bedside after the patient has received treatment and note that she is still in significant pain, so you order 1L 0.9% saline and Dilaudid 1mg IV, and also, because the patient has failed conservative management in the setting of moderate-severe hydronephrosis you consult urology. The patient is admitted for observation and goes to the OR the following morning for ureteroscopy with stent placement and is discharged home later that evening.

Summary and Take Home points:

1. The NEJM article is a landmark article for POC US in the ED. It should empower those who are competent in focused renal US to know that no matter what group the study subject was randomized to (POC US, radiology US or CT), the primary outcome of a “missed high-risk diagnosis with complication” was no different. What was different however was a 41% decrease in total radiation exposure between the POC US group and the CT group (even greater difference between the radiology performed US group and the CT group). I strongly encourage you to read this article in its entirety.
2. A patient with a history of nephrolithiasis who has a UA and clinical picture not suggestive of infection and who has no signs of hydronephrosis on US (performed by you or by radiology) can safely be discharged to home after adequate relief of pain.
3. When performing focused renal US, images that are required are 1 long axis image of each kidney, 1 short axis image of each kidney, and a short and long axis image of the bladder (your FAST exam pelvis views)…see article by Moore for further reading on technique
4. Keep in mind that the gallbladder and right kidney are often as little as several millimeters apart from one another. Keep biliary tract disease in your differential.

Comments and questions are, as always, welcome. Links to articles are provided below.

Mark

Ultrasonography versus Computed Tomography for Suspected Nephrolithiasis

Moore-2012