Wet Reads: Right flank pain

No Comments
alt52-year-old with two days of subacute right flank pain

You are cruising through a busy evening shift and starting to wrap things up for the night. Just a few more simple cases, you tell yourself, while I get these last few major medical patients admitted.  Just waiting for their attendings to call back, etc… 

The triage nurse wheels back a 52-year-old man with some R sided flank pain. You accompany them to the room and glance at the chart while you walk.  Vitals are P 115, BP 175/105, RR 18, sat 98%, Temp
99.2F.  The brief triage assessment says “flank and abdominal pain for two days, vomiting. Father had kidney stones”.  So far so good, although the low grade fever is odd.  Probably not another AAA, you just had one last month. Maybe a kidney stone with a UTI. The patient is helped from the wheelchair into the bed.


You take a bullet history; lets get this case moving.  “Well,” the patient says, “I’ve just had this nagging in my side that won’t go away.”  He denies a sudden onset of pain, and denies urinary symptoms.  “Never had it before, Doc…boy this is bad”. By exam his pain is in the R mid-abdomen and the R flank, right along the upper urinary tract territory. Pulses are good, you don’t feel a AAA (we’re not going through THAT again). OK, a little atypical, but probably still a stone.  You are paged, “Dr. X is holding for you on line three”.  You punch in the kidney stone protocol, pain meds, and a few extra labs and a cardiac panel/EKG just to be safe.

Half hour later, your admissions are done and you are ready for Miller Time.  You hop over to CT for a quick read on the CT, ready for the “kidney stone and good-bye” plan.

What does the CT scan show? What next?
-Diagnosis on next page


The non-contrast CT scan of the abdomen strikes again!  Very clearly, and without the 2+ hour delay of full contrast, the renal stone CT scan shows classic findings of a retro-cecal appendicitis (see labeled scan).  Inflammatory stranding in the R peri-colic gutter and RLQ is prominent, as well as a dilated appendix with an appendicolith inside as a bonus.  The scan shows no renal stones, and a normal caliber aorta.
In retrospect, this case illustrates several things.  One is the danger of premature closure error.  This occurs when the clinician decides on a diagnosis too early in the case, and does not keep an open mind about other possibilities.  A better approach is to say “OK, this sounds like a kidney stone, but there are a few atypical items – like the low grade fever, no urinary symptoms and the subacute onset of pain.” Might be a stone, but we need to keep in mind the “kidney stone mimics” – namely, AAA, vascular dissections and other retro-peritoneal disasters such as bleeding or large renal infarct. 

Or, in this case, a retro-cecal appendicitis. This is classically a subacute illness and is often mistaken for a renal stone because the patient is sick and the location of the pain.  Because of the position of the appendix, there may be less evidence of localized peritonitis.  Tenderness and pain is often in the R flank, R mid-abdomen and even the R upper quadrant area.  The WBC will likely be elevated in either a stone or appendix — not helpful.  The urinalysis may be normal or abnormal in either situation.  For the appendicitis, treatment is a visit to the OR, rather than pain meds and “see your doctor tomorrow.”  Of course they will see their doctor tomorrow…after they get worse. Don’t miss this one.

Dr. Dallara practices emergency medicine in Virginia and North Carolina and directs the Emergency Medicine PREP Course. www.emprepcourse.com


Leave A Reply